EX-10.1



 Exhibit 10.1 

MAST THERAPEUTICS, INC. 

$30,000,000 
 SALES
AGREEMENT 
 February 10, 2014 

Cowen and Company, LLC 
 599 Lexington Avenue 

New York, NY 10022 
 Ladies and Gentlemen: 

Mast Therapeutics, Inc. (the “Company”), confirms its agreement (this “Agreement”) with Cowen
and Company, LLC (“Cowen”), as follows: 
 1. Issuance and Sale of Shares. The Company agrees that, from
time to time during the term of this Agreement, on the terms and subject to the conditions set forth herein, it may issue and sell through Cowen, acting as agent and/or principal, shares of the Company’s common stock, par value 0.001 per
share (the “Common Stock”), having an aggregate offering price of up to $30,000,000. Notwithstanding anything to the contrary contained herein, the parties hereto agree that compliance with the limitation set forth in this
Section 1 on the number of shares of Common Stock issued and sold under this Agreement shall be the sole responsibility of the Company, and Cowen shall have no obligation in connection with such compliance. The issuance and sale of
Common Stock through Cowen will be effected pursuant to the Registration Statement (as defined below) filed by the Company and declared effective by the Securities and Exchange Commission (the “Commission”), although nothing
in this Agreement shall be construed as requiring the Company to use the Registration Statement (as defined below) to issue the Common Stock. 

The Company has filed, in accordance with the provisions of the Securities Act of 1933, as amended, and the rules and regulations thereunder
(collectively, the “Securities Act”), with the Commission a registration statement on Form S-3 (File No. 333-179989), including a base prospectus, relating to certain securities, including the Common Stock, to be issued
from time to time by the Company, and which incorporates by reference documents that the Company has filed or will file in accordance with the provisions of the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder
(collectively, the “Exchange Act”). The Company has prepared a prospectus supplement specifically relating to the Common Stock being offered under this Agreement (the “Prospectus Supplement”) to the
base prospectus included as part of such registration statement. The Company has furnished to Cowen, for use by Cowen, copies of the prospectus included as part of such registration statement, as supplemented by the Prospectus Supplement, relating
to the Common Stock. Except where the context otherwise requires, such registration statement, as amended when it became effective, including all documents filed as part thereof or incorporated by reference therein, and including any information
contained in a Prospectus (as defined below) subsequently filed with the 







 
Commission pursuant to Rule 424(b) under the Securities Act or deemed to be a part of such registration statement pursuant to Rule 430B or 462(b) of the Securities Act, is herein called the
“Registration Statement.” The base prospectus, including all documents incorporated therein by reference, included in the Registration Statement, as it may be supplemented by the Prospectus Supplement, in the form in which
such prospectus and/or Prospectus Supplement have most recently been filed by the Company with the Commission pursuant to Rule 424(b) under the Securities Act, together with any “issuer free writing prospectus,” as defined in Rule 433 of
the Securities Act Regulations (“Rule 433”), relating to the Common Stock offered under this Agreement that (i) is required to be filed with the Commission by the Company or (ii) is exempt from filing pursuant to
Rule 433(d)(5)(i), in each case in the form filed or required to be filed with the Commission or, if not required to be filed, in the form retained in the Company’s records pursuant to Rule 433(g), is herein called the
“Prospectus.” Any reference herein to the Registration Statement, the Prospectus or any amendment or supplement thereto shall be deemed to refer to and include the documents incorporated by reference therein, and any
reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement or the Prospectus shall be deemed to refer to and include the filing after the execution hereof of any
document with the Commission deemed to be incorporated by reference therein. For purposes of this Agreement, all references to the Registration Statement, the Prospectus or to any amendment or supplement thereto shall be deemed to include any copy
filed with the Commission pursuant to either the Electronic Data Gathering Analysis and Retrieval System or Interactive Data Electronic Applications (collectively “IDEA”). 

2. Placements. Each time that the Company wishes to issue and sell the Common Stock hereunder (each, a
“Placement”), it will notify Cowen by email notice (or other method mutually agreed to in writing by the parties) (a “Placement Notice”) containing the parameters in accordance with which it desires
the shares of Common Stock to be sold, which shall at a minimum include the number of shares of Common Stock to be issued (the “Placement Shares”), the time period during which sales are requested to be made, any limitation
on the number of shares of Common Stock that may be sold in any one Trading Day (as defined in Section 3) and any minimum price below which sales may not be made, a form of which containing such minimum sales parameters necessary is attached
hereto as Schedule 1. The Placement Notice shall originate from any of the individuals from the Company set forth on Schedule 2 (with a copy to each of the other individuals from the Company listed on such schedule), and
shall be addressed to each of the individuals from Cowen set forth on Schedule 2, as such Schedule 2 may be amended from time to time. The Placement Notice shall be effective upon receipt by Cowen unless and until
(i) in accordance with the notice requirements set forth in Section 4, Cowen declines to accept the terms contained therein for any reason, in its sole discretion, (ii) the entire amount of the Placement Shares have been sold,
(iii) in accordance with the notice requirements set forth in Section 4, the Company suspends or terminates the Placement Notice for any reason, in its sole discretion, (iv) the Company issues a subsequent Placement Notice with
parameters superseding those on the earlier dated Placement Notice, or (v) the Agreement has been terminated under the provisions of Section 11. The amount of any discount, commission or other compensation to be paid by the
Company to Cowen in connection with the sale of the Placement Shares shall be calculated in accordance with the terms set forth in Schedule 3. It is expressly acknowledged and agreed that neither the Company nor Cowen will have any
obligation whatsoever with respect to a Placement or any Placement Shares unless and until the Company delivers a Placement Notice to Cowen and Cowen does not decline such 

  
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Placement Notice pursuant to the terms set forth above, and then only upon the terms specified therein and herein. In the event of a conflict between the terms of this Agreement and the terms of
a Placement Notice, the terms of the Placement Notice will control. 
 3. Sale of Placement Shares by Cowen. Subject to the
terms and conditions herein set forth, upon the Company’s issuance of a Placement Notice, and unless the sale of the Placement Shares described therein has been declined, suspended, or otherwise terminated in accordance with the terms of this
Agreement, Cowen, for the period specified in the Placement Notice, will use its commercially reasonable efforts consistent with its normal trading and sales practices and applicable state and federal laws, rules and regulations and the rules of the
NYSE MKT, LLC (the “Exchange”) to sell such Placement Shares up to the amount specified, and otherwise in accordance with the terms of such Placement Notice. Cowen will provide written confirmation to the Company (including
by email correspondence to each of the individuals of the Company set forth on Schedule 2, if receipt of such correspondence is actually acknowledged by any of the individuals to whom the notice is sent, other than via auto-reply) no later than the
opening of the Trading Day (as defined below) immediately following the Trading Day on which it has made sales of Placement Shares hereunder setting forth the number of Placement Shares sold on such day, the price per share at which each sale of
Placement Shares occurs on such day, the compensation payable by the Company to Cowen pursuant to Section 2 with respect to such sales, and the Net Proceeds (as defined below) payable to the Company, with an itemization of the deductions made
by Cowen (as set forth in Section 5(a)) from the gross proceeds that it receives from such sales. Cowen may sell Placement Shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the
Securities Act, including without limitation sales made through the Exchange, on any other existing trading market for the Common Stock or to or through a market maker. If expressly authorized by the Company in a Placement Notice, Cowen may also
sell Placement Shares in privately negotiated transactions. Notwithstanding the provisions of Section 6(cc), Cowen shall not purchase Placement Shares for its own account as principal unless expressly authorized to do so by the Company in a
Placement Notice. The Company acknowledges and agrees that (i) there can be no assurance that Cowen will be successful in selling Placement Shares, and (ii) Cowen will incur no liability or obligation to the Company or any other person or
entity if it does not sell Placement Shares for any reason other than a failure by Cowen to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such Placement Shares as required under this
Section 3. For the purposes hereof, “Trading Day” means any day on which the Company’s Common Stock is purchased and sold on the principal market on which the Common Stock is listed or quoted. 

