Checkpoint Therapeutics (CKPT) 10-Q10 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2024	May 07, 2024
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-38128
Entity Registrant Name	CHECKPOINT THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2568632
Entity Address, Address Line One	95 Sawyer Road
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02453
City Area Code	781
Local Phone Number	652-4500
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	CKPT
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001651407
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Class A Common Stock
Document and Entity Information
Entity Common Stock, Shares Outstanding		700,000
Common Stock
Document and Entity Information
Entity Common Stock, Shares Outstanding		36,150,279

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 11,241	$ 4,928
Prepaid expenses and other current assets	734	450
Total current assets	11,975	5,378
Total Assets	11,975	5,378
Current Liabilities:
Accounts payable and accrued expenses	19,159	15,485
Accounts payable and accrued expenses - related party	2,941	2,815
Common stock warrant liabilities	125	125
Total current liabilities	22,225	18,425
Total Liabilities	22,225	18,425
Commitments and Contingencies (note 5)
Stockholders' Equity (Deficit)
Common stock issuable, 1,492,915 shares as of March 31, 2024 and December 31, 2023	3,419	3,419
Additional paid-in capital	311,605	297,864
Accumulated deficit	(325,278)	(314,333)
Total Stockholders' Equity (Deficit)	(10,250)	(13,047)
Total Liabilities and Stockholders' Equity (Deficit)	11,975	5,378
Common No Class
Stockholders' Equity (Deficit)
Common Stock Value	$ 4	$ 3

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023	Jun. 12, 2023
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized	80,000,000	80,000,000	80,000,000
Common stock, shares issued	34,986,279	27,042,035
Common stock, shares outstanding	34,986,279	27,042,035
Common stock, shares subscribed but unissued	1,492,915	1,492,915
Class A Common Shares
Common stock, shares issued	700,000	700,000
Common stock, shares outstanding	700,000	700,000

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
Condensed Statements of Operations - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Condensed Statements of Operations
Revenue - related party		$ 35
Operating expenses:
Research and development	$ 8,497	15,826
General and administrative	2,451	2,292
Total operating expenses	10,948	18,118
Loss from operations	(10,948)	(18,083)
Other income:
Interest income	4	43
Gain on common stock warrant liabilities		7,566
Foreign currency exchange loss	(1)
Total other income	3	7,609
Net Loss	$ (10,945)	$ (10,474)
Loss per Share:
Basic net loss per common share outstanding	$ (0.33)	$ (0.89)
Diluted net loss per common share outstanding	$ (0.33)	$ (0.89)
Basic weighted average number of common shares outstanding	32,930,977	11,749,139
Diluted weighted average number of common shares outstanding	32,930,977	11,749,139

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Shares Class A Common Shares	Common Shares	Common Shares Issuable	Additional Paid-in Capital	Accumulated Deficit	Total
Balances at Dec. 31, 2022		$ 1	$ 1,885	$ 241,117	$ (262,486)	$ (19,483)
Balances (in Shares) at Dec. 31, 2022	700,000	9,586,683
Issuance of common shares, net of offering costs - Registered direct offering				6,653		6,653
Issuance of common shares, net of offering costs - Registered direct offering (in Shares)		1,180,000
Issuance of common shares - Founders Agreement			(1,885)	2,041		156
Issuance of common shares - Founders Agreement (in Shares)		404,621
Stock-based compensation expense				969		969
Stock-based compensation expense (in Shares)		996,950
Exercise of pre-funded and common stock warrants, including inducement (in shares)		1,032,816
Net loss					(10,474)	(10,474)
Balances at Mar. 31, 2023		$ 1		250,780	(272,960)	(22,179)
Balances (in Shares) at Mar. 31, 2023	700,000	13,201,070
Balances at Dec. 31, 2023		$ 3	3,419	297,864	(314,333)	(13,047)
Balances (in Shares) at Dec. 31, 2023	700,000	27,042,035
Issuance of common shares, net of offering costs - Registered direct offering		$ 1		12,636		12,637
Issuance of common shares, net of offering costs - Registered direct offering (in Shares)		1,275,000
Issuance of common shares - Founders Agreement				396		396
Issuance of common shares - Founders Agreement (in Shares)		193,905
Stock-based compensation expense				709		709
Stock-based compensation expense (in Shares)		2,680,106
Exercise of pre-funded and common stock warrants, including inducement (in shares)		3,795,233
Net loss					(10,945)	(10,945)
Balances at Mar. 31, 2024		$ 4	$ 3,419	$ 311,605	$ (325,278)	$ (10,250)
Balances (in Shares) at Mar. 31, 2024	700,000	34,986,279

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
Condensed Statements of Cash Flows - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Cash Flows from Operating Activities:
Net loss	$ (10,945)	$ (10,474)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	709	969
Issuance of common shares - Founders Agreement	396	156
Gain on common stock warrant liabilities		(7,566)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(284)	134
Other receivables - related party		38
Accounts payable and accrued expenses	3,524	2,167
Accounts payable and accrued expenses - related party	126	545
Net cash used in operating activities	(6,474)	(14,031)
Cash Flows from Financing Activities:
Net cash provided by financing activities	12,787	6,809
Net increase (decrease) in cash and cash equivalents	6,313	(7,222)
Cash and cash equivalents at beginning of period	4,928	12,068
Cash and cash equivalents at end of period	11,241	4,846
Supplemental disclosure of noncash investing and financing activities:
Issuance of common shares - Founders Agreement		1,885
Issuance of common shares - Registered direct offering (offering costs incurred but not paid)	150	156
Registered direct offerings
Cash Flows from Financing Activities:
Proceeds from issuance of common shares	14,000	7,500
Payment of offering costs for the issuance of common shares	$ (1,213)	$ (691)

