As filed with the Securities and Exchange Commission on March 18, 2016January 15, 2021

Registration No. 333-
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON,Washington, D.C. 20549

FORM S-3
REGISTRATION STATEMENT
UNDERUnder
THE SECURITIES ACT OFThe Securities Act Of 1933

Flex Pharma,Salarius Pharmaceuticals, Inc.
(Exact nameName of registrantRegistrant as specifiedSpecified in its charter)Its Charter)

Delaware
(State or Other Jurisdiction of
Incorporation or Organization)
46-5087339
(I.R.S. Employer
Identification Number)

2450 Holcombe Blvd., Suite X
Houston, TX 77021
(832) 834-6992
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Mark J. Rosenblum
Chief Financial Officer
Salarius Pharmaceuticals, Inc.
2450 Holcombe Blvd., Suite X
Houston, TX 77021
(832) 834-6992
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Delaware46-5087339
(State or other jurisdiction(I.R.S. Employer
of incorporation or organization)Identification Number)
Andrew L. Strong
Davina K. Kaile
Pillsbury Winthrop Shaw Pittman LLP
2 Houston Center - 909 Fannin, Suite 2000
Houston, TX 77010
(713) 276-7677

800 Boylston Street, 24th Floor
Boston, MA 02199
(617) 874-1821From time to time after this registration statement becomes effective, as determined by market conditions and other factors.
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Christoph Westphal, M.D., Ph.D,
President and Chief Executive Officer
Flex Pharma, Inc.
800 Boylston Street, 24th Floor
Boston, MA 02199
(617) 874-1821
(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Lester Fagen
Marc Recht
Miguel Vega
Cooley LLP
500 Boylston Street, 14th Floor
Boston, MA 02116
(617) 937-2300


Approximate date of commencement of proposed sale to the public:public)
From time to time after the effective date of this registration statement.

If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box: obox.
If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box: ýbox.
If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering: ooffering.




If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.o
If this form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e)462 (e) under the Securities Act, check the following box.o
If this form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  o
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,”filer”, “accelerated filer”, “smaller reporting company” and “smaller reporting“emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filerAccelerated Filer
Non-accelerated filerSmaller reporting companyx
Large accelerated filer o
Emerging growth company
Accelerated filer o
Non-accelerated filer ý  (Do not check if a smaller reporting company)
Smaller reporting company o





If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  


CALCULATION OF REGISTRATION FEE

Title of Each Class of
Securities to be Registered
 
Amount
to be
Registered
 
Proposed
Maximum
Offering Price
Per Unit
 
Proposed
Maximum
Aggregate
Offering Price
 
Amount of
Registration Fee (1)
Common Stock, $0.0001 par value per share (2) (3) (3) 
Preferred Stock, $0.0001 par value per share (2) (3) (3) 
Debt Securities (2) (3) (3) 
Warrants (2) (3) (3) 
Total (2)   $125,000,000 $12,587.50


Title of Each Class of Securities to be Registered

Amount to be
Registered(1)

Proposed Maximum Offering Price
Per Share(2)

Proposed Maximum Aggregate
Offering Price

Amount of Registration Fee
Common Stock, $0.0001 par value per share, issuable upon exercise of warrants3,964,065$1.15$4,558,674.75$497.35

(1)Calculated pursuant to Rule 457(o) under the Securities Act of 1933, as amended, or the Securities Act.
(2) There are being registered hereunder such indeterminate number of shares of common stock and preferred stock, such indeterminate principal amount of debt securities and such indeterminate number of warrants to purchase common stock, preferred stock and/or debt securities which together shall have an aggregate initial offering price not to exceed $125,000,000. If any debt securities are issued at an original issue discount, then the principal amount of such debt securities shall be in such greater amount as shall result in an aggregate initial offering price not to exceed $125,000,000, less the aggregate dollar amount of all securities previously issued hereunder. Any securities registered hereunder may be sold separately or in combination with the other securities registered hereunder. The proposed maximum offering price will be determined, from time to time, by the registrant in connection with the issuance by the registrant of the securities registered hereunder. The securities registered also include such indeterminate number of shares of common stock and preferred stock and amount of debt securities as may be issued upon conversion of or exchange for preferred stock or debt securities that provide for conversion or exchange, upon exercise of warrants or pursuant to the antidilution provisions of any such securities. In addition, pursuant(1)    Pursuant to Rule 416 under the Securities Act the shares being registered hereunder include such indeterminate number of shares of common stock and preferred stock1933, as amended (the “Securities Act”), this registration statement also covers any additional securities that may be issuable with respect to the shares being registered hereunder as a result of stock splits, stock dividendsoffered or similar transactions.
(3) The proposed maximum aggregate offering price per class of security will be determined from time to time by the registrantissued in connection with the issuance by the registrantany stock split, stock dividend or pursuant to anti-dilution provisions of any of the securities registered hereunder and is not specified as to each classsecurities.
(2)    Estimated solely for purposes of securitycalculating the registration fee pursuant to General Instruction II.D. of Form S-3Rule 457(c) under the Securities Act.Act and based upon the average of the high and low prices on the Nasdaq Capital Market on January 13, 2021.

The registrantRegistrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrantRegistrant shall file a further amendment thatwhich specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.








The information in this preliminary prospectus is not complete and may be changed. WeThe selling stockholders identified herein may not sell these securities or accept an offer to buy these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seekthese securities and is not soliciting an offer to buy these securities in any jurisdictionstate where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED March 18, 2016.January 15, 2021

PRELIMINARY PROSPECTUS

image_01a.jpg
Salarius Pharmaceuticals, Inc.
$125,000,000
3,964,065 shares of Common Stock
Preferred Stock_________________________
Debt SecuritiesThis prospectus relates to the possible resale by the selling stockholders named in this prospectus of an aggregate of up to 3,964,065 shares of common stock of Salarius Pharmaceuticals, Inc., issuable upon exercise of certain outstanding common stock purchase warrants, issued by us. We are not selling any shares of common stock under this prospectus and will not receive any proceeds from the sale of the shares offered by this prospectus.
WarrantsWe have agreed to bear all of the expenses incurred in connection with the registration of these shares. The selling stockholders will pay or assume brokerage commissions and similar charges incurred for the sale of shares of our common stock.

FromThe selling stockholders identified in this prospectus, or their respective pledgees, donees, transferees or other successors-in-interest, may offer the shares from time to time we may offer and sell upthrough public or private transactions at prevailing market prices, at prices related to $125,000,000prevailing market prices or at privately negotiated prices. See “Plan of any combination of our common stock, preferred stock, debt securities or warrants described in this prospectus, either individually or in combination. We may also offer common stock or preferred stock upon the conversion of debt securities, common stock upon the conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.
This prospectus provides a general description of the securities we may offer. Each time we offer securities we will provide the specific terms of the securities offered in a supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.Distribution” beginning on page 10.
Our common stock is tradedlisted on the Nasdaq GlobalCapital Market under the symbol “FLKS.“SLRX.” On March 17, 2016,January 14, 2021, the closinglast reported sale price of our common stock on the Nasdaq GlobalCapital Market was $10.86$1.16 per share. The applicable prospectus supplement will contain information, where applicable, as to other listings, if any, on the Nasdaq Global Market or any other securities exchange of the securities covered by the applicable prospectus supplement.
_________________________
Investing in our securities involves a high degree of risk. You should review carefullyrisks. See the risks and uncertainties described undersection entitled “Risk Factors” included in or incorporated by reference into the heading “Risk Factors” contained in the applicableaccompanying prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporatedwe incorporate by reference into this prospectus.
This prospectus may not be used to consummate a sale of securities unless accompanied by a prospectus supplement.
The securities may be sold directly by us to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section titled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.
_________________________
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined ifpassed upon the adequacy or accuracy of this prospectus is truthful or complete.prospectus. Any representation to the contrary is a criminal offense.
_________________________
The date of this prospectus is                               , 2021




Prospectus dated , 2016.






TABLE OF CONTENTS
Page
i
PROSPECTUS SUMMARY1
RISK FACTORS4
4
RATIO OF EARNINGS TO FIXED CHARGES AND TO COMBINED FIXED CHARGES AND PREFERRED STOCK DIVIDENDS5
5
DESCRIPTION OF CAPITAL STOCK6
DESCRIPTION OF DEBT SECURITIES10
DESCRIPTION OF WARRANTS16
LEGAL OWNERSHIP OF SECURITIES18
21
23
23
23
23


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ABOUT THIS PROSPECTUS
This prospectus relates to the resale by the selling stockholders of up to 3,964,065 shares of common stock issuable upon exercise of certain warrants held by the selling stockholders named herein (“Warrants”), as described below under “Selling Stockholders.” We are not selling any shares of common stock under this prospectus, and will not receive any proceeds from the sale of shares of common stock by the selling stockholders, except with respect to amount received by us upon the exercise of the Warrants for cash.
This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may offer and sell, either individually or in combination, in one or more offerings, up to a total dollar amount of $125,000,000 of any combination of the securities described in this prospectus. This prospectus provides you with a general description of the securities we may offer.
Each time we offer securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change anySEC. It omits some of the information contained in the registration statement and reference is made to the registration statement for further information with regard to us and the shares of our common stock being offered by the selling stockholders. You should review the information and exhibits in the registration statement for further information about us and the shares of our common stock being offered hereby. Statements in this prospectus or inconcerning any document we filed as an exhibit to the documentsregistration statement or that we have incorporatedotherwise filed with the SEC are not intended to be comprehensive and are qualified by reference into this prospectus. We urge you to the filings. You should review the complete document to evaluate these statements. You should read this prospectus, any applicable prospectus supplement and any free writing prospectusesdocuments that we have authorized for use in connection with a specific offering, together with the information incorporated hereinincorporate by reference asin this prospectus and the additional information described under the headingheadings “Where You Can Find More Information,” and “Incorporation of Certain Information by Reference,” carefully before buying any of the securities being offered.
This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.
You should rely only on the information contained in, or incorporated by reference into, this prospectus and any applicable prospectus supplement, along with the information contained in any free writing prospectuses we have authorized for use in connection with a specific offering. We have not authorized anyone to provide you with different or additional information. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so.
making your investment decision. You should not assume that the information contained in this prospectus any applicable prospectus supplement or any related free writing prospectusdocuments we incorporate by reference herein is accurate onas of any date subsequent toother than the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.such document. Our business, financial condition, results of operations and prospects may have changed since those dates.
To the extent there is a conflict between You should rely only on the information contained in this prospectus, on the one hand, and the information contained in any document incorporated by reference filed with the SEC before the date of this prospectus, on the other hand, you should rely on the information in this prospectus. If any statement in a document incorporated by reference is inconsistent with a statement in another document incorporated by reference having a later date, the statement in the document having the later date modifies or supersedes the earlier statement.
This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below in the section titled “Where You Can Find More Information.”