4. Suspension of Sales. 

(a) The Company or Cowen may, upon notice to the other party in writing (including by email correspondence to each of the individuals of the
other party set forth on Schedule 2, if receipt of such correspondence is actually acknowledged by any of the individuals to whom the notice is sent, other than via auto-reply) or by telephone (confirmed immediately by verifiable
facsimile transmission or email correspondence to each of the individuals of the other party set forth on Schedule 2), suspend any sale of Placement Shares; provided, however, that such suspension shall not affect or impair
either party’s obligations with respect to any Placement Shares sold hereunder prior to the receipt of such notice. Each of the Parties agrees that no such notice under this Section 4 shall be effective against the other unless it
is made to one of the individuals named on Schedule 2 hereto, as such schedule may be amended from time to time. 

  
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 (b) Notwithstanding any other provision of this Agreement, during any period in which the Company
is in possession of material non-public information, the Company and Cowen agree that (i) no sale of Placement Shares will take place, (ii) the Company shall not request the sale of any Placement Shares, and (iii) Cowen shall not be
obligated to sell or offer to sell any Placement Shares. 
 (c) If either Cowen or the Company has reason to believe that the exemptive
provisions set forth in Rule 101(c)(1) of Regulation M under the Exchange Act are not satisfied with respect to the Common Stock, it shall promptly notify the other party, and Cowen may, at its sole discretion, suspend sales of the Placement Shares
under this Agreement. Cowen shall calculate on a weekly basis the average daily trading volume (as defined by Rule 100 of Regulation M under the Exchange Act) of the Common Stock. 

5. Settlement. 

(a) Settlement of Placement Shares. Unless otherwise specified in the applicable Placement Notice, settlement for sales of
Placement Shares will occur on the third (3rd) Trading Day (or such earlier day as is industry practice for regular-way trading) following the date on which such sales are made (each, a
“Settlement Date” and the first such settlement date, the “First Delivery Date”). The amount of proceeds to be delivered to the Company on a Settlement Date against receipt of the Placement Shares sold
(the “Net Proceeds”) will be equal to the aggregate sales price received by Cowen at which such Placement Shares were sold, after deduction for (i) Cowen’s commission, discount or other compensation for such sales
payable by the Company pursuant to Section 2 hereof, (ii) any other amounts due and payable by the Company to Cowen hereunder pursuant to Section 7(g) (Expenses) hereof, and (iii) any transaction fees imposed by any
governmental or self-regulatory organization in respect of such sales. 
 (b) Delivery of Placement Shares. On or before
each Settlement Date, the Company will, or will cause its transfer agent to, electronically transfer the Placement Shares being sold by crediting Cowen’s or its designee’s account (provided Cowen shall have given the Company written notice
of such designee prior to the Settlement Date) at The Depository Trust Company through its Deposit and Withdrawal at Custodian System or by such other means of delivery as may be mutually agreed upon by the parties hereto which in all cases shall be
freely tradeable, transferable, registered shares in good deliverable form. On each Settlement Date, Cowen will deliver the related Net Proceeds in same day funds to an account designated by the Company on, or prior to, the Settlement Date. The
Company agrees that if the Company, or its transfer agent (if applicable), defaults in its obligation to deliver duly authorized Placement Shares on a Settlement Date, the Company agrees that in addition to and in no way limiting the rights and
obligations set forth in Section 9(a) (Indemnification and Contribution) hereto, it will (i) hold Cowen harmless against any loss, claim, damage, or expense (including reasonable legal fees and expenses), as incurred, arising out of
or in connection with such default by the Company and (ii) pay to Cowen any commission, discount, or other compensation to which it would otherwise have been entitled absent such default. 

  
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 6. Representations and Warranties of the Company. The Company represents and warrants
to, and agrees with, Cowen that, unless such representation or warranty specifies otherwise, as of the date of this Agreement and as of each Applicable Time (as defined in Section 20 (a)): 

(a) Compliance with Registration Requirements. The Registration Statement and any Rule 462(b) Registration Statement have
been declared effective by the Commission under the Securities Act. The Company has complied to the Commission’s satisfaction with all requests of the Commission for additional or supplemental information with respect to the Registration
Statement. No stop order suspending the effectiveness of the Registration Statement or any Rule 462(b) Registration Statement is in effect and no proceedings for such purpose have been instituted or are pending or, to the knowledge of the
Company, are contemplated or threatened by the Commission. The Company meets the requirements for use of Form S-3 under the Securities Act. 

(b) No Misstatement or Omission. The Prospectus when filed complied and, as amended or supplemented, if applicable, will comply in
all material respects with the Securities Act. Each of the Registration Statement, any Rule 462(b) Registration Statement and any post-effective amendment thereto, at the time it became effective, complied and, as of each of the Settlement
Dates, if any, will comply in all material respects with the Securities Act and did not and, as of each of the Settlement Dates, if any, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the
statements therein not misleading. The Prospectus, as amended or supplemented, as of its date, did not and, as of each of the Settlement Dates, if any, will not contain any untrue statement of a material fact or omit to state a material fact
necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The representations and warranties set forth in the two immediately preceding sentences do not apply to statements in or
omissions from the Registration Statement, any Rule 462(b) Registration Statement, or any post-effective amendment thereto, or the Prospectus, or any amendments or supplements thereto, made in reliance upon and in conformity with information
relating to Cowen furnished to the Company in writing by Cowen expressly for use therein. There are no contracts or other documents required to be described in the Prospectus or to be filed as exhibits to the Registration Statement which have not
been described or filed as required. 
 (c) Offering Materials Furnished to Cowen. The Company has delivered to Cowen one
complete copy of the Registration Statement and a copy of each consent and certificate of experts filed as a part thereof, and conformed copies of the Registration Statement (without exhibits) and the Prospectus, as amended or supplemented, in such
quantities and at such places as Cowen has reasonably requested. 
 (d) Distribution of Offering Material By the Company. The
Company has not distributed and will not distribute, prior to the completion of Cowen’s distribution of the Common Stock issued and sold under this Agreement, any offering material in connection with the offering and sale of the Common Stock
issued and sold under this Agreement other than the Prospectus or the Registration Statement. 

  
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 (e) The Sales Agreement. This Agreement has been duly authorized, executed and
delivered by, and is a valid and binding agreement of, the Company, enforceable in accordance with its terms, except as rights to indemnification hereunder may be limited by applicable law and except as the enforcement hereof may be limited by
bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles. 

(f) Authorization of the Common Stock. The shares of Common Stock to be sold by Cowen under this Agreement, acting as agent and/or
principal for the Company, have been duly authorized for issuance and sale pursuant to this Agreement and, when issued and delivered by the Company to Cowen pursuant to this Agreement, will be validly issued, fully paid and nonassessable. 

(g) No Applicable Registration or Other Similar Rights. There are no persons with registration or other similar rights to have any
equity or debt securities registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived. 

(h) No Material Adverse Change. Except as otherwise disclosed in the Prospectus, subsequent to the respective dates as of which
information is given in the Prospectus: (i) there has been no material adverse change, or any development that would reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the results of
operations, business, operations or prospects, whether or not arising from transactions in the ordinary course of business, of the Company and its subsidiaries, considered as one entity (any such change is called a “Material Adverse
Change”); (ii) the Company and its subsidiaries, considered as one entity, have not incurred any material liability or obligation, direct or contingent, not in the ordinary course of business nor entered into any material
transaction or agreement not in the ordinary course of business: and (iii) there has been no dividend or distribution of any kind declared, paid or made by the Company or, except for regular quarterly dividends publicly announced by the Company
or dividends paid to the Company or other subsidiaries, any of its subsidiaries on any class of capital stock or repurchase or redemption by the Company or any of its subsidiaries of any class of capital stock. 

