X4 Pharmaceuticals (XFOR) 10-K2023 FY Annual report

We are a late clinical-stage biopharmaceutical company discovering and developing novel therapeutics for the treatment of rare diseases and those with limited treatment options, with a focus on conditions resulting from dysfunction of the immune system.

Our lead clinical candidate is mavorixafor, a small-molecule selective antagonist of chemokine receptor CXCR4, that is being developed as an oral, once-daily therapy. Due to its ability to increase the mobilization of mature, functional white blood cells into the bloodstream, we believe that mavorixafor has the potential to provide therapeutic benefit across a variety of chronic neutropenic disorders, including WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, primary immunodeficiency.

We are currently seeking approval from the U.S. Food and Drug Administration (“FDA”) for the use of oral, once-daily mavorixafor in the treatment of people aged 12 years and older with WHIM syndrome following the October 2023 acceptance of our New Drug Application (“NDA”) by the FDA. The FDA has granted the NDA Priority Review, establishing a goal of six months review from the date of acceptance and assigning a Prescription Drug User Fee Act (“PDUFA”) target action date of April 30, 2024. At this time, the FDA has notified us that they are not planning to hold an advisory committee meeting to review the filing. Due to mavorixafor’s Rare Pediatric Disease designation in the U.S. for WHIM syndrome, should mavorixafor be approved, we are eligible to receive a Priority Review Voucher (“PRV”), which may be used to obtain Priority Review for a subsequent application or sold to another drug sponsor.

The NDA is supported by our successfully completed global, pivotal, Phase 3 clinical trial (“4WHIM”) that evaluated the safety and efficacy of mavorixafor in 31 people with WHIM syndrome. The 4WHIM trial met its primary endpoint and a key secondary endpoint, demonstrating statistically significant increases in time above threshold for absolute neutrophil counts (“TAT-ANC”) in patients treated with mavorixafor and time above threshold for absolute lymphocyte counts (“TAT-ALC”) versus placebo. Additional data showed that mavorixafor treatment resulted in statistically significant reductions in annualized infection rates versus placebo and clinically meaningful reductions in both the severity and duration of infections versus placebo. Mavorixafor was generally well tolerated throughout the 52-week trial.

In anticipation of a potential second quarter 2024 U.S. launch of mavorixafor in WHIM syndrome, we have continued to build our go-to-market organization, with key hires across commercial and medical functions, increased interactions with key stakeholders and rare disease patient advocacy organizations, and launched a disease awareness campaign aiming to further the understanding of WHIM syndrome and educate patients and physicians on the importance and benefits of early diagnosis.

We believe that successfully developing mavorixafor and providing new therapeutic options to individuals in the United States diagnosed with certain chronic neutropenic disorders has the potential to revolutionize the treatment landscape, which is principally served by injectable therapies that are frequently associated with treatment-limiting adverse events.

We have developed a pipeline of small-molecule, oral antagonists of the chemokine receptor CXCR4, or C-X-C receptor type 4. CXCR4 is a cell receptor that helps regulate the movement of immune cells within the body. CXCR4 receptor stimulation by its cognate ligand, CXCL12, has been shown to play a key role in the maturation and mobilization of white blood cells such as neutrophils, lymphocytes (including both B cells and T cells), and monocytes, into the bloodstream. Because antagonism of the CXCR4 receptor has been shown to increase the trafficking of white blood cells, we believe that therapeutic inhibition of the

CXCR4/CXCL12 axis holds the potential to benefit people with a wide variety of diseases where there remain significant unmet needs, including chronic neutropenic disorders and certain types of cancer.

Chronic neutropenic disorders are rare blood conditions where people of all ages experience low levels of neutrophils and tend to be at greater risk of developing infections and certain types of cancer. Depending on the levels of circulating neutrophils in the blood, neutropenia can be categorized as mild, moderate, or severe.

We are currently focused on advancing our lead clinical candidate, mavorixafor, for the treatment of a number of chronic neutropenia indications, including WHIM syndrome, while also pursuing partnership opportunities to further advance our previous work in oncology indications.

Our deep understanding of the biology of the CXCR4 pathway has enabled us to discover and develop multiple small-molecule CXCR4 antagonists. To date, we have advanced our lead candidate, mavorixafor, into late-stage clinical development. Mavorixafor is an orally available, small-molecule CXCR4 antagonist designed to facilitate the mobilization of white blood cells from the bone marrow into the blood, to increase levels of circulating neutrophils, lymphocytes, and monocytes, and to improve immune system function.

To date, more than 350 subjects in clinical trials have been dosed with mavorixafor, with a favorable tolerability profile observed. In these trials, we have observed drug exposure levels, a 22-hour half-life, and bioavailability of mavorixafor to support once-daily oral dosing, which we believe would provide convenient dosing and facilitate patient compliance for chronic or life-long use, if approved. The manufacturing process for mavorixafor utilizes well established, small-molecule chemistry. The commercial product, if approved, can be supported by specialty pharmacy distribution.

We have successfully advanced mavorixafor through a pivotal, Phase 3 clinical trial, referred to as the 4WHIM trial, in people with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, combined primary immunodeficiency. We have also completed a Phase 1b clinical trial of a single dose of mavorixafor in people with congenital, idiopathic, or cyclic neutropenia and we are now conducting a Phase 2 clinical trial evaluating the durability, safety, and tolerability of chronic dosing of once-daily oral mavorixafor with or without concurrent treatment with injectable G-CSF in the same patient population.

We have two pre-clinical candidates: X4P-003, a second-generation CXCR4 antagonist designed to have enhanced properties relative to mavorixafor, potentially enabling broader opportunities in CXCR4-dependent disorders and primary immunodeficiencies; and X4P-002, a CXCR4 antagonist with a unique distribution profile and a demonstrated ability to cross the blood-brain barrier.

WHIM syndrome is both a rare, combined immunodeficiency and a congenital neutropenic disorder in which the body’s immune system does not function properly and has trouble fighting infections. In many patients, WHIM is caused by “gain of function” variations in the single gene that encodes for the CXCR4 receptor. In healthy individuals, the CXCR4 receptor is typically internalized into the cell after CXCL12 binds to it, enabling the receptor to be appropriately “recycled” and the signaling to be diminished. In most WHIM patients, however, a genetic variation in the receptor gene prevents the post-binding internalization (“normal recycling”) of the receptor. As a result, the CXCR4 receptor is maintained on the surface of the cell and is exposed to the ligand, which creates a perpetual “on” signal and retention of white blood cells in the bone marrow where they are produced, leading to the chronic peripheral neutropenia, lymphopenia, and monocytopenia that are the clinical hallmarks of WHIM syndrome.

Genetic testing is typically used to diagnose WHIM syndrome to confirm the presence of a genetic variation in the CXCR4 receptor. The diagnosis of WHIM syndrome may occur at any age: about one-half of reported patients are diagnosed as children, primarily before of at the age of 18 years, with the other half diagnosed as adults, mostly between 18 and 40 years of age.

The incidence and prevalence of WHIM syndrome are not well established. We believe that this is due to the relatively recent elucidation of the genetics underlying WHIM syndrome, lack of universal or accessible genetic testing, and limited medical education and awareness of the disease, which is in part driven by the lack of available disease-modifying treatments. Based on a preliminary U.S. market research study sponsored by us and conducted by a third-party research firm, we believe that the prevalence of WHIM syndrome worldwide is significantly higher than previous registries suggest.

In addition, we have also completed a study using artificial intelligence, interrogating a database of approximately 300 million American lives that included up to 10 years of insurance claims on diagnoses, drug treatments, procedures, and treatment pathways. This study suggests that there may be as many as 3,700 WHIM patients in the United States based on the WHIM-like phenotypes described.

The first CXCR4 genetic variation determined to cause WHIM syndrome was identified in 2003. Since then, several CXCR4 variations have been identified as “gain of function” variations causing WHIM syndrome. Our research has subsequently identified a number of new genetic variations, among them a new missense variation, called D84H, that is relatively frequent in the general population. The D84H mutation is the first mutation to be identified outside of the C-terminus of the CXCR4 receptor showing gain-of-function signaling and WHIM disease phenotype. We believe that the frequency of the D84H variation, as derived from broad population genomic databases, further supports our current WHIM prevalence estimate. Our research into additional WHIM-causing genetic variations is ongoing and we are continuing to identify novel pathogenic variants, further expanding our understanding of the clinical phenotype of people with WHIM syndrome.

In partnership with Invitae, a genetic information company, we sponsor a no-charge genetic testing and counseling program called PATH4WARD for individuals who may carry a genetic variation known to be associated with chronic neutropenia or primary immunodeficiency disorders (“PIDs”), including WHIM syndrome. The genetic panel looks at more than 550 genes known to be associated with PIDs; to date, the program has proven helpful not only in diagnosing WHIM, but also providing a better understanding of novel genetic variants causing PIDs and assisting participant enrollment in X4-sponsored clinical trials.

We continue to increase awareness of WHIM syndrome among patients, physicians, and their support systems through our partnerships with key patient foundations, including the Jeffrey Modell Foundation, International Patient Organisation for Primary Immunodeficiencies, and Immune Deficiency Foundation.

Currently, there are no approved therapies for the treatment of WHIM syndrome and care is limited to the treatment of the syndrome’s different symptoms, mainly the prevention and management of infections. None of these symptomatic treatments, however, address the underlying cause of this multi-faceted disease. Current symptoms and their treatment limitations are as follows:

While the costs of managing the chronic impact of WHIM syndrome are unknown, the per-patient cost of treating primary immunodeficiencies that are similar to WHIM syndrome, based on drug costs alone, exceeds $100,000 per year in the United States for therapies such as antibiotics, IVIG, SCIG and/or G-CSF, despite the limited effectiveness of these treatments. Beyond these estimated direct costs, other costs associated with direct and indirect management of the disease, such as repeated immunization, physician visits, or hospitalizations, have not been quantified but are likely to be significant. We believe that there is a significant need for a treatment targeting the underlying excessive signaling caused by genetic variations to the CXCR4 receptor, which is the established cause of WHIM syndrome.

Our approach to treating WHIM syndrome involves addressing the underlying cause of the disease by blocking CXCR4 signaling using mavorixafor, which has been shown to bind to the CXCR4 receptor in a manner that inhibits the receptor from being stimulated by CXCL12, enabling white blood cells to properly mature and release into the bloodstream and improving immune cell numbers and function.

In January 2017, we initiated a Phase 2 clinical trial of mavorixafor for the treatment of people with WHIM syndrome. This trial was an open-label, dose-escalation trial in eight WHIM patients conducted at two sites in the United States and Australia pursuant to an Investigational New Drug (“IND”) application that we submitted to the U.S. Food and Drug Administration (“FDA”) in June 2016.

The primary objective of the Phase 2 clinical trial was to determine the safety and tolerability of mavorixafor and to determine the dose of mavorixafor for exploration in a pivotal Phase 3 clinical trial. The secondary objective of the Phase 2 trial was to evaluate the potential efficacy of mavorixafor in people with WHIM syndrome by measuring biomarkers, specifically absolute neutrophil (“ANC”) and lymphocyte (“ALC”) counts, over 24-hour dosing cycles. The frequency of infections, antibiotic use, hospitalizations, severity of warts lesions, and vaccine titer levels, among other metrics, were also examined. To be included in the trial, participants must have had a confirmed genetic diagnosis of WHIM syndrome, be at least 18 years of age, and have a neutrophil count equal to or less than 400 cells per microliter or a lymphocyte count equal to or less than 650 cells per microliter.

In the trial, participants received escalating doses of mavorixafor starting at 50 mg once daily to up to 400 mg once daily. Participants were dose-escalated from their starting dose based on an in-hospital 24-hour measurement of ANC and ALC above or below the pre-defined target thresholds of 600 cells per microliter and 1,000 cells per microliter, respectively.

We completed the dose-titration portion of the Phase 2 clinical trial in March 2018 and, based on the reported results, the Data Review Committee recommended the Phase 3 dose of 400 mg administered orally once daily. The choice of time above threshold for absolute neutrophil count (“TAT-ANC”), defined as the number of hours during which the absolute neutrophil count is raised above a 500 cells per microliter threshold, was selected as the primary endpoint of the Phase 3 clinical trial.