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PROSPECTUS SUMMARY
This summary highlights selected information contained elsewhere in this prospectus or incorporated by reference in this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus (as supplemented and amended), including the risks of investing in our securities discussed under the heading “Risk Factors” contained in this prospectus (as supplemented and amended), and under similar headings in the other documents that are incorporated by reference into this prospectus. You also should carefully read the information incorporated by reference into this prospectus, including our financial data and related notes, and the exhibits to the registration statement of which this prospectus is a part. Unless otherwise mentioned or unless the context requires otherwise, all references in this report to “we,” “our,” “us,” or similar references mean Flex Pharma, Inc., a Delaware corporation.
Flex Pharma, Inc.
We are a biotechnology company that is developing innovative and proprietary treatments for nocturnal leg cramps, muscle cramps and spasms associated with severe neuromuscular conditions, and exercise-associated muscle cramps. Our product candidates are based on the potential mechanism of action we describe as Chemical Neuro Stimulation, which is the process by which a small molecule chemical signal, acting topically, induces a neuronal sensory signal that produces a beneficial effect. Our product candidates activate certain receptors in primary sensory neurons, which then act via neuronal circuits to reduce the repetitive firing, or hyperexcitability, of alpha-motor neurons in the spinal cord, thereby preventing or reducing the frequency and intensity of muscle cramps and spasms. We believe that we are the only company developing both drug and consumer products based on this mechanism of muscle cramp inhibition.
Muscle cramps and spasms are involuntary, often painful contractions producing tightness in muscles that can last several minutes and, in many instances, result in prolonged soreness. We believe that muscle cramps and spasms are driven by the hyperexcitability of alpha-motor neurons. Based on our scientific co-founders' novel insight regarding neuromuscular physiology, we developed an extract formulation that has shown statistical significance in reducing muscle cramps in our electrically induced cramp model as compared to a control. The extract formulation, and the product candidates we developed based on this extract formulation, activate the specific transient receptor potential, or TRP, ion channel receptors found on the surface of the mouth, esophagus and/or stomach, which trigger signals in sensory neurons that are relayed to the spinal cord. This sensory signaling is thought to increase the activity of inhibitory spinal interneurons, which reduce alpha-motor neuron hyperexcitability, thereby preventing muscle cramps and spasms.
Based on independent third-party survey results, we estimate that approximately four million U.S. adults over the age of 65 suffer from nocturnal leg cramps on a daily basis. There is no drug product currently approved in the United States for the treatment of nocturnal leg cramps. In February 2016, our extract formulation demonstrated efficacy in a randomized, controlled, blinded study of 50 healthy subjects who experienced nocturnal leg cramps at least three nights per week. In our nocturnal leg cramps study, statistically significant effects were demonstrated on key endpoints, including cramp frequency (p<0.05); cramp-free days (p<0.01), the physician-rated Clinical Global Impression of Change (p<0.01), cramp pain measures (p<0.05), and specific sleep disturbance measures (p<0.05). We plan to initiate another nocturnal leg cramp study in 2016 with a single molecule, chemically synthesized, TRP ion channel activator.
In 2016, we expect to initiate two studies of our lead drug product candidate, FLX-787, in patients suffering from cramps, spasms and spasticity associated with multiple sclerosis, or MS, and amyotrophic lateral sclerosis, or ALS. FLX-787 was developed based on our extract formulation and is a single molecule, chemically synthesized, TRP ion channel activator that has demonstrated statistically significant efficacy in our electrically induced cramp model. According to the National Institute of Neurological Disorders and Stroke, between 250,000 and 350,000 people in the United States suffer from multiple sclerosis, or MS, approximately 84% of whom experience spasticity. Based on a report published by the Centers for Disease Control, we estimate that over 12,000 people in the United States suffer from ALS. Our randomized, blinded, controlled cross-over studies of MS and ALS patients will be conducted outside the United States.
In the second quarter of 2016, we expect to launch a consumer brand and cornerstone product to prevent and treat exercise-associated muscle cramps, or EAMCs. We developed a consumer product based on our extract formulation that will be marketed primarily to endurance athletes experiencing EAMCs. Our consumer product will be a 50 milliliter beverage containing a proprietary formulation of organic TRP activators. We expect to launch our consumer brand and first consumer product in three select markets, Los Angeles, California, Boulder, Colorado and Boston, Massachusetts, and also expect a significant online presence. We have conducted pre-launch activities in each of these locations, which have included, among other things, attending athletic events, providing product samples, gathering feedback, educating potential consumers of our product and launching a print and digital media campaign.






Company Information
We were incorporated in Delaware on February 26, 2014. Our principal executive offices are located at 800 Boylston Street, 24th Floor, Boston, MA 02199 and our phone number is (617) 874-1821. Our corporate website address is www.flex-pharma.com. The information contained on our website is not a part of this prospectus, and the inclusion of our website address in the prospectus is an inactive textual reference only.
We are an “emerging growth company,” as defined in the Jumpstart Our Business Startups Act of 2012, or JOBS Act. We will cease to be an emerging growth company on the date that is the earliest of (i) the last day of the fiscal year in which we have total annual gross revenues of $1.0 billion or more; (ii) December 31, 2020; (iii) the date on which we have issued more than $1.0 billion in non-convertible debt during the previous three years; or (iv) the date on which we are deemed to be a large accelerated filer under the rules of the SEC.

The Securities We May Offer
We may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination, up to a total dollar amount of $125,000,000, from time to time under this prospectus, together with the applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of the relevant offering. We may also offer common stock, preferred stock and/or debt securities upon the exercise of warrants. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:
designation or classification;
aggregate principal amount or aggregate offering price;
maturity date, if applicable;
original issue discount, if any;
rates and times of payment of interest or dividends, if any;
redemption, conversion, exercise, exchange or sinking fund terms, if any;
conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange;
ranking, if applicable;
restrictive covenants, if any;
voting or other rights, if any; and
material or special U.S. federal income tax considerations, if any.
The applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change any of the information contained in this prospectus or in the documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.
This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.
We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents or underwriters, we will include in the applicable prospectus supplement:
the names of those agents or underwriters;
applicable fees, discounts and commissions to be paid to them;

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details regarding over-allotment options, if any; and
the estimated net proceeds to us.
Common Stock. We may issue shares of our common stock from time to time. The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders. Subject to preferences that may be applicable to any then outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably such dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets legally available for distribution to stockholders remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive rights and no right to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to our common stock. When we issue shares of common stock under this prospectus, the shares will be fully paid and non-assessable. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock which we may designate in the future.
Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. If we sell any series of preferred stock under this prospectus and any applicable prospectus supplement, our board of directors will determine the designations, voting powers, preferences and rights of the preferred stock being offered, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Convertible preferred stock may be convertible into our common stock or exchangeable for our other securities. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.
We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of the certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.
Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into our common stock or preferred stock. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.
The debt securities will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. A form of indenture has been filed as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC. We urgehave not authorized anyone to provide you to read the applicable prospectus supplement (andwith different information and, if you are given any free writing prospectusinformation or representation about these matters that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities.
Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. Forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental warrant agreements and forms of warrant certificates will be filed as exhibits to the registration statement of which this prospectus is a partnot contained or will be incorporated by reference from reports that we file with the SEC. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants.
We will evidence each series of warrants by warrant certificates that we will issue. Warrants may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.
Use of Proceeds
Except as described in any applicable prospectus supplement or in any free writing prospectuses we have authorized for use in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered by us hereunder,

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if any, for working capital and general corporate purposes, including research and development expenses, and selling, general and administrative expenses. See “Use of Proceeds” in this prospectus.
Nasdaq Global Market Listing
Our common stock is listed on the Nasdaq Global Market under the symbol “FLKS.” The applicable prospectus supplement will contain information, where applicable, as to other listings, if any, on the Nasdaq Global Market or other securities exchange of the securities covered by the applicable prospectus supplement.



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RISK FACTORS
Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and discussed in the section titled “Risk Factors” contained in our most recent Annual Report on Form 10-K for the year ended December 31, 2015, as well as any amendments thereto reflected in subsequent filings with the SEC, which are incorporated by reference into this prospectus in their entirety, together with other information in this prospectus, our quarterly reports,you must not rely on that information.

All references in this prospectus supplement to “Salarius,” the “Company,” “we,” “us” and documents incorporated by reference“our” refer Salarius Pharmaceuticals, Inc. and any free writing prospectus that we may authorize for use in connection with this offering. The risks described in these documents are notits consolidated subsidiaries, except where the only ones we face, but those that we consider to be material. There may be other economic, business, competitive, regulatorycontext otherwise requires or other factors that are not presently known to us or that we currently believe are immaterial that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section below titled “Special Note Regarding Forward-Looking Statements.”as otherwise indicated.
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus each prospectus supplement and the informationdocuments we have filed with the SEC that are incorporated by reference in this prospectus and each prospectussupplement, contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, that involve substantial risks and uncertainties. These statements relate to future periods, future events or our future operating or financial plans or performance. All statements other than statements of historical facts contained in this prospectus,fact, including statements identified by words such as “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “plan,” “intend,” “expect,” and similar expressions are forward-looking statements, and include but are not limited to the following:
our ability to successfully initiate and complete clinical trials and regulatory submissions;
expected dose escalation and dose expansion;
expected number of additional clinical sites;
expected cohort readouts;
expected therapeutic options for SP-2577 and related effects;
timing of development and future milestones;
the development, expected timeline, and commercial potential of any product candidates;
the effect of changes in macroeconomic factors beyond our control;
competition in the markets in which we do business and our competitive advantages;
our beliefs regarding our prospects for our business;
the adequacy of our capital resources and our ability to raise additional financing and the effect of failing to obtain adequate funding;
our ability to compete;
our beliefs regarding the attributes and anticipated customer benefits of our products;
our ability to hire additional personnel and retain key personnel;
our ability to expand and improve our sales performance and marketing activities;
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our ability to manage our expenditures and estimate future operating resultsexpenses, revenue, and operational requirements;
our use of proceeds;
the effect of changes to management judgments and estimates;
the impact of any modification to our pricing practices in the future;
our beliefs regarding our international operations;
our ability to take adequate precautions against claims or lawsuits made by third parties, including alleged infringement of proprietary rights;
the potential impact of foreign currency exchange rate fluctuations;
our expected quarterly cash expenditures;
the impact of accounting pronouncements and our critical accounting policies, judgments, estimates, models, and assumptions on our financial position, business strategy,results; and plans
our expectations with respect to revenue, cost of revenue, expenses, and objectives of management for future operations, are forward-looking statements. In many cases, you can identifyother financial metrics.