(i) Independent Accountants. PricewaterhouseCoopers LLP, who have expressed their opinion with respect to the financial statements
(which term as used in this Agreement includes the related notes thereto) and supporting schedules included in the Company’s Form 10-K for the fiscal year ended December 31, 2012, filed with the Commission or incorporated by reference as a
part of the Registration Statement and included in the Prospectus, is an independent registered public accounting firm as required by the Securities Act and the Exchange Act. 

(j) Preparation of the Financial Statements. The financial statements filed with the Commission as a part of or incorporated by
reference in the Registration Statement and included in the Prospectus present fairly in all material respects the consolidated financial position of the Company and its subsidiaries as of and at the dates indicated therein and the results of their
operations and cash flows for the periods specified. Such financial statements have been prepared in accordance with generally accepted accounting principles in the United States applied on a consistent basis throughout the periods involved, except
as may be expressly stated in the related notes thereto. No other financial statements or supporting schedules are required to be included in or incorporated in the Registration Statement. 

  
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 (k) Incorporation and Good Standing of the Company and its Subsidiaries. The Company
has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Delaware and has corporate power and authority to own, lease and operate its properties and to conduct its business as described in
the Prospectus and to enter into and perform its obligations under this Agreement. SynthRx, Inc. is the Company’s only significant subsidiary (as defined in Rule 1-02 (w) of Regulation S-X of the Exchange Act) (the
“Significant Subsidiary”). All references herein to “subsidiaries” of the Company shall be deemed to refer to such single subsidiary, mutatis mutandis. The Significant Subsidiary has been duly organized and is
validly existing as a corporation in good standing under the laws of the State of Delaware and has the requisite power and authority to own, lease and operate its properties and to conduct its business as described in the Prospectus. Each of the
Company and the Significant Subsidiary is duly qualified as a foreign corporation or foreign partnership to transact business and is in good standing in the State of California and each other jurisdiction in which such qualification is required,
whether by reason of the ownership or leasing of property or the conduct of business, except for such jurisdictions (other than the State of California) where the failure to so qualify or to be in good standing would not, individually or in the
aggregate, result in a Material Adverse Change. Except as described in the Prospectus, all of the issued and outstanding equity interests of the Significant Subsidiary have been duly authorized and validly issued, are fully paid and nonassessable
and are owned by the Company free and clear of any security interest, mortgage, pledge, lien, encumbrance or claim. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the subsidiaries
listed in Exhibit 21.1 to the Company’s most recent Annual Report on Form 10-K and other than (i) those subsidiaries not required to be listed on Exhibit 21.1 by Item 601 of Regulation S-K under the Exchange Act and
(ii) those subsidiaries formed since the last day of the most recently ended fiscal year. 
 (l) Capital Stock Matters. The
Common Stock conforms in all material respects to the description thereof contained in the Prospectus. All of the issued and outstanding shares of Common Stock have been duly authorized and validly issued, are fully paid and nonassessable and have
been issued in compliance with federal and state securities laws. None of the outstanding shares of Common Stock were issued in violation of any preemptive rights, rights of first refusal or other similar rights to subscribe for or purchase
securities of the Company. There are no authorized or outstanding options, warrants, preemptive rights, rights of first refusal or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any
capital stock of the Company or any of its subsidiaries other than those accurately described in all material respects in the Prospectus. The description of the Company’s stock option, stock bonus and other stock plans or arrangements, and the
options or other rights granted thereunder, set forth in the Prospectus accurately and fairly presents in all material respects the information required to be shown with respect to such plans, arrangements, options and rights. 

(m) Non-Contravention of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor any of its
subsidiaries is in violation of its charter or by-laws or is in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under any indenture, mortgage, loan or credit agreement, note,
contract, franchise, lease or other instrument to which the Company or any of its subsidiaries is a party or by which it or any of them may be bound, or to which any of the property or assets of the 


  
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Company or any of its subsidiaries is subject (each, an “Existing Instrument”), except for such Defaults as would not, individually or in the aggregate, result in a
Material Adverse Change. The Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby (i) have been duly authorized by all necessary corporate action and will not result in
any violation of the provisions of the charter or by-laws of the Company or any subsidiary, (ii) will not conflict with or constitute a breach of, or Default under, or result in the creation or imposition of any lien, charge or encumbrance upon
any property or assets of the Company or any of its subsidiaries pursuant to, or require the consent of any other party to, any Existing Instrument, except for such conflicts, breaches, Defaults, liens, charges or encumbrances as would not,
individually or in the aggregate, result in a Material Adverse Change and (iii) will not result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company or any subsidiary. Except for
such consent, approval, authorization or other order of, or registration or filing with, the Exchange, no consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or
agency, is required for the Company’s execution, delivery and performance of this Agreement and consummation of the transactions contemplated hereby and by the Prospectus, except such as have been obtained or made by the Company and are in full
force and effect under the Securities Act, applicable state securities or blue sky laws and from the Financial Industry Regulatory Authority (“FINRA”). 

(n) No Material Actions or Proceedings. Except as disclosed in the Prospectus, there are no legal or governmental actions, suits
or proceedings pending or, to the Company’s knowledge, threatened (i) against the Company or any of its subsidiaries, (ii) to the Company’s knowledge, which has as the subject thereof any officer or director of the Company and is
required to be disclosed by the Company pursuant to the Exchange Act, (iii) which has as the subject thereof any property owned or leased by the Company or any of its subsidiaries or (iv) relating to environmental or discrimination
matters, where in any such case (A) there is a reasonable possibility that such action, suit or proceeding might be determined adversely to the Company or such subsidiary and (B) any such action, suit or proceeding, if so determined
adversely, would reasonably be expected to result in a Material Adverse Change or adversely affect the ability of the Company to consummate the transactions contemplated by this Agreement. No material labor dispute with the employees of the Company
or any of its subsidiaries exists or, to the Company’s knowledge, is threatened or imminent. 
 (o) All Necessary Permits,
etc. Except as otherwise disclosed in the Prospectus, the Company and each subsidiary possess or has obtained such valid and current certificates, authorizations or permits issued by the appropriate state, federal or foreign regulatory agencies
or bodies necessary to conduct their respective businesses, other than those the failure to possess or own would not result in a Material Adverse Change, and neither the Company nor any subsidiary has received any written notice of proceedings
relating to the revocation or modification of, or non-compliance with, any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse
Change. 
 (p) Tax Law Compliance. Subject to any permitted extensions, the Company and its consolidated subsidiaries have filed
all necessary federal, state and foreign income, property and franchise tax returns and have paid all taxes required to be paid by any of them and, if due and 

  
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payable, any related or similar assessment, fine or penalty levied against any of them except as may be being contested in good faith and by appropriate proceedings. The Company has made adequate
charges, accruals and reserves in the applicable financial statements referred to in Section 1 (i) above in respect of all federal, state and foreign income, property and franchise taxes for all periods as to which the tax liability of the
Company or any of its consolidated subsidiaries has not been finally determined. 
 (q) Insurance. Except as otherwise described
in the Prospectus, each of the Company and its subsidiaries are insured by insurers believed to be financially sound and reputable, with policies in such amounts and with such deductibles and covering such risks as are customary for the business for
which it is engaged. The Company has no reason to believe that it or any subsidiary will not be able (i) to renew its existing insurance coverage as and when such policies expire or (ii) to obtain comparable coverage from similar
institutions as may be necessary or appropriate to conduct its business as now conducted and at a cost that would not result in a Material Adverse Change. 