Organization and Description of

Organization and Description of Business Operations	3 Months Ended
Organization and Description of Business Operations	Mar. 31, 2024
Organization and Description of Business Operations
Organization and Description of Business Operations	Note 1 - Organization and Description of Business Operations Checkpoint Therapeutics, Inc. (the “Company” or “Checkpoint”) was incorporated in Delaware on November 10, 2014. Checkpoint is a clinical-stage immunotherapy and targeted oncology company focused on the acquisition, development and commercialization of novel treatments for patients with solid tumor cancers. The Company may acquire rights to these technologies by licensing the rights or otherwise acquiring an ownership interest in the technologies, funding their research and development and eventually either out-licensing or bringing the technologies to market. The Company is a majority-controlled subsidiary of Fortress Biotech, Inc. (“Fortress”). The Company’s common stock is listed on the NASDAQ Capital Market and trades under the symbol “CKPT.” Liquidity, Capital Resources and Going Concern The Company has incurred substantial operating losses since its inception and expects to continue to incur significant operating losses for the foreseeable future and may never become profitable. As of March 31, 2024, the Company had an accumulated deficit of $325.3 million. In February 2023, the Company closed on a registered direct offering (the “February 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,180,000 shares of its common stock at a purchase price of $5.25 per share in a registered direct offering. In addition, the offering includes 248,572 shares of common stock in the form of pre-funded warrants at a price of $5.2499. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,428,572 shares of common stock and Series B warrants to purchase up to 1,428,572 shares of common stock. The Series A and B warrants are exercisable In April 2023, the Company closed on a registered direct offering (the “April 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,700,000 shares of its common stock at a purchase price of $3.60 per share of common stock in a registered direct offering. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,700,000 shares of common stock and Series B warrants to purchase up to 1,700,000 shares of common stock. The Series A and B warrants are exercisable In May 2023, the Company closed on a registered direct offering (the “May 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,650,000 shares of its common stock at a purchase price of $3.071 per share of common stock in a registered direct offering. In addition, the offering includes 1,606,269 shares of common stock in the form of pre-funded warrants at a price of $3.0709. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,256,269 shares of common stock and Series B warrants to purchase up to 3,256,269 shares of common stock. The Series A and B warrants are exercisable In July 2023, the Company closed on a registered direct offering (the “July 2023 Registered Direct Offering”) for the issuance and sale of an aggregate of 2,427,186 shares of its common stock at a purchase price of $3.09 per share of common stock in a registered direct offering. In addition, the offering includes 809,062 shares of common stock in the form of pre-funded warrants at a price of $3.0899. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,236,248 shares of common stock and Series B warrants to purchase up to 3,236,248 shares of common stock. The Series A and B warrants are exercisabl date and the Series B warrants will expire eighteen months following the issuance date. The total gross proceeds from the offering were approximately $10.0 million with net proceeds of approximately $9.1 million after deducting approximately $0.9 million in commissions and other transaction costs. In October 2023, the Company entered into an inducement offer letter agreement (the “October 2023 Inducement”) with a certain holder of its existing warrants to exercise for cash an aggregate of 6,325,354 shares of the Company’s common stock at a reduced exercise price of $1.76 per share. The warrants were issued to the holder on December 16, 2022 with an exercise price of $4.075 per share and on February 22, 2023 with an exercise price of $5.00 per share as part of registered direct offerings. As part of the October 2023 Inducement, the Company agreed to issue new unregistered Series A Warrants to purchase up to 6,325,354 shares of Common Stock and new unregistered Series B Warrants to purchase up to 6,325,354 shares of Common Stock. The Series A and B warrants are exercisable immediately upon issuance with an exercise price In January 2024, the Company closed on a registered direct offering (the “January 2024 Registered Direct Offering”) for the issuance and sale of an aggregate of 1,275,000 shares of its common stock at a purchase price of $1.805 per share of common stock. In addition, the offering includes 6,481,233 shares of common stock in the form of pre-funded warrants at a price of $1.8049. In a concurrent private placement, Checkpoint issued and sold common warrants (the “January 2024 Common Stock Warrants”) to purchase up to 7,756,233 shares of common stock. The January 2024 Common Stock Warrants are exercisable immediately upon issuance with an exercise price of $1.68 per share and will expire five years following the issuance date. The total gross proceeds from the January 2024 Registered Direct Offering were approximately $14.0 million with net proceeds of approximately $12.8 million after deducting approximately $1.2 million in commissions and other transaction costs. The Company expects to continue to use the proceeds from previous financing transactions primarily for general corporate purposes, which may include financing the Company’s growth, developing new or existing product candidates, and funding capital expenditures, acquisitions, and investments. In accordance with Accounting Standards Codification (“ASC”) 205-40, Going Concern The Company believes that its cash and cash equivalents are only sufficient to fund its operating expenses into the third quarter of 2024, assuming no exercises of outstanding cash warrants. The Company has suffered recurring losses from operations and has a net capital deficiency that raises substantial doubt regarding the Company’s ability to continue as a going concern for a period of one year after the date that these financial statements are issued. Management’s plans to alleviate the conditions that raise substantial doubt include reduced 2024 spending, including projected savings through delaying the development timelines of certain programs and the pursuit of additional cash resources through public or private equity or debt financings and potential partnerships. Management has concluded that the likelihood that its plan to successfully obtain sufficient funding from one or more of these sources, or adequately reduce expenditures, while reasonably possible, is less than probable. Accordingly, the Company has concluded that substantial doubt exists about the Company’s ability to continue as a going concern for a period of at least 12 months from the date of issuance of these financial statements. The Company’s estimate as to how long it expects its existing cash to be able to continue to fund its operations is based on assumptions that may prove to be wrong, and it could use its available capital resources sooner than it currently expects. Further, changing circumstances, some of which may be beyond its control, could cause the Company to consume capital faster than it currently anticipates, and it may need to seek additional funds sooner than planned. The Company cannot be certain that additional funding will be available to it on acceptable terms, or at all. The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of the uncertainties described above.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
Significant Accounting Policies	Mar. 31, 2024
Significant Accounting Policies
Significant Accounting Policies	Note 2 - Significant Accounting Policies Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and notes required by GAAP for complete financial statements. Therefore, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2023, which were included in the Company’s Form 10-K, and filed with the SEC on March 22, 2024. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2023 Annual Report on Form 10-K. Cash and Cash Equivalents The Company considers highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. In accordance with Accounting Standards Codification (“ASC”) 730-10-25-1, Research and Development Annual Equity Fee Under the Founders Agreement with Checkpoint dated March 17, 2015, and amended and restated in July 2016 and October 2017 (the “Founders Agreement”), Fortress is entitled to an annual equity fee on January 1 of each year equal to 2.5% of fully diluted outstanding equity of the Company, payable in Checkpoint common shares (“Annual Equity Fee”). The Annual Equity Fee was part of the consideration payable for formation of the Company, identification of certain assets, including the license contributed to Checkpoint by Fortress (see Note 4). The Company records the Annual Equity Fee in connection with the Founders Agreement with Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. Due to the nature of the Company’s assets and stage of development, future share prices and shares outstanding cannot be estimated prior to the issuance of the Annual Equity Fee. Due to these uncertainties, the Company has concluded that it is unable to reasonably estimate the contingent consideration until shares are actually issued on January 1 of each year. Pursuant to the Founders Agreement, the Company was to issue 1,492,915 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2024. The Company did not have enough unreserved authorized shares under its certificate of incorporation on January 1, 2024 to issue the shares for the Annual Equity Fee. Therefore, in December 2023, Fortress and Checkpoint mutually agreed to defer the issuance until such time as certificate of incorporation has been amended in order to increase the number of authorized that may be issued thereunder. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2024 prior to the issuance of the December 31, 2023 financial statements, the Company recorded approximately $3.4 million in research and development expense and a credit to Common shares issuable - Founders Agreement during the year ended December 31, 2023. Stock-Based Compensation Expenses The Company expenses stock-based compensation over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes Model. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the Condensed Statements of Operations based upon the underlying individual’s role at the Company. In addition, because some of the restricted stock, restricted stock units and options issued to employees, directors and consultants vest upon achievement of certain milestones, the total expense is uncertain. Compensation expense for such awards that vest upon the achievement of milestones is recognized when the achievement of such milestones is probable. Common Stock Warrant Liability The Company has issued freestanding warrants to purchase shares of its common stock in connection with its financing activities and accounts for them in accordance with applicable accounting guidance as either liabilities or as equity instruments depending on the specific terms of the warrant agreements. Warrants classified as liabilities are remeasured each period they are outstanding. Any resulting gain or loss related to the change in the fair value of the warrant liability is recognized in gain (loss) on common stock warrant liabilities, a component of other income (loss), in the Condensed Statements of Operations. The Company estimates the fair value of common stock warrant liabilities using the Black-Scholes Model. The assumptions used in calculating the fair value represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. Fair Value Measurement The Company follows the accounting guidance in ASC 820 for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to their liquid or short-term nature, such as accounts payable and accrued expenses. Revenue from Contracts with Customers The Company recognizes revenue under ASC 606, “ Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer. ● Step 2: Identify the performance obligations in the contract. ● Step 3: Determine the transaction price. ● Step 4: Allocate the transaction price to the performance obligations in the contract. ● Step 5: Recognize revenue when the company satisfies a performance obligation. In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct); and ● the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. When determining the transaction price, an entity must consider the effects of all of the following: ● variable consideration; ● constraining estimates of variable consideration; ● the existence of a significant financing component in the contract; ● noncash consideration; and ● consideration payable to a customer. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Revenue for a sales-based or usage-based royalty promised in exchange for a license of intellectual property is recognized only when (or as) the later of the following events occurs: a. the subsequent sale or usage occurs; and b. the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). Incremental contract costs are expensed when incurred when the amortization period of the asset that would have been recognized is one year or less; otherwise, incremental contract costs are recognized as an asset and amortized over time as services are provided to a customer. Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not to be sustained upon audit, the Company recognizes the largest amount with a greater than 50% likelihood of being realized. The Company does not recognize any portion of the benefit for tax positions that are not more likely than not to be sustained upon audit. As of March 31, 2024 and December 31, 2023, the Company determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against its net deferred tax asset. Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The following table summarizes potentially dilutive securities outstanding at March 31, 2024 and 2023 that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive: March 31, 2024 2023 Warrants (Note 6) 42,139,278 6,516,211 Stock options (Note 6) 127,000 27,000 Unvested restricted stock awards (Note 6) 3,742,676 1,251,072 Unvested restricted stock units (Note 6) 598,246 619,884 Total 46,607,200 8,414,167 Comprehensive Loss The Company has no components of comprehensive loss other than net loss. Thus, comprehensive loss is the same as net loss for the periods presented. Recently Issued Accounting Pronouncements During the three-month period ended March 31, 2024, there were no new accounting pronouncements or updates to recently issued accounting pronouncements as disclosed in the Company’s Form 10-K for the year ended December 31, 2023 that affect the Company’s present or future results of operations, overall financial condition, liquidity or disclosures.

License Agreements

License Agreements	3 Months Ended
License Agreements	Mar. 31, 2024
License Agreements
License Agreements	Note 3 – License Agreements Dana-Farber Cancer Institute In March 2015, the Company entered into an exclusive license agreement with Dana-Farber Cancer Institute (“Dana Farber”) to develop a portfolio of fully human immuno-oncology targeted antibodies targeting PD-L1, Glucocorticoid-induced TNFR-related protein (“GITR”) and Carbonic anhydrase IX (“CAIX”). Dana-Farber is eligible to receive payments of up to an aggregate of approximately $21.5 million for each licensed product upon the Company’s successful achievement of certain clinical development, regulatory and first commercial sale milestones, of which $5.0 million of these milestones have been expensed for the antibody targeting PD-L1. In addition, Dana-Farber is eligible to receive up to an aggregate of $60.0 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales, in addition to royalty payments based on a tiered low to mid-single digit percentage of net sales. Dana-Farber also receives an annual license maintenance fee of $50,000, which is creditable against future milestone payments or royalties. In connection with the license agreement with Dana-Farber, the Company entered into a collaboration agreement with TG Therapeutics, Inc. (“TGTX”) to develop and commercialize the anti-PD-L1 and anti-GITR antibody research programs in the field of hematological malignancies, while the Company retained the right to develop and commercialize these antibodies in solid tumors. Michael Weiss, Chairman of the Board of Directors of Checkpoint and Fortress’ Executive Vice Chairman, Strategic Development, is also the Executive Chairman, President and Chief Executive Officer and a stockholder of TGTX. Effective September 30, 2023, the Company and TGTX agreed to mutually terminate the collaboration agreement. For the three months ended March 31, 2023, the Company recognized approximately $29,000 in revenue related to the collaboration agreement in the Condensed Statements of Operations. Adimab, LLC In October 2015, Fortress entered into a collaboration agreement with Adimab, LLC (“Adimab”) to discover and optimize antibodies using their proprietary core technology platform. Under this agreement, Adimab optimized cosibelimab, the Company’s anti-PD-L1 antibody which it originally licensed from Dana-Farber. In January 2019, Fortress transferred the rights to the optimized antibody to the Company, and Checkpoint entered into a collaboration agreement directly with Adimab on the same day. Under the terms of the agreement, Adimab is eligible to receive additional payments from the Company of up to an aggregate of approximately $2.5 million upon various filings for regulatory approvals to commercialize the product. In addition, Adimab is eligible to receive royalty payments based on a tiered low single digit percentage of net sales. In February 2023 the Company expensed a non-refundable milestone payment of $2.2 million to research and development expenses upon the United States Food and Drug Administration’s filing acceptance of the Company’s Biologics License Application (“BLA”) for cosibelimab in metastatic or locally advanced cutaneous squamous cell carcinoma. NeuPharma, Inc. In March 2015, Fortress entered into an exclusive license agreement with NeuPharma, Inc. (“NeuPharma”) to develop and commercialize novel irreversible, 3rd generation EGFR inhibitors, including olafertinib, on a worldwide basis other than certain Asian countries. On the same date, Fortress assigned all of its right and interest in the EGFR inhibitors to the Company. NeuPharma is eligible to receive additional payments of up to an aggregate of approximately $39.0 million upon the Company’s successful achievement of certain clinical development and regulatory milestones covering up to three indications, of which $22.5 million are due upon various regulatory approvals to commercialize the products. In addition, NeuPharma is eligible to receive payments of up to an aggregate of $40.0 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales across all indications, in addition to royalty payments based on a tiered mid to high-single digit percentage of net sales. Jubilant Biosys Limited In May 2016, the Company entered into a license agreement with Jubilant Biosys Limited (“Jubilant”), whereby the Company obtained an exclusive, worldwide license to Jubilant’s family of patents covering compounds that inhibit BET proteins such as BRD4, including CK-103. Jubilant is eligible to receive payments up to an aggregate of approximately $88.4 million upon the Company’s successful achievement of certain clinical development and regulatory milestones, of which $59.5 million are due upon various regulatory approvals to commercialize the products. In addition, Jubilant is eligible to receive payments up to an aggregate of $89.3 million upon the Company’s successful achievement of certain sales milestones based on aggregate net sales, in addition to royalty payments based on a tiered low to mid-single digit percentage of net sales. In connection with the license agreement with Jubilant, the Company entered into a sublicense agreement with TGTX, a related party, to develop and commercialize the compounds licensed in the field of hematological malignancies, while the Company retained the right to develop and commercialize these compounds in the field of solid tumors. Effective September 30, 2023, the Company and TGTX agreed to mutually terminate the sublicense agreement. For the three months ended March 31, 2023, the Company recognized approximately $6,000 in revenue related to the sublicense agreement in the Condensed Statements of Operations. The collaborations with TGTX each contained single material performance obligations under Topic 606, which was the granting of a license that is functional intellectual property. The Company’s performance obligations were satisfied at the point in time when TGTX had the ability to use and benefit from the right to use the intellectual property. The performance obligations of the original agreements were satisfied prior to the adoption of Topic 606. The performance obligation of the amendment to the collaboration agreement was satisfied in June 2019.

