Rockwell Medical (RMTI) 424B5Prospectus supplement for primary offering

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Filed Pursuant to Rule 424(b)(5)
Registration Statement No. 333-227363

PROSPECTUS SUPPLEMENT
(To Prospectus dated October 1, 2018)

3,191,489 Shares

Common Stock

              We are offering 3,191,489 shares of our common stock.

              Our common stock is listed on The Nasdaq Global Market under the symbol "RMTI." On February 3, 2020, the last reported sale price per share of our common stock was $2.78 per share.

              The underwriter has agreed to purchase our common stock from us at a price of $2.22 per share which will result in approximately $7.1 million of proceeds to us, before offering expenses, and assuming no exercise by the underwriter of the option described below. The underwriter may offer the shares of common stock from time to time for sale in one or more transactions on The Nasdaq Global Market, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or at negotiated prices subject to receipt and acceptance by it and subject to its right to reject any order in whole or in part.

              Investing in our securities involves certain risks. See "Risk Factors" beginning on Page S-4 of this prospectus supplement and in the accompanying prospectus, and in the other documents that are incorporated by reference and any related free writing prospectus, for certain risks you should consider. You should read the entire prospectus supplement and the accompanying prospectus, including any information incorporated by reference, carefully before you make your investment decision.

              We have granted the underwriter a 30-day option to purchase up to 478,723 additional shares of common stock from us. If the underwriter exercises the option in full, the total proceeds to us, before offering expenses, will be approximately $8.1 million.

              Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

              The underwriter expects to deliver the shares of common stock to purchasers on or about February 6, 2020.

Sole Book-Running Manager

Cantor

Prospectus Supplement dated February 4, 2020.

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PROSPECTUS SUPPLEMENT

PROSPECTUS

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ABOUT THIS PROSPECTUS SUPPLEMENT

              This prospectus supplement and the accompanying prospectus relate to an offering of shares of our common stock. Before buying any of the common stock that we are offering, we urge you to carefully read this prospectus supplement and the accompanying prospectus, together with the information incorporated by reference as described under the headings "Where You Can Find Additional Information" and "Incorporation of Certain Information by Reference" in this prospectus supplement. These documents contain important information that you should consider when making your investment decision. Unless the context otherwise requires, references in this prospectus supplement to "Rockwell," "we," "us," "our" and "ours" refer to Rockwell Medical, Inc., and include its consolidated subsidiaries where the context so requires.

              This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering of common stock and also adds to, updates and changes information contained in the accompanying prospectus and the documents incorporated by reference. The second part is the accompanying prospectus, which gives more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent the information contained in this prospectus supplement differs from or conflicts with the information contained in the accompanying prospectus or any document incorporated by reference, the information in this prospectus supplement will control. If any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference into this prospectus supplement and the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

              We have not, and the underwriter has not, authorized anyone to provide you with information different from that which is contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus and in any free writing prospectus that we may authorize for use in connection with this offering. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give to you. No one is making offers to sell or seeking offers to buy these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information contained in this prospectus supplement is accurate as of the date on the front cover of this prospectus supplement only and that any information we have incorporated by reference or included in the accompanying prospectus is accurate only as of the date given in the document incorporated by reference or as of the date of the prospectus, as applicable, regardless of the time of delivery of this prospectus supplement, the accompanying prospectus, any related free writing prospectus, or any sale of our common stock. Our business, financial condition, results of operations and prospects may have changed since those dates.

              We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference into this prospectus supplement or the accompanying prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

              This prospectus supplement, the accompanying prospectus and the information incorporated herein and therein by reference include trademarks, servicemarks and tradenames owned by us or other companies. All trademarks, servicemarks and tradenames included or incorporated by reference in this prospectus supplement or the accompanying prospectus are the property of their respective owners.

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NOTE REGARDING FORWARD LOOKING STATEMENTS

              We make "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, in this prospectus supplement and the accompanying prospectus, including the documents that we incorporate by reference herein and therein. Our forward-looking statements are subject to risks and uncertainties and include information about our expectations and possible or assumed future results of our operations. When we use words such as "may," "might," "will," "should," "believe," "expect," "anticipate," "estimate," "continue," "could," "plan," "potential," "predict," "forecast," "projected," "intend" or similar expressions, or make statements regarding our intent, belief or current expectations, we are making forward-looking statements. Our forward-looking statements also include, without limitation, statements about our competitors, statements regarding the commercialization of our new products, statements regarding Dialysate Triferic and the intravenous ("I.V.") formulation of Triferic, and statements regarding our anticipated future financial condition, operating results, cash flows and business and financing plans.

              We claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 for all of our forward-looking statements. While we believe that our forward-looking statements are reasonable, you should not place undue reliance on any such forward-looking statements, which are based on information available to us on the date of this report or, if made elsewhere, as of the date made. Because these forward-looking statements are based on estimates and assumptions that are subject to significant business, economic and competitive uncertainties, many of which are beyond our control or are subject to change, actual results could be materially different. Factors that might cause such a difference include, without limitation, the risks and uncertainties discussed in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein, including without limitation under the heading "Risk Factors" beginning on page S-4 of this prospectus supplement and under similar headings in the accompanying prospectus and in the other documents that are incorporated by reference herein or therein. Although it is not possible to identify all of these factors, they include, among others, the following:

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Risks relating to the U.S. Food and Drug Administration ("FDA") acceptance for review of our New Drug Application ("NDA") for I.V. Triferic and risks relating to the FDA's approval of this NDA for commercialization of I.V. Triferic;



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Acceptance of our products by doctors, patients or payors;



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Availability of reimbursement for our products;



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Ability to use existing inventory before shelf life expiration;



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Expectations regarding the safety and efficacy of our products;



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Expectations regarding the timing of submissions to, and decisions made by, the FDA, and other regulatory agencies, including foreign regulatory agencies;



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Ability to secure adequate protection for, and licensure of, our intellectual property;



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Estimates regarding the capacity of manufacturing and other facilities to support our products;



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Expectations or ability to enter into marketing and other partnership agreements;



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Ability to compete against other companies and research institutions;



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Ability to attract and retain key personnel;



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Expectations for increases or decreases in expenses;

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Expectations for incurring capital expenditures to expand our research and development and manufacturing capabilities;



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Expectations for generating revenue or becoming profitable on a sustained basis;



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Expectations regarding the effect of changes in accounting guidance or standards on our operating results;



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Impact of healthcare reform laws;



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Impact of potential shareholder activism;



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Ability to obtain additional financing and raise capital as necessary to fund operations or pursue business opportunities;



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Our stock price and its volatility; and



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Other risks more fully discussed in the "Risk Factors" section in this prospectus supplement, the accompanying prospectus and the risk factors and cautionary statements described in other documents that we file from time to time with the SEC, specifically under "Risk Factors" and elsewhere in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q.

              Other factors not currently anticipated may also materially and adversely affect our financial condition, operating results, cash flows and business and financing plans. We do not undertake any obligation to update or alter any statements whether as a result of new information, future events or otherwise, except as required by law.

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RISK FACTORS

              Investing in our securities involves risks. Before making an investment decision, you should carefully consider the risks and other information we include or incorporate by reference in this prospectus supplement and the accompanying prospectus, and in any free writing prospectus that we have authorized for use in connection with this offering. In particular, you should consider the risk factors described below, as well as under the heading "Risk Factors" in ourAnnual Report on Form 10-K for the year ended December 31, 2018 and our Quarterly Report on Form 10-Q for the quarters endedMarch 31, 2019,June 30, 2019 andSeptember 30, 2019, each of which are on file with the SEC and are incorporated herein by reference, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future. In addition to those risk factors, there may be additional risks and uncertainties which are not currently known to us or that we currently deem immaterial. Our business, financial condition or results of operations could be materially and adversely affected by any of these risks. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities.

Risks Relating to this Offering

Our management team may invest or spend the proceeds of this offering in ways with which you may not agree or in ways which may not yield a significant return.

              The net proceeds from this offering will be used for the continued commercialization of Dialysate Triferic and, if approved, I.V. Triferic, as well as research and development and general corporate purposes. Our management will have considerable discretion in the application of the net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. The net proceeds may be used for purposes that do not increase our operating results or enhance the value of our common stock. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

You may experience immediate and substantial dilution in the net tangible book value per share of the common stock you purchase.

              The price per share of our common stock being offered may be higher than the net tangible book value per share of our common stock outstanding prior to this offering. Based on an aggregate of 3,191,489 shares sold at an assumed public offering price of $2.35 per share, for aggregate net proceeds of $6.9 million in this offering, and after deducting the underwriting discount and estimated offering expenses payable by us, you will suffer immediate and substantial dilution of $1.91 per share, representing the difference between the as adjusted net tangible book value per share of our common stock as of September 30, 2019 after giving effect to this offering and the assumed public offering price. See the section entitled "Dilution" below for a more detailed discussion of the dilution you will incur if you purchase common stock in this offering.

You may experience future dilution as a result of future equity offerings.

              To raise additional capital, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in any other offering at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock, or securities convertible or exchangeable into common stock, in future transactions may be higher or lower than the price per share paid by investors in this offering.

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USE OF PROCEEDS

              We estimate that the net proceeds from the sale of the shares of common stock that we are offering will be approximately $6.9 million, or approximately $8.0 million if the underwriter exercises in full its option to purchase up to 478,723 additional shares of common stock, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

              We intend to use the net proceeds from the sale of the shares of common stock offered hereby primarily for the continued commercialization of Dialysate Triferic and, if approved, I.V. Triferic, as well as research and development and general corporate purposes.

              The amounts and timing of our actual expenditures will depend on numerous factors, including our development and commercialization efforts, as well as the amount of cash used in our operations. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering, and investors will be relying on the judgment of our management regarding the application of the net proceeds from this offering. We therefore cannot estimate with certainty the portion of the net proceeds to be used for each of the purposes described above. We may also find it necessary or advisable to use the net proceeds for other purposes. Pending the uses described above, we plan to invest the net proceeds from this offering in short-term, investment-grade, interest-bearing obligations, certificates of deposit or obligations of the United States.

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DILUTION

              Our net tangible book value as of September 30, 2019 was approximately $22.8 million, or $0.36 per share. We calculate net tangible book value per share by dividing the net tangible book value, which is tangible assets less total liabilities, by the number of outstanding shares of our common stock. Dilution represents the difference between the amount per share paid by purchasers of shares in this offering and the as adjusted net tangible book value per common share immediately after giving effect to this offering.

              After giving effect to the sale of shares of our common stock in this offering, and after deducting the underwriting discounts and offering expenses payable by us, our as adjusted net tangible book value as of September 30, 2019 would have been approximately $29.7 million, or $0.44 per share. This represents an immediate increase in net tangible book value of $0.08 per share to existing stockholders and an immediate dilution of $1.91 per share to investors purchasing our common stock in this offering at the assumed public offering price. The following table illustrates this dilution on a per share basis:

              If the underwriter exercises its option to purchase 478,723 additional shares of common stock in full, our as adjusted net tangible book value will increase to $0.46 per share, representing an immediate increase in net tangible book value to existing stockholders of $0.10 per share and an immediate dilution in net tangible book value of $1.89 per share to investors purchasing our common stock in this offering at the assumed public offering price.