(r) No Price Stabilization or Manipulation. The Company has not taken and will not take, directly or indirectly, any action
designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Common Stock. 

(s) Related Party Transactions. There are no business relationships or related-party transactions involving the Company or any
subsidiary or any other person required to be described in the Prospectus which have not been described as required. 
 (t) Exchange
Act Compliance. The documents incorporated or deemed to be incorporated by reference in the Prospectus, at the time they were or hereafter are filed with the Commission, complied and will comply in all material respects with the requirements of
the Exchange Act, and, when read together with the other information in the Prospectus, at each Applicable Time, will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to
make the fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. 

(u) No Unlawful Contributions or Other Payments. Neither the Company nor any of its subsidiaries nor, to the Company’s
knowledge, any employee or agent of the Company or any subsidiary, has made any contribution or other payment to any official of, or candidate for, any federal, state or foreign office in violation of any law or of the character required to be
disclosed in the Prospectus. 
 (v) Company’s Accounting System. The Company maintains a system of accounting controls in a
manner designed to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorization; (ii) transactions are recorded as necessary to permit preparation of financial
statements in accordance with generally accepted accounting principles in the United States and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management’s general or specific
authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences. 

  
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 (w) Compliance with Environmental Laws. Except as otherwise described in the
Prospectus, and except as would not, individually or in the aggregate, result in a Material Adverse Change (i) neither the Company nor any of its subsidiaries is in violation of any federal, state, local or foreign law or regulation relating to
pollution or protection of human health or the environment (including, without limitation, ambient air, surface water, groundwater, land surface or subsurface strata) or wildlife, including without limitation, laws and regulations relating to
emissions, discharges, releases or threatened releases of chemicals, pollutants, contaminants, wastes, toxic substances, hazardous substances, petroleum and petroleum products (collectively, “Materials of Environmental
Concern”), or otherwise relating to the manufacture, processing, distribution, use, treatment, storage, disposal, transport or handling of Materials of Environment Concern (collectively, “Environmental Laws”),
which violation includes, but is not limited to, noncompliance with any permits or other governmental authorizations required for the operation of the business of the Company or its subsidiaries under applicable Environmental Laws, or noncompliance
with the terms and conditions thereof, nor has the Company or any of its subsidiaries received any written communication, whether from a governmental authority, citizens group, employee or otherwise, that alleges that the Company or any of its
subsidiaries is in violation of any Environmental Law; (ii) there is no claim, action or cause of action filed with a court or governmental authority, no investigation with respect to which the Company has received written notice, and no
written notice by any person or entity alleging potential liability for investigatory costs, cleanup costs, governmental responses costs, natural resources damages, property damages, personal injuries, attorneys’ fees or penalties arising out
of, based on or resulting from the presence, or release into the environment, of any Material of Environmental Concern at any location owned, leased or operated by the Company or any of its subsidiaries, now or in the past (collectively,
“Environmental Claims”), pending or, to the Company’s knowledge, threatened in writing against the Company or any of its subsidiaries or any person or entity whose liability for any Environmental Claim the Company or any
of its subsidiaries has retained or assumed either contractually or by operation of law; and (iii) to the Company’s knowledge, there are no past or present actions, activities, circumstances, conditions, events or incidents, including,
without limitation, the release, emission, discharge, presence or disposal of any Material of Environmental Concern, that would reasonably be expected to result in a violation of any Environmental Law or an Environmental Claim against the Company or
any of its subsidiaries or against any person or entity whose liability for any Environmental Claim the Company or any of its subsidiaries has retained or assumed either contractually or by operation of law. 

(x) Intellectual Property. Except as otherwise disclosed in the Prospectus, the Company and its subsidiaries own or possess the
valid right to use all (i) patents, patent applications, trademarks, trademark registrations, service marks, service mark registrations, Internet domain name registrations, copyrights, copyright registrations, licenses, trade secret rights
(“Intellectual Property Rights”) and (ii) inventions, software, works of authorships, trade names, databases, formulae, know how, Internet domain names and other intellectual property (including trade secrets and other unpatented
and/or unpatentable proprietary confidential information, systems, or procedures), in each case reasonably necessary to conduct their respective businesses as now conducted, except for those rights as such failure to own, possess, license, or
acquire such rights would not reasonably be expected to result in a Material Adverse Change (collectively, “Intellectual Property Assets”). The Company and its subsidiaries have not received written notice of any challenge, which is, to
their knowledge, still pending, by any other 

  
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person to the rights of the Company and its subsidiaries with respect to any Intellectual Property Rights or Intellectual Property Assets owned or used by the Company or its subsidiaries. Except
as would not reasonably be expected to result in a Material Adverse Change, to the knowledge of the Company, (i) the Company and its subsidiaries’ respective businesses as now conducted do not give rise to any infringement of, any
misappropriation of, or other violation of, any valid and enforceable Intellectual Property Rights of any other person, (ii) all licenses for the use of material Intellectual Property Rights described in the Prospectus are valid, binding upon,
and enforceable by or against the parties thereto in accordance to its terms, (iii) the Company has complied in all material respects with, and is not in breach, nor has received any written asserted or threatened claim of breach, of any such
Intellectual Property license, and the Company has no knowledge of any breach or anticipated breach by any other person to any Intellectual Property license. Except as described in the Prospectus, to the Company’s knowledge, no claim has been
made against the Company alleging the infringement by the Company of any patent, trademark, service mark, trade name, copyright, trade secret, license in or other intellectual property right or franchise right of any person. The Company has taken
all reasonable steps to protect, maintain and safeguard its Intellectual Property Rights, including the execution of appropriate nondisclosure and confidentiality agreements. The consummation of the transactions contemplated by this Agreement will
not result in the loss or impairment of or payment of any additional amounts with respect to, nor require the consent of any other person in respect of, the Company’s right to own, use, or hold for use any of the Intellectual Property Rights as
owned, used or held for use in the conduct of the business as currently conducted. 
 (y) Regulatory Authorizations. Except as
disclosed in the Prospectus, each of the Company and its subsidiaries possesses all certificates, authorizations and permits issued by the appropriate federal, state or foreign regulatory authorities necessary to conduct its business as currently
conducted (including without limitation, those required for the manufacture and distribution of its product candidates for clinical and nonclinical testing, and the clinical and nonclinical testing of any product candidates) as disclosed in the
Prospectus, except where the failure to possess such certificates, authorizations and permits would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Change. 

(z) Brokers. There is no broker, finder or other party that is entitled to receive from the Company any brokerage or finder’s
fee or other fee or commission as a result of any transactions contemplated by this Agreement, except as may otherwise exist with respect to Cowen pursuant to this Agreement. 

(aa) No Outstanding Loans or Other Indebtedness. Except as described in the Prospectus, there are no outstanding loans, advances
(except normal advances for business expenses in the ordinary course of business) or guarantees or indebtedness by the Company to or for the benefit of any of the officers or directors of the Company or any of the members of any of them. 

(bb) No Reliance. The Company has not relied upon Cowen or legal counsel for Cowen for any legal, tax or accounting advice in
connection with the offering and sale of the Placement Shares. 
 (cc) Cowen Purchases. The Company acknowledges and agrees that
Cowen has informed the Company that Cowen may, to the extent permitted under the Securities Act and the Exchange Act, purchase and sell shares of Common Stock outside of this Agreement for its own account while this Agreement is in effect. 