Related Party Agreements

Related Party Agreements	3 Months Ended
Related Party Agreements	Mar. 31, 2024
Related Party Agreements
Related Party Agreements	Note 4 – Related Party Agreements Founders Agreement and Management Services Agreement with Fortress Effective March 17, 2015, the Company entered into a Founders Agreement with Fortress, which was amended in July 2016 and October 2017. The Founders Agreement provides, that in exchange for the time and capital expended in the formation of Checkpoint and the identification of specific assets the acquisition of which resulted in the formation of a viable emerging growth life science company, the Company shall: (i) issue annually to Fortress, on January 1 of each year, shares of common stock equal to two and one-half percent (2.5%) of the fully diluted outstanding equity of Checkpoint at the time of issuance; (ii) pay an equity fee in shares of common stock, payable within five (5) business days of the closing of any equity or debt financing for Checkpoint or any of its respective subsidiaries that occurs after the effective date of the Founders Agreement and ending on the date when Fortress no longer has majority voting control in Checkpoint’s voting equity, equal to two and one-half percent (2.5%) of the gross amount of any such equity or debt financing; and (iii) pay a cash fee equal to four and one half percent (4.5%) of Checkpoint’s annual net sales, payable on an annual basis, within ninety (90) days of the end of each calendar year. In the event of a change in control (as it is defined in the Founders Agreement), Checkpoint will pay a one-time change in control fee equal to five times (5x) the product of (i) monthly net sales for the twelve (12) months immediately preceding the change in control and (ii) four and one-half percent (4.5%). The Founders Agreement has a term of fifteen years, after which it automatically renews for one-year periods unless Fortress gives the Company notice of termination. The Founders Agreement will also automatically terminate upon a change of control. Effective March 17, 2015, the Company entered into a Management Services Agreement (the “MSA”) with Fortress. Pursuant to the terms of the MSA, for a period of five (5) years, Fortress will render advisory and consulting services to the Company. Services provided under the MSA may include, without limitation, (i) advice and assistance concerning any and all aspects of Checkpoint’s operations, clinical trials, financial planning and strategic transactions and financings and (ii) conducting relations on behalf of the Company with accountants, attorneys, financial advisors and other professionals (collectively, the “Services”). The Company is obligated to utilize clinical research services, medical education, communication and marketing services and investor relations/public relation services of companies or individuals designated by Fortress, provided those services are offered at market prices. However, the Company is not obligated to take or act upon any advice rendered from Fortress and Fortress shall not be liable for any of the Company’s actions or inactions based upon their advice. Fortress and its affiliates, including all members of its Board of Directors, have been contractually exempt from fiduciary duties to the Company relating to corporate opportunities. In consideration for the Services, the Company will pay Fortress an annual consulting fee of $0.5 million (the “Annual Consulting Fee”), payable in advance in equal quarterly installments on the first business day of each calendar quarter in each year, provided, however, that such Annual Consulting Fee shall be increased to $1.0 million for each calendar year in which the Company has net assets in excess of $100 million at the beginning of the calendar year. The MSA shall be automatically extended for additional five-year periods unless Fortress or the Company provides notice to the other party of its desire not to automatically extend the term. For each of the three months ended March 31, 2024 and 2023, the Company recognized $125,000 in expense in the Condensed Statements of Operations related to the MSA. Caribe BioAdvisors, LLC In December 2016, the Company entered into an advisory agreement effective January 1, 2017 with Caribe BioAdvisors, LLC (“Caribe”), owned by Michael Weiss, to provide the advisory services of Mr. Weiss as Chairman of the Board. Pursuant to the agreement, Caribe will be paid an annual cash fee of $60,000, in addition to any and all annual equity incentive grants paid to members of the board. In June 2023, Mr. Weiss assigned the agreement to Hawkins BioVentures, LLC. For each of the three months ended March 31, 2024 and 2023, the Company recognized approximately $27,000 in expense in the Condensed Statements of Operations related to the advisory agreement, including approximately $12,000 in expense related to annual equity incentive grants.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies
Commitments and Contingencies	Note 5 – Commitments and Contingencies Leases The Company is not a party to any leases for office space or equipment. License Agreements The Company has undertaken to make contingent milestone payments to the licensors of its portfolio of product candidates. In addition, the Company would pay royalties to such licensors based on a percentage of net sales of each product candidate following regulatory marketing approval (See Note 3). Litigation The Company recognizes a liability for a contingency when it is probable that liability has been incurred and when the amount of loss can be reasonably estimated. When a range of probable loss can be estimated, the Company accrues the most likely amount of such loss, and if such amount is not determinable, then the Company accrues the minimum of the range of probable loss. The Company expenses legal costs as they are incurred. The Company and certain of its executive officers have been named as defendants in a consolidated putative stockholder class action lawsuit pending in the United States District Court for the Southern District of New York. The action is styled Moore v. Checkpoint Therapeutics, Inc., et al., No. 1:24-cv-02613-PAE (the “Securities Class Action”). The Complaint in the Securities Class Action (the “Complaint”), which was filed on April 5, 2024, alleges that defendants violated the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and SEC Rule 10b-5 promulgated thereunder by making false and misleading statements and omissions, and the Complaint alleges that the executive officers named as defendants are control persons under Section 20(a) of the Exchange Act. The Complaint was filed on behalf of stockholders who purchased shares of the Company’s common stock between March 10, 2021 and December 15, 2023, and the Complaint seeks, among other things, monetary damages on behalf of the purported class. The Company has been named as a nominal defendant and certain of its current and former directors and executive officers have been named as defendants in a derivative lawsuit pending in the United States District Court for the Southern District of New York. The action is styled Geary v. Oliviero, et al., No. 1:24-cv-03471 (the “Derivative Action”). The Complaint in the Derivative Action, which was filed on May 6, 2024, asserts claims against all defendants under Delaware law for, among other things, breach of fiduciary duty, claims against all defendants under Section 14(a) of the Exchange Act, and claims for contribution under the federal securities laws against certain of the defendants. The Company is reviewing the Complaint and Derivative Action and has not yet formally responded to them but believes that both allegations are without merit and intends to defend itself and its directors and executive officers vigorously. There is no assurance, however, that the Company or the other defendants will be successful in their defense of either of these allegations or that the Company’s insurance policy coverage will be available or adequate to fund any settlement or judgment or the litigation costs of these actions. Moreover, the Company is unable to predict the outcome or reasonably estimate a range of possible losses at this time.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2024
Stockholders' Equity
Stockholders' Equity	Note 6 – Stockholders’ Equity Common Stock At the Company’s 2023 Annual Meeting of Stockholders held on June 12, 2023, its stockholders approved an amendment to its certificate of incorporation to increase the number of authorized shares of common stock available to issue by 30,000,000 to 80,000,000 with a par value of $0.0001 per share, of which 700,000 shares are designated as “Class A common stock.” The amendment was filed with the Secretary of State of the State of Delaware on June 14, 2023. As of March 31, 2024 and December 31, 2023, there were 700,000 shares of Class A common stock issued and outstanding to Fortress. The holders of common stock are entitled to one vote per share of common stock held. The Class A common stockholders are entitled to a number of votes per share equal to 1.1 times a fraction, the numerator of which is the sum of the shares of outstanding common stock and the denominator of which is the number of shares of Class A common stock. Accordingly, the holder of shares of Class A common stock will be able to control or significantly influence all matters requiring approval by our stockholders, including the election of directors and the approval of mergers or other business combination transactions. Each share of Class A common stock is convertible, at the option of the holder thereof, into one (1) fully paid and non-assessable share of common stock subject to adjustment for stock splits and combinations. Registered Direct Offerings In November 2020, the Company filed a shelf registration statement on Form S-3 (the “November 2020 Form S-3”), which was declared effective in December 2020 (File No. 333-251005). Under the November 2020 Form S-3, the Company may sell up to a total of $100 million of its securities. In February 2023, the Company closed on the February 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,180,000 shares of its common stock at a purchase price of $5.25 per share of common stock. In addition, the offering includes 248,572 shares of common stock in the form of pre-funded warrants at a price of $5.2499. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,428,572 shares of common stock and Series B warrants to purchase up to 1,428,572 shares of common stock (collectively, the “February 2023 Common Stock Warrants”). The Series A and B warrants are exercisable price of $5.00 per share. The Series A warrants will expire five years following the issuance date and the Series B warrants will expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 85,714 shares of common stock with an exercise price of $6.5625 per share. The total gross proceeds from the February 2023 Registered Direct Offering were approximately $7.5 million with net proceeds of approximately $6.7 million after deducting approximately $0.8 million in commissions and other transaction costs. The shares of common stock and the shares underlying the pre-funded warrants were registered for sale under the November 2020 S-3. In March 2023, the Company filed a registration statement on Form S-3 to register the February 2023 Common Stock Warrants and placement agent warrants, which was declared effective May 5, 2023 (File No. 333-270474). In February 2023, the pre-funded warrants from the February 2023 Registered Direct Offering were fully exercised. The February 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification. In April 2023, the Company closed on the April 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,700,000 shares of its common stock at a purchase price of $3.60 per share of common stock. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,700,000 shares of common stock and Series B warrants to purchase up to 1,700,000 shares of common stock (collectively, the “April 2023 Common Stock Warrants”). The Series A and B warrants are exercisable The November 2020 Form S-3 expired in December 2023. In March 2023, the Company filed a shelf registration statement on Form S-3 (the “March 2023 Form S-3”), which was declared effective May 5, 2023 (File No. 333-270843). Under the March 2023 Form S-3, the Company may sell up to a total of $150 million of its securities. In May 2023, the Company closed on the May 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,650,000 shares of its common stock at a purchase price of $3.071 per share of common stock. In addition, the offering includes 1,606,269 shares of common stock in the form of pre-funded warrants at a price of $3.0709. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,256,269 shares of common stock and Series B warrants to purchase up to 3,256,269 shares of common stock (collectively, the “May 2023 Common Stock Warrants”). The Series A and B warrants are exercisable In July 2023, the Company closed on the July 2023 Registered Direct Offering for the issuance and sale of an aggregate of 2,427,186 shares of its common stock at a purchase price of $3.09 per share of common stock in a registered direct offering. In addition, the offering includes 809,062 shares of common stock in the form of pre-funded warrants at a price of $3.0899. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,236,248 shares of common stock and Series B warrants to purchase up to 3,236,248 shares of common stock (collectively, the “July 2023 Common Stock Warrants”). The Series A and B warrants are exercisable Series B warrants will expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 194,175 shares of common stock with an exercise price of $3.8625 per share. The total gross proceeds from the July 2023 Registered Direct Offering were approximately $10.0 million with net proceeds of approximately $9.1 million after deducting approximately $0.9 million in commissions and other transaction costs. The shares of common stock and the shares underlying the pre-funded warrants, July 2023 Common Stock Warrants, and placement agent warrants were registered for sale under the March 2023 S-3. In September 2023, the pre-funded warrants from the July 2023 Registered Direct Offering were fully exercised. The July 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification. In January 2024, the Company closed on the January 2024 Registered Direct Offering for the issuance and sale of an aggregate of 1,275,000 shares of its common stock at a purchase price of $1.805 per share of common stock. In addition, the offering includes 6,481,233 shares of common stock in the form of pre-funded warrants at a price of $1.8049. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. In a concurrent private placement, Checkpoint issued and sold the January 2024 Common Stock Warrants to purchase up to 7,756,233 shares of common stock. The January 2024 Common Stock Warrants are exercisable immediately upon issuance with an exercise price of $1.68 per share and will expire five years following the issuance date. The Company also issued the placement agent warrants to purchase up to 465,374 shares of common stock with an exercise price of $2.2563 per share. The total gross proceeds from the January 2024 Registered Direct Offering were approximately $14.0 million with net proceeds of approximately $12.8 million after deducting approximately $1.2 million in commissions and other transaction costs. The shares of common stock and the shares underlying the pre-funded warrants were registered for sale under the March 2023 S-3. In March 2024, the Company filed a registration statement on Form S-3 to register the January 2024 Common Stock Warrants and placement agent warrants, which was declared effective April 5, 2024 (File No. 333-278397). As of May 7, 2024, 2,656,000 pre-funded warrants from the January 2024 Registered Direct Offering were fully exercised. As of March 31, 2024, approximately $77.7 million of securities remain available for sale under the March 2023 Form S-3. The Company may offer the securities under the Form S-3’s from time to time in response to market conditions or other circumstances if it believes such a plan of financing is in the best interests of its stockholders. Warrant Inducement In October 2023, the Company entered into the October 2023 Inducement with a certain holder of its existing warrants to exercise for cash an aggregate of 6,325,354 shares of the Company’s common stock at a reduced exercise price of $1.76 per share. The exercised warrants included warrants issued in a December 2022 registered direct offering with an original exercise price of $4.075 per share and the February Common Stock Warrants issued in the February 2023 Registered Direct Offering with an original exercise price of $5.00 per share. As part of the October 2023 Inducement, the Company agreed to issue new unregistered Series A Warrants to purchase up to 6,325,354 shares of Common Stock and new unregistered Series B Warrants to purchase up to 6,325,354 shares of Common Stock (collectively, the “October 2023 Common Stock Warrants”). The Series A and B warrants are exercisable immediately upon issuance with an exercise price Upon the close of the transaction, the Company issued the holder 110,000 of the 6,325,354 shares of common stock that were issuable upon exercise of the existing warrants. Due to the beneficial ownership limitation provisions in the inducement offer letter agreement, the remaining 6,215,354 shares were initially unissued, and held in abeyance for the benefit of the holder until notice from the holder that the shares may be issued in compliance with the agreement. In January 2024, the final shares held in abeyance were issued to the holder. Shares Issued Under the Founders Agreement Pursuant to the Founders Agreement, the Company issued 368,907 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2023 (see Notes 2 and 4). Pursuant to the Founders Agreement, the Company issued to Fortress 2.5% of the aggregate number of shares of common stock issued in the February 2023 Registered Direct Offering noted above. Accordingly, the Company issued 35,714 shares of common stock to Fortress and recorded expense of approximately $156,000 related to this grant, which is included in general and administrative expenses in the Company’s Condensed Statements of Operations for the three months ended March 31, 2023. Pursuant to the Founders Agreement, the Company was to issue 1,492,915 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of the Company on January 1, 2024. The Company did not have enough unreserved authorized shares under its certificate of incorporation on January 1, 2024 to issue the shares for the Annual Equity Fee. Therefore, in December 2023, Fortress and Checkpoint mutually agreed to defer the issuance until such time as the certificate of incorporation has been amended in order to increase the number of authorized shares that may be issued thereunder (see Notes 2 and 4). Pursuant to the Founders Agreement, the Company issued to Fortress 2.5% of the aggregate number of shares of common stock issued in the January 2024 Registered Direct Offering. Accordingly, the Company issued 193,905 shares of common stock to Fortress and recorded expense of approximately $396,000 related to this issuance, which is included in general and administrative expenses in the Company’s Condensed Statements of Operations for the three months ended March 31, 2024. Equity Incentive Plan The Company has in effect the Amended and Restated 2015 Incentive Plan (“2015 Incentive Plan”). The 2015 Incentive Plan was adopted in March 2015 by our stockholders. Under the 2015 Incentive Plan, the compensation committee of the Company’s board of directors is authorized to grant stock-based awards to directors, officers, employees and consultants. An amendment to the 2015 Incentive Plan was approved by stockholders in June 2023 to increase the shares available for issuance to 6,000,000 shares. The plan expires 10 years from the effective date of the amendment and limits the term of each option to no more than 10 years from the date of grant. As of March 31, 2024, 852,712 shares are available for issuance under the 2015 Incentive Plan. Restricted Stock Awards Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted stock award activity for the three months ended March 31, 2024: Weighted Average Number of Grant Date Fair Shares Value Non-vested at December 31, 2023 1,316,120 $ 6.88 Granted 2,704,000 1.99 Forfeited (23,894) 6.28 Vested (253,550) 7.72 Non-vested at March 31, 2024 3,742,676 $ 3.30 As of March 31, 2024, there was $4.4 million of total unrecognized compensation cost related to non-vested restricted stock, which is expected to be recognized over a weighted-average period of 1.9 years. This amount does not include, as of March 31, 2024, 1,466,733 shares of restricted stock outstanding which are performance-based and vest upon achievement of certain corporate milestones. The expense is recognized over the vesting period of the award. Stock-based compensation for milestone awards will be measured and recorded if and when it is probable that the milestone will be achieved. Restricted Stock Units The following table summarizes restricted stock units activity for the three months ended March 31, 2024: Weighted Average Number of Grant Date Fair Shares Value Non-vested at December 31, 2023 615,884 $ 2.77 Forfeited (17,638) 2.25 Non-vested at March 31, 2024 598,246 $ 2.78 As of March 31, 2024, all restricted stock units outstanding are performance-based and vest upon achievement of certain corporate milestones. The expense for milestone awards will be measured and recorded if and when it is probable that the milestone will be achieved. Stock Options The following table summarizes stock option award activity for the three months ended March 31, 2024: Weighted Average Remaining Weighted Average Contractual Life Stock Options Exercise Price (in years) Outstanding as of December 31, 2023 127,000 $ 8.88 8.60 Outstanding as of March 31, 2024 127,000 $ 8.88 8.35 Vested and exercisable as of March 31, 2024 20,250 $ 24.74 5.83 Upon the exercise of stock options, the Company will issue new shares of its common stock.The Company used the Black-Scholes Model for determining the estimated fair value of stock-based compensation related to stock options. Warrants A summary of warrant activities for the three months ended March 31, 2024 is presented below: Weighted Average Remaining Weighted Average Contractual Life Warrants Exercise Price (in years) Outstanding as of December 31, 2023 30,097,671 $ 2.36 3.00 Granted 14,702,840 0.96 Exercised (2,661,233) — Outstanding as of March 31, 2024 42,139,278 $ 2.02 4.07 Upon the exercise of warrants, the Company will issue new shares of its common stock. Stock-Based Compensation The following table summarizes stock-based compensation expense for the three months ended March 31, 2024 and 2023 ($ in thousands): For the three months ended March 31, 2024 2023 Research and development $ 490 $ 390 General and administrative 220 579 Total stock-based compensation expense $ 709 $ 969