Following completion of the dose-titration portion of the Phase 2 clinical trial, participants were allowed to continue on study drug in a Phase 2 open-label extension trial. In June 2020, we announced the following positive data from the open-label extension portion of the Phase 2 clinical trial:

In December 2021, we announced the following additional data from the Phase 2 open-label extension trial of mavorixafor in people with WHIM syndrome:

In June 2019, we initiated 4WHIM, a pivotal, global, randomized, double-blind, placebo-controlled, multicenter Phase 3 clinical trial designed to evaluate the efficacy and safety of mavorixafor in people with genetically confirmed WHIM syndrome. Originally designed to enroll 18-28 patients, the trial achieved full enrollment in September 2021, with 31 participants aged 12 and older receiving either 200-400 mg mavorixafor or placebo orally once daily for 52 weeks; all participants then became eligible to receive treatment with mavorixafor in an open-label trial extension.

The primary endpoint of the 4WHIM trial was a clinically relevant reduction of duration of severe neutropenia as measured by the increase in TAT-ANC (500 cells per microliter) in peripheral blood. Secondary endpoints include time above threshold-absolute lymphocyte count (TAT-ALC) of ≥ 1,000 cells per microliter over a 24-hour period, a composite clinical efficacy endpoint for mavorixafor based on total infection score and total wart change score, total wart change score for mavorixafor based on central

blinded, independent review of 3 target skin regions, total infection score for mavorixafor based on number and severity of infections adjudicated by a blinded, independent adjudication committee; and a number of quality-of-life measurements and other exploratory endpoints.

In November 2022, we reported positive top-line results from the Phase 3 4WHIM trial:

In the second quarter of 2023, we presented additional data and analysis of the secondary and exploratory endpoints of the 4WHIM trial. Additional data presented revealed that mavorixafor treatment also resulted in statistically significant reductions in annualized infection rates versus placebo and effected clinically meaningful reductions in the both the severity and duration of infections versus placebo in trial participants. More specifically, the additional data showed the following:

In August 2023, we submitted to the FDA an NDA with the goal of obtaining approval for mavorixafor for the treatment of people in the United States, aged 12 and older, with WHIM syndrome. The FDA accepted the NDA in late October 2023 for priority review and established a PDUFA target action date of April 30, 2024.

Mavorixafor has received multiple special designations from global regulatory authorities in WHIM syndrome, including Breakthrough Therapy Designation, Fast Track Designation, and Rare Pediatric Designation in the United States, and orphan designation in both the United States and European Union. In addition, upon approval of an NDA, we are eligible to receive a Priority Review Voucher (“PRV”) as a result of mavorixafor’s Rare Pediatric Designation in the United States. If obtained, such PRV could potentially be sold to a third party.

Due to its demonstrated ability to durably elevate levels of circulating white blood cells across multiple clinical trials, we believe that mavorixafor may be useful in the treatment of people with a variety of chronic neutropenic disorders.

Chronic neutropenia is defined as periods lasting more than three months persistently or intermittently where there are abnormally low levels of neutrophils circulating in the blood, and may be idiopathic (of unknown origin), cyclic (episodes typically occurring every three weeks), or congenital (of genetic causation). Similar to WHIM syndrome, chronic neutropenia disorders are rare blood conditions similarly characterized by increased risks of infections and cancer due to abnormally low levels of neutrophils in the body. In all cases, the CXCL12/CXCR4 pathway is the key regulator of neutrophil release from the bone marrow.

The incidence and prevalence of chronic neutropenic disorders are not well established. In December 2022, we presented results from what we believe was the first study examining the prevalence of chronic neutropenia disorders (including idiopathic, cyclic, and congenital neutropenia) in the United States; we believe that determining the estimated projected prevalence of chronic neutropenic disorders is a key step to understanding the extent of existing unmet medical needs in this patient population.

In 2022, we also completed an electronic medical records study to better understand the risk of serious or severe infection in people with chronic neutropenia in the United States, analyzing the medical records of 44 healthcare organizations treating approximately 66 million patients. The analysis examined patients who had experienced at least two Serious Infections Events (“SIEs”) following documentation of chronic neutropenia in each calendar year compared with those who did not have neutropenia. SIEs are defined as infections requiring hospitalization or intravenous antibiotics or that result in disability or death.

People living with chronic neutropenia have few treatment options and may be treated with G-CSF, an injectable therapy approved in the United States for the treatment of severe, chronic neutropenia. G-CSF is used to stimulate the bone marrow to produce neutrophils. Side effects of G-CSF include disabling bone pain, which can be more severe in certain age groups. Additional, less common, treatment-limiting complications of chronic G-CSF administration include myelofibrosis and leukemia. In chronic neutropenia cases that are unresponsive to G-CSF, or if leukemia has developed, bone marrow transplants have been made with varying degrees of success. Bone marrow transplantation is often applied to severe neutropenia from bone marrow failure. Bone marrow transplants bring additional risks into the management of the disorders.

In 2022, we conducted a proof-of-concept Phase 1b open-label, multicenter study designed to assess the safety and tolerability of oral mavorixafor, with or without injectable G-CSF, in participants with chronic neutropenic disorders, including idiopathic, cyclic, and congenital neutropenia. Participants received a single dose of 400 mg oral mavorixafor to assess the magnitude of treatment response.

In September 2022, we announced positive results from the Phase 1b clinical trial:

Following these positive results, an amendment to the Phase 1b clinical trial was initiated aiming to evaluate the use of daily oral mavorixafor with or without injectable G-CSF for up to 6 months in participants with chronic neutropenic disorders as a Phase 2 clinical trial. The ongoing Phase 2 trial is assessing the durability of ANC responses, the potential of mavorixafor to enable patients to taper down dosing with G-CSF, and to evaluate the tolerability of mavorixafor in combination with G-CSF in chronic use. The trial is now fully enrolled and we expect to report additional data in the second quarter of 2024.

The pharmaceutical and biotechnology industries are characterized by rapidly advancing technologies, intense competition, and a strong emphasis on proprietary products. We face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, governmental agencies, and public and private research institutions. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

Many of our competitors may have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals, and marketing approved products than we do. Other firms also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient enrollment for clinical trials, as well as in acquiring technologies complementary to, or

necessary for, our programs. Mergers and acquisitions in the pharmaceutical, biotechnology, and diagnostic industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early stage companies may also prove to be significant competitors to us, particularly through collaborative arrangements with large and established companies.

Our commercial opportunities could be reduced or eliminated if our competitors develop and commercialize therapeutics that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain marketing approvals for their products more rapidly than we may obtain approval for our products, which could result in our competitors establishing a strong market position before we are able to enter the market. In addition, our ability to compete may be affected because in some cases insurers or other third-party payors, including government programs, seek to encourage the use of generic products. This may have the effect of making branded products less attractive to buyers from a cost perspective.

We are aware of other companies that are developing injectable CXCR4 inhibitors. However, we are not aware of any companies with CXCR4 antagonist programs in development for the indications of WHIM syndrome or chronic neutropenia. With regard to chronic neutropenia, we are not aware of any companies who are developing an oral therapy to elevate neutrophils in the blood. Filgrastim injections (human G-CSF) and two biosimilars (Zarxio and Nivestym) are FDA approved to reduce the incidence and duration of after-effects of severe neutropenia (e.g. fever, infections, oropharyngeal ulcers) in symptomatic patients with severe neutropenia.

We do not own or operate, and currently have no plans to establish, manufacturing facilities for the production of clinical or commercial quantities of mavorixafor or any of our other product candidates. We currently rely, and expect to continue to rely, on third parties for the manufacture of any of our product or product candidates.

We also have a master services agreement in place with Catalent Inc. (“Catalent”), which is our sole manufacturer for the final capsule drug product formulation of mavorixafor. The term of the master services agreement with Catalent expires on September 10, 2024, and may be terminated by (1) us upon 30 days-notice to Catalent or (2) by either party following a material breach by the other party that remains uncured for 30 days. We are in the process of transitioning the master services agreement with Catalent to a commercial supply agreement to support our potential WHIM launch and subsequent commercial supply.

We are currently building a commercial infrastructure to support sales of mavorixafor should the FDA provide marketing approval for mavorixafor in the United States. We expect to manage sales, marketing and distribution through internal resources and third-party relationships. Upon obtaining approval of our NDA by the FDA, we plan to have a field sales force who will provide information about our approved drug product to health care providers who are known to or potentially could have WHIM patients under their care.

We have entered into agreements with a third-party logistics company (“3PL”) for the warehousing and distribution of our drug product. We have also entered into an agreement with a specialty pharmacy, who will purchase our labelled drug product and dispense such drug product to patients pursuant to prescriptions provided by health care providers. The specialty pharmacy will also serve as our point of contact for inbound health care provider and patient inquiries, prescription processing, insurance investigation and patient on-boarding.

In July 2019, we entered into a license agreement with Abbisko Therapeutics Co Ltd. (“Abbisko”). Under the terms of the agreement, we granted Abbisko the exclusive right to develop, manufacture and commercialize mavorixafor in mainland China, Taiwan, Hong Kong and Macau. The agreement provides Abbisko with the exclusive rights in this territory to develop and commercialize mavorixafor in combination with checkpoint inhibitors or other agents in oncology indications. Pancreatic cancer, ovarian cancer and triple negative breast cancer are expected to be explored initially. We retain the full rest-of-world rights to develop and commercialize mavorixafor outside of Greater China for all indications and the ability to utilize data generated pursuant to the Abbisko collaboration for rest-of-world development. In addition, Abbisko has the right of first refusal if we determine to pursue additional products in the Abbisko Territory, as defined in the agreement. We entered into a separate agreement in April 2020 whereby we will provide Abbisko with a clinical supply and, if the product is commercialized in the territory licensed by Abbisko, we intend to enter into a commercial supply of the licensed compound.

Orange Book Listing

Any product is eligible for priority review if it treats a serious or life-threatening condition and, if approved, would provide a significant improvement in safety and effectiveness compared to available therapies. The FDA will attempt to direct additional resources to the evaluation of an application for a new drug designated for priority review to facilitate the review.

In the EU, medicinal products can only be commercialized after obtaining a marketing authorization (“MA”).

The centralized MA is issued by the European Commission through the centralized procedure, based on the opinion of the Committee for Medicinal Products for Human Use (“CHMP”), of the EMA, and is valid throughout the entire territory of the EU and the additional Member States of the European Economic Area (Iceland, Liechtenstein and Norway) (“EEA”). The centralized procedure is mandatory for certain types of products, including products produced by biotechnological processes, products designated as orphan medicinal products, advanced-therapy medicinal products (gene-therapy, somatic cell-therapy, or tissue-engineered medicines) and medicinal products containing a new active substance indicated for the treatment of HIV, AIDS, cancer, neurodegenerative disorders, diabetes, auto-immune and other immune dysfunctions or viral diseases. The centralized procedure is optional for products containing a new active substance not yet authorized in the EU, or for products that constitute a significant therapeutic, scientific, or technical innovation or which are in the interest of public health in the EU.

Under the centralized procedure, the EMA’s CHMP is responsible for conducting the initial assessment of a product and for several post-authorization and maintenance activities, such as the assessment of modifications or extensions to an existing MA. The maximum timeframe for the evaluation of an MA application by the EMA is 210 days, excluding clock stops when additional written or oral information is to be provided by the applicant in response to questions asked by the CHMP. Clock stops may extend the timeframe of evaluation of an MA application considerably beyond 210 days. Where the CHMP gives a positive opinion, it provides the opinion together with supporting documentation to the European Commission, who makes the final decision to grant an MA, which is issued within 67 days of receipt of the EMA’s recommendation. Accelerated assessment might be granted by the CHMP in exceptional cases, when a medicinal product is expected to be of major public health interest, particularly from the point of view of therapeutic innovation. If the CHMP accepts such request, the time limit of 210 days will be reduced to 150 days, excluding clock stops, but it is possible that the CHMP may revert to the standard time limit for the centralized procedure if it determines that the application is no longer appropriate to conduct an accelerated assessment.