              The number of shares of common stock shown above to be outstanding after this offering is based on the 63,887,384 shares outstanding as of September 30, 2019 and excludes:

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1,403,400 shares of common stock issued subsequent to September 30, 2019 through the date of this prospectus supplement under our ATM facility;



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7,782,257 shares of common stock issuable upon the exercise of outstanding stock options as of September 30, 2019 at a weighted-average exercise price of $7.35 per share;



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988,958 shares of performance-based restricted stock units outstanding as of September 30, 2019;



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388,125 shares of common stock issuable upon the exercise of outstanding performance-based stock options as of September 30, 2019, at an exercise price of $4.70;



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593,964 shares of common stock issuable upon the vesting of restricted stock units outstanding as of September 30, 2019;



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146,800 shares of common stock issuable upon the vesting of performance stock units outstanding as of September 30, 2019;



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2,770,781 shares of common stock issuable upon the exercise of outstanding warrants at an exercise price of $4.96 per share as of September 30, 2019; and

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1,152,007 shares of common stock reserved for issuance pursuant to future equity awards under our 2018 Incentive Plan as of September 30, 2019, as well as any future increases in the number of shares of our common stock reserved for future issuance under this plan.

              Except as otherwise indicated, all information contained in this prospectus:

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assumes that the underwriter does not exercise its option to purchase additional shares; and



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assumes no exercise of outstanding stock options or warrants or vesting of restricted stock units or performance stock units after September 30, 2019.

              To the extent that outstanding options or warrants are exercised or restricted stock units or performance stock units vest, investors purchasing shares in this offering could experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or equity-based securities, the issuance of these securities could result in further dilution to our stockholders.

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UNDERWRITING

              We have entered into an underwriting agreement with Cantor Fitzgerald & Co., as underwriter, with respect to the common stock being offered hereby. Subject to the terms and conditions of the underwriting agreement, the underwriter has agreed to purchase from us the shares of common stock offered by this prospectus supplement.

              The underwriting agreement provides that the obligations of the underwriter are subject to certain conditions precedent and that the underwriter has agreed to purchase all of the shares of common stock sold under the underwriting agreement if any of these shares are purchased.

              We have agreed to indemnify the underwriter against specified liabilities, including liabilities under the Securities Act of 1933, as amended (the "Securities Act"), and to contribute to payments the underwriter may be required to make in respect thereof.

              The underwriter is offering the shares of common stock, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel and other conditions specified in the underwriting agreement. The underwriter reserves the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

              Underwriting discounts and commissions and offering expenses.    The underwriter is purchasing the shares of common stock from us at $2.22 per share (representing approximately $7.1 million aggregate proceeds to us, before offering expenses). The underwriter may offer the shares of common stock from time to time to purchasers directly or through agents, or through brokers in brokerage transactions on The Nasdaq Global Market, or to dealers in negotiated transactions or in a combination of such methods of sale, or otherwise, at a fixed price or prices, which may be changed, or at market prices prevailing at the time of sale, at prices related to such prevailing market prices or at negotiated prices subject to receipt and acceptance by it and subject to its right to reject any order in whole or in part. The difference between the price, at which the underwriter purchases shares from us and the price at which the underwriter resells such shares may be deemed underwriting compensation. If the underwriter effects such transactions by selling shares of common stock to or through dealers, such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriter and/or purchasers of shares of common stock for whom they may act as agents or to whom they may sell as principal.

              We estimate that the total expenses of the offering payable by us, other than the underwriting discounts and commissions, will be approximately $160,000, which includes up to $75,000 that we have agreed to reimburse the underwriter for the fees incurred by the underwriter in connection with this offering.

              Option to purchase additional shares.    We have granted the underwriter an option, exercisable for 30 days from the date of this prospectus supplement, to purchase, from time to time, in whole or in part, up to an aggregate 478,723 additional shares from us at the price set forth on the cover page of this prospectus supplement.

              Stabilization.    In connection with this offering, the underwriter may engage in stabilizing transactions, overallotment transactions, syndicate covering transactions and purchases to cover positions created by short sales in accordance with Regulation M under the Securities Exchange Act of 1934, as amended (the "Exchange Act").

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Stabilizing transactions permit bids to purchase shares of common stock so long as the stabilizing bids do not exceed a specified maximum, and are engaged in for the purpose of preventing or retarding a decline in the market price of the common stock while the offering is in progress.

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Overallotment transactions involve sales by the underwriter of shares of common stock in excess of the number of shares of common stock the underwriter is obligated to purchase. This creates a short position which may be either a covered short position or a naked short position. In a covered short position, the number of shares of common stock overallotted by the underwriter, if any, is not greater than the number of shares of common stock that it may purchase in the option to purchase additional shares. In a naked short position, the number of shares of common stock involved is greater than the number of shares of common stock in the option to purchase additional shares, if any. The underwriter may close out any short position by exercising its option to purchase additional shares, if any, and/or purchasing shares of common stock in the open market.



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Syndicate covering transactions involve purchases of common stock in the open market after the distribution has been completed in order to cover syndicate short positions. In determining the source of shares of common stock to close out the short position, the underwriter will consider, among other things, the price of shares of common stock available for purchase in the open market as compared with the price at which the underwriter may purchase shares of common stock through exercise of the option to purchase additional shares, if any. If the underwriter sells more shares of common stock than could be covered by exercise of the option to purchase additional shares, if any, and, therefore, has a naked short position, the position can be closed out only by buying shares of common stock in the open market. A naked short position is more likely to be created if the underwriter is concerned that after pricing there could be downward pressure on the price of the shares of common stock in the open market that could adversely affect investors who purchase in the offering.

              These stabilizing transactions and syndicate covering transactions may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result, the price of our common stock in the open market may be higher than it would otherwise be in the absence of these transactions. Neither we nor the underwriter make any representation or prediction as to the effect that the transactions described above may have on the price of our common stock. These transactions may be effected on The Nasdaq Global Market, in the over-the-counter market or otherwise and, if commenced, may be discontinued at any time.

              Passive market making.    In connection with this offering, the underwriter may engage in passive market making transactions in our common stock on The Nasdaq Global Market in accordance with Rule 103 of Regulation M under the Exchange Act, during a period before the commencement of offers or sales of common stock and extending through the completion of the distribution. A passive market maker must display its bid at a price not in excess of the highest independent bid of that security. However, if all independent bids are lowered below the passive market maker's bid that bid must then be lowered when specified purchase limits are exceeded.

              Lock-up agreements.    We, our executive officers and directors and certain of our other existing security holders have agreed not to sell or transfer any common stock or securities convertible into or exchangeable or exercisable for common stock, for 60 days after the date of this prospectus without first obtaining the written consent of the underwriter. Specifically, we and these other persons have agreed not to directly or indirectly:

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offer, pledge, announce the intention to sell, sell, or contract to sell any common stock;



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sell any option or contract to purchase any common stock;



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purchase any option or contract to sell any common stock;



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grant any option, right or warrant to purchase any common stock;

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make any short sale or otherwise dispose of or transfer any common stock;



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enter into any swap or other agreement that transfers, in whole or in part, the economic consequence of ownership of any common stock, whether any such swap or agreement is to be settled by delivery of common stock or other securities, in cash or otherwise;



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make any demand for or exercise any right with respect to the registration of any common stock;



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publicly disclose the intention to do any of the foregoing; or



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engage in any hedging or other transaction which is designed to or which reasonably could be expected to lead to or result in a sale or disposition of common stock.

The restrictions described in the immediately preceding paragraph do not apply to:

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transfers or dispositions of shares of our common stock:



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as abona fide gift;



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to any trust for the direct or indirect benefit of the party subject to the lock-up restrictions or the immediate family of such person;



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by operation of law pursuant to a qualified domestic order or in connection with a divorce settlement;



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to any partnership, corporation or limited liability company controlled by the party subject to the lock-up restrictions or the immediate family of such person;



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by testate succession or intestate succession to the beneficiary of the party subject to the lock-up restrictions;



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as distributions to limited partners, limited liability company members or stockholders of the party subject to the lock-up restrictions; or



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to a corporation, partnership, limited liability company, trust or other business entity that is a direct or indirect affiliate (as defined in Rule 405 promulgated under the Securities Act) of the party subject to the lock-up restrictions;



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sales or transfers of common stock made pursuant to a trading plan pursuant to Rule 10b5-1 under the Exchange Act ("Rule 10b5-1") that has been entered into prior to the date of this prospectus;



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the establishment of a trading plan pursuant to Rule 10b5-1 for the transfer of shares of common stock, provided that such plan does not provide for the transfer of common stock during the restricted period;



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the exercise, conversion or exchange of any stock options, warrants, rights or convertible securities outstanding as of the date of this prospectus supplement or subsequently granted pursuant to our equity incentive plans, including any exercise effected by the delivery or sale of the party subject to the lock-up restrictions' common stock to us (including, without limitation, to finance a "cashless" exercise), provided that the underlying shares shall continue to be subject to the restrictions on transfer set forth in the lock-up agreement, except to the extent such securities are withheld by us to cover tax liabilities; or



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the transfer of shares of common stock (or any security convertible into or exercisable or exchangeable for common stock) pursuant to abona fide third-party tender offer, merger, consolidation or other similar transaction made to all holders of common stock and involving a change of control.

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              This lock-up provision applies to common stock and to securities convertible into or exchangeable or exercisable for common stock. It also applies to common stock owned now or acquired later by the person executing the agreement or for which the person executing the agreement later acquires the power of disposition.

              Other Activities and Relationships.    The underwriter and certain of its affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The underwriter and certain of its affiliates may in the future perform, various commercial and investment banking and financial advisory services for us and our affiliates, for which they will receive customary fees and expenses. In the ordinary course of their various business activities, the underwriter and certain of its affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investment and securities activities may involve securities and/or instruments issued by us and our affiliates. If the underwriter or its affiliates have a lending relationship with us, they may routinely hedge their credit exposure to us consistent with their customary risk management policies. The underwriter and its affiliates may hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities or the securities of our affiliates, including potentially the common stock offered hereby. Any such short positions could adversely affect future trading prices of the common stock offered hereby. The underwriter and its affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments. Additionally, Cantor Fitzgerald & Co. is the agent under our Controlled Equity Offering^SM Sales Agreement, dated March 22, 2019.

Notice to Investors

Australia

              This prospectus supplement and the accompanying prospectus are not a disclosure document for the purposes of Australia's Corporations Act 2001 (Cth) of Australia, or Corporations Act, has not been lodged with the Australian Securities & Investments Commission and is only directed to the categories of exempt persons set out below. Accordingly, if you receive this prospectus supplement in Australia:

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You confirm and warrant that you are either:



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"sophisticated investor" under section 708(8)(a) or (b) of the Corporations Act;



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a "sophisticated investor" under section 708(8)(c) or (d) of the Corporations Act and that you have provided an accountant's certificate to the company which complies with the requirements of section 708(8)(c)(i) or (ii) of the Corporations Act and related regulations before the offer has been made;



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a person associated with the company under Section 708(12) of the Corporations Act; or



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"professional investor" within the meaning of section 708(11)(a) or (b) of the Corporations Act.

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To the extent that you are unable to confirm or warrant that you are an exempt sophisticated investor or professional investor under the Corporations Act, any offer made to you under this prospectus supplement is void and incapable of acceptance.

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You warrant and agree that you will not offer any of the shares issued to you pursuant to this prospectus supplement for resale in Australia within 12 months of those shares being issued unless any such resale offer is exempt from the requirement to issue a disclosure document under section 708 of the Corporations Act.

Canada

              This prospectus supplement constitutes an "exempt offering document" as defined in and for the purposes of applicable Canadian securities laws. No prospectus has been filed with any securities commission or similar regulatory authority in Canada in connection with the offer and sale of the common stock. No securities commission or similar regulatory authority in Canada has reviewed or in any way passed upon this prospectus supplement or on the merits of the common stock and any representation to the contrary is an offence.

              Canadian investors are advised that this prospectus supplement has been prepared in reliance on section 3A.3 of National Instrument 33-105Underwriting Conflicts ("NI 33-105"). Pursuant to section 3A.3 of NI 33-105, this prospectus supplement is exempt from the requirement that we and the underwriter(s) provide investors with certain conflicts of interest disclosure pertaining to "connected issuer" and/or "related issuer" relationships that may exist between us and the underwriter(s) as would otherwise be required pursuant to subsection 2.1(1) of NI 33-105.