Common Stock Warrant Liabilitie

Common Stock Warrant Liabilities	3 Months Ended
Common Stock Warrant Liabilities	Mar. 31, 2024
Common Stock Warrant Liabilities
Common Stock Warrant Liabilities	Note 7 – Common Stock Warrant Liabilities On December 16, 2022, the Company closed on an offering for the sale of shares of its common stock and pre-funded warrants as part of a registered direct offering. The common stock and the pre-funded warrants were sold together with Series A and Series B common stock warrants. The Company also issued the placement agent warrants to purchase shares of common stock as part of the offering. After the October 2023 Inducement, only the placement agent warrants remained outstanding from this offering. The Company accounts for warrants as either equity-classified or liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in ASC 480, Distinguishing Liabilities from Equity Derivatives and Hedging - Contracts in Entity’s Own Equity The Company deemed the placement agent warrants issued in December 2022 to be classified as liabilities on the balance sheet as they contain terms for redemption of the underlying security that are outside its control. The warrants were recorded at the time of closing at a fair value, determined by using the Black-Scholes Model, and will be revalued at each reporting period thereafter for as long as they remain outstanding. The Company revalued the warrants at March 31, 2024 and December 31, 2023, resulting in a fair value of approximately $125,000 for each period. Common Stock Warrant Liabilities Common Stock Warrant liabilities at December 31, 2023 $ 125 Change in fair value of Common Stock Warrant liabilities — Common Stock Warrant liabilities at March 31, 2024 $ 125 The Company used the Black-Scholes Model for determining the estimated fair value of the common stock warrant liabilities. A summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability is determined using Level 3 inputs as follows: March 31, December 31, 2024 2023 Exercise price $ 5.41 $ 5.41 Volatility 107.5 % 96.4 % Expected life 3.7 4.0 Risk-free rate 4.2 % 3.8 % Dividend yield — —

Accounts Payable and Accrued Ex

Accounts Payable and Accrued Expenses	3 Months Ended
Accounts Payable and Accrued Expenses	Mar. 31, 2024
Accounts Payable and Accrued Expenses
Accounts Payable and Accrued Expenses	Note 8 - Accounts Payable and Accrued Expenses At March 31, 2024 and December 31, 2023, accounts payable and accrued expenses consisted of the following ($ in thousands): March 31, December 31, 2024 2023 Accounts payable $ 11,923 $ 6,570 Accrued compensation 435 1,206 Accrued Research and development 6,218 7,123 Other 583 586 Total accounts payable and accrued expenses $ 19,159 $ 15,485

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2024
Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X of the Exchange Act. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim condensed financial statements reflect all adjustments, which include only normal recurring adjustments necessary for the fair statement of the balances and results for the periods presented. They may not include all of the information and notes required by GAAP for complete financial statements. Therefore, these condensed financial statements should be read in conjunction with the Company’s audited financial statements and notes thereto for the year ended December 31, 2023, which were included in the Company’s Form 10-K, and filed with the SEC on March 22, 2024. The results of operations for any interim periods are not necessarily indicative of the results that may be expected for the entire fiscal year or any other interim period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes in the Company’s significant accounting policies to those previously disclosed in the 2023 Annual Report on Form 10-K.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received rather than when the payment is made. Upfront and milestone payments due to third parties that perform research and development services on the Company’s behalf will be expensed as services are rendered or when the milestone is achieved. Research and development costs primarily consist of personnel related expenses, including salaries, benefits, travel, and other related expenses, stock-based compensation, payments made to third parties for license and milestone costs related to in-licensed products and technology, payments made to third party contract research organizations for preclinical and clinical studies, investigative sites for clinical trials, consultants, the cost of acquiring and manufacturing clinical trial materials, costs associated with regulatory filings, laboratory costs and other supplies. In accordance with Accounting Standards Codification (“ASC”) 730-10-25-1, Research and Development
Annual Equity Fee	Annual Equity Fee Under the Founders Agreement with Checkpoint dated March 17, 2015, and amended and restated in July 2016 and October 2017 (the “Founders Agreement”), Fortress is entitled to an annual equity fee on January 1 of each year equal to 2.5% of fully diluted outstanding equity of the Company, payable in Checkpoint common shares (“Annual Equity Fee”). The Annual Equity Fee was part of the consideration payable for formation of the Company, identification of certain assets, including the license contributed to Checkpoint by Fortress (see Note 4). The Company records the Annual Equity Fee in connection with the Founders Agreement with Fortress as contingent consideration. Contingent consideration is recorded when probable and reasonably estimable. Due to the nature of the Company’s assets and stage of development, future share prices and shares outstanding cannot be estimated prior to the issuance of the Annual Equity Fee. Due to these uncertainties, the Company has concluded that it is unable to reasonably estimate the contingent consideration until shares are actually issued on January 1 of each year. Pursuant to the Founders Agreement, the Company was to issue 1,492,915 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of Checkpoint on January 1, 2024. The Company did not have enough unreserved authorized shares under its certificate of incorporation on January 1, 2024 to issue the shares for the Annual Equity Fee. Therefore, in December 2023, Fortress and Checkpoint mutually agreed to defer the issuance until such time as certificate of incorporation has been amended in order to increase the number of authorized that may be issued thereunder. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2024 prior to the issuance of the December 31, 2023 financial statements, the Company recorded approximately $3.4 million in research and development expense and a credit to Common shares issuable - Founders Agreement during the year ended December 31, 2023.
Stock-Based Compensation Expenses	Stock-Based Compensation Expenses The Company expenses stock-based compensation over the requisite service period based on the estimated grant-date fair value of the awards and forfeiture rates. The Company accounts for forfeitures as they occur. The Company estimates the fair value of stock option grants using the Black-Scholes Model. The assumptions used in calculating the fair value of stock-based awards represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment. All stock-based compensation costs are recorded in general and administrative or research and development costs in the Condensed Statements of Operations based upon the underlying individual’s role at the Company. In addition, because some of the restricted stock, restricted stock units and options issued to employees, directors and consultants vest upon achievement of certain milestones, the total expense is uncertain. Compensation expense for such awards that vest upon the achievement of milestones is recognized when the achievement of such milestones is probable.
Common Stock Warrant Liability	Common Stock Warrant Liability The Company has issued freestanding warrants to purchase shares of its common stock in connection with its financing activities and accounts for them in accordance with applicable accounting guidance as either liabilities or as equity instruments depending on the specific terms of the warrant agreements. Warrants classified as liabilities are remeasured each period they are outstanding. Any resulting gain or loss related to the change in the fair value of the warrant liability is recognized in gain (loss) on common stock warrant liabilities, a component of other income (loss), in the Condensed Statements of Operations. The Company estimates the fair value of common stock warrant liabilities using the Black-Scholes Model. The assumptions used in calculating the fair value represent management’s best estimates and involve inherent uncertainties and the application of management’s judgment.
Fair Value Measurement	Fair Value Measurement The Company follows the accounting guidance in ASC 820 for its fair value measurements of financial assets and liabilities measured at fair value on a recurring basis. Under this accounting guidance, fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance requires fair value measurements be classified and disclosed in one of the following three categories: Level 1: Quoted prices in active markets for identical assets or liabilities. Level 2: Observable inputs other than Level 1 prices, for similar assets or liabilities that are directly or indirectly observable in the marketplace. Level 3: Unobservable inputs which are supported by little or no market activity and that are financial instruments whose values are determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant judgment or estimation. The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Certain of the Company’s financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate their fair value due to their liquid or short-term nature, such as accounts payable and accrued expenses.
Revenue from Contracts with Customers	Revenue from Contracts with Customers The Company recognizes revenue under ASC 606, “ Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer. ● Step 2: Identify the performance obligations in the contract. ● Step 3: Determine the transaction price. ● Step 4: Allocate the transaction price to the performance obligations in the contract. ● Step 5: Recognize revenue when the company satisfies a performance obligation. In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct); and ● the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. When determining the transaction price, an entity must consider the effects of all of the following: ● variable consideration; ● constraining estimates of variable consideration; ● the existence of a significant financing component in the contract; ● noncash consideration; and ● consideration payable to a customer. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Revenue for a sales-based or usage-based royalty promised in exchange for a license of intellectual property is recognized only when (or as) the later of the following events occurs: a. the subsequent sale or usage occurs; and b. the performance obligation to which some or all of the sales-based or usage-based royalty has been allocated has been satisfied (or partially satisfied). Incremental contract costs are expensed when incurred when the amortization period of the asset that would have been recognized is one year or less; otherwise, incremental contract costs are recognized as an asset and amortized over time as services are provided to a customer.
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax effects attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and operating loss and tax credit carryforwards. The Company establishes a valuation allowance if management believes it is more likely than not that the deferred tax assets will not be recovered based on an evaluation of objective verifiable evidence. For tax positions that are more likely than not to be sustained upon audit, the Company recognizes the largest amount with a greater than 50% likelihood of being realized. The Company does not recognize any portion of the benefit for tax positions that are not more likely than not to be sustained upon audit. As of March 31, 2024 and December 31, 2023, the Company determined, based upon available evidence, that it is more likely than not that the net deferred tax asset will not be realized and, accordingly, has provided a full valuation allowance against its net deferred tax asset.
Net Loss per Share	Net Loss per Share Net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share does not reflect the effect of shares of common stock to be issued upon the exercise of stock options and warrants, as their inclusion would be anti-dilutive. The following table summarizes potentially dilutive securities outstanding at March 31, 2024 and 2023 that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive: March 31, 2024 2023 Warrants (Note 6) 42,139,278 6,516,211 Stock options (Note 6) 127,000 27,000 Unvested restricted stock awards (Note 6) 3,742,676 1,251,072 Unvested restricted stock units (Note 6) 598,246 619,884 Total 46,607,200 8,414,167
Comprehensive Loss	Comprehensive Loss The Company has no components of comprehensive loss other than net loss. Thus, comprehensive loss is the same as net loss for the periods presented.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements During the three-month period ended March 31, 2024, there were no new accounting pronouncements or updates to recently issued accounting pronouncements as disclosed in the Company’s Form 10-K for the year ended December 31, 2023 that affect the Company’s present or future results of operations, overall financial condition, liquidity or disclosures.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	3 Months Ended
Significant Accounting Policies (Tables)	Mar. 31, 2024
Significant Accounting Policies
Summary of potentially dilutive securities outstanding, that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	March 31, 2024 2023 Warrants (Note 6) 42,139,278 6,516,211 Stock options (Note 6) 127,000 27,000 Unvested restricted stock awards (Note 6) 3,742,676 1,251,072 Unvested restricted stock units (Note 6) 598,246 619,884 Total 46,607,200 8,414,167