We have based these forward-looking statements by terms such as “may,” “should,” “expects,” “plans,” “anticipates,” “could,” “intends,” “target,” “projects,” “contemplates,” “believes,” “estimates,” “predicts,” “potential,” or “continue” or the negative of these terms or other similar expressions.
The forward-looking statements contained in this prospectus reflecton our views as of the date of this prospectuscurrent expectations and projections about future events and trends that we believe may affect our financial condition, results of operations, strategy, short- and long-term business operations and objectives, and financial requirements. These statements are subject to known and unknown risks, uncertainties and assumptions and changes in circumstances that may cause our actual results, performance, or achievements to differ significantly from those expressed or implied in any forward-looking statement. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future events, results, performance, or achievements. A number of important factors could cause actual results to differ materially from those indicatedprojected or otherwise implied by the forward-looking statements, including without limitation, those factors describedthe following: risks and uncertainties associated with our ability to manage our business plans, strategies, and outlooks and any business-related forecasts or referencedprojections; the availability of sufficient resources to meet our business objectives and operational requirements; the ability to project future cash utilization and reserves needed for contingent future liabilities and business operations; the fact that the results of earlier studies and trials may not be predictive of future clinical trial results; the ability to protect our intellectual property rights; risks related to the drug development and the regulatory approval process; the impact of competitive products and technological changes; the impact of new legislation or regulations, or of judicial decisions, on our business; legal and regulatory uncertainties; our ability to compete against third parties; the economic environment; our ability to manage future growth; the market price of our common stock; and foreign currency exchange rate fluctuations. You should not place undue reliance on these forward-looking statements.
We discuss in greater detail, and incorporate by reference into this prospectus and the accompanying prospectus, many of these risks, uncertainties and assumptions under the heading “Risk Factors.” In addition, those “Risk Factors” may be updated from time to time byAdditional cautionary statements or discussions of risks, uncertainties, and assumptions that could affect our filings under the Securities Exchange Act of 1934, as amended,results or the Exchange Act. Except as requiredachievement of the expectations described in forward-looking statements are also contained in the documents we incorporate by law, after the date ofreference into this prospectus. Any forward-looking statement made by us in this prospectus, we are under no duty to update or revise any of the documents incorporated by reference in this prospectus speaks only as of the date on which it was made. We expressly disclaim any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in our expectations with regard thereto or incorporated by reference herein, whether as a result of new information, futureany change in events, conditions, or otherwise.circumstances on which any such statement is based. You should, however, review additional disclosures we make in our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and Current Reports on Form 8-K filed with the SEC.
You should read this prospectus each prospectus supplement and the informationdocuments that we incorporateincorporated by reference in this prospectus completely and with the understanding that our actual future results, levels of activity, and performance as well as other events and circumstances may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.

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PROSPECTUS SUMMARY
    This summary highlights important features of this offering and the information included or incorporated by reference in this prospectus. This summary may not contain all of the information that is important to you. You should read the entire prospectus carefully, including “Risk Factors,” before deciding to invest in our common stock.

Salarius Pharmaceuticals, Inc.
We are a clinical-stage biopharmaceutical company focused on developing effective treatments for cancers with high, unmet medical need. Specifically, we are developing treatments for cancers caused by dysregulated gene expression, i.e., genes are incorrectly turned on or off. The field concerned with gene expression regulation is called ‘epigenetics’. As cancers are often diseases driven by gene dysregulation, epigenetics is an area of interest for cancer treatment. Our lead epigenetic based technology, seclidemstat (“SP-2577”), may treat cancers by restoring correct gene expression.
SP-2577, which we call seclidemstat, was licensed from the University of Utah Research Foundation in 2011. SP-2577 is a small molecule that inhibits the epigenetic enzyme lysine specific demethylase 1 (“LSD1”). LSD1’s enzymatic activity can cause genes to turn on or off and thereby affect the cell’s gene expression and overall activity. In addition, LSD1 can act via its scaffolding properties (protein-protein interactions), independently of its enzymatic function, to alter gene expression and modulate cell fate. In healthy cells, LSD1 is necessary for stem cell maintenance and normal cell development processes. However, in several cancers LSD1 is highly expressed and acts to incorrectly silence or activate genes leading to disease progression. High levels of LSD1 expression are often associated with aggressive cancer phenotypes and poor patient prognosis. Hence, development of targeted LSD1 inhibitors is of interest for the treatment of various cancers. SP-2577 uses a novel, reversible mechanism to effectively inhibit LSD1’s enzymatic and scaffolding properties and thereby treat and prevent cancer progression.
Our first indication of interest for SP-2577 is a devastating bone and soft-tissue cancer called Ewing sarcoma. Ewing sarcoma mostly afflicts adolescents and young adults, with the median age of diagnosis being 15. The most commonly expressed fusion oncoprotein in Ewing sarcoma is the EWS-FLI fusion protein, which is present in approximately 85% of Ewing sarcoma cases. The LSD1 enzyme associates with EWS-FLI (and other E26 Transformation-Specific (“ETS”) fusion proteins) and is thought to promote tumor growth. We believe the SP-2577 molecule helps inhibit EWS-FLI activity by disrupting EWS-FLI from associating with LSD1 and other proteins that are necessary for its cancer promoting activity. Therefore, we believe that SP-2577 can potentially reverse the cancer promotion gene expression and thereby possibly prevent Ewing sarcoma tumor growth and promote cancer cell death. Preclinical studies of SP-2577 in certain Ewing sarcoma animal models showed a significant tumor reduction as well as a significant survival benefit compared to untreated animals. Our ongoing Phase 1/2 clinical trial is designed as a single agent dose escalation followed by a dose expansion study. The trial can enroll up to 50 relapsed or refractory Ewing sarcoma patients. The primary objectives of the study are to assess the safety and tolerability of SP-2577. Secondary objectives include assessing preliminary efficacy of SP-2577. We recently announced that we plan to amend the Ewing sarcoma trial to also include up to 30 Ewing-related sarcoma patients upon reaching the dose expansion phase.
As LSD1 can interact with over 60 regulatory proteins other than EWS-FLI, we believe that LSD1 may also play a critical role in progression of various other cancer types. These include both solid tumors and hematologic malignancies. In the second quarter of 2019, we initiated a second company-sponsored Phase 1/2 trial to study SP-2577 in Advanced Solid Tumors. The Advanced Solid Tumor (“AST”) trial is a single agent dose escalation, dose expansion study enrolling patients with advanced malignancies, excluding Ewing sarcoma or central nervous system tumors. In addition, we are conducting preclinical work with SP-2577 for use in hematologic cancers.
Recent data from “LSD1 Ablation Stimulates Anti-tumor Immunity and Enables Checkpoint Blockade” by W. Sheng, et al. and “Inhibition of Histone Lysine-specific Demethylase 1 Elicits Breast Tumor Immunity and Enhances Antitumor Efficacy of Immune Checkpoint Blockade” by Y. Qin, et al. suggests that LSD1 plays a role in tumor immune activity and can sensitize tumors to checkpoint inhibitors. These recent works have sparked interest in combining LSD1 inhibitors with checkpoint inhibitors. We are conducting preclinical work with SP-2577 in this area.
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We have no products approved for commercial sale and have not generated any revenue from product sales. We have never been profitable and have incurred operating losses in each year since inception. We had an accumulated deficit of $17,661,406 as of September 30, 2020. Substantially all of our operating losses resulted from expenses incurred in connection with our research and development programs and from general and administrative costs associated with our operations.
Our financial statements are prepared using Generally Accepted Accounting Principles in the United States of America (“GAAP”) applicable to a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Our financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts and classification of liabilities should we be unable to continue as a going concern.
We expect to continue to incur significant expenses and increasing operating losses for at least the next several years as we initiate and continue the clinical development of, and seek regulatory approval for, our product candidates, add personnel necessary to continue to operate as a public company upon closing of the merger, and work to develop an advanced clinical pipeline of product candidates. We expect that our operating losses will fluctuate significantly from quarter-to-quarter and year-to-year due to timing of clinical development programs and efforts to achieve regulatory approval.
As of September 30, 2020, the Cancer Prevention and Research Institution of Texas ("CPRIT") fund matching requirements had been fully met. As of September 30, 2020, we have received an aggregate of $9.6 million from the CPRIT grant. A portion of the remaining $9.1 million CPRIT grant was for a castration-resistant prostate study (approximately $2.6 million). The Company has elected not to pursue this study, and accordingly this amount will no longer be available. The Company was approved for an extension with a contract end date of May 31, 2021.
We believe that our $9.6 million in cash and cash equivalents on hand as of September 30, 2020, and the expected CPRIT funds available are sufficient to fund our anticipated operating and capital requirements into the second half of 2021, however, we will continue to require substantial additional capital to continue our clinical development activities. Accordingly, we will need to raise substantial additional capital to continue to fund our operations as a whole. The amount and timing of our future funding requirements will depend on many factors, including the pace and results of our development, regulatory and commercialization efforts. Failure to raise capital as and when needed, on favorable terms or at all, would have a negative impact on our financial condition and our ability to develop and commercialize our product candidates and to fund our operations.
We intend, when required, to obtain additional capital through the sale of equity securities in one or more offerings or through issuances of debt instruments. We may also consider new collaborations or selectively partnering our technology. However, we cannot provide any assurance that we will be successful in accomplishing any of our plans to obtain additional capital or be able to do so on favorable terms or on terms acceptable to us.
Corporate Information
    We were incorporated as Flex Pharma, Inc. (“Flex Pharma”) in Delaware in February 2014. In July 2019, our wholly owned subsidiary, Falcon Acquisition Sub, LLC, merged with and into Salarius Pharmaceuticals, LLC (“Private Salarius”), with Private Salarius becoming our wholly owned subsidiary (the “Merger”), and we changed our named to Salarius Pharmaceuticals, Inc. Our principal executive offices are located at 2450 Holcombe Blvd., Suite X, Houston, TX 77021, and our telephone number is (832) 834-6992. Our website address is www.salariuspharma.com. We do not incorporate the information on, or accessible through, our website into this prospectus, and you should not consider any information on, or accessible through, our website as part of this prospectus.