Resale Restrictions

              The offer and sale of the common stock in Canada is being made on a private placement basis only and is exempt from the requirement that we prepare and file a prospectus under applicable Canadian securities laws. Any resale of the common stock acquired by a Canadian investor in this offering must be made in accordance with applicable Canadian securities laws, which may vary depending on the relevant jurisdiction, and which may require resales to be made in accordance with Canadian prospectus requirements, pursuant to a statutory exemption from the prospectus requirements, in a transaction exempt from the prospectus requirements or otherwise under a discretionary exemption from the prospectus requirements granted by the applicable local Canadian securities regulatory authority. These resale restrictions may under certain circumstances apply to resales of the common stock outside of Canada.

Representations of Purchasers

              Each Canadian investor who purchases the common stock will be deemed to have represented to us and the underwriter(s) that the investor (i) is purchasing the common stock as principal, or is deemed to be purchasing as principal in accordance with applicable Canadian securities laws, for investment only and not with a view to resale or redistribution; (ii) is an "accredited investor" as such term is defined in section 1.1 of National Instrument 45-106Prospectus Exemptions ("NI 45-106") or, in Ontario, as such term is defined in section 73.3(1) of the Securities Act (Ontario); and (iii) is a "permitted client" as such term is defined in section 1.1 of National Instrument 31-103Registration Requirements, Exemptions and Ongoing Registrant Obligations.

Taxation and Eligibility for Investment

              Any discussion of taxation and related matters contained in this prospectus supplement does not purport to be a comprehensive description of all of the tax considerations that may be relevant to a Canadian investor when deciding to purchase the common stock and, in particular, does not address

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any Canadian tax considerations. No representation or warranty is hereby made as to the tax consequences to a resident, or deemed resident, of Canada of an investment in the common stock or with respect to the eligibility of the common stock for investment by such investor under relevant Canadian federal and provincial legislation and regulations.

Rights of Action for Damages or Rescission

              Securities legislation in certain of the Canadian jurisdictions provides certain purchasers of securities pursuant to an offering memorandum (such as this prospectus supplement), including where the distribution involves an "eligible foreign security" as such term is defined in Ontario Securities Commission Rule 45-501Ontario Prospectus and Registration Exemptions and in Multilateral Instrument 45-107Listing Representation and Statutory Rights of Action Disclosure Exemptions, as applicable, with a remedy for damages or rescission, or both, in addition to any other rights they may have at law, where the offering memorandum, or other offering document that constitutes an offering memorandum, and any amendment thereto, contains a "misrepresentation" as defined under applicable Canadian securities laws. These remedies, or notice with respect to these remedies, must be exercised or delivered, as the case may be, by the purchaser within the time limits prescribed under, and are subject to limitations and defences under, applicable Canadian securities legislation. In addition, these remedies are in addition to and without derogation from any other right or remedy available at law to the investor.

Language of Documents

              Upon receipt of this document, each Canadian investor hereby confirms that it has expressly requested that all documents evidencing or relating in any way to the sale of the securities described herein (including for greater certainty any purchase confirmation or any notice) be drawn up in the English language only.Par la réception de ce document, chaque investisseur Canadien confirme par les présentes qu'il a expressément exigé que tous les documents faisant foi ou se rapportant de quelque manière que ce soit à la vente des valeurs mobilières décrites aux présentes (incluant, pour plus de certitude, toute confirmation d'achat ou tout avis) soient rédigés en anglais seulement.

European Economic Area

              In relation to each member state of the European Economic Area which has implemented the Prospectus Directive, each, a Relevant Member State, with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State, which is referred to as the Relevant Implementation Date, no offer of any securities which are the subject of the offering contemplated by this prospectus supplement has been or will be made to the public in that Relevant Member State other than any offer where a prospectus has been or will be published in relation to such securities that has been approved by the competent authority in that Relevant Member State or, where appropriate, approved in another Relevant Member State and notified to the relevant competent authority in that Relevant Member State in accordance with the Prospectus Directive, except that with effect from and including the Relevant Implementation Date, an offer of such securities may be made to the public in that Relevant Member State:

a)

to any legal entity which is a "qualified investor" as defined in the Prospectus Directive;



b)

to fewer than 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the representative of the underwriter for any such offer; or



c)

to any other circumstances falling within Article 3(2) of the Prospectus Directive,

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provided that no such offer of securities shall require us or the underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

              For the purposes of this provision, the expression an "offer to the public" in relation to any securities in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the securities to be offered so as to enable an investor to decide to purchase or subscribe the securities, as the same may be varied in that Relevant Member State by any measure implementing the Prospectus Directive in that Relevant Member State and the expression "Prospectus Directive" means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State), and includes any relevant implementing measure in the Relevant Member State.

Hong Kong

              No securities have been offered or sold, and no securities may be offered or sold, in Hong Kong, by means of any document, other than to persons whose ordinary business is to buy or sell shares or debentures, whether as principal or agent; or to "professional investors" as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong and any rules made under that Ordinance; or in other circumstances which do not result in the document being a "prospectus" as defined in the Companies Ordinance (Cap. 32) of Hong Kong or which do not constitute an offer to the public within the meaning of the Companies Ordinance (Cap. 32) of Hong Kong. No document, invitation or advertisement relating to the securities has been issued or may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted under the securities laws of Hong Kong) other than with respect to securities which are or are intended to be disposed of only to persons outside Hong Kong or only to "professional investors" as defined in the Securities and Futures Ordinance (Cap. 571) of Hong Kong and any rules made under that Ordinance.

              This prospectus supplement has not been registered with the Registrar of Companies in Hong Kong. Accordingly, this prospectus supplement may not be issued, circulated or distributed in Hong Kong, and the securities may not be offered for subscription to members of the public in Hong Kong. Each person acquiring the securities will be required, and is deemed by the acquisition of the securities, to confirm that he is aware of the restriction on offers of the securities described in this prospectus supplement and the relevant offering documents and that he is not acquiring, and has not been offered any securities in circumstances that contravene any such restrictions.

Israel

              In the State of Israel this prospectus supplement shall not be regarded as an offer to the public to purchase shares of common stock under the Israeli Securities Law, 5728-1968, which requires a prospectus to be published and authorized by the Israel Securities Authority, if it complies with certain provisions of Section 15 of the Israeli Securities Law, 5728-1968, including, inter alia, if: (i) the offer is made, distributed or directed to not more than 35 investors, subject to certain conditions (the "Addressed Investors"); or (ii) the offer is made, distributed or directed to certain qualified investors defined in the First Addendum of the Israeli Securities Law, 5728-1968, subject to certain conditions (the "Qualified Investors"). The Qualified Investors shall not be taken into account in the count of the Addressed Investors and may be offered to purchase securities in addition to the 35 Addressed Investors. We have not and will not take any action that would require it to publish a prospectus in accordance with and subject to the Israeli Securities Law, 5728-1968. We and the underwriter have not and will not distribute this prospectus supplement or make, distribute or direct an offer to subscribe for

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our common stock to any person within the State of Israel, other than to Qualified Investors and up to 35 Addressed Investors.

              Qualified Investors may have to submit written evidence that they meet the definitions set out in of the First Addendum to the Israeli Securities Law, 5728-1968. In particular, we may request, as a condition to be offered common stock, that Qualified Investors will each represent, warrant and certify to us and/or to anyone acting on our behalf: (i) that it is an investor falling within one of the categories listed in the First Addendum to the Israeli Securities Law, 5728-1968; (ii) which of the categories listed in the First Addendum to the Israeli Securities Law, 5728-1968 regarding Qualified Investors is applicable to it; (iii) that it will abide by all provisions set forth in the Israeli Securities Law, 5728-1968 and the regulations promulgated thereunder in connection with the offer to be issued common stock; (iv) that the shares of common stock that it will be issued are, subject to exemptions available under the Israeli Securities Law, 5728-1968: (a) for its own account; (b) for investment purposes only; and (c) not issued with a view to resale within the State of Israel, other than in accordance with the provisions of the Israeli Securities Law, 5728-1968; and (v) that it is willing to provide further evidence of its Qualified Investor status. Addressed Investors may have to submit written evidence in respect of their identity and may have to sign and submit a declaration containing, inter alia, the Addressed Investor's name, address and passport number or Israeli identification number.

Japan

              The offering has not been and will not be registered under the Financial Instruments and Exchange Law of Japan (Law No. 25 of 1948 of Japan, as amended), or FIEL, and the underwriter will not offer or sell any securities, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means, unless otherwise provided herein, any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the FIEL and any other applicable laws, regulations and ministerial guidelines of Japan.

Singapore

              This prospectus supplement has not been and will not be lodged or registered with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and any other document or material in connection with the offer or sale, or the invitation for subscription or purchase of the securities may not be issued, circulated or distributed, nor may the securities be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to the public or any member of the public in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore, or the SFA, (ii) to a relevant person as defined under Section 275(2), or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions, specified in Section 275 of the SFA, or (iii) otherwise pursuant to, and in accordance with the conditions of any other applicable provision of the SFA. Where the securities are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

a)

a corporation (which is not an accredited investor as defined under Section 4A of the SFA) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or



b)

a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary is an accredited investor, shares, debentures and units of shares and debentures of that corporation or the beneficiaries' rights and interest in

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that trust shall not be transferable for six months after that corporation or that trust has acquired the Offer Shares under Section 275 of the SFA except:

i.

to an institutional investor under Section 274 of the SFA or to a relevant person defined in Section 275(2) of the SFA, or to any person pursuant to an offer that is made on terms that such shares, debentures and units of shares and debentures of that corporation or such rights and interest in that trust are acquired at a consideration of not less than $200,000 (or its equivalent in a foreign currency) for each transaction, whether such amount is to be paid for in cash or by exchange of securities or other assets, and further for corporations, in accordance with the conditions, specified in Section 275 of the SFA;



ii.

where no consideration is given for the transfer; or



iii.

where the transfer is by operation of law.

              Solely for the purposes of its obligations pursuant to Section 309B of the SFA, we have determined, and hereby notify all relevant persons (as defined in the CMP Regulations 2018), that the shares are "prescribed capital markets products" (as defined in the CMP Regulations 2018) and Excluded Investment Products (as defined in MAS Notice SFA 04-N12: Notice on the Sale of Investment Products and MAS Notice FAA-N16: Notice on Recommendations on Investment Products).

Switzerland

              The securities may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange, or SIX, or on any other stock exchange or regulated trading facility in Switzerland. This prospectus supplement has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this prospectus supplement nor any other offering or marketing material relating to the securities or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

              Neither this prospectus supplement nor any other offering or marketing material relating to us, the offering or the securities have been or will be filed with or approved by any Swiss regulatory authority. In particular, this prospectus supplement will not be filed with, and the offer of securities will not be supervised by, the Swiss Financial Market Supervisory Authority and the offer of securities has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes, or CISA. The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of securities.

United Kingdom

              This prospectus supplement is only being distributed to, and is only directed at, persons in the United Kingdom that are qualified investors within the meaning of Article 2(1)(e) of the Prospectus Directive that are also (i) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended, which is referred to as the Order, and/or (ii) high net worth entities falling within Article 49(2)(a) to (d) of the Order and other persons to whom it may lawfully be communicated, each such person being referred to as a relevant person.

              This prospectus supplement and its contents are confidential and should not be distributed, published or reproduced (in whole or in part) or disclosed by recipients to any other persons in the

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United Kingdom. Any person in the United Kingdom that is not a relevant person should not act or rely on this document or any of its contents.

Miscellaneous

              Our common stock is traded on The Nasdaq Global Market under the symbol "RMTI."

              The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company.