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
Stockholders' Equity (Tables)	Mar. 31, 2024
Stockholders' Equity
Summary of restricted stock award activity	Weighted Average Number of Grant Date Fair Shares Value Non-vested at December 31, 2023 1,316,120 $ 6.88 Granted 2,704,000 1.99 Forfeited (23,894) 6.28 Vested (253,550) 7.72 Non-vested at March 31, 2024 3,742,676 $ 3.30
Summary of restricted stock units activity	Weighted Average Number of Grant Date Fair Shares Value Non-vested at December 31, 2023 615,884 $ 2.77 Forfeited (17,638) 2.25 Non-vested at March 31, 2024 598,246 $ 2.78
Summary of stock option award activity	Weighted Average Remaining Weighted Average Contractual Life Stock Options Exercise Price (in years) Outstanding as of December 31, 2023 127,000 $ 8.88 8.60 Outstanding as of March 31, 2024 127,000 $ 8.88 8.35 Vested and exercisable as of March 31, 2024 20,250 $ 24.74 5.83
Summary of warrant activities	Weighted Average Remaining Weighted Average Contractual Life Warrants Exercise Price (in years) Outstanding as of December 31, 2023 30,097,671 $ 2.36 3.00 Granted 14,702,840 0.96 Exercised (2,661,233) — Outstanding as of March 31, 2024 42,139,278 $ 2.02 4.07
Summary of stock-based compensation expense	The following table summarizes stock-based compensation expense for the three months ended March 31, 2024 and 2023 ($ in thousands): For the three months ended March 31, 2024 2023 Research and development $ 490 $ 390 General and administrative 220 579 Total stock-based compensation expense $ 709 $ 969

Common Stock Warrant Liabilit_2

Common Stock Warrant Liabilities (Tables)	3 Months Ended
Common Stock Warrant Liabilities (Tables)	Mar. 31, 2024
Common Stock Warrant Liabilities
Summary of common stock warrant liabilities	Common Stock Warrant Liabilities Common Stock Warrant liabilities at December 31, 2023 $ 125 Change in fair value of Common Stock Warrant liabilities — Common Stock Warrant liabilities at March 31, 2024 $ 125
Summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability that are categorized within Level 3 of the fair value hierarchy	March 31, December 31, 2024 2023 Exercise price $ 5.41 $ 5.41 Volatility 107.5 % 96.4 % Expected life 3.7 4.0 Risk-free rate 4.2 % 3.8 % Dividend yield — —

Accounts Payable and Accrued _2

Accounts Payable and Accrued Expenses (Tables)	3 Months Ended
Accounts Payable and Accrued Expenses (Tables)	Mar. 31, 2024
Accounts Payable and Accrued Expenses
Schedule of accounts payable and accrued expenses	At March 31, 2024 and December 31, 2023, accounts payable and accrued expenses consisted of the following ($ in thousands): March 31, December 31, 2024 2023 Accounts payable $ 11,923 $ 6,570 Accrued compensation 435 1,206 Accrued Research and development 6,218 7,123 Other 583 586 Total accounts payable and accrued expenses $ 19,159 $ 15,485

Organization and Description _2

Organization and Description of Business Operations (Details) - USD ($)	1 Months Ended
	Jan. 31, 2024	Oct. 31, 2023	Jul. 31, 2023	May 31, 2023	Apr. 30, 2023	Feb. 28, 2023	Mar. 31, 2024	Dec. 31, 2023	Nov. 30, 2023	Feb. 22, 2023	Dec. 16, 2022
Organization and Description of Business Operations
Accumulated deficit							$ (325,278,000)	$ (314,333,000)
Number of warrants issued		110,000
Number of warrants issued and sold to purchase shares									6,215,354
Pre-funded warrants
Organization and Description of Business Operations
Class of warrants exercise price	$ 0.0001		$ 0.0001			$ 0.0001
February 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold						1,180,000
Purchase price per share						$ 5.25
Number of warrants issued						248,572
Class of warrants exercise price		$ 5
Total gross proceeds from Issuance of common stock						$ 7,500,000
Net proceeds from offering						6,700,000
Amount of commissions and other transaction costs						$ 800,000
February 2023 Registered Direct Offering \| Pre-funded warrants
Organization and Description of Business Operations
Number of warrants issued						248,572
Class of warrants exercise price						$ 5.2499
February 2023 Registered Direct Offering \| Series A Warrants
Organization and Description of Business Operations
Class of warrants exercise price						$ 5
Expiration term of warrants (in years)						5 years
February 2023 Registered Direct Offering \| Series A Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares						1,428,572
February 2023 Registered Direct Offering \| Series B Warrants
Organization and Description of Business Operations
Class of warrants exercise price						$ 5
Expiration term of warrants (in years)						18 months
February 2023 Registered Direct Offering \| Series B Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares						1,428,572
April 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold					1,700,000
Purchase price per share					$ 3.60
Total gross proceeds from Issuance of common stock					$ 6,100,000
Net proceeds from offering					5,500,000
Amount of commissions and other transaction costs					$ 600,000
April 2023 Registered Direct Offering \| Series A Warrants
Organization and Description of Business Operations
Class of warrants exercise price					$ 3.35
Expiration term of warrants (in years)					5 years
April 2023 Registered Direct Offering \| Series A Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares					1,700,000
April 2023 Registered Direct Offering \| Series B Warrants
Organization and Description of Business Operations
Class of warrants exercise price					$ 3.35
Expiration term of warrants (in years)					18 months
April 2023 Registered Direct Offering \| Series B Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares					1,700,000
May 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold				1,650,000
Purchase price per share				$ 3.071
Number of warrants issued				1,606,269
Class of warrants exercise price				$ 3.0709
Total gross proceeds from Issuance of common stock				$ 10,000,000
Net proceeds from offering				9,100,000
Amount of commissions and other transaction costs				$ 900,000
May 2023 Registered Direct Offering \| Pre-funded warrants
Organization and Description of Business Operations
Number of warrants issued				1,606,269
Class of warrants exercise price				$ 0.0001
May 2023 Registered Direct Offering \| Series A Warrants
Organization and Description of Business Operations
Class of warrants exercise price				$ 2.821
Expiration term of warrants (in years)				5 years
May 2023 Registered Direct Offering \| Series A Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares				3,256,269
May 2023 Registered Direct Offering \| Series B Warrants
Organization and Description of Business Operations
Class of warrants exercise price				$ 2.821
Expiration term of warrants (in years)				18 months
May 2023 Registered Direct Offering \| Series B Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares				3,256,269
July 2023 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold			2,427,186
Purchase price per share			$ 3.09
Total gross proceeds from Issuance of common stock			$ 10,000,000
Net proceeds from offering			9,100,000
Amount of commissions and other transaction costs			$ 900,000
July 2023 Registered Direct Offering \| Pre-funded warrants
Organization and Description of Business Operations
Class of warrants exercise price			$ 3.0899
Number of warrants issued and sold to purchase shares			809,062
July 2023 Registered Direct Offering \| Series A Warrants
Organization and Description of Business Operations
Class of warrants exercise price			$ 2.84
Expiration term of warrants (in years)			5 years
July 2023 Registered Direct Offering \| Series A Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares			3,236,248
July 2023 Registered Direct Offering \| Series B Warrants
Organization and Description of Business Operations
Class of warrants exercise price			$ 2.84
Expiration term of warrants (in years)			18 months
July 2023 Registered Direct Offering \| Series B Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares			3,236,248
October 2023 Registered Direct Offering
Organization and Description of Business Operations
Class of warrants exercise price		$ 1.76								$ 5	$ 4.075
Number of warrants issued and sold to purchase shares		6,325,354
Total gross proceeds from Issuance of common stock		$ 11,100,000
Net proceeds from offering		10,000,000
Amount of commissions and other transaction costs		$ 1,100,000
October 2023 Registered Direct Offering \| Series A Warrants
Organization and Description of Business Operations
Class of warrants exercise price		$ 1.51
Expiration term of warrants (in years)		5 years
October 2023 Registered Direct Offering \| Series A Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares		6,325,354
October 2023 Registered Direct Offering \| Series B Warrants
Organization and Description of Business Operations
Class of warrants exercise price		$ 1.51
Expiration term of warrants (in years)		24 months
October 2023 Registered Direct Offering \| Series B Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares		6,325,354
January 2024 Registered Direct Offering
Organization and Description of Business Operations
Number of shares issued and sold	1,275,000
Purchase price per share	$ 1.805
Number of warrants issued	6,481,233
Class of warrants exercise price	$ 1.8049
Expiration term of warrants (in years)	5 years
Total gross proceeds from Issuance of common stock	$ 14,000,000
Net proceeds from offering	12,800,000
Amount of commissions and other transaction costs	$ 1,200,000
January 2024 Registered Direct Offering \| Pre-funded warrants
Organization and Description of Business Operations
Number of warrants issued	6,481,233
Class of warrants exercise price	$ 1.8049
January 2024 Registered Direct Offering \| Common Stock Warrants
Organization and Description of Business Operations
Class of warrants exercise price	$ 1.68
Number of warrants issued and sold to purchase shares	7,756,233
Expiration term of warrants (in years)	5 years
January 2024 Registered Direct Offering \| Common Stock Warrants \| Maximum
Organization and Description of Business Operations
Number of warrants issued and sold to purchase shares	7,756,233