    The Merger is deemed to be a reverse acquisition under the guidance of ASC 805 and, as such, Private Salarius has been determined to be the accounting acquirer in the Merger, but not the legal acquirer. As a result, upon consummation of the Merger, the historical financial statements of Private Salarius became the historical financial statements of Salarius, the combined company.


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THE OFFERING
Securities offered by the selling stockholders
3,964,065 shares of our common stock issuable upon exercise of the Warrants.


Common stock outstanding immediately prior to this offering
23,808,546 shares.

Terms of the offering

The selling stockholders will determine when and how they will sell the common stock offered in this prospectus, as described in “Plan of Distribution.”

Use of proceeds
We will not receive any proceeds from the sale of the shares of common stock covered by this prospectus.

Risk factors
See “Risk Factors” beginning on page 6, for a discussion of factors you should carefully consider before deciding to invest in our common stock.

Nasdaq Capital Market symbolOur common stock is listed on the Nasdaq Capital Market under the symbol “SLRX.” On January 14, 2020, the last reported sale price of our common stock on the Nasdaq Capital Market was $1.16 per share.
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RISK FACTORS
Investing in our securities involves risk. Prior to making a decision about investing in our securities, you should carefully consider the specific factors discussed under the heading “Risk Factors” included in or incorporated by reference into the applicable prospectus supplement together with all of the other information contained in the prospectus supplement or appearing in or incorporated by reference into this prospectus, including the risk factors incorporated by reference to our most recent Annual Report on Form 10-K, any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and any amendments made thereto. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities.

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USE OF PROCEEDS
We will retain broad discretion over the use of the netnot receive any proceeds from the sale of the securitiesshares offered hereby. Except as described in any applicable prospectus supplement or in any free writing prospectuses we have authorized for use in connection with a specific offering, we currently intendpursuant to usethis prospectus. The selling stockholders will receive all of the net proceeds from the sale of the securitiesshares of common stock offered by this prospectus. For information about the selling stockholders, see “Selling Stockholders.” Assuming all of the Warrants are exercised for 3,964,065 shares of common stock by payment of cash, we will receive aggregate gross proceeds of approximately $3.6 million.

    The selling stockholders will pay any underwriting discounts and commissions and expenses incurred by the selling stockholders for brokerage, accounting, tax or legal services or any other expenses incurred by the selling stockholders in disposing of the shares. We will bear all other costs, fees and expenses incurred in effecting the registration of the shares covered by this prospectus, including all registration and filing fees and fees and expenses of our counsel and accountants.
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SELLING STOCKHOLDERS
We have prepared this prospectus to allow the selling stockholders or their pledgees, donees, transferees or other successors in interest, to offer for resale, from time to time, up to 3,964,065 shares of our common stock issuable to the selling stockholders upon exercise of the Warrants currently held by the respective selling stockholders.
    On February 11, 2020, Salarius consummated a registered public offering of 7,101,307 Class A units and 1,246,519 Class B units. Each Class A unit consisted of one share of the Company’s common stock and a five-year warrant to purchase one share of Common Stock at an exercise price of $1.15 per share. Each Class B unit consisted of one share of the Company’s Series A convertible preferred stock, par value $0.0001 per share, and a warrant.
    On December 11, 2020, the Company entered into warrant exercise inducement offer letters (“Inducement Letters”) with the selling stockholders pursuant to which such holders agreed to exercise for cash, their Warrants to purchase 3,964,065 shares of common stock in exchange for the Company’s agreement to (i) lower the exercise price of the Warrants held by the selling stockholders to $0.90 and (ii) issue new warrants to purchase up to 3,964,065 shares of Common Stock. Each of the new warrants is exercisable at a price per share of $1.182 and expires on June 11, 2026. The Company also agreed to file a registration statement covering the resale of the shares of common stock issued or issuable upon the exercise of the Warrants no later than 15 days following the date of the Inducement Letters.

The table below lists the selling stockholders and other information regarding the beneficial ownership of the common shares by each of the selling stockholders. The second column lists the number of common shares beneficially owned by each selling stockholder, based on its ownership of the common shares and warrants, as of January 12, 2021, assuming exercise of any warrants held by the selling stockholders on that date, without regard to any limitations on exercises. The third column lists the common shares being offered by this prospectus by the selling stockholders.
    We do not know if, when or in what amounts the selling stockholders may offer their shares for sale. The selling stockholders may sell some, all or none of the shares offered by this prospectus. Because the number of shares the selling stockholders may offer and sell is not presently known, and because there are currently no agreements, arrangements or understandings with respect to the sale of any of the shares, we cannot estimate the number of shares that will be held by each selling stockholder after completion of this offering.


Shares Beneficially Owned Prior to the Offering(1)
Maximum Number of Shares of Common Stock to be Offered Pursuant to this Prospectus
Shares Beneficially Owned
After the Offering(1)(2)


Name of Selling
Stockholder
NumberPercentage of Outstanding Common StockNumberPercentage of Outstanding Common Stock
Armistice Capital Master Fund Ltd.(3)
999,9994.2%855,146144,853*
AIGH Investment Partners LP(4) (7)
963,0434.0%876,08786,956*
WVP Emerging Manager Onshore Fund, LLC – AIGH Series(5) (7)
265,5641.1%178,60886,956*
WVP Emerging Manager Onshore Fund, LLC – Optimized Equity Series(6)(7)
162,695*75,73986,956*
Lincoln Park Capital Fund LLC(8)
1,370,9385.8%804,347566,5912.4%
Alpha Capital Anstalt(9)
671,1042.8%485,869185,235*
Hudson Bay Master Fund Ltd.(10)
804,3473.4%688,269116,078*
TOTALS5,237,69021.3%3,964,0651,273,6252.4%
* Less than 1%
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(1)For purposes of calculating beneficial ownership, we have assumed the exercise of any warrants held by the selling stockholders, without regard to any limitations on exercises and is otherwise determined in accordance with Rule 13d-3 under the Exchange Act. Under such rule, beneficial ownership includes any shares over which the selling stockholder has sole or shared voting power or investment power and any shares that the selling stockholder has the right to acquire within 60 days of such date through the exercise of any options or other rights. The percentage of shares beneficially owned is based on 23,808,546 shares of our common stock outstanding at the close of business on January 12, 2021.
(2)Assumes that the selling stockholders dispose of all of the shares of common stock covered by this prospectus and do not acquire beneficial ownership of any additional shares.
(3)Includes 999,999 shares of common stock issuable upon exercise of warrants held by Armistice Capital Master Fund Ltd., a Cayman Islands exempted company (the “Master Fund”), which are subject to certain beneficial ownership limitations. The shares are directly held by Master Fund and may be deemed to be indirectly beneficially owned by: (i) Armistice Capital, LLC (“Armistice Capital”), as the investment manager of the Master Fund; and (ii) Steven Boyd, as the Managing Member of Armistice Capital. Armistice Capital and Steven Boyd disclaim beneficial ownership of the securities except to the extent of their respective pecuniary interests therein.
(4)Includes (i) 876,087 shares of common stock issuable upon exercise of warrants held by AIGH Investment Partners, L.P. (“AIGH IP LP”) and (ii) 86,956 shares of common stock issuable upon exercise of warrants held by AIGH Investment Partners LLC (“AIGH LLC”) all of which are subject to certain beneficial ownership limitations.
(5)Includes (i) 178,608 shares of common stock issuable upon exercise of warrants held by WVP Emerging Manager Onshore Fund, LLC - AIGH Series (“WVP AIGH”) and (ii) 86,956 shares of common stock issuable upon exercise of warrants held by AIGH LLC all of which are subject to certain beneficial ownership limitations.
(6)Includes (i) 75,739 shares of common stock issuable upon exercise of warrants held by WVP Emerging Manager Onshore Fund, LLC - Optimized Equity Series (“WVP OES”), and (ii) 86,956 shares of common stock issuable upon exercise of warrants held by AIGH LLC all of which are subject to certain beneficial ownership limitations.
(7)Mr. Orin Hirschman is the managing member of AIGH Capital Management, LLC, a Maryland limited liability company (“AIGH CM”), who is an advisor or sub-advisor with respect to the securities held by AIGH IP LP, WVP AIGH, and WVP OES, and president of AIGH LLC.  Mr. Hirschman has voting and investment control over the securities indirectly held by AIGH CM, directly by AIGH IP, AIGH LLC and Mr. Hirschman and his family directly. The address for AIGH CM, AIGH IP, AIGH LLC and Mr. Hirschman is 6006 Berkeley Avenue, Baltimore, Maryland 21209.  
(8)Includes (i) 599,591 shares of common stock and (ii) 804,347 shares of common stock issuable upon exercise of warrants held by Lincoln Park Capital Fund LLC which are subject to certain beneficial ownership limitations. Joshua Scheinfeld and Jonathan Cope, the principals of Lincoln Park are deemed to be beneficial owners of all the common stock owned by Lincoln Park. Messrs. Scheinfeld and Cope have shared voting power over the shares.
(9)Includes (i) 185,235 shares of common stock and (ii) 485,869 shares of common stock issuable upon exercise of warrants held by Alpha Capital Anstalt which are subject to certain beneficial ownership limitations. Nicola Feuerstein has sole voting and dispositive power over the securities held for the account of this selling stockholder. The selling stockholder’s address is Lettstrasse 32, 9490 Vaduz, Principality of Liechtenstein.
(10) Includes 804,347 shares of common stock issuable upon exercise of warrants held by Hudson Bay Master Fund Ltd. which are subject to certain beneficial ownership limitations. Hudson Bay Capital Management LP, the investment manager of Hudson Bay Master Fund Ltd., has voting and investment power over these securities. Sander Gerber is the managing member of Hudson Bay Capital GP LLC, which is the general partner of Hudson Bay Capital Management LP. Each of Hudson Bay Master Fund Ltd. and Sander Gerber disclaims beneficial ownership over these securities.