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LEGAL MATTERS

              Gibson, Dunn & Crutcher LLP of San Francisco, California will pass upon the validity of the shares of common stock offered hereby. Cantor Fitzgerald & Co. is being represented in connection with this offering by Cooley LLP, New York, New York.

EXPERTS

              The financial statements incorporated in this prospectus supplement by reference to theAnnual Report on Form 10-K for the year ended December 31, 2018 have been so incorporated in reliance on the report of Marcum LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting. The financial statements incorporated in this prospectus supplement by reference to theAnnual Report on Form 10-K for the year ended December 31, 2017 have been so incorporated in reliance on the report of Plante & Moran, PLLC, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

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WHERE YOU CAN FIND ADDITIONAL INFORMATION

              We file annual, quarterly and current reports, proxy statements and other information with the SEC. We also filed a registration statement on Form S-3, including exhibits, under the Securities Act with respect to the securities offered by this prospectus supplement and the accompanying prospectus. This prospectus supplement and the accompanying prospectus are a part of that registration statement, but do not contain all of the information included in the registration statement or the exhibits. You can find our public filings with the SEC on the internet at a web site maintained by the SEC located atwww.sec.gov.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

              SEC rules allow us to "incorporate by reference" much of the information we file with the SEC, which means that we can disclose important information to you by referring you to those publicly available documents. The information that we incorporate by reference into this prospectus supplement and the accompanying prospectus is considered to be part of this prospectus supplement. These documents may include Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements. You should read the information incorporated by reference because it is an important part of this prospectus supplement.

              This prospectus supplement incorporates by reference the documents listed below, other than those documents or the portions of those documents deemed to be furnished and not filed in accordance with SEC rules:

•

ourAnnual Report on Form 10-K for the year ended December 31, 2018, which was filed on March 18, 2019 (including information specifically incorporated by reference therein from ourProxy Statement filed with the SEC on April 30, 2019);



•

our Quarterly Reports on Form 10-Qfor the quarter ended March 31, 2019, which was filed on May 10, 2019,for the quarter ended June 30, 2019, which was filed on August 9, 2019, andfor the quarter ended September 30, 2019, which was filed on November 12, 2019;



•

our Current Reports on Form 8-K filed with the SEC onMarch 22, 2019,June 12, 2019, as amended onJune 28, 2019,June 19, 2019,June 20, 2019,July 2, 2019,July 2, 2019,July 11, 2019,July 30, 2019,August 7, 2019,August 30, 2019,September 6, 2019,October 22, 2019,January 9, 2020,January 15, 2020 andJanuary 15, 2020; and



•

the description of our common stock contained in our registration statement on Form 8-A which was filed on January 23, 1998, including any amendments or reports filed for the purpose of updating such description.

              We also incorporate by reference all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus supplement but prior to the termination of this offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

              Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.

              We will provide, without charge to you, upon written or oral request, a copy of any or all of the documents incorporated by reference in this prospectus supplement, other than exhibits to those documents, unless the exhibits are specifically incorporated by reference in those documents. Requests should be directed to our principal executive offices at:

Rockwell Medical, Inc.
411 Hackensack Ave., Suite 501
Hackensack, NJ 07601
(248) 960-9009
Attention: David Kull, Secretary

              You can also find these filings on our website atwww.rockwellmed.com. We are not incorporating the information on our website other than these filings into this prospectus supplement.

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PROSPECTUS

ROCKWELL MEDICAL, INC.

DEBT SECURITIES
COMMON STOCK
PREFERRED STOCK
WARRANTS
SUBSCRIPTION RIGHTS
SECURITIES PURCHASE CONTRACTS
UNITS

        We may offer and sell from time to time up to $200 million of any combination of the securities described in this prospectus, from time to time, in one or more offerings, in amounts, at prices and on terms determined at the times of offerings.

        This prospectus describes the general manner in which our securities may be offered using this prospectus. We will provide specific terms of the securities, including the offering prices, in one or more supplements to this prospectus. The supplements may also add, update or change information contained in this prospectus. You should read this prospectus and the prospectus supplement relating to the specific issue of securities carefully before you invest.

        We may offer the securities for sale directly to the purchasers or through one or more underwriters, dealers and agents to be designated at a future date. The supplements to this prospectus will provide the specific terms of the plan of distribution.

        Our common stock is listed on the Nasdaq Global Market and traded under the symbol "RMTI." The last reported sale price of the common stock on September 13, 2018 was $4.12 per share. Each prospectus supplement will indicate if the securities offered thereby will be listed on any securities exchange.

        Investing in our securities involves risk. Please read carefully the section entitled "Risk Factors" on Page 4 of this prospectus and any similar section contained in the applicable prospectus supplement and/or other offering material concerning factors you should consider before investing in our securities which may be offered hereby.

        Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is October 1, 2018.

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ABOUT THIS PROSPECTUS

        Unless the context otherwise requires, references in this prospectus to "Rockwell," "we," "us," "our" and "ours" refer to Rockwell Medical, Inc., and include its consolidated subsidiaries where the context so requires.

        This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, using a "shelf" registration process. Under this shelf registration process, we may, from time to time, sell the securities described in this prospectus, in one or more offerings, up to the maximum aggregate dollar amount $200,000,000. This prospectus provides you with a general description of the securities that we may offer. Each time we offer securities, we will provide a prospectus supplement and/or other offering material that will contain specific information about the terms of that offering. The prospectus supplement and/or other offering material may also add, update or change information contained in this prospectus. You should read this prospectus and the applicable prospectus supplement and any other offering material together with the additional information described under the heading "Where You Can Find More Information."

        You should rely only on the information contained or incorporated by reference in this prospectus and in any prospectus supplement or other offering material. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making offers to sell the securities in any jurisdiction in which an offer is not authorized or in which the person making that offer is not qualified to do so or to anyone to whom it is unlawful to make an offer. You should not assume that the information contained in this prospectus or any prospectus supplement or any other offering material, or the information we previously filed with the SEC that we incorporate by reference in this prospectus or any prospectus supplement, is accurate as of any date other than its respective date. Our business, financial condition, results of operations and prospects may have changed since those dates.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

        We make forward-looking statements in this registration statement and may make such statements in future filings with the Securities and Exchange Commission, or SEC. We may also make forward-looking statements in our press releases or other public or shareholder communications. Our forward-looking statements are subject to risks and uncertainties and include information about our expectations and possible or assumed future results of our operations. When we use words such as "may," "might," "will," "should," "believe," "expect," "anticipate," "estimate," "continue," "could," "plan," "potential," "predict," "forecast," "project," "intend," or similar expressions, or make statements regarding our intent, belief, or current expectations, we are making forward-looking statements.

        These forward-looking statements are neither promises nor guarantees of future performance due to a variety of risks and uncertainties, many of which are beyond our control, which could cause actual results to differ materially from those indicated by these forward-looking statements, including, without limitation, risks relating to:

•

the timing and commercial success of the commercial launch of our proprietary products and new business strategy;



•

the timing and success of obtaining Medicare and other third-party reimbursement approval for our products, including Triferic;



•

the timing and success of filing of applications for new regulatory approvals in the United States and abroad, including for our planned intravenous formulation of Triferic;



•

our liquidity and capital resources;

1

•

future results of operations and the financial condition of the Company;



•

our dependence on key employees and our ability to integrate new members of our management team;



•

the timing and success of clinical studies of the Company's drug candidates, including planned studies of Triferic in China and a pediatric study of Triferic;



•

the manufacture of our products in compliance with the FDA's current Good Manufacturing Practices;



•

the ability to maintain compliance with SEC and Nasdaq rules; and



•

other risks more fully discussed in the "Risk Factors" section in this prospectus, the section of any accompanying prospectus supplement entitled "Risk Factors" and the risk factors and cautionary statements described in other documents that we file from time to time with the SEC, specifically under "Risk Factors" and elsewhere in our most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q.

        We claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 for all of our forward-looking statements. While we believe that our forward-looking statements are reasonable, you should not place undue reliance on any such forward-looking statements, which are based on information available to us on the date of this report or, if made elsewhere, as of the date made. Because these forward-looking statements are based on estimates and assumptions that are subject to significant business, economic and competitive uncertainties, many of which are beyond our control or are subject to change, actual results could be materially different. See "Risk Factors" in this prospectus for more information. You should consider these factors and other cautionary statements made in this prospectus and in the documents we incorporate by reference as being applicable to all related forward-looking statements wherever they appear in this prospectus and in the documents incorporated by reference.

        Other factors not currently anticipated may also materially and adversely affect our results of operations, cash flows and financial position. We do not undertake any obligation to update or alter any statements whether as a result of new information, future events or otherwise, except as required by law.

2

OUR COMPANY

        We are a specialty pharmaceutical company targeting end-stage renal disease ("ESRD") and chronic kidney disease with products for the treatment of iron deficiency, secondary hyperparathyroidism and hemodialysis (also referred to as "dialysis").

        We are currently marketing and developing unique, proprietary renal drug therapies. These renal drug therapies support disease management initiatives to improve the quality of life and care of dialysis patients and are designed to deliver safe and effective therapy, while decreasing drug administration costs and improving patient convenience and outcome. We have also obtained licenses for certain dialysis related drugs which we are developing and planning to market in major markets globally either directly or through license partners.

        We are also a manufacturer of hemodialysis concentrates/dialysates to dialysis providers and distributors in the United States and abroad. We manufacture, sell and distribute hemodialysis concentrates and other ancillary medical products and supplies used in the treatment of patients with ESRD. We also supply dialysis concentrates to distributors serving a number of foreign countries, primarily in the Americas and the Pacific Rim. The majority of our sales occur in the United States.

        We are regulated by the United States Food and Drug Administration ("FDA") under the Federal Drug and Cosmetics Act, as well as by other federal, state and local agencies. We hold several FDA product approvals including both drugs and medical devices.

        We are a Michigan corporation and our corporate headquarters are located at 30142 Wixom Road, Wixom, Michigan 48393. Our telephone number is (248) 960-9009 and our Internet website address is www.rockwellmed.com. We do not incorporate the information on our website into this prospectus, and you should not consider it part of this prospectus.

3

RISK FACTORS

        Investing in our securities involves risks. Before making an investment decision, you should carefully consider the risks and other information we include or incorporate by reference in this prospectus and any prospectus supplement. In particular, you should consider the risk factors described under the heading "Risk Factors" in our most recentAnnual Report on Form 10-K and in Item 1A of ourQuarterly Report on Form 10-Q for the period ended June 30, 2018 under the heading "Risk Factors," as may be revised or supplemented by our subsequent Quarterly Reports on Form 10-Q or Current Reports of Form 8-K, each of which are on file with the SEC and are incorporated herein by reference, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future. In addition to those risk factors, there may be additional risks and uncertainties of which are not currently known to us or that we currently deem immaterial. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities. Additional risk factors may be included in a prospectus supplement relating to a particular offering of securities.

4

USE OF PROCEEDS

        Except as may be otherwise set forth in the applicable prospectus supplement accompanying this prospectus, the net proceeds from the sale of the securities will be used for general corporate purposes, including potentially expanding existing businesses, acquiring businesses and investing in other business opportunities. Pending such use, we may temporarily invest the net proceeds in short-term investments.

5

DILUTION

        We will set forth in a prospectus supplement the following information regarding any material dilution of the equity interests of investors purchasing securities in an offering under this prospectus:

•

the net tangible book value per share of our equity securities before and after the offering;



•

the amount of the increase in such net tangible book value per share attributable to the cash payments made by purchasers in the offering; and



•

the amount of the immediate dilution from the public offering price which will be absorbed by such purchasers.

6

SECURITIES TO BE OFFERED

        We may offer, from time to time and in one or more offerings, debt securities, shares of common stock, shares of preferred stock, warrants, subscription rights, securities purchase contracts and units. Set forth herein and below is a general description of the securities that we may offer hereunder. We will set forth in the applicable prospectus supplement a specific description of the securities that may be offered under this prospectus. The terms of the offering of securities, the initial offering price and the net proceeds will be contained in the prospectus supplement and/or other offering material relating to such offering.