In the EU, innovative medicinal products approved on the basis of a complete and independent data package qualify for eight years of data exclusivity upon the grant of an MA and an additional two years of market exclusivity. The data exclusivity, if granted, prevents generic or biosimilar applicants from referencing the innovator’s preclinical and clinical trial data contained in the dossier of the reference product when applying for a generic or biosimilar MA in the EU, during a period of eight years from the date on which the reference product was first authorized in the EU. During the additional two-year period of market exclusivity, a generic or biosimilar MA application can be submitted and authorized, and the innovator’s data may be referenced,

but no generic or biosimilar product can be placed on the EU market until the expiration of the market exclusivity. The overall ten-year period will be extended to a maximum of eleven years if, during the first eight years of those ten years, the MA holder obtains an MA for one or more new therapeutic indications which, during the scientific evaluation prior to their MA, are determined to bring a significant clinical benefit in comparison with currently approved therapies. There is no guarantee that a product will be considered by the EMA to be an innovative medicinal product, and products may not qualify for data exclusivity. Even if a product is considered to be an innovative medicinal product so that the innovator gains the prescribed period of data exclusivity, another company could nevertheless also market another version of the product if such company obtained an MA based on an MA application with a complete and independent data package of pharmaceutical tests, preclinical tests and clinical trials.

In the EU, the European Commission grants orphan designation in respect of a product, after receiving the opinion of the EMA’s Committee for Orphan Medicinal Products, if its sponsor can establish that: (1) the product is intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition; (2) either (i) such condition affects no more than five in 10,000 persons in the EU when the application is made, or (ii) it is unlikely that the product, without the benefits derived from orphan status, would generate sufficient return in the EU to justify the necessary investment in its development; and (3) there exists no satisfactory method of diagnosis, prevention or treatment of such condition authorized for marketing in the EU, or, if such a method exists, the product would be a significant benefit to those affected by that condition.

In the EU, orphan designation entitles a party to financial incentives such as reduction of fees or fee waivers and 10 years of market exclusivity is granted following the grant of an MA. During this market exclusivity period, neither the EMA nor the European Commission nor any of the competent authorities in the EU Members States can accept an application or grant an MA for a “similar medicinal product.” A “similar medicinal product” is defined as a medicinal product containing a similar active substance or substances as contained in an authorized orphan medicinal product, and which is intended for the same therapeutic indication. This period may be reduced to six years if, at the end of the fifth year, it is established that the orphan designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity. An MA may be granted to a similar medicinal product to an authorized orphan product in very select cases, such as if: (i) it is established that a similar medicinal product is safer, more effective or otherwise clinically superior to the authorized product; (ii) the MA holder for the authorized orphan product consents to the authorization of the similar medicinal product; or (iii) the MA holder for the authorized orphan product cannot supply enough orphan medicinal product. Orphan designation must be requested before submitting an application for an MA. Orphan designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process.

If authorization for a medicinal product in the EU is obtained, the holder of the MA is required to comply with a range of requirements applicable to the manufacturing, marketing, promotion, and sale of medicinal products. These include:

Payments made to physicians in certain EU Member States must be publicly disclosed. Moreover, agreements with physicians often must be the subject of prior notification and approval by the physician’s employer, his or her competent professional organization as well as the regulatory authorities of the individual EU Member States. These requirements are provided in the national laws, industry codes or professional codes of conduct, applicable in the EU Member States. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines or imprisonment.

The aforementioned EU rules are generally applicable in the EEA.

Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to it, we may be subject to significant civil, criminal and administrative penalties, damages, fines, imprisonment, exclusion from government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any of the physicians or other healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, they may be subject to significant criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

We were incorporated under the laws of the State of Delaware in 2010 under the name Arsanis Inc. Following the Merger with X4 Therapeutics Inc. (formerly X4 Pharmaceuticals Inc.) on March 13, 2019, we changed our name to X4 Pharmaceuticals, Inc. Our principal executive offices are located at 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134 and our telephone number is (857) 529-8300.

We own or have rights to various trademarks, service marks and trade names that we use in connection with the operation of our business. This Annual Report on Form 10-K may also contain trademarks, service marks and trade names of third parties, which are the property of their respective owners. Our use or display of third parties’ trademarks, service marks, trade names or products in this Annual Report on Form 10-K is not intended to, and does not imply a relationship with, or endorsement or sponsorship by us. Solely for convenience, the trademarks, service marks and trade names referred to in this Annual Report on Form 10-K may appear without the ®, ™ or SM symbols, but the omission of such references is not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the right of the applicable owner of these trademarks, service marks and trade names.

Our business faces significant risks and uncertainties. If any of the following risks are realized, our business, financial condition and results of operations could be materially and adversely affected. You should carefully review and consider the full discussion of our risk factors in the section titled “Risk Factors” in Part I, Item 1A of this Annual Report. Some of the more significant risks include the following:

We may be forced to delay or reduce the scope of our development programs and/or limit or cease our operations if we are unable to obtain additional funding to support our current operating plan. We have identified conditions and events that raise substantial doubt about our ability to continue as a going concern.

Our operations have consumed a large amount of cash since inception. To date, we have funded our operations primarily with proceeds from sales of common stock, warrants and prefunded warrants for the purchase of our preferred stock and our common stock, sales of preferred stock, proceeds from the issuance of convertible debt and borrowings under loan and security agreements. We expect our research and development expenses to increase in future periods as we continue to advance the clinical development of our product candidates and prepare for the launch and commercialization of any product candidates for which we receive regulatory approval, including potentially building our own commercial organization to address the U.S. and certain other markets. In addition, if we obtain marketing approval for any of our product candidates that are not then subject to licensing, collaboration or similar arrangements with third parties, we expect to incur significant commercialization expenses related to product sales, marketing, distribution and manufacturing. Furthermore, we expect to incur additional costs associated with operating as a public company.

We cannot be certain that additional funding will be available on acceptable terms, or at all. If we are unable to raise additional capital when needed or in sufficient amounts or on terms acceptable to us, we could be forced to delay, reduce or eliminate our     research and development programs or any future commercialization efforts of one or more of our product candidates or one or more of our other research and development initiatives. In addition, when we need to secure additional financing, such additional fundraising efforts may divert our management from our day-to-day activities, which may adversely affect our ability to develop and commercialize our product candidates. Any of these events could significantly harm our business, financial condition and prospects, and our stockholders could lose all or part of their investment in our company.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through public or private equity or debt financings, third-party funding, marketing and distribution arrangements, as well as other collaborations, strategic alliances and licensing arrangements, or any combination of these approaches. Other than our common stock purchase agreement with Lincoln Park Capital Fund LLC (“Lincoln Park”), pursuant to which Lincoln Park is obligated, subject to certain limitations and conditions, to purchase up to a remaining $47.0 million in the aggregate of shares of our common stock, we do not have any committed external sources of funds and may seek to raise additional capital at any time. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a holder of our common stock. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures, declaring dividends or other distributions, acquiring or licensing intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business and may result in liens being placed on additional assets such as intellectual property. For example, our debt facility with Hercules contains a minimum cash financial covenant that we project we would be in violation of in the first quarter of 2025 based on our current cash flow projections, assuming we do not raise additional funding and our drug candidate is not approved by the FDA. If we default on such indebtedness, with Hercules or a future lender, we could be required to pledge additional assets, or the lenders could enforce remedies on the current collateral.

To date, we have not generated revenues from any product sales. Our ability to generate revenue and become profitable depends upon our ability to successfully obtain marketing approval and commercialize our product candidates, including mavorixafor, or other product candidates that we may develop, in-license or acquire in the future. Even if we are able to successfully achieve regulatory approval for these product candidates, we are unable to predict the extent of any future losses and do not know when any of these product candidates will generate revenue for us, if at all. Our ability to generate revenue from mavorixafor or any of our current or future product candidates also depends on a number of additional factors, including our ability to:

We may develop mavorixafor, and may develop future product candidates, in combination with one or more currently approved therapies. Even if any product candidate we develop were to receive marketing approval or be commercialized for use in combination with other existing therapies, we would continue to be subject to the risks that the FDA or similar regulatory authorities outside of the United States could revoke approval of the therapy used in combination with our product candidate or that safety, efficacy, manufacturing or supply issues could arise with these existing therapies. Combination therapies are commonly used for the treatment of diseases, and we would be subject to similar risks if we develop any of our product candidates for use in combination with other drugs. This could result in our own products being removed from the market or being less successful commercially.

We may also evaluate mavorixafor or any other future product candidates in combination with one or more other cancer therapies that have not yet been approved for marketing by the FDA or similar regulatory authorities outside of the United States. We will not be able to market and sell mavorixafor or any product candidate we develop in combination with any such unapproved therapies that do not ultimately obtain marketing approval.

If the FDA or similar regulatory authorities outside of the United States do not approve these other drugs or revoke their approval, or if safety, efficacy, manufacturing or supply issues arise with, the drugs that we choose to evaluate in combination with mavorixafor or any product candidate we develop, we may be unable to obtain approval of or market mavorixafor or any other product candidate we develop.

We are not permitted to market mavorixafor or any other product candidate in the United States until we receive approval of an New Drug Application (“NDA”) from the FDA, or in any foreign countries until we receive the requisite approval from such countries or jurisdictions, such as approval of the marketing authorization application in the European Union from the European Commission. Our NDA submission may receive a refusal to file response from the FDA, and even if filed by the FDA, we may receive a Complete Response Letter rather than approval for commercial marketing. In addition, we may be required by the FDA to conduct additional clinical trials and/or nonclinical studies to support potential approval. Successfully completing clinical trials and obtaining approval of an NDA is a complex, lengthy, expensive and uncertain process, and the FDA, or a comparable foreign regulatory authority, may delay, limit or deny approval of mavorixafor for the treatment of WHIM syndrome or other indications for many reasons, including, among others:

We are party to license agreements with Genzyme, Beth Israel Deaconess Medical Center, Georgetown University and Dana-Farber Cancer Institute under which we were granted rights to patents and patent applications that are important to our business. We rely on these license agreements in order to be able to use various proprietary technologies that are material to our business, including certain patents and patent applications that cover our product candidates, including mavorixafor. Our rights to use these patents and patent applications and employ the inventions claimed in these licensed patents are subject to the continuation of and our compliance with the terms of our license agreements.

Even if our clinical trials are completed as planned, we cannot be certain that their results will support the safety and/or efficacy of our product candidates, that the FDA or foreign government authorities will agree with our conclusions regarding such results, or that the FDA or foreign governmental authorities will not require additional clinical trials. Success in preclinical testing and early clinical trials does not ensure that later clinical trials will be successful and the results of later clinical trials often do not replicate the results of prior clinical trials and preclinical testing. The clinical trial results may fail to demonstrate that our product candidates are safe for humans and effective for the intended indications. This failure could cause us to abandon a product candidate and may delay development of other product candidates. Any delay in, or termination of, our clinical trials will delay or prevent the submission of our marketing applications (NDA and/or MAA) and, ultimately, our ability to obtain approval and commercialize our product candidates and generate product revenues. Information about certain clinical trials, including results (positive or negative) will be made public according to each country’s clinical trial register policies. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs.

To receive the required approval to commercialize any product candidates, we must demonstrate through extensive clinical trials that our product candidates are safe and effective in humans. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. We may be unable to establish clinical endpoints that applicable regulatory authorities would consider clinically meaningful, and a clinical trial can fail at any stage of testing. Clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in

clinical trials have nonetheless failed to receive marketing approval of their product candidates.

In addition, we may experience delays in our current or future clinical trials, including our Phase 2 clinical trial of mavorixafor for the treatment of chronic neutropenic disorders. For example, as a result of the COVID-19 pandemic, we experienced delays in clinical trial site activation and slower patient enrollment in our clinical trials of mavorixafor for the treatment of WHIM syndrome, Waldenström’s and chronic neutropenia disorders. Clinical trials may be delayed, suspended or terminated for a variety of reasons, including the following:

Undesirable side effects caused by any of our product candidates that we may develop or acquire could cause us or the FDA or other regulatory authorities to interrupt, delay or halt our clinical trials and could result in more restrictive labels or the delay or denial of marketing approval by the FDA or other regulatory authorities of such product candidates. Results of our clinical trials could reveal a high and unacceptable severity and prevalence of these or other side effects. In such an event, our trials could be suspended or terminated and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of our product candidates for any or all targeted indications. In addition, any drug-related side effects could affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. Any

of these occurrences may harm our business, financial condition and prospects significantly.

Identifying and qualifying patients to participate in clinical trials of our product candidates is critical to our success. The timing of our clinical trials depends on the rate at which we can recruit, enroll and retain patients in testing our product candidates, and we have made certain assumptions about the rate at which we can enroll patients in our clinical trials. The timing of our clinical trials depends in part on the speed at which we can recruit patients to participate in testing mavorixafor and any other current or future product candidates that we may develop as well as completion of required follow-up periods. For example, as a result of the COVID-19 pandemic, we previously have experienced a slower enrollment pace in some of our clinical trials.