  
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 (dd) Compliance with Certain Laws, Rules, Procedures, Etc. Except as disclosed in the
Prospectus, to the Company’s knowledge, the conduct of the preclinical and clinical testing, and manufacture of the products of the Company or any subsidiary is in compliance, in all material respects, with all laws, rules and regulations
applicable to such activities, including without limitation applicable good laboratory practices, good clinical practices and good manufacturing practices, except for such non-compliance as would not, individually or in the aggregate, reasonably be
expected to result in a Material Adverse Change. The descriptions of the results of such tests and trials contained in the Prospectus are accurate in all material respects. Except as otherwise disclosed in the Prospectus, the Company has not
received notice of adverse finding, warning letter or clinical hold notice from the FDA or any non-U.S. counterpart of any of the foregoing, or any untitled letter or other correspondence or notice from the FDA or any other governmental authority or
agency or any institutional or ethical review board alleging or asserting noncompliance with any law, rule or regulation applicable in any jurisdiction, except notices, letters, and correspondences and non-U.S. counterparts thereof alleging or
asserting such noncompliance as would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Change. Except as disclosed in the Prospectus, neither the Company nor any subsidiary has, either voluntarily or
involuntarily, initiated, conducted or issued, or caused to be initiated, conducted or issued, any recall, field correction, market withdrawal or replacement, safety alert, warning, “dear doctor” letter, investigator notice, or other
notice or action relating to an alleged or potential lack of safety or efficacy of any product of the Company or any subsidiary, any alleged product defect of any product of the Company or the subsidiary, or any violation of any material applicable
law, rule, regulation or any clinical trial or marketing license, approval, permit or authorization for any product of the Company or any subsidiary, and the Company is not aware of any facts or information that would cause it to initiate any such
notice or action and has no knowledge or reason to believe that the FDA, the EMEA or any other governmental agency or authority or any institutional or ethical review board or other non-governmental authority intends to impose, require, request or
suggest such notice or action, except in each case, as would not, individually or in the aggregate, reasonably be expected to result in a Material Adverse Change. The Company has not received and is otherwise not aware of any notices, correspondence
or other communication from the FDA or other governmental regulatory agency or subdivision thereof, or any institutional or ethical review boards, asserting non-compliance with any applicable statutes, rules, regulations, orders, or other laws, or
requiring or requesting the termination, suspension or modification of any preclinical or clinical studies, tests, investigations, or trials conducted by, or on behalf of, the Company or any subsidiary or in which the Company or any subsidiary has
participated. 
 The Company acknowledges that Cowen and, for purposes of the opinions to be delivered pursuant to Section 7 hereof, counsel to
the Company and counsel to Cowen, will rely upon the accuracy and truthfulness of the foregoing representations and hereby consents to such reliance. 

7. Covenants of the Company. The Company covenants and agrees with Cowen that: 

(a) Registration Statement Amendments. After the date of this Agreement and during any period in which a Prospectus relating to
any Placement Shares is required to be delivered by 

  
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Cowen under the Securities Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172 under the Securities Act), (i) the Company will notify Cowen
promptly of the time when any subsequent amendment to the Registration Statement, other than documents incorporated by reference, has been filed with the Commission and/or has become effective or any subsequent supplement to the Prospectus has been
filed and of any request by the Commission for any amendment or supplement to the Registration Statement or Prospectus (insofar as it relates to the transactions contemplated hereby) or for additional information, (ii) the Company will not file
any amendment or supplement to the Registration Statement or Prospectus, other than documents incorporated by reference, relating to the Placement Shares or a security convertible into the Placement Shares unless a copy thereof has been submitted to
Cowen within two days before the filing and Cowen has not reasonably objected thereto within the two day period (provided, however, that (A) the failure of Cowen to make such objection shall not relieve the Company of any obligation or
liability hereunder, or affect Cowen’s right to rely on the representations and warranties made by the Company in this Agreement and (B) the Company has no obligation to provide Cowen any advance copy of such filing or to provide Cowen an
opportunity to object to such filing if such filing does not name Cowen or does not relate to the transactions contemplated hereunder; provided, further, that the only remedy Cowen shall have with respect to the failure by the Company to provide
Cowen with such copy shall be to cease making sales under this Agreement) and the Company will furnish to Cowen at the time of filing thereof a copy of any document that upon filing is deemed to be incorporated by reference into the Registration
Statement or Prospectus, except for those documents available via IDEA; and (iii) the Company will cause each amendment or supplement to the Prospectus, other than documents incorporated by reference, to be filed with the Commission as required
pursuant to the applicable paragraph of Rule 424(b) of the Securities Act (the determination to file or not file any amendment or supplement with the Commission under this Section 7(a), based on the Company’s reasonable opinion or
reasonable objections, shall be made exclusively by the Company). 
 (b) Notice of Commission Stop Orders. The Company will
advise Cowen, promptly after it receives notice or obtains knowledge thereof, of the issuance or threatened issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement, of the suspension of the
qualification of the Placement Shares for offering or sale in any jurisdiction, or of the initiation or threatening of any proceeding for any such purpose; and it will promptly use its commercially reasonable efforts to prevent the issuance of any
stop order or to obtain its withdrawal if such a stop order should be issued. 
 (c) Delivery of Prospectus; Subsequent Changes.
During any period in which a Prospectus relating to the Placement Shares is required to be delivered by Cowen under the Securities Act with respect to a pending sale of the Placement Shares, (including in circumstances where such requirement may be
satisfied pursuant to Rule 172 under the Securities Act), the Company will comply in all material respects with all requirements imposed upon it by the Securities Act, as from time to time in force, and to file on or before their respective due
dates (taking into account any extensions available under the Exchange Act) all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Sections 13(a), 13(c), 14, 15(d) or any
other provision of or under the Exchange Act. If during such period any event occurs as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material


  
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fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances then existing, not misleading, or if during such period it is necessary to amend
or supplement the Registration Statement or Prospectus to comply with the Securities Act, the Company will promptly notify Cowen to suspend the offering of Placement Shares during such period and the Company will promptly amend or supplement the
Registration Statement or Prospectus (at the expense of the Company) so as to correct such statement or omission or effect such compliance; provided, however, that the Company may delay any such amendment or supplement if, in the judgment of
the Company, it is in the best interests of the Company to do so. 
 (d) Listing of Placement Shares. During any period in which
the Prospectus relating to the Placement Shares is required to be delivered by Cowen under the Securities Act with respect to a pending sale of the Placement Shares (including in circumstances where such requirement may be satisfied pursuant to Rule
172 under the Securities Act), the Company will use its commercially reasonable efforts to cause the Placement Shares to be listed on the Exchange and to qualify the Placement Shares for sale under the securities laws of such jurisdictions as Cowen
reasonably designates and to continue such qualifications in effect so long as required for the distribution of the Placement Shares; provided, however, that the Company shall not be required in connection therewith to qualify as a foreign
corporation or dealer in securities or file a general consent to service of process in any jurisdiction. 
 (e) Delivery of
Registration Statement and Prospectus. The Company will furnish to Cowen and its counsel (at the expense of the Company) copies of the Registration Statement, the Prospectus (including all documents incorporated by reference therein) and all
amendments and supplements to the Registration Statement or Prospectus that are filed with the Commission during any period in which a Prospectus relating to the Placement Shares is required to be delivered under the Securities Act (including all
documents filed with the Commission during such period that are deemed to be incorporated by reference therein), in each case as soon as reasonably practicable and in such quantities as Cowen may from time to time reasonably request and, at
Cowen’s request, will also furnish copies of the Prospectus to each exchange or market on which sales of the Placement Shares may be made; provided, however, that the Company shall not be required to furnish any document (other than the
Prospectus) to Cowen to the extent such document is available on IDEA. 
 (f) Earnings Statement. The Company will make
generally available to its security holders as soon as practicable, but in any event not later than 15 months after the end of the Company’s current fiscal quarter, an earnings statement covering a 12-month period that satisfies the provisions
of Section 11(a) and Rule 158 of the Securities Act. For the avoidance of doubt, the Company’s compliance with the reporting requirements of the Exchange Act shall be deemed to satisfy this Section 7(f). 