7

RATIO OF EARNINGS TO FIXED CHARGES

        As of the date of this prospectus and for the previous five fiscal years, we had no fixed charges and no shares of preferred stock for which we are required to make dividend payments. Accordingly, we have no ratio of earnings to fixed charges and no ratio of earnings to combined fixed charges and preferred stock dividends, to illustrate for these periods. To the extent applicable at the time of filing, we will provide any ratios of earnings to fixed charges in the applicable prospectus supplement or in a document that we file with the SEC and incorporate by reference in the future.

8

DESCRIPTION OF DEBT SECURITIES

        The following description of the terms of the debt securities sets forth general terms that may apply to the debt securities and provisions of the indenture that will govern the debt securities, and is not complete. We will describe the particular terms of any debt securities in the prospectus supplement relating to those debt securities.

        The debt securities will be our senior debt securities and will be issued under an indenture between us and a trustee, a form of which is incorporated by reference into this prospectus and attached as an exhibit to the registration statement of which this prospectus is a part. See "Where You Can Find More Information." We refer to this indenture as the "indenture."

        The following is a summary of some provisions of the indenture. The following summary does not purport to be complete, and is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture, including the definitions of specified terms used in the indenture, and the debt securities. We encourage you to read the indenture and the debt securities because they, and not this description, set forth your rights as a holder of our debt securities. We will describe the particular terms of any debt securities in the prospectus supplement relating to those debt securities. Parenthetical section references under this heading are references to sections in the indenture unless we indicate otherwise.

General Terms

        The indenture does not limit the amount of debt securities that we may issue. (Section 301). The indenture provides that debt securities may be issued up to the principal amount authorized by us from time to time. The debt securities will be unsecured and will have the same rank as all of our other unsecured debt. None of our subsidiaries, if any, will have any obligations with respect to the debt securities. Therefore, our rights and the rights of our creditors, including holders of senior debt securities and subordinated debt securities, to participate in the assets of any subsidiary will be subject to the prior claims of the creditors of any such subsidiaries.

        We may issue the debt securities in one or more separate series of senior debt securities. (Section 301). The prospectus supplement relating to the particular series of debt securities being offered will specify the particular amounts, prices and terms of those debt securities. These terms may include:

•

the title of the debt securities and the series in which the debt securities will be included;



•

the authorized denominations and aggregate principal amount of the debt securities;



•

the date or dates on which the principal and premium, if any, are payable;



•

the rate or rates per annum at which the debt securities will bear interest, if there is any interest, or the method or methods of calculating interest and the date from which interest will accrue;



•

the place or places where the principal of and any premium and interest on the debt securities will be payable;



•

the dates on which the interest will be payable and the corresponding record dates;



•

the period or periods within which, the price or prices at which, and the terms and conditions on which, the debt securities may be redeemed, in whole or in part, at our option;



•

whether the debt securities of the series will be issued in whole or in part;



•

whether the debt securities of the series will be issued in the form of a global security and, if so, the name of the applicable depositary and global exchange agent;

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•

any obligation to redeem, repay or purchase debt securities pursuant to any sinking fund or analogous provisions or at the option of a holder;



•

the portion of the principal amount of the debt securities payable upon declaration of the acceleration of the maturity of the debt securities;



•

the person to whom any interest on any debt security will be payable if other than the person in whose name the debt security is registered on the applicable record date;



•

any events of default, covenants or warranties applicable to the debt securities;



•

the currency, currencies or composite currency of denomination of the debt securities;



•

the currency, currencies or composite currencies in which payments on the debt securities will be payable and whether the holder may elect payment to be made in a different currency;



•

whether and under what conditions we will pay additional amounts to holders of the debt securities;



•

the terms and conditions of any conversion or exchange provisions in respect of the debt securities;



•

the terms pursuant to which our obligation under the indenture may be terminated through the deposit of money or government obligations;



•

whether the debt securities of the series will be subordinated in right of payment to senior indebtedness; and



•

any other specific terms of the debt securities not inconsistent with the indenture. (Section 301).

Unless otherwise specified in the applicable prospectus supplement, the debt securities will not be listed on any securities exchange.

        Unless the applicable prospectus supplement specifies otherwise, we will issue the debt securities in fully registered form without coupons. If we issue debt securities of any series in bearer form, the applicable prospectus supplement will describe the special restrictions and considerations, including special offering restrictions and special federal income tax considerations, applicable to those debt securities and to payment on and transfer and exchange of those debt securities.

U.S. Federal Income Tax Considerations

        We may issue the debt securities as original issue discount securities, bearing no interest or bearing interest at a rate, which, at the time of issuance, is below market rates, to be sold at a substantial discount below their principal amount. We will describe some special U.S. federal income tax and other considerations applicable to any debt securities that are issued as original issue discount securities in the applicable prospectus supplement. We encourage you to consult with your own tax and financial advisors on these important matters.

Payment, Registration, Transfer and Exchange

        Subject to any applicable laws or regulations, we will make payments on the debt securities at a designated office or agency, unless the applicable prospectus supplement otherwise sets forth. At our option, however, we may also make interest payments on the debt securities in registered form:

•

by checks mailed to the persons entitled to interest payments at their registered addresses; or



•

by wire transfer to an account maintained by the person entitled to interest payments as specified in the security register.

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Unless the applicable prospectus supplement otherwise indicates, we will pay any installment of interest on debt securities in registered form to the person in whose name the debt security is registered at the close of business on the regular record date for that installment of interest. (Section 307). If a holder wishes to receive payment by wire transfer, the holder should provide the paying agent with written wire transfer instructions at least 15 days prior to the payment date.

        Unless the applicable prospectus supplement otherwise sets forth, debt securities issued in registered form will be transferable or exchangeable at the agency we may designate from time to time. Debt securities may be transferred or exchanged without service charge, other than any tax or other governmental charge imposed in connection with the transfer or exchange. (Section 305).

Book-Entry Procedures

        The applicable prospectus supplement for each series of debt securities will state whether those debt securities will be subject to the following provisions.

        Unless debt securities in physical form are issued, we will issue the debt securities in whole or in part in the form of one or more global certificates, which we refer to as global securities, in denominations of $1,000 or any integral multiple of $1,000. We will deposit the global securities with or on behalf of The Depository Trust Company, which we refer to as DTC, and registered in the name of Cede & Co., as nominee of DTC. Beneficial interests in the global securities may be held through the Euroclear System ("Euroclear") and Clearstream Banking, S.A. ("Clearstream") (as indirect participants in DTC).

        We have provided the following descriptions of the operations and procedures of DTC, Euroclear and Clearstream solely as a matter of convenience. These operations and procedures are solely within the control of DTC, Euroclear and Clearstream and are subject to change by them from time to time. Neither we, any underwriter nor the trustee take any responsibility for these operations or procedures, and you are urged to contact DTC, Euroclear or Clearstream directly to discuss these matters.

        DTC has advised us that:

•

DTC is a limited-purpose trust company organized under the New York Banking Law, a "banking organization" within the meaning of the New York Banking Law, a member of the Federal Reserve System, a "clearing corporation" within the meaning of the New York Uniform Commercial Code and a "clearing agency" registered under Section 17A of the Exchange Act;



•

DTC holds securities that its direct participants deposit with DTC and facilitates the settlement among direct participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in direct participants' accounts, thereby eliminating the need for physical movement of securities certificates;



•

direct participants include securities brokers and dealers, trust companies, clearing corporations and other organizations;



•

DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, which is owned by the users of its regulated subsidiaries;



•

access to the DTC system is also available to indirect participants such as securities brokers and dealers, banks and trust companies that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly; and



•

the rules applicable to DTC and its direct and indirect participants are on file with the SEC.

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        We expect that under procedures established by DTC:

•

upon deposit of the global securities with DTC or its custodian, DTC will credit on its internal system the accounts of direct participants designated by the underwriters with portions of the principal amounts of the global securities; and



•

ownership of the debt securities will be shown on, and the transfer of ownership of the debt securities will be effected only through, records maintained by DTC or its nominee, with respect to interests of direct participants, and the records of direct and indirect participants, with respect to interests of persons other than participants.

        Investors in the global securities who are participants in DTC's system may hold their interests therein directly through DTC. Investors in the global notes who are not participants may hold their interests therein indirectly through organizations (including Euroclear and Clearstream) which are participants in such system. Euroclear and Clearstream may hold interests in the global securities on behalf of their participants through customers' securities accounts in their respective names on the books of their respective depositories, which are Euroclear Bank S.A./N.V., as operator of Euroclear, and Citibank, N.A., as depository of Clearstream. All interests in a securities, including those held through Euroclear or Clearstream, may be subject to the procedures and requirements of DTC. Those interests held through Euroclear or Clearstream may also be subject to the procedures and requirements of such systems.

        The laws of some jurisdictions require that purchasers of securities take physical delivery of those securities in the form of a certificate. For that reason, it may not be possible to transfer interests in a global security to those persons. In addition, because DTC can act only on behalf of its participants, who in turn act on behalf of persons who hold interests through participants, the ability of a person having an interest in a global security to pledge or transfer that interest to persons or entities that do not participate in DTC's system, or otherwise to take actions in respect of that interest, may be affected by the lack of a physical definitive security in respect of that interest.

        So long as DTC or its nominee is the registered owner of a global security, DTC or that nominee will be considered the sole owner or holder of the debt securities represented by that global security for all purposes under the indenture and under the debt securities. Except as described below, owners of beneficial interests in a global security will not be entitled to have debt securities represented by that global security registered in their names, will not receive or be entitled to receive the debt securities in the form of a physical certificate and will not be considered the owners or holders of the debt securities under the indenture or under the debt securities, and may not be entitled to give the trustee directions, instructions or approvals. For that reason, each holder owning a beneficial interest in a global security must rely on DTC's procedures and, if that holder is not a direct or indirect participant in DTC, on the procedures of the DTC participant through which that holder owns its interest, to exercise any rights of a holder of debt securities under the indenture or the global security.

        Neither we nor the trustee will have any responsibility or liability for any aspect of DTC's records relating to the debt securities or relating to payments made by DTC on account of the debt securities, or any responsibility to maintain, supervise or review any of DTC's records relating to the debt securities.

        We will make payments on the debt securities represented by the global securities to DTC or its nominee, as the registered owner of the debt securities. We expect that when DTC or its nominee receives any payment on the debt securities represented by a global security, DTC will credit participants' accounts with payments in amounts proportionate to their beneficial interests in the global security as shown in DTC's records. We also expect that payments by DTC's participants to owners of beneficial interests in the global security held through those participants will be governed by standing instructions and customary practice as is now the case with securities held for the accounts of

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customers registered in the names of nominees for such customers. DTC's participants will be responsible for those payments.

        Payments on the debt securities represented by the global securities will be made in immediately available funds. Transfers between participants in DTC will be made in accordance with DTC's rules and will be settled in immediately available funds.

        Transfers between participants in DTC will be effected in accordance with DTC's procedures, and will be settled in same-day funds, and transfers between participants in Euroclear and Clearstream will be effected in accordance with their respective rules and operating procedures.

        Cross-market transfers between the participants in DTC, on the one hand, and Euroclear or Clearstream participants, on the other hand, will be effected through DTC in accordance with DTC's rules on behalf of Euroclear or Clearstream, as the case may be, by its depository; however, such cross-market transactions will require delivery of instructions to Euroclear or Clearstream, as the case may be, by the counterparty in such system in accordance with the rules and procedures and within the established deadlines (European time) of such system. Euroclear or Clearstream, as the case may be, will, if the transaction meets its settlement requirements, deliver instructions to its respective depository to take action to effect final settlement on its behalf by delivering or receiving interests in the relevant global security in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Euroclear participants and Clearstream participants may not deliver instructions directly to the depositories for Euroclear or Clearstream.