Significant Accounting Polici_4

Significant Accounting Policies (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
	Jan. 01, 2024	Jan. 01, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Mar. 17, 2015
Fortress Biotech, Inc
Significant Accounting Policies
Percentage of shares issued for offering and annual equity fee	2.50%					2.50%
Number of shares issued and sold	1,492,915	368,907	193,905	35,714
Research and development
Significant Accounting Policies
Value of common stock shares issued					$ 3.4

Significant Accounting Polici_5

Significant Accounting Policies - Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	46,607,200	8,414,167
Warrants
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	42,139,278	6,516,211
Stock options
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	127,000	27,000
Unvested restricted stock awards
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	3,742,676	1,251,072
Unvested restricted stock units
Significant Accounting Policies
Potentially dilutive securities that were excluded from the computation of diluted net loss per share, as they would be anti-dilutive	598,246	619,884

License Agreements (Details)

License Agreements (Details) - USD ($)	1 Months Ended	3 Months Ended
License Agreements (Details) - USD ($)	Mar. 31, 2015	Mar. 31, 2024	Feb. 28, 2023	Jan. 31, 2019	May 31, 2016
NeuPharma, Inc. \| Additional sales milestone
License Agreements
Maximum potential milestone payments	$ 40,000,000
NeuPharma, Inc. \| Clinical and development milestone
License Agreements
Maximum potential milestone payments	39,000,000
NeuPharma, Inc. \| Regulatory approvals to commercialize the products
License Agreements
Maximum potential milestone payments	22,500,000
Dana-Farber Cancer Institute
License Agreements
Amount of milestone expensed	5,000,000
Maintenance fee	50,000
Dana-Farber Cancer Institute \| First commercial sale milestone
License Agreements
Maximum potential milestone payments	21,500,000
Dana-Farber Cancer Institute \| Additional sales milestone
License Agreements
Maximum potential milestone payments	$ 60,000,000
Adimab, LLC \| PD-L1 \| Research and development
License Agreements
Non-Refundable milestone payment			$ 2,200,000
Adimab, LLC \| Regulatory approvals to commercialize the products
License Agreements
Maximum potential milestone payments				$ 2,500,000
Jubilant Biosys Limited \| Additional sales milestone
License Agreements
Maximum potential milestone payments					$ 89,300,000
Jubilant Biosys Limited \| Regulatory approvals to commercialize the products
License Agreements
Maximum potential milestone payments					59,500,000
Jubilant Biosys Limited \| Clinical development and regulatory milestones
License Agreements
Maximum potential milestone payments					$ 88,400,000
Collaboration Agreement With TGTX
License Agreements
Revenue recognition milestone revenue recognized		$ 29,000
Sublicense Agreement with TGTX
License Agreements
Revenue recognition milestone revenue recognized		$ 6,000

Related Party Agreements (Detai

Related Party Agreements (Details)		1 Months Ended	3 Months Ended
Related Party Agreements (Details)	Mar. 17, 2015 USD ($) item	Dec. 31, 2016 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)
Fortress Biotech, Inc \| Founders Agreement
Related Party Agreements
Issuance of common stock, percentage of outstanding diluted equity	2.50%
Number of business days	5 days
Voting equity, percentage of equity or debt financing	2.50%
Cash fee, percentage of annual net sales	4.50%
Cash fees, maximum number of days	90 days
Control fees, number of times \| item	5
Control fees, monthly net sales	12 months
Cash fee, percentage of monthly net sales	4.50%
Agreement term	15 years
Agreement renewal term	1 year
Fortress Biotech, Inc \| Management Services Agreement
Related Party Agreements
Number of period	5 years
Annual consulting fee	$ 500,000
Increase in annual consulting fee	1,000,000
Excess in net assets value	$ 100,000,000
Agreement extension term	5 years
Costs and expenses, related party			$ 125,000	$ 125,000
Caribe Bioadvisors LLC
Related Party Agreements
Annual advisory service fee		$ 60,000
Costs and expenses, related party			27,000	27,000
Caribe Bioadvisors LLC \| Equity Incentive Grants
Related Party Agreements
Costs and expenses, related party			$ 12,000	$ 12,000

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Stock Awards (Details) - Restricted Stock	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Stockholders' Equity
Non-vested beginning balance \| shares	1,316,120
Number of Shares, Granted \| shares	2,704,000
Number of Shares, Forfeited \| shares	(23,894)
Number of Shares, Vested \| shares	(253,550)
Non-vested ending balance \| shares	3,742,676
Weighted Average Exercise Price, beginning balance \| $ / shares	$ 6.88
Weighted Average Grant Date Fair Value, Granted \| $ / shares	1.99
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	6.28
Weighted Average Grant Date Fair Value, Vested \| $ / shares	7.72
Weighted Average Exercise Price , ending balance \| $ / shares	$ 3.30

Stockholders' Equity - Restri_2

Stockholders' Equity - Restricted Stock Units (Details) - Unvested restricted stock units	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Number of Shares
Non-vested beginning balance \| shares	615,884
Number of Shares, Forfeited \| shares	(17,638)
Non-vested ending balance \| shares	598,246
Weighted Average Grant Date Fair Value
Weighted Average Exercise Price, beginning balance \| $ / shares	$ 2.77
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	2.25
Weighted Average Exercise Price , ending balance \| $ / shares	$ 2.78

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options (Details) - Stock Options - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Stockholders' Equity
Stock options, Outstanding (beginning)	127,000
Stock options, Outstanding (ending)	127,000	127,000
Vested and exercisable as of December 31, 2023	20,250
Weighted Average Exercise Price, Outstanding (beginning)	$ 8.88
Weighted Average Exercise Price, Outstanding (ending)	8.88	$ 8.88
Weighted Average Exercise Price, Vested and exercisable as of December 31, 2023	$ 24.74
Weighted Average Remaining Contractual Life, Outstanding (in years)	8 years 4 months 6 days	8 years 7 months 6 days
Weighted Average Remaining Contractual Life, Vested and exercisable as of December 31, 2023 (in years)	5 years 9 months 29 days

Stockholders' Equity - Warrants

Stockholders' Equity - Warrants (Details) - Warrants - $ / shares	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Warrants, Outstanding beginning balance	30,097,671
Warrants, Granted	14,702,840
Warrants, Exercised	(2,661,233)
Warrants, Outstanding ending balance	42,139,278
Warrants, Weighted Average Exercise Price, beginning balance	$ 2.36
Weighted Average Exercise Price, Granted	0.96
Warrants, Weighted Average Exercise Price, Exercised	0
Warrants, Weighted Average Exercise Price, ending balance	$ 2.02
Warrants, Remaining contractual life	4 years 25 days	3 years

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Stockholders' Equity
Total stock-based compensation expense	$ 709	$ 969
Research and development
Stockholders' Equity
Total stock-based compensation expense	490	390
General and administrative
Stockholders' Equity
Total stock-based compensation expense	$ 220	$ 579

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)

1 Months Ended

3 Months Ended

May 07, 2024 shares

Jan. 01, 2024 shares

Jan. 01, 2023 shares

Jan. 31, 2024 USD ($) $ / shares shares

Oct. 31, 2023 USD ($) $ / shares shares

Jul. 31, 2023 USD ($) $ / shares shares

May 31, 2023 USD ($) $ / shares shares

Apr. 30, 2023 USD ($) $ / shares shares

Feb. 28, 2023 USD ($) $ / shares shares

Mar. 31, 2024 USD ($) Vote multiplier $ / shares shares

Mar. 31, 2023 USD ($) shares

Dec. 31, 2023 $ / shares shares

Nov. 30, 2023 shares

Jun. 12, 2023 $ / shares shares

Feb. 22, 2023 $ / shares

Dec. 16, 2022 $ / shares

Nov. 30, 2020 USD ($)