(g) Expenses. The Company, whether or not the transactions contemplated hereunder are consummated or this Agreement is terminated,
in accordance with the provisions of Section 11 hereunder, will pay the following expenses all incident to the performance of its obligations hereunder, including, but not limited to, expenses relating to (i) the preparation, printing and
filing of the Registration Statement and each amendment and supplement thereto, of each Prospectus and of each amendment and supplement thereto, (ii) the preparation, issuance and 

  
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delivery of the Placement Shares, (iii) the qualification of the Placement Shares under securities laws in accordance with the provisions of Section 7(d) of this Agreement,
including filing fees (provided, however, that any fees or disbursements of counsel for Cowen in connection therewith shall be paid by Cowen except as set forth in (vii) below), (iv) the printing and delivery to Cowen of copies of the
Prospectus and any amendments or supplements thereto, and of this Agreement, (v) the fees and expenses incurred in connection with the listing or qualification of the Placement Shares for trading on the Exchange, (vi) filing fees and
expenses, if any, of the Commission and the FINRA Corporate Financing Department and (vii) the reasonable fees and disbursements of Cowen’s counsel, in an aggregate amount not to exceed $30,000, provided, however, in no event shall the
total compensation paid to Cowen exceed 8.0% of the gross proceeds to the Company from the sale of Placement Shares. 
 (h) Use of
Proceeds. The Company will use the Net Proceeds as described in the Prospectus in the section entitled “Use of Proceeds.” 

(i) Notice of Other Sales. During the pendency of any Placement Notice given hereunder, and for 3 trading days following the
termination of any Placement Notice given hereunder, the Company shall provide Cowen notice as promptly as reasonably possible before it offers to sell, contracts to sell, sells, grants any option to sell or otherwise disposes of any shares of
Common Stock (other than Placement Shares offered pursuant to the provisions of this Agreement) or securities convertible into or exchangeable for Common Stock, warrants or any rights to purchase or acquire Common Stock; provided, that such
notice shall not be required in connection with the (i) issuance, grant or sale of Common Stock, options to purchase shares of Common Stock or Common Stock issuable upon the exercise of options or other equity awards pursuant to any stock
incentive plan or other stock plan or arrangement described in the Prospectus or pursuant to any qualifying employment inducement award under the Exchange rules, (ii) the issuance of securities in connection with an acquisition, merger or sale
or purchase of assets or (iii) the issuance or sale of Common Stock pursuant to any dividend reinvestment plan that the Company may adopt from time to time provided the implementation of such is disclosed to Cowen in advance, (iv) any
shares of common stock issuable upon the exchange, conversion or redemption of securities or the exercise of warrants, options or other rights in effect or outstanding or (v) filing of any registration statement under the Securities Act, or any
pre-effective or post-effective amendment or prospectus supplement thereto, other than the Registration Statement, relating to the Placement Shares or that is intended to commence a public offering of equity, equity-linked or other derivative
securities of the Company. 
 (j) Change of Circumstances. The Company will, at any time during a fiscal quarter in which the
Company intends to tender a Placement Notice or sell Placement Shares, advise Cowen promptly after it shall have received notice or obtained knowledge thereof, of any information or fact that would alter or affect in any material respect any
opinion, certificate, letter or other document required to be provided to Cowen pursuant to this Agreement. 
 (k) Due Diligence
Cooperation. The Company will cooperate with any reasonable due diligence review conducted by Cowen or its agents in connection with the transactions contemplated hereby, including, without limitation, providing information and making available
documents and senior corporate officers, during regular business hours and at the Company’s principal offices, as Cowen may reasonably request. 

  
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 (l) Required Filings Relating to Placement of Placement Shares. The Company agrees
that on such dates as the Securities Act shall require, the Company will (i) file a prospectus supplement with the Commission under the applicable paragraph of Rule 424(b) under the Securities Act (each and every filing under Rule 424(b), a
“Filing Date”), which prospectus supplement will set forth, within the relevant period, the amount of Placement Shares sold through Cowen, the Net Proceeds to the Company and the compensation payable by the Company to Cowen
with respect to such Placement Shares (provided that the Company may satisfy its obligations under this Section 7(l)(i) by effecting a filing in accordance with the Exchange Act with respect to such information), and (ii) deliver such
number of copies of each such prospectus supplement to each exchange or market on which such sales were effected as may be required by the rules or regulations of such exchange or market. 

(m) Representation Dates; Certificate. On or prior to the First Delivery Date and each time the Company (i) amends or
supplements the Registration Statement or the Prospectus relating to the Placement Shares (other than a prospectus supplement filed in accordance with Section 7(l) of this Agreement) by means of a post-effective amendment, sticker, or
supplement but not by means of incorporation of document(s) by reference to the Registration Statement or the Prospectus relating to the Placement Shares; (ii) files an annual report on Form 10-K under the Exchange Act; (iii) files its
quarterly reports on Form 10-Q under the Exchange Act; or (iv) files a current report on Form 8-K containing amended financial information (other than information “furnished” pursuant to Items 2.02 or 7.01 of Form 8-K) under the
Exchange Act (each date of filing of one or more of the documents referred to in clauses (i) through (iv) shall be a “Representation Date”); the Company shall furnish Cowen, if requested by Cowen, with a
certificate, in the form attached hereto as Exhibit 7(m) within three (3) Trading Days of any Representation Date if requested by Cowen. The requirement to provide a certificate under this Section 7(m) shall be waived for any
Representation Date occurring at a time at which no Placement Notice is pending, which waiver shall continue until the earlier to occur of the date the Company delivers a Placement Notice hereunder (which for such calendar quarter shall be
considered a Representation Date) and the next occurring Representation Date; provided, however, that such waiver shall not apply for any Representation Date on which the Company files its annual report on Form 10-K. Notwithstanding
the foregoing, if the Company subsequently decides to sell Placement Shares following a Representation Date when the Company relied on such waiver and did not provide Cowen with a certificate under this Section 7(m), then before the
Company delivers the Placement Notice or Cowen sells any Placement Shares, the Company shall provide Cowen with a certificate, in the form attached hereto as Exhibit 7(m), dated the date of the Placement Notice. 

(n) Legal Opinion. On or prior to the First Delivery Date and within three (3) Trading Days of each Representation Date with
respect to which the Company is obligated to deliver a certificate in the form attached hereto as Exhibit 7(m) for which no waiver is applicable, the Company shall cause to be furnished to Cowen a written opinion of DLA Piper LLP (US)
(“Company Counsel”), or other counsel satisfactory to Cowen, in form and substance satisfactory to Cowen and its counsel, dated the date that the opinion is required to be delivered, substantially similar to the forms of
opinion provided to Cowen, modified, as necessary, to relate to the Registration Statement and the Prospectus as then amended or supplemented; provided, however, that in lieu of such opinions for subsequent Representation Dates,
Company Counsel may furnish Cowen with a letter (a “Reliance Letter”) to the effect that Cowen may rely on a 