If the size of the commercial opportunities in any of our target indications is smaller than we anticipate, we may not be able to achieve profitability and growth. Our lead clinical candidate, mavorixafor, is being developed as an oral, once-daily therapy for the potential treatment of WHIM syndrome and other chronic neutropenic disorders. We have completed a pivotal, Phase 3 clinical trial (the “4WHIM trial”) in people with WHIM syndrome, and are currently advancing mavorixafor in a Phase 2 clinical trial in people with certain chronic neutropenic disorders. We are currently aware of only a few small available patient registries for WHIM syndrome, and we rely on various estimates and assumptions to estimate the addressable WHIM syndrome population. Based on a broad online survey of physicians to validate current prevalence estimates and additional research using artificial intelligence, which interrogated a database of more than 300 million anonymized patient records that spanned 10 years of insurance claims, we estimate there are up to 3,700 diagnosed and undiagnosed WHIM patients in the United States, many of whom were previously undiagnosed. If the commercial opportunity in any of our target indications, including WHIM syndrome, is smaller than we anticipate, whether because our estimates of the addressable patient population prove to be incorrect or for other reasons, our potential future revenue from mavorixafor may be adversely affected and our business may suffer.

The results of pre-clinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. Interpretation of results from early, usually smaller, trials that suggest positive trends in some subjects, require caution. Results from later-stage clinical trials enrolling more subjects may fail to show the desired safety and efficacy results or otherwise fail to be consistent with the results of earlier trials of the same product candidate. Inconsistencies may occur for a variety of reasons, including differences in trial design, trial endpoints (or lack of trial endpoints in exploratory studies), subject population, number of subjects, subject selection criteria, trial duration, drug dosage and formulation or lack of statistical power in the earlier trials.

Data obtained from preclinical and clinical activities are subject to varying interpretations, which may delay, limit, or prevent regulatory approval. In addition, we may experience regulatory delays or rejections as a result of many factors, including due to changes in regulatory policy during the period of our product candidate development. Any such delays could negatively impact our business, financial condition, results of operations and prospects.

From time to time, we may publish interim top-line or preliminary data from our clinical trials. Interim data from clinical trials are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Preliminary or top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. Preliminary or top-line data may include, for example, data regarding a small percentage of the patients enrolled in a clinical trial, and such preliminary data should not be viewed as an indication, belief or guarantee that other patients enrolled in such clinical trial will achieve similar results or that the preliminary results from such patients will be maintained. As a result, interim and preliminary data should be viewed with caution until the final data are available. Differences between preliminary or interim data and final data could significantly harm our business prospects and may cause the trading price of our common stock to fluctuate significantly.

If we obtain regulatory approval for a product candidate, it would be subject to extensive ongoing requirements by the FDA and comparable foreign regulatory authorities governing the manufacture, quality control, further development, labeling, packaging, storage, distribution, safety surveillance, import, export, advertising, promotion, recordkeeping and reporting of safety and other post-market information. The safety profile and efficacy of any product will continue to be closely monitored by the FDA and comparable foreign regulatory authorities after approval. If the FDA or comparable foreign regulatory authorities become aware of new safety information after approval of any of our product candidates, these regulatory authorities may require labeling changes or the FDA may require establishment of a Risk Evaluation Mitigation Strategy (“REMS”), or similar strategy, impose significant restrictions on a product’s indicated uses or marketing, impose ongoing requirements for potentially costly post-approval studies or post-market surveillance. Progress reports are required at quarterly intervals, every six months and at annual intervals depending upon the country, and more frequently if serious adverse events occur.

Any product candidate for which we obtain marketing approval will be subject to continual requirements of and review by the FDA and other regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration and listing requirements, cGMP requirements, quality assurance and corresponding maintenance of records and documents and requirements regarding the distribution of samples to physicians and recordkeeping. Even if marketing approval of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the product may be marketed or to other conditions of approval, or contain requirements for costly post-marketing testing and surveillance to monitor the safety or efficacy of the drug. The FDA closely regulates the post-approval marketing and promotion of drugs to ensure that they are marketed only for the approved indications and in accordance with the provisions of the approved labeling.

In addition, manufacturers of drugs and their facilities are subject to continual review and periodic inspections by the FDA and other regulatory authorities for compliance with cGMP regulations. If a regulatory agency discovers previously unknown problems with a product, such as adverse events of unanticipated severity or frequency, or problems with the facility where the product is manufactured, a regulatory agency may impose restrictions on that product, the manufacturing facility or us, including requiring recall or withdrawal of the product from the market or suspension of manufacturing. If we, our product candidates or the manufacturing facilities for our product candidates fail to comply with cGMPs and other applicable regulatory requirements, the FDA may, among other things:

The occurrence of any event or penalty described above, or any other sanction by a regulatory authority or other governmental entity, may inhibit our ability to commercialize our products and generate revenue.

The FDA and other regulatory agencies strictly regulate the promotional claims that may be made about drug products. These regulations include standards and restrictions for direct-to-consumer advertising, industry-sponsored scientific and educational activities, promotional activities involving the internet and off-label promotion. Any regulatory approval that the FDA grants is limited to those indications and patient populations for which a drug is deemed to be safe and effective by the FDA.

While physicians in the United States may choose, and are generally permitted, to prescribe products for uses that are not described in the product’s labeling and for uses that differ from those tested in clinical trials and approved by the regulatory authorities, our ability to promote any of our products candidates, if approved, will be limited to those indications and populations that are specifically approved by the FDA or such other regulatory agencies, and if we are found to have promoted such off-label uses, we may become subject to significant liability. For example, the federal government has levied large civil and criminal fines against companies for alleged improper promotion and in some instances has also required companies to enter into corporate integrity agreements under which specified promotional conduct is changed or curtailed. If we cannot successfully manage the promotion of our product candidates, if approved, we could become subject to significant liability, which would materially adversely affect our business and financial condition.

We have obtained both Breakthrough Therapy and Fast Track designations for mavorixafor for the treatment of adult patients with WHIM and we may pursue those designations for other product candidates as well. A breakthrough therapy is defined as a product that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. For product candidates that have been designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the trial can help identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. A breakthrough therapy designation affords the possibility of rolling review, enabling the FDA to review portions of our marketing application before submission of a complete application, and possibly, priority review.

If a drug is intended for the treatment of a serious or life-threatening condition or disease and the drug demonstrates the potential to address unmet medical needs for the condition, the sponsor may apply for Fast Track designation.

Regulatory authorities in some jurisdictions, including the United States and European Union, may designate drugs for the treatment or prevention of rare diseases or conditions with relatively small patient populations as orphan drugs. Under the Orphan Drug Act of 1983, the (“Orphan Drug Act”), the FDA may designate a product as an orphan drug if it is a drug intended to treat a rare disease or condition, which is defined as a patient population of fewer than 200,000 individuals in the United States. We received orphan drug designation from the FDA for mavorixafor for the treatment of WHIM syndrome in October 2018, and from the EMA in July 2019. We also received orphan drug designation in the U.S. for mavorixafor for the treatment of Waldenström’s macroglobulinemia in June 2022. If a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a seven-year period of marketing exclusivity, which precludes the FDA from approving another marketing application for the same drug for the same indication during that time period with some exceptions. In the European Union, the applicable period is 10 years, during which no marketing authorization may be granted for a similar medicinal product to the authorized orphan product for the same indication. The exclusivity period in the European Union can be reduced to six years if, at the end of the fifth year, it is established that the product no longer meets the criteria for orphan designation, including if the drug is sufficiently profitable so that marketing exclusivity is no longer justified. Orphan drug exclusivity may be lost in both the United States and European Union under certain limited situations, such as the inability of the holder of the orphan drug designation to produce sufficient quantities of the drug to meet the needs of patients with

the rare disease or condition or for certain other reasons.

In 2012, Congress authorized the FDA to award priority review vouchers to sponsors of certain rare pediatric disease product applications. This program is designed to encourage development of new drug and biological products for prevention and treatment of certain rare pediatric diseases. Specifically, under this program, a sponsor who receives an approval for a drug or biologic for a “rare pediatric disease” that meets certain criteria may qualify for a voucher that can be redeemed to receive a priority review of a subsequent marketing application for a different product. The sponsor of a rare pediatric disease drug product receiving a priority review voucher may transfer (including by sale) the voucher to another sponsor. The voucher may be further transferred any number of times before the voucher is used, as long as the sponsor making the transfer has not yet submitted the application. The FDA may also revoke any priority review voucher if the rare pediatric disease drug for which the voucher was awarded is not marketed in the U.S. within one year following the date of approval.

The FDA has granted rare pediatric disease designation for mavorixafor for the treatment of WHIM syndrome; however, there is no guarantee that we will be able to obtain a priority review voucher, even if mavorixafor is approved by the FDA. Under the current statutory provisions, FDA may not award a rare pediatric disease priority review voucher to sponsors of marketing applications unless the drug has received rare pediatric disease designation as of September 30, 2024 and is approved by the FDA no later than September 30, 2026. Even though we received rare pediatric disease designation by the current statutory deadline of September 30, 2024 we may not receive the voucher if we do not obtain approval by September 2026. It is possible that Congress may extend the date by which a rare pediatric disease-designed drug must obtain approval in order to receive a priority review voucher, but even if such legislation is enacted, we may not obtain approval by that date, and even if we do, we may not obtain a priority review voucher.

Even if we obtain regulatory approval for any of our product candidates that we may develop or acquire in the future, the product may not gain market acceptance among hospitals, physicians, health care payors, patients and the medical community. Market acceptance of any of our product candidates for which we receive approval depends on a number of factors, including:

We do not have a sales or marketing infrastructure and have no experience in the sale, marketing or distribution of pharmaceutical products. To achieve commercial success for any approved product for which we retain sales and marketing responsibilities, we must either develop a sales and marketing organization or outsource these functions to other third parties. In the future, we may choose to build a focused sales and marketing infrastructure to sell some of our product candidates if and when they are approved.

Even if we are ultimately successful in obtaining regulatory approval of mavorixafor for the treatment of WHIM syndrome or another indication, in order to market and sell mavorixafor and our other product candidates in development, we currently intend to build and develop our own sales, marketing and distribution operations. Although our management team has previous experience with such efforts, there can be no assurance that we will be successful in building these operations. If we are unable to establish adequate sales, marketing and distribution capabilities, we may not be able to generate product revenue and may not become profitable. We will also be competing with many companies that currently have extensive and well-funded sales and marketing operations. If any of our product candidates are approved, we may be unable to compete successfully against these more established companies.

There are risks involved both with establishing our own sales and marketing capabilities and with entering into arrangements with third parties to perform these services. For example, recruiting and training a sales force is expensive and time consuming and could delay any product launch. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

Factors that may inhibit our efforts to commercialize our product candidates on our own include:

If we enter into arrangements with third parties to perform sales, marketing and distribution services, our product revenue or the profitability of these product revenue to us may be lower than if we were to market and sell any products that we develop ourselves. In addition, we may not be successful in entering into arrangements with third parties to sell and market our product candidates or may be unable to do so on terms that are favorable to us. We may have little control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our products effectively. If we do not establish sales and marketing capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our product candidates.

The development and commercialization of new drug products is highly competitive. We face competition with respect to our current product candidates, and will face competition with respect to any product candidates that we may seek to develop or commercialize in the future, from major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide. Some of these competitive products and therapies are based on scientific approaches that are the same as or similar to our approach and others are based on entirely different approaches. Potential competitors also include academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization.

We are developing our lead product candidate, mavorixafor, for the treatment of WHIM syndrome and other chronic neutropenic disorders. We are aware of other companies that are developing CXCR4 inhibitors that are in a similar stage of development as mavorixafor, including BioLineRx, Noxxon, Upsher-Smith, Polyphor and Glycomimetics. To our knowledge, there do not appear to be any competitors with programs in development for WHIM syndrome or chronic neutropenia disorders. With respect to chronic neutropenia, filgrastim injections (human granulocyte colony-stimulating factor (G-CSF)) and two biosimilars (Zarxio

In many diseases, these drugs are administered in combination to enhance efficacy. Some of the currently approved drug therapies are branded and subject to patent protection, and others are available on a generic basis. Many of these approved drugs are well-established therapies and are widely accepted by physicians, patients and third-party payors. Insurers and other third-party payors may also encourage the use of generic products. We expect that if any of our product candidates are approved, they will be priced at a significant premium over competitive generic products. This may make it difficult for us to achieve our business strategy of using our product candidates in combination with existing therapies or replacing existing therapies with our product candidates.