        DTC has advised us that it will take any action permitted to be taken by a holder of notes only at the direction of one or more participants to whose account DTC has credited the interests in the global securities and only in respect of such portion of the aggregate principal amount of the notes as to which such participant or participants has or have given such direction. However, if there is an event of default under the notes, DTC reserves the right to exchange the global securities for certificated notes, and to distribute such notes to its participants.

        Although DTC, Euroclear and Clearstream have agreed to the foregoing procedures to facilitate transfers of interests in the global securities among participants in DTC, Euroclear and Clearstream, they are under no obligation to perform or to continue to perform such procedures, and may discontinue such procedures at any time. None of the trustee, us or any of their or our respective agents will have any responsibility for the performance by DTC, Euroclear or Clearstream or their respective direct or indirect participants of their respective obligations under the rules and procedures governing their operations.

        Physical certificates will be issued to holders of a global security, or their nominees, if:

•

DTC advises the trustee in writing that DTC is no longer willing, able or eligible to discharge properly its responsibilities as depository and we are unable to locate a qualified successor; or



•

we decide in our sole discretion to terminate the book-entry system through DTC. (Section 305).

In such event, the trustee will notify all holders of debt securities through DTC participants of the availability of such physical debt securities. Upon surrender by DTC of a definitive global note representing the debt securities and receipt of instructions for reregistration, the trustee will reissue the debt securities in physical form to holders or their nominees. (Section 305).

        Debt securities in physical form will be freely transferable and exchangeable at the office of the trustee upon compliance with the requirements set forth in the indenture.

        No service charge will be imposed for any registration of transfer or exchange, but payment of a sum sufficient to cover any tax or other governmental charge may be required. (Section 305).

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Same Day Settlement and Payment

        We will make payments in respect of the notes represented by the global securities (including principal, premium, if any, and interest) by wire transfer of immediately available funds to the accounts specified by the global securities holder. We will make all payments of principal, interest and premium, if any, with respect to certificated notes by wire transfer of immediately available funds to the accounts specified by the holders of the certificated notes or, if no such account is specified, by mailing a check to each such holder's registered address. The notes represented by the global securities are expected to be eligible to trade in DTC's Same-Day Funds Settlement System, and any permitted secondary market trading activity in such notes will, therefore, be required by DTC to be settled in immediately available funds. We expect that secondary trading in any certificated notes will also be settled in immediately available funds.

        Because of time zone differences, the securities account of a Euroclear or Clearstream participant purchasing an interest in a global security from a participant in DTC will be credited, and any such crediting will be reported to the relevant Euroclear or Clearstream participant, during the securities settlement processing day (which must be a business day for Euroclear and Clearstream) immediately following the settlement date of DTC. DTC has advised us that cash received in Euroclear or Clearstream as a result of sales of interests in a global securities by or through a Euroclear or Clearstream participant to a participant in DTC will be received with value on the settlement date of DTC but will be available in the relevant Euroclear or Clearstream cash account only as of the business day for Euroclear or Clearstream following DTC's settlement date.

Consolidation, Merger or Sale by the Company

        The indenture generally permits a consolidation or merger between us and another U.S. legal entity. It also permits the sale or transfer by us of all or substantially all of our property and assets to another legal entity. These transactions are permitted if:

•

(A) we are the continuing or surviving legal entity, or (B) the resulting or acquiring legal entity, if other than us, assumes all of our responsibilities and liabilities under the indenture, including the payment of all amounts due on the debt securities and performance of the covenants in the indenture;



•

immediately after the transaction, no event of default exists. (Section 801); and



•

the trustee shall have received an officer's certificate and an opinion stating such consolidation, merger, conveyance, transfer or lease and, if applicable, the corresponding supplemental indenture, are in compliance with the base indenture.

        Even though the indenture contains the provisions described above, we are not required by the indenture to comply with those provisions if we sell all of our property and assets to another U.S. legal entity if, immediately after the sale, that legal entity is one of our wholly-owned subsidiaries. (Section 801).

        If we consolidate or merge with or into any other legal entity or sell all or substantially all of our assets according to the terms and conditions of the indenture, the resulting or acquiring legal entity will be substituted for us in the indenture with the same effect as if it had been an original party to the indenture. As a result, the successor legal entity may exercise our rights and powers under the indenture, in our name or in its own name and we will be released from all our liabilities and obligations under the indenture and under the debt securities. (Section 801).

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Events of Default, Notice and Certain Rights on Default

        Unless otherwise stated in the applicable prospectus supplement, an "event of default," when used with respect to any series of debt securities, means any of the following:

•

failure to pay interest on any debt security of that series for 30 days after the payment is due;



•

failure to pay the principal of or any premium on any debt security of that series when due;



•

failure to deposit any sinking fund payment on debt securities of that series when due;



•

failure to perform any other covenant in the indenture that applies to debt securities of that series for 90 days after we have received written notice of the failure to perform in the manner specified in the indenture;



•

an event of default under any debt by the company or any significant subsidiary of the company (including a default with respect to any series of debt securities) that results in debt of an outstanding principal amount greater than $75,000,000 becoming or being declared due and payable;



•

certain events in bankruptcy, insolvency or reorganization; or



•

any other event of default that may be specified for the debt securities of that series when that series is created. (Section 502).

        If an event of default for any series of debt securities occurs and continues, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of the series may declare the entire principal of all the debt securities of that series to be due and payable immediately. If a declaration occurs, the holders of a majority of the aggregate principal amount of the outstanding debt securities of that series can, subject to certain conditions, rescind the declaration. (Section 502).

        The prospectus supplement relating to each series of debt securities which are original issue discount securities will describe the particular provisions that relate to the acceleration of maturity of a portion of the principal amount of that series when an event of default occurs and continues.

        An event of default for a particular series of debt securities does not necessarily constitute an event of default for any other series of debt securities issued under the indenture.

        The indenture requires us to furnish an officer's certificate to the trustee each year as to the knowledge of our principal executive, financial or accounting officer of our compliance with all conditions and covenants under the indenture. (Section 1008). The trustee will transmit by mail to the holders of debt securities of a series notice of any default.

        Other than its duties in the case of a default, the trustee will not be obligated to exercise any of its rights or powers under an indenture at the request, order or direction of any holders, unless the holders offer the trustee indemnification satisfactory to the trustee. (Section 603). If indemnification satisfactory to the trustee is provided, then, subject to certain other rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series may, with respect to the debt securities of that series, direct the time, method and place of:

•

conducting any proceeding for any remedy available to the trustee; or



•

exercising any trust or power conferred upon the trustee. (Section 512).

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        The holder of a debt security of any series will have the right to begin any proceeding with respect to the indenture or for any remedy only if:

•

the holder has previously given the trustee written notice of a continuing event of default with respect to that series;



•

the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made a written request of, and offered reasonable indemnification to, the trustee to begin the proceeding;



•

the trustee has not started the proceeding within 60 days after receiving the request; and



•

the trustee has not received directions inconsistent with the request from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series during those 60 days. (Section 507).

        The holders of not less than a majority in aggregate principal amount of any series of debt securities, by notice to the trustee for that series, may waive, on behalf of the holders of all debt securities of that series, any past default or event of default with respect to that series and its consequences. (Section 513). A default or event of default in the payment of the principal of, or premium or interest on, any debt security and certain other defaults may not, however, be waived. (Sections 508 and 513).

Modification of the Indenture

        We, as well as the trustee for a series of debt securities, may enter into one or more supplemental indentures, without the consent of, or notice to, the holders of any of the debt securities, in order to:

•

evidence the succession of another corporation to us and the assumption of our covenants by a successor;



•

add to our covenants or surrender any of our rights or powers;



•

add additional events of default for any series;



•

change or eliminate any restrictions on the payment of principal of (or premium, if any, on) debt securities, provided such action will not adversely affect the interest of holders of any series of debt securities in any material respect;



•

permit or facilitate the issuance of debt securities in uncertificated form, provided such action will not adversely affect the interests of holders of any series of debt securities in any material respect;



•

secure the debt securities;



•

establish the form or terms of debt securities not yet issued;



•

evidence and provide for successor trustees;



•

add, change or eliminate any provision affecting registration as to principal of debt securities;



•

change or eliminate provisions or add any other provisions that are required or desirable in accordance with any amendments to the Trust Indenture Act of 1939, which we refer to in this prospectus as the Trust Indenture Act, on the condition that this action does not adversely affect the interests of any holder of debt securities of any series issued under the indenture in any material respect;



•

comply with requirements of the SEC in order to maintain the qualification of the indenture under the Trust Indenture Act;

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•

provide for uncertificated debt securities in addition to or in place of certificated debt securities;



•

make any change that would provide additional rights or benefits to holders of debt securities or any series, or that does not adversely affect the legal rights of such holders under the indenture;



•

supplement any provisions of the indenture to facilitate defeasance and discharge of any series of debt securities, provided such action will not adversely affect the interest of the holders of debt securities of such series or any other series;



•

conform text of the indenture or any debt securities to the description thereof in any prospectus supplement;



•

cure any ambiguity or correct any mistake; or



•

to make any other provision with respect to the indenture, provided that such actions will not adversely affect the interests of the holders, as determined in good faith by the board of directors of the company. (Section 901).

        In addition, with the consent of the holders of not less than a majority in aggregate principal amount of the outstanding debt securities of all series affected by the supplemental indenture, we and the trustee may execute supplemental indentures adding any provisions to or changing or eliminating any of the provisions of the indenture or any supplemental indenture or modifying the rights of the holders of debt securities of that series. No such supplemental indenture may, however, without the consent of the holder of each debt security that is affected:

•

change the time for payment of principal or interest on any debt security;



•

reduce the principal of, or any installment of principal of, or interest on, any debt security;



•

reduce the amount of premium, if any, payable upon the redemption of any debt security;



•

change any obligation of the company to pay additional amounts;



•

reduce the amount of principal payable upon acceleration of the maturity of an original issue discount debt security;



•

impair the right to institute suit for the enforcement of any payment on or for any debt security;



•

reduce the percentage in principal amount of the outstanding debt securities of any series the consent of whose holders is required for modification or amendment of the indenture or for waiver of compliance with certain provisions of the indenture or for waiver of certain defaults;



•

modify the provisions relating to waiver of some defaults or any of the foregoing provisions;



•

change the currency of payment;



•

adversely affect the right to repayment of debt securities of any series at the option of the holders of those debt securities; or



•

change the place of payment. (Section 902).

        Any supplemental indenture will be filed with the SEC as an exhibit to:

•

a post-effective amendment to the registration statement of which this prospectus is a part;



•

an annual report on Form 10-K;



•

a quarterly report on Form 10-Q; or



•

a current report on Form 8-K.

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Defeasance and Covenant Defeasance

        When we use the term defeasance, we mean discharge from some or all of our obligations under the indenture. If we deposit with the trustee sufficient cash or government obligations to pay the principal, interest, any premium and any mandatory sinking fund or analogous payments due to the stated maturity or a redemption date of the debt securities of a particular series, then at our option:

•

we will be discharged from our obligations for the debt securities of that series, the holders of the debt securities of the affected series will no longer be entitled to the benefits of the indenture, except for registration of transfer and exchange of debt securities and replacement of lost, stolen or mutilated debt securities, and those holders may look only to the deposited funds or obligations for payment, which is referred to as "defeasance"; or



•

we will no longer be under any obligation to comply with certain covenants under the indenture as it relates to that series, and some events of default will no longer apply to us, which is referred to as "covenant defeasance." (Sections 403 and 1501).