  
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prior opinion delivered under this Section 7(n) to the same extent as if it were dated the date of such letter (except that statements in such prior opinion shall be deemed to relate
to the Registration Statement and the Prospectus as amended or supplemented at such Representation Date). 
 (o) Comfort Letter.
On or prior to the First Delivery Date and within five (5) Trading Days of each Representation Date with respect to which the Company is obligated to deliver a certificate in the form attached hereto as Exhibit 7(m) for which no waiver
is applicable, the Company shall cause its independent accountants to furnish Cowen letters (the “Comfort Letters”), dated the date of the Comfort Letter is delivered, in form and substance satisfactory to Cowen,
(i) confirming that they are an independent registered public accounting firm within the meaning of the Securities Act and the PCAOB, (ii) stating, as of such date, the conclusions and findings of such firm with respect to the financial
information and other matters ordinarily covered by accountants’ “comfort letters” to Cowen in connection with registered public offerings (the first such letter, the “Initial Comfort Letter”) and
(iii) updating the Initial Comfort Letter with any information that would have been included in the Initial Comfort Letter had it been given on such date and modified as necessary to relate to the Registration Statement and the Prospectus, as
amended and supplemented to the date of such letter. 
 (p) Market Activities. The Company will not, directly or indirectly,
(i) take any action designed to cause or result in, or that constitutes or might reasonably be expected to constitute, the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the
Placement Shares or (ii) sell, bid for, or purchase the Placement Shares, or pay anyone any compensation for soliciting purchases of the Placement Shares other than Cowen; provided, however, that the Company may bid for and purchase shares of
its common stock in accordance with Rule 10b-18 under the Exchange Act. 
 (q) Insurance. The Company and its subsidiaries shall
maintain, or caused to be maintained, insurance in such amounts and covering such risks as are generally deemed prudent and customary for the business for which it is engaged. 

(r) Compliance with Laws. The Company and its subsidiaries shall maintain, or cause to be maintained, all material environmental
permits or other governmental authorizations necessary to conduct their businesses as described in the Prospectus, and the Company and its subsidiaries shall conduct their businesses, or cause their businesses to be conducted, in substantial
compliance with such permits and other governmental authorizations and under applicable environmental laws, except where the failure to maintain or be in compliance with such permits and other governmental authorizations would not reasonably be
expected to have a Material Adverse Change. 
 (s) Investment Company Act. The Company will conduct its affairs in such a manner
so as to reasonably ensure that neither it nor the subsidiaries will be or become, at any time prior to the termination of this Agreement, an “investment company,” as such term is defined in the Investment Company Act, assuming no change
in the Commission’s current interpretation as to entities that are not considered an investment company. 

  
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 (t) Securities Act and Exchange Act. The Company will use its commercially reasonable
efforts to comply in all material respects with all requirements imposed upon it by the Securities Act and the Exchange Act as from time to time in force, so far as necessary to permit the continuance of sales of, or dealings in, the Placement
Shares as contemplated by the provisions hereof and the Prospectus. 
 (u) No Offer to Sell. Other than a free writing
prospectus (as defined in Rule 405 under the Act) approved in advance by the Company and Cowen in its capacity as principal or agent hereunder, neither Cowen nor the Company (including its agents and representatives, other than Cowen in its capacity
as such) will make, use, prepare, authorize, approve or refer to any written communication (as defined in Rule 405 under the Act), required to be filed with the Commission, that constitutes an offer to sell or solicitation of an offer to buy Common
Stock relating to the Placement Shares to be sold by Cowen as principal or agent hereunder 
 (v) Sarbanes-Oxley Act. The
Company and the Subsidiaries will use their commercially reasonable efforts to comply in all material respects with all effective applicable provisions of the Sarbanes-Oxley Act. 

(w) Form S-3. The Company shall notify Cowen no later two (2) Trading Days prior to any time or date it does not expect to
meet the requirements for the use of the Registration Statement pursuant to General Instruction I.B.1 of Form S-3 under the Securities Act. 

8. Conditions to Cowen’s Obligations. The obligations of Cowen hereunder with respect to a Placement will be subject to the
continuing accuracy and completeness of the representations and warranties made by the Company herein, to the due performance by the Company of its obligations hereunder, to the completion by Cowen of a due diligence review satisfactory to Cowen in
its reasonable judgment, and to the continuing satisfaction (or waiver by Cowen in its sole discretion) of the following additional conditions: 

(a) Registration Statement Effective. The Registration Statement shall be effective and shall be available for (i) all sales
of Placement Shares issued pursuant to all prior Placement Notices and (ii) the sale of all Placement Shares contemplated to be issued by any Placement Notice. 

(b) No Material Notices. None of the following events shall have occurred and be continuing: (i) receipt by the Company or
any of its subsidiaries of any request for additional information from the Commission or any other federal or state governmental authority during the period of effectiveness of the Registration Statement, the response to which would require any
post-effective amendments or supplements to the Registration Statement or the Prospectus; (ii) the issuance by the Commission or any other federal or state governmental authority of any stop order suspending the effectiveness of the
Registration Statement or the initiation of any proceedings for that purpose; (iii) receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the Placement Shares
for sale in any jurisdiction or the initiation or threatening of any proceeding for such purpose; (iv) the occurrence of any event that makes any material statement made in the Registration Statement or the Prospectus or any material document
incorporated or deemed to be incorporated therein by reference untrue in any material respect or that requires the making of any changes in the Registration Statement, related Prospectus or such documents so that, in the case of the Registration
Statement, it will not contain any materially untrue statement of a material fact or omit to state any material fact required to be stated therein necessary to make the statements 

  
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therein not misleading and, that in the case of the Prospectus, it will not contain any materially untrue statement of a material fact or omit to state any material fact required to be stated
therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading. 

(c) No Misstatement or Material Omission. Cowen shall not have advised the Company that the Registration Statement or Prospectus,
or any amendment or supplement thereto, contains an untrue statement of fact that in Cowen’s reasonable opinion is material, or omits to state a fact that in Cowen’s opinion is material and is required to be stated therein or is necessary
to make the statements therein not misleading. 
 (d) Material Changes. Except as contemplated in the Prospectus, or disclosed
in the Company’s reports filed with the Commission, there shall not have been any material adverse change, on a consolidated basis, in the authorized capital stock of the Company or any Material Adverse Change or any development that would
reasonably be expected to result in a Material Adverse Change, or any downgrading in or withdrawal of the rating assigned to any of the Company’s securities (other than asset backed securities) by any rating organization or a public
announcement by any rating organization that it has under surveillance or review its rating of any of the Company’s securities (other than asset backed securities), the effect of which, in the case of any such action by a rating organization
described above, in the reasonable judgment of Cowen (without relieving the Company of any obligation or liability it may otherwise have), is so material as to make it impracticable or inadvisable to proceed with the offering of the Placement Shares
on the terms and in the manner contemplated in the Prospectus. 
 (e) Company Counsel Legal Opinion. Cowen shall have received
the opinions of Company Counsel or Reliance Letter required to be delivered pursuant Section 7(n) on or before the date on which such delivery of such opinion or Reliance Letter is required pursuant to Section 7(n). 

(f) Cowen Counsel Legal Opinion. Cowen shall have received from LeClairRyan, A Professional Corporation, counsel for Cowen, such
opinion or opinions, on or before the date on which the delivery of the Company Counsel legal opinion is required pursuant to Section 7(n), with respect to such matters as Cowen may reasonably require, and the Company shall have
furnished to such counsel such documents as they request for enabling them to pass upon such matters. 
 (g) Comfort Letter.
Cowen shall have received the Comfort Letter required to be delivered pursuant Section 7(o) on or before the date on which such delivery of such opinion is required pursuant to Section 7(o). 

(h) Representation Certificate. Cowen shall have received the certificate required to be delivered pursuant to
Section 7(m) on or before the date on which delivery of such certificate is required pursuant to Section 7(m). 

(i) No Suspension. Trading in the Common Stock shall not have been suspended on the Exchange. 

  
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 (j) Other Materials. On each date on which the Company is required to deliver a
certificate pursuant to Section 7(m), the Company shall have furnished to Cowen such appropriate further information, certificates and documents as Cowen may have reasonably requested. All such opinions, certificates, letters and other
documents shall have been in compliance with the provisions hereof. The Company will furnish Cowen with such conformed copies of such opinions, certificates, letters and other documents as Cowen shall have reasonably requested. 