Our competitors may develop products that are more effective, have a better safety profile, are more convenient or less costly than any that we are developing or that would render our product candidates obsolete or non-competitive. Our competitors may also obtain marketing approval from the FDA or other regulatory authorities for their products sooner than we may obtain approval for our product candidates, which could result in our competitors establishing a strong market position before we are able to enter the market.

Many of our competitors have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties may compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

Approval of a product candidate in the United States by the FDA does not ensure approval of such product candidate by regulatory authorities in other countries or jurisdictions, and approval by a foreign regulatory authority does not ensure approval by regulatory authorities in other foreign countries or by the FDA. Clinical trials conducted in one country may not be accepted by regulatory authorities in other countries. Even if the FDA grants marketing approval for a product candidate, comparable foreign regulatory authorities also must approve the manufacturing and marketing of the product candidate in those countries. Approval procedures vary among jurisdictions and can involve requirements and administrative review periods different from, and more onerous than, those in the United States, including additional preclinical studies or clinical trials. In many countries outside the United States, a product candidate must be approved for reimbursement before it can be approved for sale in that country. In some cases, the price that we intend to charge for any product candidates, if approved, is also subject to approval. Obtaining approval for any future product candidates in the European Union from the European Commission following the opinion of the EMA would be a lengthy and expensive process. Even if a product candidate is approved, the FDA or the European Commission, as the case may be, may limit the indications for which the drug may be marketed, require extensive warnings on the drug labeling or require expensive and time-consuming additional clinical trials or reporting as conditions of approval. Obtaining foreign regulatory approvals and compliance with foreign regulatory requirements could result in significant delays, difficulties and costs for us and could delay or prevent the introduction of any future product candidates in certain countries.

If we seek approval of our product candidates outside of the United States, we expect that we will be subject to additional risks in commercialization including:

We have no prior experience in these areas. In addition, there are complex regulatory, tax, labor and other legal requirements imposed by many of the individual countries in and outside of Europe with which we will need to comply. Many biopharmaceutical companies have found the process of marketing their own products in foreign countries to be very challenging.

The laws and regulations that govern marketing approvals, pricing, coverage and reimbursement for new drug products vary widely from country to country. Current and future legislation may significantly change the approval requirements in ways that could involve additional costs and cause delays in obtaining approvals. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted and, in some markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain marketing approval for a product in a particular country, but then be subject to price regulations that delay our commercial launch of the product, possibly for lengthy time periods, and negatively impact the revenues we are able to generate from the sale of the product in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more product candidates, even if our product candidates obtain marketing approval.

Our ability to commercialize mavorixafor or any other product candidate successfully also will depend in part on the extent to which coverage and adequate reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and other third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. A primary trend in the U.S. and E.U. healthcare industries and elsewhere is cost containment.

Government authorities and other third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. We cannot be sure that coverage and reimbursement will be available for mavorixafor or any other product that we commercialize and, if coverage and reimbursement is available, the level of reimbursement. Reimbursement may impact the demand for, or the price of, any product candidate for which we obtain marketing approval. Obtaining and maintaining adequate reimbursement for mavorixafor may be particularly difficult because of the higher prices typically associated with drugs directed at smaller populations of patients. In addition, third-party payors are likely to impose strict requirements for reimbursement of a higher priced drug, and any launch of a competitive product is likely to create downward pressure on the price initially charged. If reimbursement is not available or is available only to a limited degree, we may not be able to successfully commercialize any product candidate for which we obtain marketing approval. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

There may be significant delays in obtaining coverage and reimbursement for newly approved drugs, and coverage may be more limited than the purposes for which the drug is approved by the applicable regulatory authority. Moreover, eligibility for coverage and reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, intellectual property, manufacturing, sale and distribution expenses. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent.

Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs, and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. In the United States, third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies. In the European Union, reference pricing systems and other measures may lead to cost containment and reduced prices. Our inability to promptly obtain coverage and adequate reimbursement rates from both government-funded and private payors for any approved products that we develop could have a material adverse effect on our operating results, our ability to raise capital needed to develop product candidates and commercialize products and our overall financial condition.

In some countries, particularly the countries of the European Union, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidate to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be harmed, possibly materially.

We face an inherent risk of product liability exposure related to the testing of our product candidates in human clinical trials and will face an even greater risk with respect to commercial sales of any products that we may develop. If we cannot successfully defend ourselves against claims that our product candidates or products caused injuries, we could incur substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:

Although we do not currently have any drugs on the market, we are, and once we begin commercializing our product candidates, we will be subject to additional healthcare statutory and regulatory requirements and enforcement by the federal government and the states and foreign governments in the jurisdictions in which we conduct our business. Healthcare providers and third-party payors will play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our current and future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships

through which we research, as well as market, sell and distribute any products for which we obtain marketing approval. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, structuring and commission(s), certain customer incentive programs and other business arrangements generally. Activities subject to these laws also involve the improper use of information received in the course of patient recruitment for clinical trials. See the section in this Annual Report on Form 10-K for the fiscal year ended December 31, 2023 entitled “Business – Government Regulation – Other Healthcare Laws and Compliance Requirements.”

In the United States and some foreign jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of our product candidates, restrict post-approval activities and affect our ability to sell profitably any product candidates for which we obtain marketing approval.

Legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for pharmaceutical products. We cannot be sure whether additional legislative changes will be enacted, or whether FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals, if any, of our product candidates may be. In addition, increased scrutiny by the U.S. Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing conditions and other requirements.

See the sections of this Annual Report on Form 10-K for the fiscal year ended December 31, 2023 entitled, “Business – Government Regulation – Pharmaceutical Coverage, Pricing and Reimbursement” and “Business – Government Regulation – Healthcare Reform.”

Our operations are subject to anti-corruption laws, including the Foreign Corrupt Practices Act (“FCPA”) and other anti-corruption laws that apply in countries where we do business and may do business in the future. The FCPA and these other laws generally prohibit us, our officers and employees and intermediaries from bribing, being bribed or making other prohibited payments to government officials or other persons to obtain or retain business or gain some other business advantage. We may in the future operate in jurisdictions that pose a high risk of potential FCPA violations, and may participate in collaborations and relationships with third parties whose actions could potentially subject us to liability under the FCPA or local anti-corruption laws. In addition, we cannot predict the nature, scope or effect of future regulatory requirements to which its international operations might be subject or the manner in which existing laws might be administered or interpreted.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, the ability to hire and retain key personnel and accept the payment of user fees, and statutory, regulatory and policy changes. Average review times at the agency have fluctuated in recent years as a result. In addition, government funding of the SEC and other government agencies on which our operations may rely, including those that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years the U.S. government has shut down several times and certain regulatory agencies, such as the FDA and the SEC, have had to furlough critical FDA, SEC and other government employees and stop critical activities. If a prolonged government shutdown occurs, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business. Further, in our operations as a public company, future government shutdowns could impact our ability to access the public markets and obtain necessary capital in order to properly capitalize and continue our operations.

To meet our projected needs for clinical supplies to support our development activities through regulatory approval and commercial manufacturing, the manufacturers with whom we currently work will need to increase its frequency and/or scale of production or we will need to find additional or alternative manufacturers. We have not yet secured alternate suppliers in the event the current manufacturer we utilize is unable to meet demand, or if otherwise we experience any problems with them. If such problems arise and we are unable to arrange for alternative third-party manufacturing sources, we are unable to find an alternative third party capable of reproducing the existing manufacturing method or we are unable to do so on commercially reasonable terms or in a timely manner, we may not be able to complete development of our product candidates, or market or distribute them.

We have relied upon and plan to continue to rely upon third-party contract research organizations, or CROs, and clinical data management organizations to monitor and manage data for our ongoing preclinical and clinical programs. Although we control only certain aspects of their activities, we are responsible for ensuring that each of our studies is conducted in accordance with the applicable protocol and legal, regulatory and scientific standards, and our reliance on the CROs does not relieve us of our regulatory responsibilities. We also rely on third parties to conduct our preclinical studies in accordance with Good Laboratory Practice, or GLP, requirements and the Laboratory Animal Welfare Act of 1966 requirements, where applicable. We, our CROs and our clinical trial sites are required to comply with regulations and current Good Clinical Practices, or GCP, and comparable foreign requirements to ensure that the health, safety and rights of patients are protected in clinical trials, and that data integrity is assured. Regulatory authorities ensure compliance with GCP requirements through periodic inspections of trial sponsors and trial sites. If we, any of our CROs or our clinical trial sites fail to comply with applicable GCP requirements, the clinical data generated in our clinical trials or a specific site may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications.

Any significant disruption in our supplier relationships could harm our business. We currently rely on a single source supplier of mavorixafor, as well a single supplier for the finished product capsules for mavorixafor. If either of these single source suppliers suffers a major natural or man-made disaster at its manufacturing facility, we would not be able to manufacture mavorixafor on a commercial scale until a qualified alternative supplier is identified. Although alternative sources of supply exist, the number of third party suppliers with the necessary manufacturing and regulatory expertise and facilities is limited, and it could be expensive and take a significant amount of time to arrange for alternative suppliers. Any significant delay in the supply of a product candidate or its key materials for an ongoing clinical study could considerably delay completion of our clinical studies, product testing and potential regulatory approval of our product candidates. If we or our manufacturers are unable to purchase these key materials after regulatory approval of our product candidates, the commercial launch of our product candidates would be delayed, which would impair our ability to generate revenues from the sale of our product candidates.

We are exposed to the risk that our employees, principal investigators, CROs, CMOs and consultants may engage in fraudulent conduct or other illegal activity. Misconduct by these parties could include intentional failures to comply with FDA regulations or similar regulations of comparable foreign regulatory authorities, to provide accurate information to the FDA or comparable foreign regulatory authorities, to comply with manufacturing standards we have established, to comply with federal and state healthcare fraud and abuse laws and regulations and similar laws and regulations established and enforced by comparable foreign regulatory authorities, to report financial information or data accurately or to disclose unauthorized activities to us. In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive laws and regulations intended to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing and promotion, sales commission, customer incentive programs and other business arrangements. Employee or third party misconduct could also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and serious harm to our reputation. It is not always possible to identify and deter employee misconduct and the precautions we take to detect and prevent this activity, such as employee training, may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business and results of operations, including the imposition of significant fines or other sanctions.

Our drug development programs and the potential commercialization of our product candidates will require substantial additional cash to fund expenses. For some of our product candidates, we may decide to collaborate with pharmaceutical and biotechnology companies for the development and potential commercialization of those product candidates.

We have, and may selectively seek in the future, third-party collaborators for the development and commercialization of our product candidates. Our likely collaborators for any collaboration arrangements include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies and biotechnology companies. If we enter into any such arrangements with any third parties, we will likely have limited control over the amount and timing of resources that our collaborators dedicate to the development or commercialization of our product candidates. Our ability to generate revenue from these arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements.

Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may have a significant impact on our ability to protect our technology and enforce our intellectual property rights.

Furthermore, the patent positions of companies engaged in the development and commercialization of biologics and pharmaceuticals are particularly uncertain. We cannot assure you that our efforts to seek patent protection for our technology and products will not be negatively impacted by the changes described above, future rulings in district court cases or changes in guidance or procedures issued by the USPTO. We cannot fully predict what impact the Supreme Court’s decisions may have on the ability of life science companies to obtain or enforce patents relating to their products and technologies in the future.

Moreover, although the Supreme Court has held in Myriad that isolated segments of naturally occurring DNA are not patent-eligible subject matter, certain third parties could allege that activities that we may undertake infringe other gene-related patent claims, and we may deem it necessary to defend ourselves against these claims by asserting non-infringement and/or invalidity positions, or pay to obtain a license to these claims. In any of the foregoing or in other situations involving third-party intellectual

property rights, if we are unsuccessful in defending against claims of patent infringement, we could be forced to pay damages or be subjected to an injunction that would prevent us from utilizing the patented subject matter. Such outcomes could harm our business.

We depend on our ability to protect our proprietary technology. We rely on trade secret, patent, copyright and trademark laws, and confidentiality, licensing and other agreements with employees and third parties, all of which offer only limited protection. Our success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries with respect to our proprietary technology and products. Where we have the right to do so under our license agreements, we seek to protect our proprietary position by filing patent applications in the United States and abroad related to our novel technologies and products that are important to our business.