        Unless the applicable prospectus supplement specifies otherwise and except as described below, the conditions to both defeasance and covenant defeasance are as follows:

•

it must not result in a breach or violation of, or constitute a default or event of default under, the indenture, or result in a breach or violation of, or constitute a default under, any other of our material agreements or instruments;



•

certain bankruptcy-related defaults or events of default with respect to us must not have occurred and be occurring during the period commencing on the date of the deposit of the trust funds to defease the debt securities and ending on the 91st day after that date;



•

we must deliver to the trustee an officer's certificate and an opinion of counsel addressing compliance with the conditions of the defeasance or covenant defeasance; and



•

we must comply with any additional conditions to the defeasance or covenant defeasance that the indenture may impose on us. (Sections 403 and 1501).

        In the event that government obligations deposited with the trustee for the defeasance of such debt securities decrease in value or default subsequent to their being deposited, we will have no further obligation, and the holders of the debt securities will have no additional recourse against us, for any decrease in value or default. If indicated in the prospectus supplement, in addition to obligations of the United States or an agency or instrumentality of the United States, government obligations may include obligations of the government or an agency or instrumentality of the government issuing the currency in which debt securities of such series are payable.

        We may exercise our defeasance option for the debt securities even if we have already exercised our covenant defeasance option. If we exercise our defeasance option, payment of the debt securities may not be accelerated because of default or an event of default. If we exercise our covenant defeasance option, payment of the debt securities may not be accelerated because of default or an event of default with respect to the covenants to which the covenant defeasance is applicable. If, however, acceleration occurs, the realizable value at the acceleration date of the money and government obligations in the defeasance trust could be less than the principal and interest then due on the debt securities, because the required deposit in the defeasance trust is based on scheduled cash flow rather than market value, which will vary depending on interest rates and other factors.

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Conversion and Exchange Rights

        The debt securities of any series may be convertible into or exchangeable for other securities of our company or another issuer or property or cash on the terms and subject to the conditions set forth in the applicable prospectus supplement. (Section 301).

Governing Law

        The indenture and the debt securities will be governed by, and construed under, the laws of the State of New York without regard to conflicts of laws principles thereof.

Regarding the Trustee

        We may from time to time maintain lines of credit, and have other customary banking relationships, with the trustee under the indenture.

        The indenture and provisions of the Trust Indenture Act that are incorporated by reference therein contain limitations on the rights of the trustee, should it become one of our creditors, to obtain payment of claims in certain cases or to realize on certain property received by it in respect of any such claim as security or otherwise. The trustee is permitted to engage in other transactions with us or any of our affiliates; provided, however, that if it acquires any conflicting interest (as defined under the Trust Indenture Act), it must eliminate such conflict or resign.

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DESCRIPTION OF CAPITAL STOCK

        The following description of our capital stock summarizes general terms and provisions that apply to our capital stock and provisions of our restated articles of incorporation and amended and restated bylaws. This description is only a summary. For more detailed information, you should refer to our restated articles of incorporation and amended and restated bylaws filed as exhibits to the registration statement, of which this prospectus is a part and incorporated by reference into this prospectus. See "Where You Can Find More Information."

General

        Our authorized capital stock consists of 120,000,000 shares of common stock, no par value per share, and 2,000,000 shares of preferred stock, no par value per share. As of September 13, 2018, 51,435,224 shares of our common stock were outstanding. As of the date of this prospectus, no shares of our preferred stock were outstanding.

Common Stock

        Holders of our common stock are entitled to one vote for each share held of record on all matters on which shareholders are generally entitled to vote. The majority of votes cast by the holders of shares entitled to vote on an action at a meeting at which a quorum is present is generally required to take shareholder action, unless a greater vote is required. Directors are elected by a plurality of the votes cast at any election, but the election of a director-nominee in an uncontested election requires a majority vote under our Principles of Corporate Governance. There is no cumulative voting of shares.

        Holders of our common stock are entitled to receive dividends when, as and if declared by our board of directors out of funds legally available for the payment of dividends. Upon the liquidation, dissolution or winding up of the Company, holders of common stock are entitled to share pro rata in any assets available for distribution to shareholders after payment of all obligations of the Company and after provision has been made with respect to each class of stock, if any, having preference over the common stock. Holders of common stock do not have cumulative voting rights or preemptive, subscription or conversion rights and shares of common stock are not redeemable. The shares of common stock presently outstanding are duly authorized, validly issued, fully paid and non-assessable. There will be a prospectus supplement relating to any offering of common stock offered by this prospectus.

Preferred Stock

        Our board of directors is authorized to issue from time to time up to 2 million shares of preferred stock without shareholder approval. Our board of directors has the discretion to determine the rights, preferences and limitations, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences. It is not possible to state the actual effect of the issuance of any shares of preferred stock on the rights of the holders of common stock until our board of directors determines the specific rights associated with the preferred stock. The effects of issuing preferred stock could include one or more of the following:

•

decreasing the amount of earnings and assets available for distribution to holders of common stock;



•

restricting dividends on the common stock;



•

diluting the voting power of the common stock;



•

impairing the liquidation rights of the common stock; or



•

delaying, deferring or preventing changes in our control or management.

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        As of the date of this prospectus, there were no shares of preferred stock outstanding.

Anti-Takeover Effects of Michigan Law and Our Certificate of Incorporation and Bylaws

        The directors of the Company serve staggered three-year terms. Directors may not be removed without cause. The restated articles of incorporation also set the minimum and maximum number of directors constituting the entire board at three and fifteen, respectively, with the exact number to be determined by the board from time to time.

        Our restated articles of incorporation and amended and restated bylaws contain provisions that could have the effect of delaying, deterring or preventing a merger, tender offer or other takeover attempt. Our restated articles of incorporation authorize the board to issue up to 120 million shares of common stock (less shares already outstanding or reserved for issuance) and up to two million shares of preferred stock without shareholder approval. In addition, the restated articles of incorporation provide that shareholder action without a meeting requires the unanimous consent of the shareholders, unless the applicable action has been approved by the Board prior to execution of the shareholder consent. Our amended and restated bylaws permit incumbent directors to fill any vacancies on the board of directors, however occurring, whether by an increase in the number of directors, death, resignation, retirement, disqualification, removal from office or otherwise, unless filled by proper action of the shareholders. Furthermore, our amended and restated bylaws require shareholders to give advance notice of director nominations and proposals to be presented at meetings of shareholders.

        These provisions may delay shareholder actions with respect to business combinations and the election of new members to our board of directors. As such, the provisions could discourage open market purchases of our common stock because a shareholder who desires to participate in a business combination or elect a new director may consider them disadvantageous.

        Subject to certain exceptions, Chapter 7A of the Michigan Business Corporation Act prohibits a corporation from engaging in any business combination with an interested shareholder (generally defined as a shareholder who beneficially owns 10% or more of the voting power of the Company) unless approved by (1) 90% of the votes of each class of stock entitled to vote and (2) two-thirds of the votes of each class of stock entitled to be cast by the shareholders other than the interested shareholder. We are currently not subject to Chapter 7A but may opt in at any time by resolution of our board of directors.

Nasdaq Global Market Listing

        Our common stock is listed on the Nasdaq Global Market under the symbol "RMTI."

Transfer Agent and Registrar

        The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company.

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DESCRIPTION OF WARRANTS

        We may issue other warrants in the future for the purchase of debt securities, common stock, preferred stock, units or other securities. Warrants may be issued independently or together with debt securities, common stock, preferred stock or units offered by any prospectus supplement and/or other offering material and may be attached to or separate from any such offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent, provided that we may also act as warrant agent and enter into warrant agreements directly with the purchasers of securities offered pursuant to this prospectus. In each case, the terms of the warrants will be set forth in the prospectus supplement and/or other offering material relating to the particular issue of warrants. The warrant agent, if any, will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders of warrants or beneficial owners of warrants.

     ��  The following summary of certain provisions of the warrants we may issue in the future does not purport to be complete and is subject to, and is qualified in its entirety by reference to, all provisions of the warrant agreements.

        Reference is made to the prospectus supplement and/or other offering material relating to the particular issue of warrants offered pursuant to such prospectus supplement and/or other offering material for the terms of and information relating to such warrants, including, where applicable:

•

the designation, aggregate principal amount, currencies, denominations and terms of the series of debt securities purchasable upon exercise of warrants to purchase debt securities and the price at which such debt securities may be purchased upon such exercise;



•

the number of shares of common stock or preferred stock purchasable upon the exercise of warrants and the price at which such number of shares of common stock or preferred stock may be purchased upon such exercise;



•

the designation and number of units of other securities purchasable upon the exercise of warrants to purchase other securities and the price at which such number of units of such other securities may be purchased upon such exercise;



•

the date on which the right to exercise such warrants shall commence and the date on which such right shall expire;



•

U.S. federal income tax consequences applicable to such warrants;



•

the amount of warrants outstanding as of the most recent practicable date; and



•

any other terms of such warrants.

        Warrants will be issued in registered form only. The exercise price for warrants will be subject to adjustment in accordance with the applicable prospectus supplement and/or other offering material.

        Each warrant will entitle the holder thereof to purchase such principal amount of debt securities or such number of shares of common stock, preferred stock, units or other securities at such exercise price as shall in each case be set forth in, or calculable from, the prospectus supplement and/or other offering material relating to the warrants, which exercise price may be subject to adjustment upon the occurrence of certain events as set forth in such prospectus supplement and/or other offering material. After the close of business on the expiration date, or such later date to which such expiration date may be extended by us, unexercised warrants will become void. The place or places where, and the manner in which, warrants may be exercised shall be specified in the prospectus supplement and/or other offering material relating to such warrants.

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        Prior to the exercise of any warrants to purchase debt securities, common stock, preferred stock, units or other securities, holders of such warrants will not have any of the rights of holders of the underlying securities, as the case may be, purchasable upon such exercise, including the right to receive payments of principal of, premium, if any, or interest, if any, on the debt securities purchasable upon such exercise or to enforce covenants in the applicable indenture, or to receive payments of dividends, if any, on the common stock purchasable upon such exercise, or to exercise any applicable right to vote.

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DESCRIPTION OF SUBSCRIPTION RIGHTS

        We may issue subscription rights to purchase debt securities, common stock, preferred stock, warrants, units other securities described in this prospectus or any combination thereof. These subscription rights may be issued independently or together with any other security offered by us and may or may not be transferable by the shareholder receiving the subscription rights in such offering. In connection with any offering of subscription rights, we may enter into a standby arrangement with one or more underwriters or other investors pursuant to which the underwriters or other investors may be required to purchase any securities remaining unsubscribed for after such offering.

        To the extent appropriate, the applicable prospectus supplement will describe the specific terms of the subscription rights to purchase shares of our securities offered thereby, including the following:

•

the date of determining the shareholders entitled to the rights distribution;



•

the price, if any, for the subscription rights;



•

the exercise price payable for the debt securities, common stock, preferred stock, warrants, units or other securities upon the exercise of the subscription right;



•

the number of subscription rights issued to each shareholder;



•

the amount of debt securities, common stock, preferred stock, warrants, units or other securities that may be purchased per each subscription right;



•

any provisions for adjustment of the amount of securities receivable upon exercise of the subscription rights or of the exercise price of the subscription rights;



•

the extent to which the subscription rights are transferable;



•

the date on which the right to exercise the subscription rights shall commence, and the date on which the subscription rights shall expire;



•

the extent to which the subscription rights may include an over-subscription privilege with respect to unsubscribed securities;



•

the material terms of any standby underwriting or purchase arrangement entered into by us in connection with the offering of subscription rights;



•

any applicable federal income tax considerations; and



•

any other terms of the subscription rights, including the terms, procedures and limitations relating to the transferability, exchange and exercise of the subscription rights.