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PLAN OF DISTRIBUTION
We are registering the shares of common stock issuable upon exercise of our outstanding Warrants to permit the resale of these shares of common stock by the selling stockholders after the date of this prospectus. We will not receive any of the proceeds from the sale by the selling stockholders of the shares of common stock, except with respect to amounts received by us hereunder, if any,upon the exercise of the Warrant for general corporate purposes, whichcash. We will bear all fees and expenses incident to our obligation to register the shares of common stock.

    The selling stockholders may include research and development, capital expenditures, working capital and general and administrative expenses. We may also usesell all or a portion of the net proceeds to acquire or invest in businesses, products and technologies that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus.We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus. Pending these uses, we intend to invest the net proceeds in investment-grade, interest-bearing securities as well as money market mutual funds.

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DESCRIPTION OF CAPITAL STOCK
Our authorized capital stock consists of 100,000,000 shares of common stock $0.0001 par value per share,held by it and 10,000,000 shares of preferred stock, $0.0001 par value per share. A description of material terms and provisions of our certificate of incorporation and bylaws affecting the rights of holders of our capital stock is set forth below. The description is intended as a summary, and is qualified in its entirety by reference to our certificate of incorporation and the bylaws.
As of March 17, 2016 there were 17,956,817 shares of common stock outstanding, no shares of preferred stock outstanding and warrants and options to purchase an aggregate of 2,344,130 shares of common stock outstanding.
Common stock

Voting rights. Holders of our common stock are entitled to one vote for each share of common stock held of record on all matters submitted to a vote of the stockholders, including the election of directors, and do not have cumulative voting rights.
Dividend rights. Subject to preferences that may be applicable to any then outstanding preferred stock, holders of our common stock are entitled to receive dividends, if any, as may be declaredoffered hereby from time to time by our board of directors out of legally available funds.
Liquidation. Indirectly or through one or more underwriters, broker-dealers or agents. If the event of our liquidation, dissolution or winding up, holders of our common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities, subject to the satisfaction of any liquidation preference granted to the holders of any then outstanding shares of preferred stock.
Rights and Preferences. Holders of our common stock have no preemptive, conversion, subscription or other rights, and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of our common stock are subject to and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that we may designate and issue in the future.
Fully Paid and Nonassessable. All outstanding shares of common stock are fully paidsold through underwriters or broker-dealers, the selling stockholders will be responsible for underwriting discounts or commissions or agent’s commissions. The shares of common stock may be sold in one or more transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale or at negotiated prices. These sales may be effected in transactions pursuant to one or more of the following methods:

on any national securities exchange or quotation service on which the securities may be listed or quoted at the time of sale;
in the over-the-counter market;
in transactions otherwise than on these exchanges or systems or in the over-the-counter market;
through the writing or settlement of options, whether such options are listed on an options exchange or otherwise;
ordinary brokerage transactions and nonassessable,transactions in which the broker-dealer solicits purchasers;
block trades in which the broker-dealer will attempt to sell the shares as agent but may position and resell a portion of the block as principal to facilitate the transaction;
purchases by a broker-dealer as principal and resale by the broker-dealer for its account;
an exchange distribution in accordance with the rules of the applicable exchange;
privately negotiated transactions;
short sales made after the date the registration statement of which this prospectus forms a part is declared effective by the SEC;
broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share;
a combination of any such methods of sale; and
any other method permitted pursuant to applicable law.

The selling stockholders may also sell the shares of common stock under Rule 144 promulgated under the Securities Act, or any other exemption under the Securities Act, if available, rather than under this prospectus.
In connection with distributions of the shares or otherwise, each selling stockholder is permitted to enter into hedging transactions with broker-dealers or other financial institutions. In connection with such permitted transactions, broker-dealers or other financial institutions may engage in short sales of the common stock in the course of hedging the positions they assume with a selling stockholder. Each selling stockholder may also sell the common stock short and redeliver the shares to close out such permitted short positions. Each selling stockholder may also enter into option or other transactions with broker-dealers or other financial institutions that require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus, as supplemented or amended to reflect such transaction. Each selling stockholder may also pledge shares to a broker-dealer or other financial institution, and, upon a default, such broker-dealer or other financial institution, may effect sales of the pledged shares pursuant to this prospectus, as supplemented or amended to reflect such transaction.
In effecting sales, broker-dealers or agents engaged by a selling stockholder may arrange for other broker-dealers to participate. Broker-dealers or agents may receive commissions, discounts or concessions from the selling stockholder in amounts to be negotiated immediately prior to the sale.
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In offering the shares covered by this prospectus, the selling stockholders and any broker-dealers who execute sales for the selling stockholders may be deemed “underwriters” within the meaning of the Securities Act in connection with such sales. Any profits realized by a selling stockholder and the compensation of any broker-dealers may be deemed to be underwriting discounts and commissions.
In order to comply with the securities laws of some states, if applicable, the shares must be sold in those states only through registered or licensed brokers or dealers. In addition, some states may restrict the selling stockholders from selling their respective shares unless such shares have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and is complied with.
The selling stockholders and any other person participating in such distribution will be subject to applicable provisions of the Exchange Act and the rules and regulations thereunder, including, without limitation, to the extent applicable, Regulation M of the Exchange Act, which may limit the timing of purchases and sales of any of the shares of common stock by the selling stockholders and any other participating person. To the extent applicable, Regulation M may also restrict the ability of any person engaged in the distribution of the shares of common stock to be issued under this prospectus, when they are paid for, will be fully paid and nonassessable.
Preferred stock

Our board of directors hasengage in market-making activities with respect to the authority, without further action by our stockholders, to issue up to 10,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. The issuanceAll of our preferred stock could adverselythe foregoing may affect the voting powermarketability of holdersthe shares of common stock and the likelihoodability of any person or entity to engage in market-making activities with respect to the shares of common stock. The selling stockholders may indemnify any broker-dealer that such holders will receive dividend payments and payments upon liquidation. In addition,participates in transactions involving the issuance of preferred stock could have the effect of delaying, deferring or preventing a change of control of our company or other corporate action.
Our board of directors will fix the designations, voting powers, preferences and rightssale of the preferredshares against some liabilities, including liabilities arising under the Securities Act.

    There can be no assurance that the selling stockholders will sell any or all of the shares of common stock of each series we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibitregistered pursuant to the registration statement, of which this prospectus isforms a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that contains the terms of the series of preferred stock we are offering. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:
the title and stated value;
the number of shares we are offering;
the liquidation preference per share;
the purchase price;
the dividend rate, period and payment date and method of calculation for dividends;
whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

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the procedures for any auction and remarketing, if applicable;
the provisions for a sinking fund, if applicable;
the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;
any listing of the preferred stock on any securities exchange or market;
whether the preferred stock will be convertible into our common stock or other equity securities, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;
whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange price, or how it will be calculated, and the exchange period;
voting rights, if any;
preemptive rights, if any;
restrictions on transfer, sale or other assignment, if any;
whether interests in the preferred stock will be represented by depositary shares;
a discussion of material or special U.S. federal income tax considerations applicable to the preferred stock;
the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;
any limitations on the issuance of any class or series of preferred stock ranking senior to or on parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and
any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.
The laws of the state of Delaware, the state of our incorporation, provide that the holders of preferred stock will have the right to vote separately as a class on any proposal involving fundamental changes in the rights of holders of such preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

If we issue and sell shares of preferred stock pursuant to this prospectus, the shares will be fully paid and nonassessable and will not have, or be subject to, any preemptive or similar rights. The issuance of preferred stock could adversely affect the voting power, conversion or other rights of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. Preferred stock could be issued quickly with terms designed to delay, deter or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of our common stock.
Forum

Our amended and restated certificate of incorporation provides that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf, any action asserting a claim of breach of a fiduciary duty owed by any director, officer or other employee of the company to us or our stockholders, any action asserting a claim arising pursuant to any provision of the Delaware General Corporation Law, or any action asserting a claim governed by the internal affairs doctrine. Our amended and restated certificate of incorporation further provides that any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock is deemed to have notice of and consented to the foregoing provision. Although our amended and restated certificate of incorporation includes these provisions, it is possible that a court could rule that such provisions are inapplicable or unenforceable

Anti-takeover Provisions
Certificate of Incorporation and Bylaws. Our amended and restated certificate of incorporation provides for our board of directors to be divided into three classes, with staggered three-year terms. Only one class of directors will be elected at each annual meeting of our stockholders, with the other classes continuing for the remainder of their respective three-year terms. Because our stockholders do not have cumulative voting rights, our stockholders holding a majority of the shares of common stock outstanding will be able to elect all of

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our directors. Our amended and restated certificate of incorporation and amended and restated bylaws provide that all stockholder action must be effected at a duly called meeting of stockholders and not by a consent in writing, and that only our board of directors or chairman of the board may call a special meeting of stockholders.
Our amended and restated certificate of incorporation requires a 662/3% stockholder vote for the amendment, repeal or modification of certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws relating to the classification of our board of directors, the requirement that stockholder actions be effected at a duly called meeting, and the designated parties entitled to call a special meeting of the stockholders. The combination of the classification of our board of directors, the lack of cumulative voting and the 662/3% stockholder voting requirements will make it more difficult for our existing stockholders to replace our board of directors as well as for another party to obtain control of us by replacing our board of directors. Since our board of directors has the power to retain and discharge our officers, these provisions could also make it more difficult for existing stockholders or another party to effect a change in management. In addition, the authorization of undesignated preferred stock makes it possible for our board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change control of our company.
These provisions may have the effect of deterring hostile takeovers or delaying changes in control of our company or management. These provisions are intended to enhance the likelihood of continued stability in the composition of our board of directors and its policies and to discourage certain types of transactions that may involve an actual or threatened acquisition of us. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal. The provisions also are intended to discourage certain tactics that may be used in proxy fights. However, such provisions could have the effect of discouraging others from making tender offers for our shares and, as a consequence, they also may inhibit fluctuations in the market price of our shares that could result from actual or rumored takeover attempts. Such provisions may also have the effect of preventing changes in our management.
Section 203 of the Delaware General Corporation Law
We are subject to Section 203 of the Delaware General Corporation Law, which prohibits a publicly-held Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:
before such date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested holder;
upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or
on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of at least 50% of the outstanding voting stock that is not owned by the interested stockholder.
In general, Section 203 defines business combination to include the following:
any merger or consolidation involving the corporation and the interested stockholder;
any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;
subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;
any transaction involving the corporation that has the effect of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; or
the receipt by the interested stockholder of the benefit of any loss, advances, guarantees, pledges or other financial benefits by or through the corporation.
In general, Section 203 defines an "interested stockholder" as an entity or person who, together with the person's affiliates and associates, beneficially owns, or within three years prior to the time of determination of interested stockholder status did own, 15% or more of the outstanding voting stock of the corporation.