The patent prosecution process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. In addition, it is also possible that we will fail to identify patentable aspects of further inventions made in the course of our development and commercialization activities before they are publicly disclosed, making it too late to obtain patent protection on them. Further, given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. We expect to seek extensions of patent terms where these are available in any countries where we are prosecuting patents. This includes in the United States under the Drug Price Competition and Patent Term Restoration Act of 1984, which permits a patent term extension of up to five years beyond the expiration of a patent that covers an approved product where the permission for the commercial marketing or use of the product is the first permitted commercial marketing or use, and as long as the remaining term of the patent does not exceed 14 years. However, the applicable authorities, including the FDA in the United States, and any equivalent regulatory authority in other countries, may not agree with our assessment of whether such extensions are available, and may refuse to grant extensions to our patents, or may grant more limited extensions than we request. If this occurs, our competitors may be able to take advantage of our investment in development and clinical trials by referencing our clinical and preclinical data and launch their product earlier than might otherwise be the case.

Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection. The laws of foreign countries may not protect our rights to the same extent as the laws of the United States, and these foreign laws may also be subject to change. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after filing or in some cases not at all. Therefore, we cannot be certain that we or our licensors were the first to make the inventions claimed in our owned or licensed patents or pending patent applications, or that we or our licensors were the first to file for patent protection of such inventions.

Periodic maintenance fees on any issued patent are due to be paid to the USPTO, and foreign patent agencies in several stages over the lifetime of the patent. The USPTO and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other requirements during the patent application process. While an inadvertent lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Non-compliance events that could result in abandonment or lapse of a patent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submit formal documents. If we or our licensors fail to maintain the patents and patent applications covering our product candidates, our competitors might be able to enter the market, which would have a material adverse effect on our business.

Patents have a limited lifespan. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest U.S. non-provisional filing date. Various extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired, we may be open to competition from competitive products, including generics or biosimilars. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours.

In addition to the possibility of litigation relating to infringement claims asserted against it, we may become a party to other patent litigation and other proceedings, including inter partes review proceedings, post-grant review proceedings, derivation proceedings declared by the USPTO and similar proceedings in foreign countries, regarding intellectual property rights with respect to our current or future technologies or product candidates or products. The cost to us of any patent litigation or other proceeding, even if resolved in our favor, could be substantial. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their substantially greater financial resources. Patent litigation and other proceedings may also absorb significant management time. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could impair our ability to compete in the marketplace.

We are a party to several license agreements and may need to obtain additional licenses from others to advance our research and development activities or allow the commercialization of our current product candidates and any that we may identify and pursue in the future. Our currently license agreements impose, and we expect that future license agreements will impose, various development, diligence, commercialization, and other obligations on us. In spite of our efforts, our licensors might conclude that we have materially breached our obligations under such license agreements and might therefore terminate the license agreements, thereby removing or limiting our ability to develop and commercialize products and technology covered by these license agreements. If these in-licenses are terminated, or if the underlying patents fail to provide the intended exclusivity, competitors or other third parties may gain the freedom to seek regulatory approval of, and to market, products identical to ours and we may be required to cease our development and commercialization of our product candidates. Any of the foregoing could have a material adverse effect on our competitive position, business, financial conditions, results of operations, and prospects.

We may need to obtain licenses to patents and other proprietary rights held by third parties to develop, manufacture and market our product candidates. If we are unable to timely obtain these licenses on commercially reasonable terms and maintain these licenses, our ability to commercially market our product candidates may be inhibited or prevented, which could have a material adverse effect on our business, results of operations, financial condition and cash flows.

Our commercial success depends upon our ability to develop, manufacture, market and sell our product candidates, and to use our proprietary technologies without infringing the proprietary rights of third parties. We may become party to, or threatened with, future adversarial proceedings or litigation regarding intellectual property rights with respect to our products and technology, including interference and various post grant proceedings before the USPTO, non-U.S. opposition proceedings, and German nullity proceedings. Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future.

Litigation or other legal proceedings relating to intellectual property claims, with or without merit, is unpredictable and generally expensive and time consuming and is likely to divert significant resources from our core business, including distracting our technical and management personnel from their normal responsibilities. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock and negatively impact our ability to raise additional funds. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distribution activities.

In addition to seeking patents for some of our technologies and product candidates, we also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. We seek to protect these trade secrets, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to them, such as our employees, corporate collaborators, outside scientific collaborators, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality, non-competition, non-solicitation, and invention assignment agreements with our employees and consultants that obligate them to assign to us any inventions developed in the course of their work for us. However, we cannot guarantee that we have executed these agreements with each party that may have or have had access to our trade secrets or that the agreements we have executed will provide adequate protection. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. As a result, we may be forced to bring claims against third parties, or defend claims that they bring against us, to determine ownership of what we regard as our intellectual property. Monitoring unauthorized disclosure is difficult and we do not know whether the procedures that we have followed to prevent such disclosure are or will be adequate. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside the United States may be less willing or unwilling to protect trade secrets. If any of the technology or information that we protect as trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to, or independently developed by, a competitor, our competitive position would be harmed.

Our employees, including members of our senior management, were previously employed at other biotechnology or pharmaceutical companies, including our competitors or potential competitors. All such individuals, including each member of our senior management, executed proprietary rights, non-disclosure and non-competition agreements in connection with such previous employment. Although we try to ensure that our employees do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these employees have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such employee’s former employer. We are not aware of any threatened or pending claims related to these matters or concerning the agreements with our senior management, but in the future litigation may be necessary to defend against such claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management.

Filing, prosecuting and defending patents on all of our product candidates throughout the world would be prohibitively expensive. In general, we have sought patent protection of our intellectual property in the following jurisdictions: US, Canada, China, Japan and in countries within Europe via the European Patent Office. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and further, may export otherwise infringing products to territories where we have patent protection, but where enforcement is not as strong as that in the United States. These products may compete with our products in jurisdictions where we do not have any issued patents and our patent claims or other intellectual property rights may not be effective or sufficient to prevent them from so competing.

As another example, the complexity and uncertainty of European patent laws have increased in recent years. In Europe, a new unitary patent system will likely be introduced by the end of 2023, which would significantly impact European patents, including those granted before the introduction of such a system. Under the unitary patent system, European applications will soon have the option, upon grant of a patent, of becoming a Unitary Patent which will be subject to the jurisdiction of the Unitary Patent Court (“UPC”). As the UPC is a new court system, there is no precedent for the court, increasing the uncertainty of any litigation. Patents granted before the implementation of the UPC will have the option of opting out of the jurisdiction of the UPC and remaining as national patents in the UPC countries. Patents that remain under the jurisdiction of the UPC will be potentially vulnerable to a single UPC-based revocation challenge that, if successful, could invalidate the patent in all countries who are signatories to the UPC. We cannot predict with certainty the long-term effects of any potential changes.

Because of the specialized scientific and managerial nature of our business, we rely heavily on our ability to attract and retain qualified scientific, technical and managerial personnel. We are also highly dependent upon members of our current management team, including Paula Ragan, Ph.D., our Chief Executive Officer. The loss of the services provided by these individuals will adversely impact the achievement of our objectives. These individuals could leave our employment at any time, as they are “at will” employees. Effective succession planning is also important to our long-term success. Failure to ensure effective transfer of knowledge and smooth transitions involving key employees could hinder our strategic planning and execution. While we expect to engage in an orderly transition process if and when we integrate newly appointed officers and managers, we face a variety of risks and uncertainties relating to management transition, including diversion of management attention from business concerns, failure to retain other key personnel, or loss of institutional knowledge. In addition, the loss of the services of any of our executive officers, other key employees, and other scientific and medical advisors, and an inability to find suitable replacements could result in delays in product development, and harm our business.    

As of December 31, 2023, we had 93 full-time employees. As our development and commercialization plans and strategies develop, or as a result of any future acquisitions, we will need additional managerial, operational, development, sales, marketing, financial and other resources. Our management, personnel and systems currently in place will not be adequate to support this future growth. Future growth would impose significant added responsibilities on our employees, including:

The pharmaceutical industry is highly competitive and is subject to rapid and significant technological change, which could render certain of our products obsolete or uncompetitive. This is particularly true in the development of therapeutics for oncology indications where new products and combinations of products are rapidly being developed that change the treatment paradigm for patients. There is no assurance that our product candidates will be the best, have the best safety profile, be the first to market, or be the most economical to make or use. The introduction of competitive therapies as alternatives to our product candidates could dramatically reduce the value of those development projects or chances of successfully commercializing those product candidates, which could have a material adverse effect on our long-term financial success.

We will compete with companies in the United States and internationally, including major pharmaceutical and chemical companies, specialized CROs, research and development firms, universities and other research institutions. Many of our competitors have greater financial resources and selling and marketing capabilities, greater experience in clinical testing and human clinical trials of pharmaceutical products and greater experience in obtaining FDA and other regulatory approvals than we do. In addition, some of our competitors may have lower development and manufacturing costs.

We rely significantly on information technology and any failure, inadequacy, interruption or security lapse of that technology or loss of data, including any cyber security incidents, could compromise sensitive information related to our business, prevent us from accessing critical information or expose us to liability which could harm our ability to operate our business effectively and adversely affect our business and reputation.

In the ordinary course of our business, we, our contract research organizations and other third parties on which we rely collect and store sensitive data, including legally protected patient health information, personally identifiable information about our employees, intellectual property, and proprietary business information. We manage and maintain our applications and data utilizing on-site systems. These applications and data encompass a wide variety of business-critical information including research and development information and business and financial information.

The secure processing, storage, maintenance and transmission of this critical information is vital to our operations and business strategy. Additionally, despite the implementation of security measures, our internal computer systems and those of third parties with which we contract are vulnerable to damage from cyber-attacks, computer viruses, breaches, unauthorized access, interruptions due to employee error or malfeasance or other disruptions, or damage from natural disasters, terrorism, war and telecommunication and electrical failures.     

In addition, we have implemented a work model that has enabled substantially all of our employees to periodically work remotely, which may make us more vulnerable to cyberattacks. Any such event could compromise our networks and the information stored there could be accessed by unauthorized parties, publicly disclosed, lost or stolen. We have measures in place that are designed to detect and respond to such security incidents and breaches of privacy and security mandates. Any such access, disclosure or other loss of information could result in legal claims or proceedings, liability under laws that protect the privacy of personal information, government enforcement actions and regulatory penalties. Unauthorized access, loss or dissemination could also disrupt our operations, including our ability to conduct research, development and commercialization activities, process and prepare company financial information, manage various selling, general and administrative aspects of our business and damage our reputation, in addition to possibly requiring substantial expenditures of resources to remedy, any of which could adversely affect our business. The loss of clinical trial data could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. In addition, there can be no assurance that we will promptly detect any such disruption or security breach, if at all. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability and our research, development and commercialization efforts could be delayed.

Our net operating loss (“NOL”) carryforwards could expire unused and be unavailable to offset future tax liabilities because of their limited duration or because of restrictions under U.S. tax law. As of December 31, 2023, we had U.S. federal and state NOLs of $400.0 million and $389.0 million, respectively. Our NOLs generated in tax years ending on or prior to December 31, 2017 are only permitted to be carried forward for 20 years under applicable U.S. tax law. Under the Tax Act, as modified by the CARES

Act, our federal NOLs generated in tax years ending after December 31, 2017 may be carried forward indefinitely, but the deductibility of federal NOLs, particularly for tax years beginning after December 31, 2020, may be limited. It is uncertain if and to what extent various states will conform to the Tax Act and the CARES Act.

Section 382 of the Internal Revenue Code of 1986, as amended, or Section 382, contains rules that limit the ability of a company that undergoes an ownership change to utilize its net operating losses, or NOLs, and tax credits existing as of the date of such ownership change. Under the rules, such an ownership change is generally any change in ownership of more than 50% of a company’s stock within a rolling three-year period. The rules generally operate by focusing on changes in ownership among stockholders considered by the rules as owning, directly or indirectly, 5% or more of the stock of a company and any change in ownership arising from new issuances of stock by the company. We have experienced multiple ownership changes since our inception and are conducting a study to assess whether an ownership change has occurred and whether these ownership changes will limit the future use of our NOL carryforwards. Future ownership changes as defined by Section 382 may further limit the amount of NOL carryforwards that could be utilized annually to offset future taxable income.