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DESCRIPTION OF SECURITIES PURCHASE CONTRACTS

        We may issue securities purchase contracts, which consist of contracts obligating holders to purchase from us, and obligating us to sell to the holders, a specified number of shares of common stock, preferred stock, warrants, units, debt securities or other securities at a future date or dates, which we refer to in this prospectus as "securities purchase contracts." The terms and conditions for any purchase and sale rights or obligations, as well as the price per share of the underlying securities (if applicable) and the number or value of the underlying securities, may be fixed at the time the securities purchase contracts are issued or may be determined by reference to a specific formula set forth in the securities purchase contracts.

        The securities purchase contracts may be issued separately or as part of units, other securities or debt obligations of third parties, including U.S. treasury securities, securing the holders' obligations to purchase the securities under the securities purchase contracts. The securities purchase contracts may require holders to secure their obligations under the securities purchase contracts in a specified manner. The securities purchase contracts also may require us to make periodic payments to the holders thereof or vice versa, and those payments may be unsecured or refunded on some basis.

        The securities purchase contracts, and, if applicable, collateral or depositary arrangements, relating to the securities purchase contracts, will be filed with the SEC in connection with the offering of securities purchase contracts. The prospectus supplement and/or other offering material relating to a particular issue of securities purchase contracts will describe the terms of those securities purchase contracts, including the following:

•

if applicable, a discussion of material U.S. federal income tax considerations; and



•

any other information we think is important about the securities purchase contracts.

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DESCRIPTION OF UNITS

        As specified in the applicable prospectus supplement, we may issue units consisting of one or more shares of common stock, shares of preferred stock, debt securities, warrants, subscription rights and securities purchase contracts, or any combination of the foregoing.

        The applicable prospectus supplement will specify the following terms of the units:

•

the terms of the underlying securities comprising the units, including whether and under what circumstances the underlying securities may be traded separate of the units;



•

a description of the terms of any unit agreement governing the units (if any);



•

if appropriate, a discussion of material U.S. federal income tax considerations; and



•

a description of the provisions for the payment, settlement, transfer or exchange of the units.

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PLAN OF DISTRIBUTION

        We may sell securities in any one or more of the following ways from time to time: (i) through agents; (ii) to or through underwriters; (iii) through brokers or dealers; (iv) directly to purchasers, including through a specific bidding, auction or other process; (v) upon the exercise of subscription rights that may be distributed to our shareholders; or (vi) through a combination of any of these methods of sale. The applicable prospectus supplement and/or other offering material will contain the terms of the transaction, name or names of any underwriters, dealers, agents and the respective amounts of securities underwritten or purchased by them, the initial public offering price of the securities, and the applicable agent's commission, dealer's purchase price or underwriter's discount. Any dealers and agents participating in the distribution of the securities may be deemed to be underwriters, and compensation received by them on resale of the securities may be deemed to be underwriting discounts.

        Any initial offering price, dealer purchase price, discount or commission may be changed from time to time.

        The securities may be distributed from time to time in one or more transactions, at negotiated prices, at a fixed price or fixed prices (that may be subject to change), at market prices prevailing at the time of sale, at various prices determined at the time of sale or at prices related to prevailing market prices.

        Offers to purchase securities may be solicited directly by us or by agents designated by us from time to time. Any such agent may be deemed to be an underwriter, as that term is defined in the Securities Act, of the securities so offered and sold.

        If underwriters are utilized in the sale of any securities in respect of which this prospectus is being delivered, such securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at fixed public offering prices or at varying prices determined by the underwriters at the time of sale. Securities may be offered to the public either through underwriting syndicates represented by managing underwriters or directly by one or more underwriters. If any underwriter or underwriters are utilized in the sale of securities, unless otherwise indicated in the applicable prospectus supplement and/or other offering material, the obligations of the underwriters are subject to certain conditions precedent, and that the underwriters will be obligated to purchase all such securities if any are purchased.

        If a dealer is utilized in the sale of the securities in respect of which this prospectus is delivered, we will sell such securities to the dealer, as principal. The dealer may then resell such securities to the public at varying prices to be determined by such dealer at the time of resale. Transactions through brokers or dealers may include block trades in which brokers or dealers will attempt to sell shares as agent but may position and resell as principal to facilitate the transaction or in crosses, in which the same broker or dealer acts as agent on both sides of the trade. Any such dealer may be deemed to be an underwriter, as such term is defined in the Securities Act, of the securities so offered and sold.

        Offers to purchase securities may be solicited directly by us and the sale thereof may be made directly to institutional investors or others, who may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale thereof.

        If so indicated in the applicable prospectus supplement and/or other offering material, we may authorize agents and underwriters to solicit offers by certain institutions to purchase securities at the public offering price set forth in the applicable prospectus supplement and/or other offering material pursuant to delayed delivery contracts providing for payment and delivery on the date or dates stated in the applicable prospectus supplement and/or other offering material. Such delayed delivery contracts will be subject only to those conditions set forth in the applicable prospectus supplement and/or other offering material.

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        Agents, underwriters and dealers may be entitled under relevant agreements to indemnification against certain liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which such agents, underwriters and dealers may be required to make in respect thereof. The terms and conditions of any indemnification or contribution will be described in the applicable prospectus supplement and/or other offering material.

        We may also sell shares of our common stock through various arrangements involving mandatorily or optionally exchangeable securities, and this prospectus may be delivered in connection with those sales.

        We may engage in at-the-market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. To the extent that we make sales through one or more underwriters or agents in at-the-market offerings, we will do so pursuant to the terms of a sales agency financing agreement or other at-the-market offering arrangement between us and the underwriters or agents. If we engage in at-the-market sales pursuant to any such agreement or arrangement, we will issue and sell our securities through one or more underwriters or agents, which may act on an agency basis or a principal basis. During the term of any such agreement or arrangement, we may sell securities on a daily basis in exchange transactions or otherwise as we agreement with the underwriters or agents. Any such agreement or arrangement will provide that any securities sold will be sold at prices related to the then-prevailing market prices for our securities. Therefore, exact figures regarding proceeds that will be raised or commissions to be paid cannot be determined at this time. Pursuant to the terms of the agreement or arrangement, we may agree to sell, and the relevant underwriters or agents may agree to solicit offers to purchase blocks of our common stock. The terms of any such agreement or arrangement will be set forth in more detail in the applicable prospectus supplement.

        We may enter into derivative, sale or forward sale transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement and/or other offering material indicates, in connection with those transactions, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement and/or other offering material, including in short sale transactions and by issuing securities not covered by this prospectus but convertible into, or exchangeable for or representing beneficial interests in such securities covered by this prospectus, or the return of which is derived in whole or in part from the value of such securities. The third parties may use securities received under derivative, sale or forward sale transactions, or securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those transactions to close out any related open borrowings of stock. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement (or a post-effective amendment) and/or other offering material.

        Underwriters, broker-dealers or agents may receive compensation in the form of commissions, discounts or concessions from us. Underwriters, broker-dealers or agents may also receive compensation from the purchasers of shares for whom they act as agents or to whom they sell as principals, or both. Compensation as to a particular underwriter, broker-dealer or agent might be in excess of customary commissions and will be in amounts to be negotiated in connection with transactions involving shares. In effecting sales, broker-dealers may arrange for other broker-dealers to participate in the resales.

        Each series of securities will be a new issue and, other than the common stock, which is listed on the Nasdaq Global Market, will have no established trading market. We may elect to list any series of securities on an exchange, and in the case of the common stock, on any additional exchange, but, unless otherwise specified in the applicable prospectus supplement and/or other offering material, we shall not be obligated to do so. No assurance can be given as to the liquidity of the trading market for any of the securities.

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        Agents, underwriters and dealers may engage in transactions with, or perform services for us and our respective subsidiaries in the ordinary course of business.

        Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. An underwriter may carry out these transactions on the Nasdaq Global Market, in the over-the-counter market or otherwise.

        The place and time of delivery for securities will be set forth in the accompanying prospectus supplement and/or other offering material for such securities.

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WHERE YOU CAN FIND MORE INFORMATION

        We file annual, quarterly and current reports, proxy statements and other information with the SEC. We also filed a registration statement on Form S-3, including exhibits, under the Securities Act with respect to the securities offered by this prospectus. This prospectus is a part of that registration statement, but does not contain all of the information included in the registration statement or the exhibits. You may read and copy the registration statement and any other document we file at the SEC's Public Reference Room at 100 F Street, N.E., Washington D.C. 20549. You can call the SEC at 1-800-SEC-0330 for further information on the operation of the public reference room. You can also find our public filings with the SEC on the internet at a web site maintained by the SEC located at www.sec.gov.

        We are "incorporating by reference" specified documents that we file with the SEC, which means:

•

incorporated documents are considered part of this prospectus;



•

we are disclosing important information to you by referring you to those documents; and



•

information we file with the SEC will automatically update and supersede information contained in this prospectus.

        We incorporate by reference the documents listed below and any future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the registration statement on Form S-3 filed under the Securities Act with respect to securities offered by this prospectus and prior to the effectiveness of such registration statement and (ii) after the date of this prospectus and before the end of the offering of the securities pursuant to this prospectus:

•

our Annual Report on Form 10-K for the year ended December 31, 2017;



•

our Quarterly Report on Form 10-Q (as amended) for the quarter ended March 31, 2018 andour Quarterly Report on Form 10-Q for the quarter ended June 30, 2018;



•

our Definitive Proxy Statement on Schedule 14A filed April 30, 2018 and the Supplement to theDefinitive Proxy Statement on Schedule 14A filed June 7, 2018;



•

our Current Reports on Form 8-K filedMarch 21, 2018;April 19, 2018;May 23, 2018;May 25, 2018;June 7, 2018;June 19, 2018;June 21, 2018;June 21, 2018;June 27, 2018;July 13, 2018;July 25, 2018;July 30, 2018;August 3, 2018;August 7, 2018;August 8, 2018;August 14, 2018; andSeptember 4, 2018; and



•

the description of our common stock contained in or incorporated into our Registration Statement on Form 8-A filed with the SEC on January 23, 1998, including any amendment or reports filed for the purpose of updating such description.

        Information in this prospectus supersedes related information in the documents listed above, and information in subsequently filed documents supersedes related information in both this prospectus and the incorporated documents.

        We will provide, without charge to you, upon written or oral request, a copy of any or all of the documents incorporated by reference in this prospectus, other than exhibits to those documents, unless the exhibits are specifically incorporated by reference in those documents. Requests should be directed to our principal executive offices at:

Rockwell Medical, Inc.
30142 Wixom Road
Wixom, Michigan 48393
(248) 960-9009
Attention: David Kull, Secretary

        You can also find these filings on our website at www.rockwellmed.com. We are not incorporating the information on our website other than these filings into this prospectus.

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LEGAL MATTERS

        The validity of the securities offered by this prospectus will be passed upon for us by Foley & Lardner LLP. The validity of the securities offered by this prospectus will be passed upon for any underwriters or agents by counsel named in the applicable prospectus supplement. The opinions of Foley & Lardner LLP and counsel for any underwriters or agents may be conditioned upon and may be subject to assumptions regarding future action required to be taken by us and any underwriters, dealers or agents in connection with the issuance of any securities. The opinions of Foley & Lardner LLP and counsel for any underwriters or agents may be subject to other conditions and assumptions, as indicated in the prospectus supplement.

EXPERTS

        The consolidated financial statements incorporated in this prospectus by reference from the Company'sAnnual Report on Form 10-K for the year ended December 31, 2017, and the effectiveness of the Company's internal control over financial reporting as of December 31, 2017, have been audited by Plante & Moran, PLLC, independent auditors, as stated in their reports which are incorporated in this prospectus by reference, and have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

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Table of Contents

3,191,489 Shares

Common Stock

PROSPECTUS SUPPLEMENT

Sole-Book Running Manager

Cantor

February 4, 2020