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Transfer Agent and Registrar
The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar’s address is P.O. Box 43078, Providence, Rhode Island 02940. The transfer agent for any series of preferred stock that we may offerpart. Once sold under this prospectus will be named and described in the prospectus supplement for that series.
Listing on the Nasdaq Global Market
Our common stock is listed on the Nasdaq Global Market under the symbol “FLKS”. The applicable prospectus supplement will contain information, where applicable, as to other listing, if any, on the Nasdaq Global Market or other securities exchange of the preferred stock covered by such prospectus supplement.

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DESCRIPTION OF DEBT SECURITIES
We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.
We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We have filed the form of indenture as an exhibit to the registration statement, of which this prospectus isforms a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.
The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.
General
The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.
We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.
We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:
the title of the series of debt securities;
any limit upon the aggregate principal amount that may be issued;
the maturity date or dates;
the form of the debt securities of the series;
the applicability of any guarantees;
whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;
whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;
if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;
the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

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our right, if any, to defer payment of interest and the maximum length of any such deferral period;
if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;
the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;
the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;
any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;
whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;
if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;
if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;
additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;
additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;
additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;
additions to or changes in the provisions relating to satisfaction and discharge of the indenture;
additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;
the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;
whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;
the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;
any restrictions on transfer, sale or assignment of the debt securities of the series; and
any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.
Conversion or Exchange Rights
We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange

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and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.
Consolidation, Merger or Sale
Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.
Events of Default under the Indenture
Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:
if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;
if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;
if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and
if specified events of bankruptcy, insolvency or reorganization occur.
If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.
The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.
Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:
the direction so given by the holder is not in conflict with any law or the applicable indenture; and
subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.
A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

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the holder has given written notice to the trustee 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 written request, and such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and
the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.
These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.
We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.
Modification of Indenture; Waiver
We and the trustee may change an indenture without the consent of any holders with respect to specific matters:
to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;
to comply with the provisions described above under “Description of Debt Securities—Consolidation, Merger or Sale;”
to provide for uncertificated debt securities in addition to or in place of certificated debt securities;
to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;
to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;
to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;
to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under “Description of Debt Securities—General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;
to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or
to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.
In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:
extending the fixed maturity of any debt securities of any series;
reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or
reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.



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Discharge
The indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:
provide for payment;
register the transfer or exchange of debt securities of the series;
replace stolen, lost or mutilated debt securities of the series;
pay principal of and premium and interest on any debt securities of the series;
maintain paying agencies;
hold monies for payment in trust;
recover excess money held by the trustee;
compensate and indemnify the trustee; and
appoint any successor trustee.
In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.
Form, Exchange and Transfer
We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company, or DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book entry securities will be set forth in the applicable prospectus supplement.
At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.
Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.
We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.
If we elect to redeem the debt securities of any series, we will not be required to:
issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or
register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.


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Information Concerning the Trustee
The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.
Payment and Paying Agents
Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.
We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.
All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.
Governing Law
The indenture and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.

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DESCRIPTION OF WARRANTS
The following description, together with the additional information we may include in any applicable prospectus supplements and free writing prospectuses, summarizes the material terms and provisions of the warrants that we may issue under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be issued independently or together with common stock, preferred stock or debt securities offered by any prospectus supplement, and may be attached to or separate from those securities. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants that we may offer in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.
We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.
General
We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including:
the offering price and aggregate number of warrants offered;
the currency for which the warrants may be purchased;
if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;
if applicable, the date on and after which the warrants and the related securities will be separately transferable;
in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;
in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case maywill be purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;
the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;
the terms of any rights to redeem or call the warrants;
the terms of any rights to force the exercise of the warrants;
any provisions for changes to or adjustmentsfreely tradable in the exercise price or numberhands of securities issuable upon exercise of the warrants;
the dates on which the right to exercise the warrants will commence and expire;
the manner in which the warrant agreements and warrants may be modified;
a discussion of any material or special U.S. federal income tax considerations of holding or exercising the warrants;
the terms of the securities issuable upon exercise of the warrants; and

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any other specific terms, preferences, rights or limitations of or restrictions on the warrants.
Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:
in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or
in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.
Exercise of Warrants
Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.
Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant or warrant certificate, as applicable, representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth in the applicable warrant or warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent in connection with the exercise of the warrant.
Upon receipt of the required payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.
Governing Law
Unless we otherwise specify in the applicable prospectus supplement, the warrants and any warrant agreements will be governed by and construed in accordance with the laws of the State of New York.
Enforceability of Rights by Holders of Warrants
Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

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LEGAL OWNERSHIP OF SECURITIES
We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.
Book-Entry Holders
We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.
Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.
As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.
Street Name Holders
We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.
For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.
Legal Holders
Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.
For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the legal holders.
Special Considerations for Indirect Holders

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If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:
how it handles securities payments and notices;
whether it imposes fees or charges;
how it would handle a request for the holders’ consent, if ever required;
whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;
how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and
if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.
Global Securities
A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.
Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, DTC will be the depositary for all securities issued in book-entry form.
A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below in the section titled “Special Situations When a Global Security Will Be Terminated” in this prospectus. As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.
If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.
Special Considerations for Global Securities
The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.
If securities are issued only in the form of a global security, an investor should be aware of the following:
an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;
an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;
an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;
an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

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the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;
we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security, nor do we or any applicable trustee supervise the depositary in any way;
the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and
financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.
There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.
Special Situations When a Global Security Will Be Terminated
In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.
Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:
if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;
if we notify any applicable trustee that we wish to terminate that global security; or
if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.
The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

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PLAN OF DISTRIBUTION
We may sell the securities from time to time pursuant to underwritten public offerings, direct sales to the public, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:
at a fixed price or prices, which may be changed;
at market prices prevailing at the time of sale;
at prices related to such prevailing market prices; or
at negotiated prices.
We may also sell equity securities covered by this registration statement in an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended, or the Securities Act. Such offering may be made into an existing trading market for such securities in transactions at other than a fixed price, either:
on or through the facilities of the Nasdaq Global Market or any other securities exchange or quotation or trading service on which such securities may be listed, quoted or traded at the time of sale; and/or
to or through a market maker otherwise than on the Nasdaq Global Market or such other securities exchanges or quotation or trading services.
Such at-the-market offerings, if any, may be conducted by underwriters acting as principal or agent.
A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:
the name or names of the underwriters, if any;
the purchase price of the securities or other consideration therefor, and the proceeds, if any, we will receive from the sale;
any over-allotment options under which underwriters may purchase additional securities from us;
any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;
any public offering price;
any discounts or concessions allowed or reallowed or paid to dealers; and
any securities exchange or market on which the securities may be listed.
Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement.
If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.
We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.
We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery

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on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.
We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.
All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.
Any underwriter may engage in over-allotment, stabilizing transactions, short-covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment 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 price. 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 stabilizing or 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.
Any underwriters or agents that are qualified market makers on the Nasdaq Global Market may engage in passive market making transactions in the securities on the Nasdaq Global Market in accordance with Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.
In compliance with guidelines of the Financial Industry Regulatory Authority, Inc. or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