Stockholders' Equity

Common stock, increase in the number of authorized shares (in shares)

30,000,000

Common stock, shares authorized

80,000,000

Common stock, par value (in dollars per share) | $ / shares

$ 0.0001

Common stock, shares outstanding

34,986,279

27,042,035

Shelf registration statement, maximum authorized securities | $

$ 100,000,000

Common stock, shares issued

34,986,279

27,042,035

Issuance of common shares - Founders agreement | $

$ 396,000

$ 156,000

Loss on common stock warrant liabilities | $

7,566,000

Number of warrants issued

110,000

Number of warrants issued and sold to purchase shares

6,215,354

Common stock shares issuable

1,492,915

Pre-funded warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 0.0001

Non-vested restricted stock

Stockholders' Equity

Total unrecognized compensation cost related to non-vested | $

$ 4,400,000

Weighted average period (in years)

1 year 10 months 24 days

Performance Shares

Stockholders' Equity

Restricted stock outstanding non-vested

1,466,733

2015 Incentive Plan

Stockholders' Equity

Number of shares available for issuance authorized

6,000,000

Plans expires (in years)

10 years

Shares are available for issuance

852,712

February 2023 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 5.25

Number of warrants issued

248,572

Number of shares issued and sold

1,180,000

Class of warrants exercise price | $ / shares

$ 5

Total gross proceeds from Issuance of common stock | $

$ 7,500,000

Net proceeds from offering | $

6,700,000

Amount of commissions and other transaction costs | $

$ 800,000

February 2023 Registered Direct Offering | Pre-funded warrants

Stockholders' Equity

Number of warrants issued

248,572

Class of warrants exercise price | $ / shares

$ 5.2499

Warrants offering price | $ / shares

5.2499

February 2023 Registered Direct Offering | Series A Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 5

Expiration term of warrants (in years)

5 years

February 2023 Registered Direct Offering | Series B Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 5

Expiration term of warrants (in years)

18 months

February 2023 Registered Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

85,714

Class of warrants exercise price | $ / shares

$ 6.5625

February 2023 Registered Direct Offering | Maximum | Series A Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,428,572

February 2023 Registered Direct Offering | Maximum | Series B Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,428,572

April 2023 Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.60

Shelf registration statement remaining authorized securities | $

150,000,000

Number of shares issued and sold

1,700,000

Total gross proceeds from Issuance of common stock | $

$ 6,100,000

Net proceeds from offering | $

5,500,000

Amount of commissions and other transaction costs | $

$ 600,000

April 2023 Direct Offering | Series A Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 3.35

Expiration term of warrants (in years)

5 years

April 2023 Direct Offering | Series B Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 3.35

Expiration term of warrants (in years)

18 months

April 2023 Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

102,000

Class of warrants exercise price | $ / shares

$ 4.50

April 2023 Direct Offering | Maximum | Series A Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

April 2023 Direct Offering | Maximum | Series B Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

1,700,000

December 2022 direct offering

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 4.075

May 2023 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.071

Number of warrants issued

1,606,269

Number of shares issued and sold

1,650,000

Class of warrants exercise price | $ / shares

$ 3.0709

Total gross proceeds from Issuance of common stock | $

$ 10,000,000

Net proceeds from offering | $

9,100,000

Amount of commissions and other transaction costs | $

$ 900,000

May 2023 Registered Direct Offering | Pre-funded warrants

Stockholders' Equity

Number of warrants issued

1,606,269

Class of warrants exercise price | $ / shares

$ 0.0001

May 2023 Registered Direct Offering | Series A Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 2.821

Expiration term of warrants (in years)

5 years

May 2023 Registered Direct Offering | Series B Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 2.821

Expiration term of warrants (in years)

18 months

May 2023 Registered Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

195,376

Class of warrants exercise price | $ / shares

$ 3.8388

May 2023 Registered Direct Offering | Maximum | Series A Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,256,269

May 2023 Registered Direct Offering | Maximum | Series B Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,256,269

July 2023 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 3.09

Number of shares issued and sold

2,427,186

Total gross proceeds from Issuance of common stock | $

$ 10,000,000

Net proceeds from offering | $

9,100,000

Amount of commissions and other transaction costs | $

$ 900,000

July 2023 Registered Direct Offering | Pre-funded warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

809,062

Class of warrants exercise price | $ / shares

$ 3.0899

July 2023 Registered Direct Offering | Series A Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 2.84

Expiration term of warrants (in years)

5 years

July 2023 Registered Direct Offering | Series B Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 2.84

Expiration term of warrants (in years)

18 months

July 2023 Registered Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

194,175

Class of warrants exercise price | $ / shares

$ 3.8625

July 2023 Registered Direct Offering | Maximum | Series A Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,236,248

July 2023 Registered Direct Offering | Maximum | Series B Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

3,236,248

January 2024 Registered Direct Offering

Stockholders' Equity

Purchase price per share | $ / shares

$ 1.805

Number of warrants issued

6,481,233

Number of shares issued and sold

1,275,000

Class of warrants exercise price | $ / shares

$ 1.8049

Expiration term of warrants (in years)

5 years

Total gross proceeds from Issuance of common stock | $

$ 14,000,000

Net proceeds from offering | $

12,800,000

Amount of commissions and other transaction costs | $

$ 1,200,000

January 2024 Registered Direct Offering | Pre-funded warrants

Stockholders' Equity

Number of warrants issued

6,481,233

Class of warrants exercise price | $ / shares

$ 1.8049

January 2024 Registered Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

465,374

Class of warrants exercise price | $ / shares

$ 2.2563

January 2024 Registered Direct Offering | Common Stock Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

7,756,233

Class of warrants exercise price | $ / shares

$ 1.68

Expiration term of warrants (in years)

5 years

January 2024 Registered Direct Offering | Subsequent Event | Pre-funded warrants

Stockholders' Equity

Warrants, Exercised

2,656,000

January 2024 Registered Direct Offering | Maximum | Common Stock Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

7,756,233

October 2023 Registered Direct Offering

Stockholders' Equity

Proceeds from Warrant | $

$ 11,100,000

Payment of transactional costs for exercise of warrants | $

$ 1,100,000

Number of warrants issued and sold to purchase shares

6,325,354

Class of warrants exercise price | $ / shares

$ 1.76

$ 5

$ 4.075

Total gross proceeds from Issuance of common stock | $

$ 11,100,000

Net proceeds from offering | $

10,000,000

Amount of commissions and other transaction costs | $

$ 1,100,000

October 2023 Registered Direct Offering | Series A Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 1.51

Expiration term of warrants (in years)

5 years

October 2023 Registered Direct Offering | Series B Warrants

Stockholders' Equity

Class of warrants exercise price | $ / shares

$ 1.51

Expiration term of warrants (in years)

24 months

October 2023 Registered Direct Offering | Placement Agent Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

379,521

Class of warrants exercise price | $ / shares

$ 2.20

October 2023 Registered Direct Offering | Maximum | Series A Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

6,325,354

October 2023 Registered Direct Offering | Maximum | Series B Warrants

Stockholders' Equity

Number of warrants issued and sold to purchase shares

6,325,354

Fortress

Stockholders' Equity

Issuance of common shares - Founders agreement | $

$ 396,000

$ 156,000,000,000

Shelf registration statement remaining authorized securities | $

$ 77,700,000

Percentage of annual equity fee

2.50%

Common stock shares issuable

1,492,915

Number of shares issued and sold

1,492,915

368,907

193,905

35,714

Common Stock

Stockholders' Equity

Number of votes per share | Vote

Multiplier to calculate voting rights per class A common share | multiplier

1.1

Number of non assessable shares issued upon conversion

Common Stock | July 2023 Registered Direct Offering

Stockholders' Equity

Number of shares issued and sold

2,427,186

Share price | $ / shares

$ 3.09

Common Stock | January 2024 Registered Direct Offering

Stockholders' Equity

Number of shares issued and sold

1,275,000

Common Class A

Stockholders' Equity

Common stock, shares authorized

700,000

Common stock, shares outstanding

700,000

Common Stock Warrant Liabilit_3

Common Stock Warrant Liabilities - Additional Information (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
December 2022 direct offering \| Common Stock Warrant Liabilities
Common Stock Warrant Liabilities
Common Stock Warrant liabilities	$ 125,000	$ 125,000

Common Stock Warrant Liabilit_4

Common Stock Warrant Liabilities (Details) - December 2022 direct offering - Common Stock Warrant Liabilities	Mar. 31, 2024 USD ($)
Common stock warrant liabilities
Common Stock Warrant liabilities at the beginning	$ 125,000
Common Stock Warrant liabilities at the end	$ 125,000

Common Stock Warrant Liabilit_5

Common Stock Warrant Liabilities - Summary of the weighted average (in aggregate) significant unobservable inputs used in measuring the warrant liability that are categorized within Level 3 of the fair value hierarchy (Details) - Placement Agent Warrants - Level 3	Mar. 31, 2024 $ / shares Y	Dec. 31, 2023 $ / shares Y
Exercise price
Common Stock Warrant Liabilities
Measurement input \| $ / shares	5.41	5.41
Volatility
Common Stock Warrant Liabilities
Measurement input	1.075	0.964
Expected life
Common Stock Warrant Liabilities
Measurement input \| Y	3.7	4
Risk-free rate
Common Stock Warrant Liabilities
Measurement input	0.042	0.038

Accounts Payable and Accrued _3

Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts Payable and Accrued Expenses
Accounts payable	$ 11,923	$ 6,570
Accrued compensation	435	1,206
Accrued Research and development	6,218	7,123
Other	583	586
Total accounts payable and accrued expenses	$ 19,159	$ 15,485

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (10,945)	$ (10,474)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false