In October 2018, we entered into a loan and security agreement, as most recently amended in August 2023, with Hercules, secured by a lien on substantially all of our assets, excluding intellectual property. This loan contains various covenants that limit our ability to engage in specified types of transactions. These covenants limit our ability to, among other things:

The global economy, including credit and financial markets, has experienced extreme volatility and disruptions, including, among other things, severely diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, supply chain shortages, increases in inflation rates, higher interest rates and uncertainty about economic stability. For example, the COVID-19 pandemic resulted in widespread unemployment, economic slowdown and extreme volatility in the capital markets. The U.S. Federal Reserve recently raised interest rates multiple times in response to concerns about inflation and it may raise them again. Higher interest rates, coupled with reduced government spending and volatility in financial markets may increase economic uncertainty. If the equity and credit markets deteriorate, including as a result of political unrest or war, such as the war in Ukraine or in Gaza, it may make any necessary debt or equity financing more difficult to obtain in a timely manner or on favorable terms, more costly or more dilutive. Increased inflation rates can adversely affect us by increasing our costs, including labor and employee benefit costs.

On November 13, 2023, we received a letter from the Listing Qualifications Staff of The Nasdaq Stock Market LLC ("Nasdaq") indicating that, based upon the closing bid price of our common stock for the last 30 consecutive business days, we no longer meet Nasdaq Listing Rule 5550(a)(2), which requires listed companies to maintain a minimum bid price of at least $1.00 per share.

In accordance with the listing rules of Nasdaq, the Company has been given 180 calendar days, or until May 13, 2024 (the “Compliance Date”), to regain compliance with the minimum bid price requirement. If at any time before the Compliance Date, the closing bid price of the Company’s Common Stock is at least $1.00 per share for a minimum of ten consecutive business days, Nasdaq will provide written notification to the Company that it complies with the minimum bid price requirement. If the Company is unable to regain compliance before the Compliance Date, the Company may be eligible for an additional 180 calendar days to satisfy the Bid Price Rule. To qualify, the Company will be required to meet the continued listing requirement for market value of publicly held shares and all other initial listing standards for the Nasdaq Capital Market with the exception of the Bid Price Rule, and will need to provide written notice of its intention to cure the deficiency during such additional compliance period, by effecting a reverse stock split, if necessary. If it appears to Nasdaq staff that the Company will not be able to cure the deficiency, or if the Company is otherwise not eligible for the additional compliance period, and the Company does not regain compliance by the Compliance Date, Nasdaq will provide written notification to the Company that its Common Stock is subject to delisting. At that time, the Company may appeal the delisting determination to a hearings panel pursuant to the procedures set forth in the applicable Nasdaq Listing Rules. However, there can be no assurance that, if the Company does appeal the delisting determination by Nasdaq to the panel, such appeal would be successful.

If we fail to regain compliance with the Nasdaq continued listing standards, Nasdaq will provide notice that our common stock will be subject to delisting. We would then be entitled to appeal that determination to a Nasdaq hearings panel.

The notification has no immediate effect on the listing of our common stock on Nasdaq. We intend to monitor the closing bid price of our common stock and consider our available options in the event the closing bid price of our common stock remains below $1.00 per share.

We cannot assure you that we will be able to regain compliance with Nasdaq listing standards. Our failure to continue to meet the minimum bid requirement would result in our common stock being delisted from Nasdaq. We and holders of our securities could be materially adversely impacted if our securities are delisted from Nasdaq. In particular:

The market price of our common stock has been and could continue to be subject to significant fluctuations. Market prices for securities of pharmaceutical, biotechnology and other life sciences companies have historically been particularly volatile. Some of the factors that may cause the market price of our common stock to fluctuate include:

Trading in our securities is subject to the SEC’s “penny stock” rules and it is anticipated that trading in our securities will continue to be subject to the penny stock rules for the foreseeable future. The SEC has adopted regulations that generally define a penny stock to be any equity security that has a market price of less than $5.00 per share, subject to certain exceptions. These rules require that any broker-dealer who recommends our securities to persons other than prior customers and accredited investors must, prior to the sale, make a special written suitability determination for the purchaser and receive the purchaser’s written agreement to execute the transaction. Unless an exception is available, the regulations require the delivery, prior to any transaction involving a penny stock, of a disclosure schedule explaining the penny stock market and the risks associated with trading in the penny stock market. In addition, broker-dealers must disclose commissions payable to both the broker-dealer and the registered representative and current quotations for the securities they offer. The additional burdens imposed upon broker-dealers by these requirements may discourage broker-dealers from recommending transactions in our securities, which could severely limit the liquidity of our securities and consequently adversely affect the market price for our securities.

The trading market for our common stock will be influenced, in part, on the research and reports that industry or financial analysts publish about us or our business. Equity research analysts may elect not to provide research coverage of our common stock, and such lack of research coverage may adversely affect the market price of our common stock. In the event we do have equity research analyst coverage, we will not have any control over the analysts or the content and opinions included in their reports. The price of our common stock could decline if one or more equity research analysts downgrade our stock or issue other unfavorable commentary or research. If one or more equity research analysts ceases coverage of us or fails to publish reports on us regularly, demand for our common stock could decrease, which in turn could cause our stock price or trading volume to decline.

The current expectation is that we will retain our future earnings to fund the development and growth of our business. In addition, the terms of our debt agreements preclude us from paying dividends. As a result, capital appreciation, if any, of our common stock will be your sole source of gain, if any, for the foreseeable future. We are prohibited from declaring or paying any cash dividends under our existing loan and security agreement with Hercules.

In addition, we have filed registration statements on Form S-8 registering the issuance of shares of common stock subject to options or other equity awards issued or reserved for future issuance under our equity incentive plans. Shares registered under these registration statements are available for sale in the public market subject to vesting arrangements and exercise of options, as well as Rule 144 in the case of our affiliates.

We are subject to the reporting requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the Sarbanes-Oxley Act of 2002 and the rules and regulations of The Nasdaq Stock Market (“Nasdaq”). Pursuant to Section 404 of the Sarbanes-Oxley Act of 2002 (“Section 404”), we are required to perform system and process evaluation and testing of our internal control over financial reporting to allow our management to report on the effectiveness of our internal control over financial reporting in this Annual Report.

We are a “smaller reporting company” under the Exchange Act as of June 30, 2023. We may continue to be a smaller reporting company if either (i) the market value of our common stock held by non-affiliates is less than $250 million or (ii) our annual revenue was less than $100.0 million during the most recently completed fiscal year and the market value of our common stock held by non-affiliates is less than $700.0 million. As a smaller reporting company, we may rely on exemptions from certain disclosure requirements that are available to smaller reporting companies, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act and reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements. For so long as we remain a smaller reporting company, we are permitted and intend to rely on such exemptions from certain disclosure and other requirements that are applicable to other public companies that are not smaller reporting companies.

We cannot predict if investors will find our securities less attractive because we may rely on the exemptions and reduced disclosure obligations applicable to smaller reporting companies. If some investors find our securities less attractive as a result, there may be a less active trading market for our common stock and our stock price may be more volatile.

In the past, securities class action or shareholder derivative litigation has often followed certain significant business transactions, such as the sale of a business division or announcement of a merger. This risk is especially relevant for us because biopharmaceutical companies have experienced significant stock price volatility in recent years. We may become involved in this type of litigation in the future. The outcome of litigation is necessarily uncertain, and we could be forced to expend significant resources in the defense of such suits, and we may not prevail. Monitoring and defending against legal actions is time-consuming for our management and detracts from management’s ability to fully focus our internal resources on our business activities. In addition, we may incur substantial legal fees and costs in connection with any such litigation. We have not established any reserves for any potential liability relating to any such potential lawsuits. It is possible that we could, in the future, incur judgments or enter into settlements of claims for monetary damages. We currently maintain insurance coverage for some of these potential liabilities. Other potential liabilities may not be covered by insurance, insurers may dispute coverage or the amount of insurance may not be enough to cover damages awarded. In addition, certain types of damages may not be covered by insurance, and insurance coverage for all or certain forms of liability may become unavailable or prohibitively expensive in the future. A decision adverse to our interests on one or more legal matters or litigation could result in the payment of substantial damages, or possibly fines, and could have a material adverse effect on our reputation, financial condition and results of operations.

Provisions in our corporate charter and by-laws may discourage, delay or prevent a merger, acquisition or other change in control of our Company that stockholders may consider favorable, including transactions in which you might otherwise receive a premium for your shares. These provisions also could limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions:

Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with the Company for a period of three years after the date of the transaction in which the person acquired in excess of 15% of our outstanding voting stock, unless the merger or combination is approved in a prescribed manner.

Our certificate of incorporation provides that the Court of Chancery of the State of Delaware will be the exclusive forum for substantially all disputes between the Company and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with the Company or our directors, officers, employees or stockholders.

Our certificate of incorporation provides that the Court of Chancery of the State of Delaware is the exclusive forum for any derivative action or proceeding brought on the Company’s behalf, any action asserting a breach of fiduciary duty owed by our directors, officers, other employees or stockholders to the Company or our stockholders, any action asserting a claim against the Company arising pursuant to the Delaware General Corporation Law or as to which the Delaware General Corporation Law confers jurisdiction on the Court of Chancery of the State of Delaware, or any action asserting a claim arising pursuant to our certificate of incorporation or by-laws or governed by the internal affairs doctrine. This provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with the Company or our directors, officers, employees or stockholders, which may discourage such lawsuits against the Company and our directors, officers, employees or stockholders.

Alternatively, if a court were to find this provision in our certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could adversely affect our business and financial condition.

Our management recognizes the impact that cybersecurity threats could have on our business operations, our compliance with regulations, and our reputation. We have identified cybersecurity as a critical business risk as part of our overall risk management strategy, which our board of directors oversees.

We have implemented a cybersecurity program in accordance with our risk profile and business that includes, among other things, written policies, monitoring and filtering procedures, and employee training. We have also developed an incident response policy and procedure designed to facilitate the timely reporting and assessment of cybersecurity incidents.

Our cybersecurity risk management program, which is part of our enterprise risk management program, aims to identify risks related to the Company, including risks from cybersecurity threats. Our cybersecurity risk management program includes a number of components, including informal self-assessments and audits, penetration testing, and vulnerability assessments, that are conducted periodically by both internal and external resources. The Company also analyzes current and emerging cyber threats that pose a risk to the organization using various threat intelligence tools and services.

As part of our cybersecurity risk management program, we take a risk-based approach to the evaluation of third-party vendors, and apply mitigations and processes based on our evaluation of the sensitivity of the data accessed by the vendor and the maturity of the vendor’s programs. Our vendor evaluation procedures include, as appropriate, the review of vendors’ SOC 2 Type 2 reports if available, and a vendor security questionnaire. We are in the process of expanding the use of the security questionnaire to additional vendors.

Our director of information technology (“Director of IT”) is responsible for the strategic leadership and direction of the Company’s information technology organization. The Director of IT has helped organizations define and implement information technology strategies for over twenty years. Prior to joining the Company, he served in senior information technology roles for several biotechnology companies. Along with members of our finance, legal, and operations teams, the Director of IT sits on a newly-formed cyber subcommittee (“subcommittee”). The subcommittee reports to the Chief Operating Officer (“COO”) and Chief Financial Officer (“CFO”), and outputs from the Committee are provided by the COO and CFO to the Company’s executive team and the board.

The board is responsible for informed oversight of our risk management process. The board administers this oversight function through various board standing committees that address risks inherent in their respective areas of oversight. The board has delegated oversight for cybersecurity risk management to the Audit Committee. The Audit Committee reviews the Company’s policies and procedures with respect to cybersecurity risk management.

We lease approximately 1,200 square meters of laboratory and office space in Vienna, Austria under a lease that will expire in March 2028, with a monthly payment of approximately $24 thousand.

Our common stock commenced trading on the Nasdaq Global Market under the symbol “ASNS” on November 16, 2017. Prior to that date, there was no public trading market for our common stock. On March 13, 2019, we completed a business combination in accordance with the terms of the Merger Agreement, by and among us, X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc.) and the Merger Sub, pursuant to which, among other matters, Merger Sub merged with and into X4 Therapeutics, Inc., with X4 Therapeutics, Inc. continuing as our wholly-owned subsidiary and the surviving corporation of the merger. Following the Merger, on March 14, 2019, we effected a 1-for-6 reverse stock split of our common stock and changed our name to “X4 Pharmaceuticals, Inc.” On March 13, 2019, following the completion of the Merger, our common stock began trading on the Nasdaq Capital Market under the symbol “XFOR”.