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LEGAL MATTERS
Unless otherwise indicated in the applicable prospectus supplement, theThe validity of theany securities offered by this prospectus and any supplement thereto, will be passed upon for us by CooleyPillsbury Winthrop Shaw Pittman LLP, Boston, Massachusetts.Houston, Texas.
EXPERTS
The    Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements of Flex Pharma, Inc. atincluded in our Annual Report on Form 10-K for the year ended December 31, 20152019, as set forth in their report, which is incorporated by reference in this prospectus supplement and 2014,elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s report, given on their authority as experts in accounting and auditing.
    The financial statements of Salarius Pharmaceuticals, LLC, a Delaware limited liability company and a wholly owned subsidiary of Salarius Pharmaceuticals, Inc. as of and for the year December 31, 2018 have been audited by Weaver and Tidwell, L.L.P., independent registered public accounting firm, as stated in their report dated March 25, 2019, except for the effects of the recast of equity to which the date is January 10, 2020 with respect to the audit of the balance sheet of Salarius Pharmaceuticals, LLC as of December 31, 2018 and the related consolidated statements of operations, comprehensive loss, convertible preferred stock and stockholders' equity (deficit),changes in stockholders’ deficit and cash flows for the year ended December 31, 2015 and for2018, which report appears in the period from February 26, 2014 (inception) to December 31, 20142019 annual report on Form 10-K of Salarius Pharmaceuticals, Inc. and is incorporated by reference in this Prospectusprospectus supplement and Registration Statement have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forthelsewhere in their report,the registration statement. Such financial statements are incorporated by reference and are included in reliance upon such report given onthe reports of Weaver and Tidwell, L.L.P., and upon the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION
This prospectus is part of the registration statement filed with the SEC under the Securities Act and does not contain all the information set forth in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus for a copy of such contract, agreement or other document.
Because we are subject to the information and reporting requirements of the Exchange Act, weWe file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the internetInternet at the SEC’s website at http://www.sec.gov. You may also read and copy any document we file at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for furtherwww.sec.gov. Copies of certain information on the operation of the Public Reference Room.
You may also access our filingsfiled by us with the SEC are also available on our web site, www.flex-pharma.com. Other than those filings with the SEC that we specifically incorporate by reference into this prospectus or any supplement to this prospectus, information found on, or accessible through, ourwebsite at www.salariuspharma.com. Our website is not a part of this prospectus and is not incorporated into,by reference in this prospectus. This prospectus is part of a registration statement we filed with the SEC. This prospectus omits some information contained in the registration statement in accordance with SEC rules and regulations. You should review the information and exhibits in the registration statement for further information about us and the securities we are offering. Statements in this prospectus concerning any document we filed as an exhibit to the registration statement or that we otherwise filed with the SEC are not intended to be comprehensive and youare qualified by reference to these filings. You should not consider it part of this prospectus.review the complete document to evaluate these statements.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
The SEC allowspermits us to “incorporate by reference” the information from othercontained in documents that we file with it,the SEC, which means that we can disclose important information to you by referring you to those documents. The informationdocuments rather than by including them in this prospectus. Information that is incorporated by reference is considered to be part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filedand you should read it with the SEC prior to the date ofsame care that you read this prospectus, whileprospectus. Later information that we file later with the SEC will automatically update and supersede the information in this prospectus.
We incorporatethat is either contained, or incorporated by reference, intoin this prospectus, and the registration statementwill be considered to be a part of which this prospectus forms a partfrom the information ordate those documents listed below that weare filed. We have filed with the SEC:SEC, and incorporate by reference in this prospectus:
our Annual Report on Form 10-K for the fiscal year ended December 31, 2019, filed on March 23, 2020;

our Quarterly Report on Form 10-Q for the quarters ended March 31, 2020, June 30, 2020 and September 30, 2020, filed on May 14, 2020 (as amended on May 15, 2020), August 12, 2020 and November 12, 2020, respectively;

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our Current Reports on Form 8-K filed on February 12, 2020March 11, 2020April 10, 2020April 29, 2020June 18, 2020June 19, 2020, July  29, 2020, August 3, 2020, October 6, 2020, and December 11, 2020 (as amended on December 11, 2020);

the information contained in our definitive proxy statement on Schedule 14A filed on April 29, 2020 and incorporated by reference into Part III of our Annual Report on Form 10-K for the year ended December 31, 2015, filed on March 8, 2016;
our Current Report on Form 8-K filed on March 9, 2016 ;2019; and

the description of our common stock contained in our Registration Statement on Form 8-A filed on January 23, 2015, including any amendmentsamendment or reportsreport filed for the purposespurpose of updating thissuch description.

We are not, however, incorporating, in each case, any documents or information that we are deemed to furnish and not file in accordance with SEC rules.
We also incorporate by reference any filingsall additional documents that we may makefile with the SEC under the terms of Section 13(a), 13(c), 14 or 15(d) of the Exchange Act (i)that are made after the initial filing date of the filing of the registration statement of which this prospectus is a part and prior tothe effectiveness of suchthe registration statement, and (ii) afteras well as between the date of this prospectus but prior toand the termination of theany offering of the securities coveredoffered by this prospectus. We will not, however, incorporate by reference in this prospectus (excluding any documents or portions thereof that arefurnished by the Registrant, including but not deemed “filed” with the SEC, including anylimited to information furnished pursuantunder Item 2.02 and Item 7.01 and any exhibits relating to Item 2.02 or Item 7.01 furnished under Item 9.01 of our current reports on Form 8-K unless, and exceptany certification required by 18 U.S.C. § 1350).
Any statement contained in this Registration Statement or in a document incorporated by reference in this Registration Statement shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent specifiedthat a statement contained in this Registration Statement or in any subsequently filed document that is deemed to be incorporated by reference in this Registration Statement modifies or supersedes such current reports.

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We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, on written or oralYou may request a copy of any or all of the documents incorporated by reference inbut not delivered with this prospectus, including exhibits to these documents. You may request a copy of these filingsat no cost, by writing us at 800 Boylston Street, 24th Floor, Boston, MA 02199 or telephoning us at (617) 874-1821.
You also may access these filings onthe following address and number:  2450 Holcombe Blvd., Suite X, Houston, TX 77021, and our website at www.flex-pharma.com.telephone number is (832) 834-6992. We dowill not, incorporatehowever, send exhibits to those documents, unless the information on our website into this prospectus or any supplement to this prospectus and you should not consider any information on, or that can be accessed through, our website as part of this prospectus or any supplement to this prospectus (other than those filings with the SEC that weexhibits are specifically incorporate by reference into this prospectus or any supplement to this prospectus).
Any statement contained in a document incorporated or deemed to be incorporated by reference in this prospectus will be deemed modified, supersededthose documents.
We make available free of charge on our website our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports, as soon as reasonably practicable after we electronically file or replaced for purposes of this prospectusfurnish such materials to the extent thatSEC. You may obtain a statement containedfree copy of these reports in this prospectus or in any other subsequently filed document that also is or is deemed to be incorporated by reference in this prospectus modifies, supersedes or replaces such statement. Any statement that is modified or superseded will not constitute a partthe Investor Relations section of this prospectus, except as modified or superseded.our website, www.salariuspharma.com.

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$125,000,000
Common Stock
Preferred Stock
Debt Securities
Warrants





Prospectus



, 2015











PART II
INFORMATION NOT REQUIRED IN THE PROSPECTUS
Item 14. Other Expenses of Issuance and DistributionDistribution.
The following table sets forth an estimateis a statement of the fees andestimated expenses other than any underwriting discounts and commissions, payable by us in connection with the issuance and distribution of the securities being registered. All the amounts shown are estimates, except for the SEC registration fee.registered, other than underwriting discounts and commissions.

  Amount 
SEC registration fee $12,587.50 
Nasdaq Global Market listing fee  (1) 
FINRA filing fee (if applicable)  (1) 
Accounting fees and expenses  (1) 
Legal fees and expenses  (1) 
Transfer agent and registrar fees and expenses  (1) 
Printing and miscellaneous fees and expenses  (1) 
     
Total $(1) 

(1)SEC Registration FeeThese fees are calculated based on the securities offered$ 500
Legal Fees and the number of issuancesExpenses$ 25,000
Accounting Fees and accordingly cannot be estimated at this time.Expenses$ 30,000
Miscellaneous Expenses$ 5,000
Total$ 60,500

Item 15. Indemnification of Directors and OfficersOfficers.
The registrant isWe are incorporated under the laws of the State of Delaware. Section 145 of the DGCL provides that a Delaware General Corporation Law (referredcorporation may indemnify any persons who were, are, or are threatened to be made, parties to any threatened, pending, or completed action, suit, or proceeding, whether civil, criminal, administrative, or investigative (other than an action by or in the right of such corporation), by reason of the fact that such person is or was an officer, director, employee, or agent of such corporation, or is or was serving at the request of such corporation as an officer, director, employee, or agent of another corporation, partnership, joint venture, trust, or other enterprise. The indemnity may include expenses (including attorneys’ fees), judgments, fines, and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit, or proceeding, provided that such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the “DGCL”) authorizescorporation’s best interests and, with respect to any criminal action or proceeding, had no reasonable cause to believe that his or her conduct was illegal. A Delaware corporation may indemnify any persons who were, are, or are threatened to be made, a courtparty to award,any threatened, pending, or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that such person is or was a director, officer, employee, or agent of such corporation, or is or was serving at the request of such corporation as a director, officer, employee, or agent of another corporation, partnership, joint venture, trust, or other enterprise. The indemnity may include expenses (including attorneys’ fees) actually and reasonably incurred by such person in connection with the defense or settlement of such action or suit provided such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the corporation’s best interests, except that no indemnification is permitted without judicial approval if such person is adjudged to be liable to the corporation. Where an officer or director is successful on the merits or otherwise in the defense of any action referred to above or in defense of any claim, issue, or matter therein, the corporation must indemnify him or her against the expenses (including attorneys’ fees) actually and reasonably incurred.
Our amended and restated certificate of incorporation and amended and restated bylaws provide for the indemnification of our directors and officers to the fullest extent permitted under the DGCL.
Section 102(b)(7) of the DGCL permits a corporation to provide in its certificate of incorporation that a director of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duties as a director, except for liability for any:
transaction from which the director derives an improper personal benefit;
act or omission not in good faith or that involves intentional misconduct or knowing violation of law;
unlawful payment of dividends or unlawful stock purchase or redemption; or
breach of a director’s duty of loyalty to the corporation or its stockholders.
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Our amended and restated certificate of incorporation includes such a provision. Expenses incurred by any officer or director in defending any such action, suit, or proceeding in advance of its final disposition will be paid by us, provided, however, that if the DGCL requires, such advancement will be made only upon delivery to us of an undertaking, by or on behalf of such director or officer, to repay all amounts so advanced if it shall ultimately be determined that such director or officer is not entitled to be indemnified by us.
Section 174 of the DGCL provides, among other things, that in the case of any willful or negligent approval of an unlawful payment of dividends or an unlawful stock purchase or redemption, the directors under whose administration such violation happened may be held liable for such actions. A director who was either absent when the unlawful actions were approved or dissented at the time may avoid liability by causing his or her dissent to such actions to be entered in the books containing minutes of the meetings of the board of directors to grant, indemnity to directors and officers in terms sufficiently broad to permitat the time such indemnification under certain circumstances for liabilities, including reimbursement for expenses incurred, arising under the Securities Act of 1933, as amended,action occurred or the Securities Act.
The registrant’s certificate of incorporation provides for indemnificationimmediately after such absent director receives notice of the registrant’s directors, officers, authorized representatives, and other agents to the maximum extentunlawful acts.
As permitted by the DGCL, we have entered into, and the registrant’s bylaws provide for indemnificationcontinue to enter into, separate indemnity agreements with each of our directors and executive officers that require us to indemnify such persons against any and all costs and expenses (including attorneys’, witness, or other professional fees) actually and reasonably incurred by such persons in connection with any action, suit, or proceeding (including derivative actions), whether actual or threatened, to which any such person may be made a party by reason of the registrant’s directors, officers, authorized representatives, and other agentsfact that such person is or was a director or officer or is or was acting or serving as an officer, director, employee, or agent of ours or any of our affiliated enterprises. Under these agreements, we are not required to the maximum extentprovide indemnification for certain matters, including:
indemnification beyond that permitted by the DGCL.DGCL;
In addition,indemnification for any proceeding with respect to the registrantunlawful payment of remuneration to the director or officer;
indemnification for certain proceedings involving a final judgment that the director or officer is required to disgorge profits from the purchase or sale of our stock;
indemnification for proceedings involving a final judgment that the director’s or officer’s conduct was in bad faith, knowingly fraudulent or deliberately dishonest or constituted willful misconduct or a breach of his or her duty of loyalty, but only to the extent of such specific determination;
indemnification for proceedings or claims brought by an officer or director against us or any of our directors, officers, employees, or agents, except for (1) claims to establish a right of indemnification or proceedings, (2) claims approved by our board of directors, (3) claims required by law, (4) when there has entered into indemnification agreements with its directors and officers containing provisions that arebeen a change in some respects broader than the specific indemnification provisions containedcontrol as defined in the DGCL.indemnification agreement with each director or officer, or (5) by us in our sole discretion pursuant to the powers vested to us under the Delaware General Corporate Law;
indemnification for settlements the director or officer enters into without our consent, provided there has been no change in control as defined in the indemnification agreement with each director and officer; or
indemnification in violation of any undertaking required by the Securities Act, or in any registration statement we file.

    The indemnification agreements requirealso set forth certain procedures that will apply in the registrant, among other things, to indemnify itsevent of a claim for indemnification thereunder.
    There is at present no pending litigation or proceeding involving any of our directors against certain liabilities that may arise by reason of their status or service as directors and to advance their expenses incurred as a result of any proceeding against themexecutive officers as to which they could be indemnified.indemnification is required or permitted, and we are not currently aware of any threatened litigation or proceeding that may result in a claim for indemnification.
The registrant maintains
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    We have an insurance policiespolicy in place that indemnify itscovers our officers and directors and officers against variouswith respect to certain liabilities, including liabilities arising under the Securities Act and the Securities Exchange Act of 1934, as amended, that might be incurred by any director or officer in his capacity as such.otherwise.
Item 16.    ExhibitsExhibits.
The following exhibits to theare filed as part of, or incorporated by reference into this registration statement are listed in the exhibit index attached hereto and are incorporated herein by reference.statement:
Exhibit No.Description
4.1
4.2
4.3
4.4
Form of Common Stock Purchase Warrant (incorporated by reference to Exhibit 4.1 to the Registrant’s Current Report on Form 8-K filed with the SEC on December 11, 2020).
5.1*
23.1*
23.2*
23.3*
24.1*Power of Attorney (included on the signature page hereof).
* Filed herewith.
Item 17.    UndertakingsUndertakings.
The undersigned registrantRegistrant hereby undertakes:
(1)    To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:
(i)    To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

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(ii)    To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SECSecurities and Exchange Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20%20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and
(iii)    To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;
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provided, however, that paragraphs (1)(i), (1)(ii) and (1)(iii) of this sectionabove do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SECSecurities and Exchange Commission by the registrantRegistrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.
(2)    That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
(3)    To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.
(4)    That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:
(i) If the registrant is relying on Rule 430B:
(A)    Each prospectus filed by the registrantRegistrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and
(B)    Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date; ordate. 
(ii) If the registrant is subject to Rule 430C, each prospectus filed pursuant to Rule 424(b) as part of a registration statement relating to an offering, other than registration statements relying on Rule 430B or other than prospectuses filed in reliance on Rule 430A, shall be deemed to be part of and included in the registration statement as of the date it is first used after effectiveness; provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such first use, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such date of first use.

(5)    That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser: (i) any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424; (ii) any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant; (iii) the portion of any other free writing prospectus relating to the offering containing material information about the

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undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and (iv) any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.
(6)     That, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’sRegistrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
(7)     That for purposes of determining any liability under the Securities Act of 1933, (i) the information omitted from the form of prospectus filed as part of the registration statement in reliance upon Rule 430A and contained in the form of prospectus filed by the registrant pursuant to Rule 424(b)(l) or (4) or 497(h) under the Securities Act of 1933 shall be deemed to be a part of the registration statement as of the time it was declared effective; and (ii) each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
(8)     To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the SEC under Section 305(b)(2) of the Trust Indenture Act.
Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the Registrant pursuant to our organizational documentsany charter provision, by law or otherwise, the registrantRegistrant has been advised that in the opinion of the SECSecurities and Exchange Commission such indemnification
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is against public policy as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrantRegistrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person of the registrant in connection with the securities being registered, the registrantRegistrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by the registrantit is against public policy as expressed in the Securities Act of 1933 and will be governed by the final adjudication of such issue.


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SIGNATURES
Pursuant to the requirements of the Securities Act, of 1933, the registrantRegistrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statementRegistration Statement to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Boston, Commonwealth of Massachusetts,Houston, Texas on March 18, 2016.January 15, 2021.

SALARIUS PHARMACEUTICALS, INC.
FLEX PHARMA, INC.
By:/s/ Christoph WestphalMark J. Rosenblum
Christoph Westphal, M.D., Ph.D.Mark J. Rosenblum
Executive Vice President and Chief ExecutiveFinancial Officer

POWER OF ATTORNEY
EachKNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Christoph WestphalDavid J. Arthur and John McCabe, and each of them,Mark J. Rosenblum as his or her true and lawful attorneys-in-factattorney-in-fact and agents,agent, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments, (includingincluding post-effective amendments, to this Registration Statement, and any registration statementsstatement relating to the offering covered by this Registration Statement and filed pursuant to Rule 462) to this registration statement,462(b) under the Securities Act, and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission,SEC, granting unto said attorneys-in-factattorney-in-fact and agents,agent full power and authority to do and perform each and every act and thing requisite and necessary to be done, in connection therewith, as fully tofor all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorney-in-factattorney in fact and agent, or his substitutessubstitute or substitute,substitutes, may lawfully do or cause to be done by virtue hereof.
Pursuant to the requirements of the Securities Act, of 1933, this registration statementRegistration Statement has been signed by the following persons in the capacities and on the dates indicated.

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NameTitleDate
/s/ David J. Arthur
President and Chief Executive Officer and Director (Principal Executive Officer)
January 15, 2021
David J. Arthur
SignatureTitleDate
/s/ Christoph Westphal

Mark J. Rosenblum
Chief Executive Officer,Vice President and Director (Principal ExecutiveChief Financial Officer)
March 18, 2016
Christoph Westphal, M.D., Ph. D.
/s/ John McCabe

Vice President, Finance
(Principal Financial and Accounting Officer)
March 18, 2016January 15, 2021
John McCabeMark J. Rosenblum
/s/ Jeffrey Capello

DirectorMarch 18, 2016
Jeffrey Capello
/s/ Peter Barton Hutt

DirectorMarch 18, 2016
Peter Barton Hutt
/s/ Marc Kozin

DirectorMarch 18, 2016
Marc Kozin
/s/ Roderick MacKinnon

DirectorMarch 18, 2016
Roderick MacKinnon
/s/ Robert Perez

DirectorMarch 18, 2016
Robert Perez
/s/ Stuart Randle

DirectorMarch 18, 2016
Stuart Randle
/s/ John Sculley

DirectorMarch 18, 2016
John Sculley

/s/ Michelle Stacy

DirectorMarch 18, 2016
Michelle Stacy





EXHIBIT INDEX

Exhibit
No.
 Description of Exhibit Form File No. Exhibit Filing Date     
           
1.1*

 Form of Underwriting Agreement      ��  
           
3.1 
Amended and Restated Certificate of Incorporation of the Registrant

 8-k 001-36812 3.1 February 9, 2015 
3.2 Amended and Restated Bylaws of the Registrant 8-k 001-36812 3.2 February 9, 2015 
  


         
4.1 
Reference is made to Exhibits 3.1 and 3.2 above

         
4.2 
Specimen Common Stock Certificate

 S-1/A 333-201276 4.1 January 13, 2015 
4.3 
Amended and Restated Investor Rights Agreement among the Registrant and certain of its security holders, dated as of July 23, 2014

 S-1 333-195169 4.2 December 29, 2014 
4.5* 
Specimen Preferred Stock Certificate and Form of Certificate of Designation of Preferred Stock.

         
4.6 
Form of Indenture

       Filed herewith 
4.7* 
Form of Note

         
4.8 
Form of Common Stock Warrant Agreement and Warrant Certificate

       Filed herewith 
4.9 
Form of Preferred Stock Warrant Agreement and Warrant Certificate

       Filed herewith 
4.10 
Form of Debt Securities Warrant Agreement and Warrant Certificate

       Filed herewith 
5.1 
Opinion of Cooley LLP

       Filed herewith 
12.1 
Statement Regarding Computation of Ratio of Earnings to Fixed Charges and Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends

          Filed herewith   
23.1 
Consent of Ernst & Young LLP, independent registered public accounting firm

          Filed herewith   
23.2 
Consent of Cooley LLP (contained in Exhibit 5.1)

           
24.1 
Power of Attorney (included on the signature page)

           
25.1** Statement of Eligibility of Trustee under the Indenture           

*To be filed by amendment or as an exhibit to a Current Report on Form 8-K and incorporated herein by reference, if applicable.
**/s/ William K. McVicarTo be filed separately under electronic form type 305B2 under Rule 305(b)(2)Chairman of the Trust Indenture Act, if applicable.BoardJanuary 15, 2021
William K. McVicar
/s/ Tess BurlesonDirectorJanuary 15, 2021
Tess Burleson
/s/ Arnold HanishDirectorJanuary 15, 2021
Arnold Hanish
/s/ Paul LammersDirectorJanuary 15, 2021
Paul Lammers
/s/ Bruce J. McCreedyDirectorJanuary 15, 2021
Bruce J. McCreedy
/s/ Jonathan LieberDirectorJanuary 15, 2021
Jonathan Lieber


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