As of March 1, 2024, there were 60 holders of record of our common stock, one of which is Cede & Co., a nominee for Depository Trust Company (“DTC”). All of the shares of common stock held by brokerage firms, banks and other financial institutions as nominees for beneficial owners are deposited into participant accounts at DTC, and are considered to be held of record by Cede & Co. as one stockholder.

We have never declared or paid cash dividends on our common stock. We currently intend to retain all available funds and any future earnings to fund the development and expansion of our business and we do not anticipate paying any cash dividends in the foreseeable future. Any future determination to declare and pay dividends will be made at the discretion of our board of directors and will depend on then-existing conditions, including our results of operations, financial condition, contractual restrictions, capital requirements, business prospects and other factors our board of directors may deem relevant.

None.

We are a late clinical-stage biopharmaceutical company discovering and developing novel therapeutics for the treatment of rare diseases and those with limited treatment options, with a focus on conditions resulting from dysfunction of the immune system.

Our lead clinical candidate is mavorixafor, a small-molecule selective antagonist of chemokine receptor CXCR4 that is being developed as an oral, once-daily therapy. Due to its ability to increase the mobilization of mature, functional white blood cells into the bloodstream, we believe that mavorixafor has the potential to provide therapeutic benefit across a variety of chronic neutropenic disorders, including WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, primary immunodeficiency for which there are no approved therapies.

We are currently seeking approval from the U.S. Food and Drug Administration (“FDA”) for the use of oral, once-daily mavorixafor in the treatment of people aged 12 years and older with WHIM syndrome following the October 2023 acceptance of our New Drug Application (“NDA”) by the FDA. The FDA has granted the NDA Priority Review, establishing a goal of six months review from the date of acceptance and assigning a Prescription Drug User Fee Act (“PDUFA”) target action date of April 30, 2024. At this time, the FDA has notified us that they are not currently planning to hold an advisory committee meeting to review the filing. Due to mavorixafor’s Rare Pediatric Disease designation in the U.S. for WHIM syndrome, we are eligible to receive a Priority Review Voucher (“PRV”) that can be used to obtain Priority Review for a subsequent application or sold to another drug sponsor should mavorixafor be approved.

The NDA is supported by our successfully completed global, pivotal, Phase 3 clinical trial (4WHIM) that evaluated the safety and efficacy of mavorixafor in people with WHIM syndrome. The 4WHIM trial met its primary endpoint and a key secondary endpoint, demonstrating statistically significant increases in time above threshold for absolute neutrophil counts (“TAT-ANC”) and time above threshold for absolute lymphocyte counts (“TAT-ALC”) in participants treated with mavorixafor versus placebo. Additional data showed that mavorixafor treatment resulted in statistically significant reductions in annualized infection rates versus placebo and clinically meaningful reductions in the both the severity and duration of infections versus placebo. Mavorixafor was generally well tolerated throughout the 52-week trial.

In anticipation of a potential second quarter of 2024 U.S. launch of mavorixafor in WHIM syndrome, we have continued to build our go-to-market organization, with key hires across commercial and medical functions, increased interactions with key stakeholders and rare disease patient advocacy organizations, and launched a disease-awareness campaign aiming to further the understanding of WHIM syndrome and educate patients and physicians on the importance and benefits of early diagnosis.

We believe that successfully developing mavorixafor and providing a new therapeutic option to individuals diagnosed with certain chronic neutropenic disorders has the potential to revolutionize the treatment landscape, which is principally served by injectable therapies (including G-CSF) that are frequently associated with treatment-limiting adverse events.

To date, we have not generated revenue from product sales. If our development efforts for our product candidates are successful and result in regulatory approval, we may generate revenue in the future from product sales. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.

Unfavorable conditions in the economy in the United States and abroad may negatively affect the growth of our business and our results of operations. The effect of macroeconomic conditions may not be fully reflected in our results of operations until future periods. If, however, economic uncertainty increases or the global economy worsens, our business, financial condition and results of operations may be harmed. For further discussion of the potential impacts of macroeconomic events on our business, financial condition, and operating results, see the section titled “Risk Factors.”

Research and development expenses consist primarily of costs incurred in connection with the discovery and development of our product candidates, including employee salaries and related expenses, expenses incurred in connection with the preclinical and clinical development of our product candidates, including under agreements with third parties, such as consultants and contract research organizations (“CROs”); the cost of manufacturing drug products for use in our preclinical studies and clinical trials, including under agreements with third parties, such as consultants and contract manufacturing organizations (“CMOs”); facilities, depreciation and other expenses, which include direct or allocated expenses for rent and maintenance of facilities and insurance; costs related to compliance with regulatory requirements; and payments made under third-party licensing agreements. We expense research and development costs as incurred.

Research and development expenses were $72.0 million for the year ended December 31, 2023, as compared to $61.1 million for the year ended December 31, 2022, reflecting an increase of $11.0 million. The increase in research and development expenses in 2023 as compared to 2022 was primarily due to a $5.0 million development milestone payment under our Genzyme agreement, approximately $2 million of higher regulatory costs associated with the preparation and submission of our NDA, and additional consulting and temporary help across our research and development organization to support our NDA submission and our ongoing clinical trials. Research and development expenses also increased in 2023 due to an increase in unallocated expenses, primarily due to an increase in head count within our manufacturing, regulatory and clinical operations functions, resulting in higher compensation expenses, including stock-based compensation.

We expect that our research and development expenses, particularly for our mavorixafor programs, will increase over the next several years as we continue to conduct our clinical trials of mavorixafor in chronic neutropenic disorders. Research and development expenses related to our X4P-002 and X4P-003 programs was not significant in 2023 or 2022 relative to our overall research and development expenses.

Selling, general and administrative expenses consist primarily of salaries and related costs, including stock-based compensation for personnel in sales and marketing, executive, finance and administrative functions. Selling, general and administrative expenses also include direct and allocated facility-related costs, as well as professional fees for legal, patent, consulting, investor and public relations, accounting, and audit services.

Selling, general and administrative expenses were $35.5 million in 2023, as compared to $27.0 million in 2022, reflecting an increase of $8.5 million. The increase in selling, general and administrative expenses in 2023 as compared to 2022 was primarily due to an increase in compensation expense due to in increase in head count, higher stock-based compensation costs and higher stock appreciation rights expense. We have added personnel to our marketing and sale operations organizations in anticipation of a potential commercial launch of our drug candidate in 2024. We have also incurred third party consulting costs associated with enabling our market access infrastructure. We expect selling, general and administrative expenses will grow in the future as we continue to build out our selling, general and administrative functions.

Goodwill is tested quantitatively for impairment at the reporting unit level annually in the fourth quarter, or more frequently when events or changes in circumstances indicate that the asset might be impaired. Examples of such events or circumstances include, but are not limited to, a significant adverse change in legal or business climate, an adverse regulatory action or unanticipated competition or when our market value, measured as the price of our common stock multiplied by shares outstanding drops below the value of our net assets.

We have determined that our company operates in a single operating segment and has a single reporting unit. To perform the quantitative test, we compare the fair value of the reporting unit to its carrying value. As we have one reporting unit, we determine its fair value based on the market approach taking into consideration the market value of the company as a whole and any control premium that might be realized upon the sale of the reporting unit. If the fair value of the reporting unit exceeds the carrying value of its net assets, goodwill is not impaired, and no further testing is required. If the fair value of the reporting unit is less than the carrying value, we measure the amount of impairment loss, if any, as the excess of the carrying value over the fair value of the reporting unit. As of December 31, 2023 we determined that goodwill was not impaired based on its quantitative test.

During the year ended December 31, 2022, a third party, who had previously acquired rights to certain intellectual property from us, terminated the arrangement and transferred these rights back us and we transferred these rights to another third party in return for $0.5 million. We have no continuing involvement in any ongoing research and development activities associated with the intellectual property. We concluded that these third parties are "non-customers" as the underlying intellectual property transferred to and from these third parties supports potential drug candidates that are not aligned with our strategic focus and, therefore, are not an output of our ordinary activities. Accordingly, we classified this transaction as a “gain on sale of non-financial asset” for the year ended December 31, 2022. There was no such transaction in year ended December 31, 2023.

The increase in other income (expense), net, of $12.7 million for the year ended December 31, 2023 as compared to 2022 was primarily due (i) an increase in interest income earned on our marketable securities and cash equivalents due to higher invested balances and higher interest rates (ii) income resulting from the decrease in the fair value of outstanding Class C warrants, which are accounted for as a liability, due primarily to a decrease in the value of our common stock and, (iii) transaction fees incurred in 2022 that did not recur in 2023 associated with the issuance of warrants that are accounted for as liabilities, partially offset by an increase in interest expense associated with the Hercules Loan agreement due to higher borrowings and a higher effective interest rate.

Sources of Liquidity

To date, we have funded our operations primarily with proceeds from sales of common stock, warrants and prefunded

warrants for the purchase of our preferred stock and our common stock, sales of preferred stock, proceeds from the issuance of

convertible debt and borrowings under loan and security agreements.

Debt Obligations

See Note 7 of the consolidated financial statements and in “Sources of Liquidity” above for a description of our debt obligation.

Lease Obligations

Funding Requirements

We believe that our current cash, cash equivalents and short-term marketable securities will allow us to fund operations into the first quarter of 2025. As noted above, based on our current financial projections and assuming no benefit from the potential FDA approval of our market candidate nor the sale of a PRV, if obtained, or any additional borrowings under our Hercules Loan

Agreement, we believe we would not maintain compliance with the minimum cash covenant of the Hercules Loan Agreement in the first quarter of 2025. In order to fund operations and satisfy the minimum cash covenant in the Hercules Loan Agreement, we will be required to raise additional capital, which may be through a combination of equity offerings, debt financings, other third-party funding, marketing and distribution arrangements, the sale of a PRV that may be granted to us if we receive FDA approval of our NDA, profits generated from the sale of our drug candidate upon the receipt of FDA approval of our NDA and other collaborations and strategic alliances. During 2024 and beyond, assuming no changes to our current operational expectations, we expect our expenses to continue to increase in connection with our ongoing activities, particularly as we advance the current and anticipated clinical trials of our product candidates in development and prepare for the launch and commercialization of any product candidates. Because of the numerous risks and uncertainties associated with research, development and commercialization of pharmaceutical product candidates, we are unable to estimate the exact amount of our funding requirements. Our short term and long term funding requirements will depend on and could increase significantly as a result of many factors, including:

Goodwill is tested quantitatively for impairment at the reporting unit level annually in the fourth quarter, or more frequently when events or changes in circumstances indicate that the asset might be impaired. Examples of such events or circumstances include, but are not limited to, a significant adverse change in legal or business climate, an adverse regulatory action or unanticipated competition.

We have determined that we operate in a single operating segment and have a single reporting unit. To perform its quantitative test, we compare the fair value of our single reporting unit to the carrying value of its net assets, including goodwill. We use our market capitalization (common shares outstanding multiplied by the price per share of our common stock) to measure the fair

value of the reporting unit. If the fair value of the reporting unit exceeds the carrying value of its net assets, goodwill is not impaired, and no further testing is required. If the fair value of the reporting unit is less than the carrying value, we measure the impairment loss as the excess of the carrying value over the fair value of the reporting unit. See Note 4 for more information on our goodwill impairment test as of December 31, 2023.

Evaluation of Disclosure Controls and Procedures

Information regarding our Code of Business Conduct and Ethics (the “Code of Conduct”) required by this item will be contained in our 2024 Proxy Statement under the caption “Information Regarding the Board of Directors and Corporate Governance – Code of Ethics,” and is hereby incorporated by reference. If we make any substantive amendments to the Code of Conduct or grant any waiver from a provision of the Code of Conduct to any executive officer or director, we will promptly disclose the nature of the amendment or waiver on our website. The full text of our Code of Conduct is available at the Investor Relations section of our website at investors.x4pharma.com/investor-relations. The reference to our website address does not constitute incorporation by reference of the information contained at or available through our website, and you should not consider it to be a part of this Annual Report on Form 10-K.

#    Certain confidential portions of this Exhibit were omitted by means of marking such portions with brackets (“[***]”) because the identified confidential portions (i) are not material and (ii) is the type of information that the Registrant treats as private or confidential.    

@    Indicates management contract or compensatory plan