(k) Securities Act Filings Made. All filings with the Commission required by Rule 424 under the Securities Act to have been filed
prior to the issuance of any Placement Notice hereunder shall have been made within the applicable time period prescribed for such filing by Rule 424. 

(l) Approval for Listing. The Placement Shares shall either have been (i) approved for listing on the Exchange, subject only
to notice of issuance, or (ii) the Company shall have filed an application for listing of the Placement Shares on the Exchange at, or prior to, the issuance of any Placement Notice. 

(m) No Termination Event. There shall not have occurred any event that would permit Cowen to terminate this Agreement pursuant to
Section 11(a). 
 9. Indemnification and Contribution. 

(a) Company Indemnification. The Company agrees to indemnify and hold harmless Cowen, the directors, officers, partners, employees
and agents of Cowen and each person, if any, who (i) controls Cowen within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, or (ii) is controlled by or is under common control with Cowen (a
“Cowen Affiliate”) from and against any and all losses, claims, liabilities, expenses and damages (including, but not limited to, any and all reasonable investigative, legal and other expenses incurred in connection with, and
any and all amounts paid in settlement (in accordance with Section 9(c)) of, any action, suit or proceeding between any of the indemnified parties and any indemnifying parties or between any indemnified party and any third party, or
otherwise, or any claim asserted), as and when incurred, to which Cowen, or any such person, may become subject under the Securities Act, the Exchange Act or other federal or state statutory law or regulation, at common law or otherwise, insofar as
such losses, claims, liabilities, expenses or damages arise out of or are based, directly or indirectly, on (x) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or the Prospectus or any
amendment or supplement to the Registration Statement or the Prospectus or in any free writing prospectus or (y) the omission or alleged omission to state in any such document a material fact required to be stated in it or necessary to make the
statements in it not misleading; provided, however, that this indemnity agreement shall not apply to the extent that such loss, claim, liability, expense or damage arises from the sale of the Placement Shares pursuant to this Agreement
and is caused directly or indirectly by an untrue statement or omission made in reliance upon and in conformity with written information relating to Cowen and furnished to the Company by Cowen expressly for inclusion in any document as described in
clause (x) of this Section 9(a). This indemnity agreement will be in addition to any liability that the Company might otherwise have. 

  
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 (b) Cowen Indemnification. Cowen agrees to indemnify and hold harmless the Company
and its directors and each officer of the Company that signed the Registration Statement, and each person, if any, who (i) controls the Company within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act
or (ii) is controlled by or is under common control with the Company (a “Company Affiliate”) against any and all loss, liability, claim, damage and expense described in the indemnity contained in
Section 9(a), as incurred, but only with respect to untrue statements or omissions, or alleged untrue statements or omissions, made in the Registration Statement (or any amendments thereto) or the Prospectus (or any amendment or
supplement thereto) or any free writing prospectus in reliance upon and in conformity with written information relating to Cowen and furnished to the Company by Cowen expressly for inclusion in any document as described in clause (x) of
Section 9(a). 
 (c) Procedure. Any party that proposes to assert the right to be indemnified under this
Section 9 will, promptly after receipt of notice of commencement of any action against such party in respect of which a claim is to be made against an indemnifying party or parties under this Section 9, notify each such
indemnifying party in writing of the commencement of such action, enclosing a copy of all papers served, but the omission so to notify such indemnifying party will not relieve the indemnifying party from (i) any liability that it might have to
any indemnified party otherwise than under this Section 9 and (ii) any liability that it may have to any indemnified party under the foregoing provision of this Section 9 unless, and only to the extent that, such
omission results in the forfeiture of substantive rights or defenses by the indemnifying party. If any such action is brought against any indemnified party and it notifies the indemnifying party of its commencement, the indemnifying party will be
entitled to participate in and, to the extent that it elects by delivering written notice to the indemnified party promptly after receiving notice of the commencement of the action from the indemnified party, jointly with any other indemnifying
party similarly notified, to assume the defense of the action, with counsel reasonably satisfactory to the indemnified party, and after notice from the indemnifying party to the indemnified party of its election to assume the defense, the
indemnifying party will not be liable to the indemnified party for any legal or other expenses except as provided below and except for the reasonable costs of investigation subsequently incurred by the indemnified party in connection with the
defense. The indemnified party will have the right to employ its own counsel in any such action, but the fees, expenses and other charges of such counsel will be at the expense of such indemnified party unless (1) the employment of counsel by
the indemnified party has been authorized in writing by the indemnifying party, (2) the indemnified party has reasonably concluded (based on advice of counsel) that there may be legal defenses available to it or other indemnified parties that
are different from or in addition to those available to the indemnifying party, (3) a conflict or potential conflict exists (based on advice of counsel to the indemnified party) between the indemnified party and the indemnifying party (in which
case the indemnifying party will not have the right to direct the defense of such action on behalf of the indemnified party) or (4) the indemnifying party has not in fact employed counsel to assume the defense of such action within a reasonable
time after receiving notice of the commencement of the action, in each of which cases the reasonable fees, disbursements and other charges of counsel will be at the expense of the indemnifying party or parties. It is understood that the indemnifying
party or parties shall not, in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonable fees, disbursements and other charges of more than one separate firm admitted to practice in such
jurisdiction at any one time for all such indemnified party or parties. All such fees, disbursements and other charges will be reimbursed 

  
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by the indemnifying party promptly as they are incurred. An indemnifying party will not, in any event, be liable for any settlement of any action or claim effected without its written consent. No
indemnifying party shall, without the prior written consent of each indemnified party, settle or compromise or consent to the entry of any judgment in any pending or threatened claim, action or proceeding relating to the matters contemplated by this
Section 9 (whether or not any indemnified party is a party thereto), unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising or that may arise out of such
claim, action or proceeding. 
 (d) Contribution. In order to provide for just and equitable contribution in circumstances in
which the indemnification provided for in the foregoing paragraphs of this Section 9 is applicable in accordance with its terms but for any reason is held to be unavailable from the Company or Cowen, the Company and Cowen will contribute
to the total losses, claims, liabilities, expenses and damages (including any investigative, legal and other expenses reasonably incurred in connection with, and any amount paid in settlement of, any action, suit or proceeding or any claim asserted,
but after deducting any contribution received by the Company from persons other than Cowen, such as persons who control the Company within the meaning of the Securities Act, officers of the Company who signed the Registration Statement and directors
of the Company, who also may be liable for contribution) to which the Company and Cowen may be subject in such proportion as shall be appropriate to reflect the relative benefits received by the Company on the one hand and Cowen on the other. The
relative benefits received by the Company on the one hand and Cowen on the other hand shall be deemed to be in the same proportion as the total Net Proceeds from the sale of the Placement Shares (before deducting expenses) received by the Company
bear to the total compensation received by Cowen from the sale of Placement Shares on behalf of the Company. If, but only if, the allocation provided by the foregoing sentence is not permitted by applicable law, the allocation of contribution shall
be made in such proportion as is appropriate to reflect not only the relative benefits referred to in the foregoing sentence but also the relative fault of the Company, on the one hand, and Cowen, on the other, with respect to the statements or
omission that resulted in such loss, claim, liability, expense or damage, or action in respect thereof, as well as any other relevant equitable considerations with respect to such offering. Such relative fault shall be determined by reference to,
among other things, whether the untrue or alleged untrue statement of a material fact or omission or alleged omission to state a material fact relates to information supplied by the Company or Cowen, the intent of the parties and their relative
knowledge, access to information and opportunity to correct or prevent such statement or omission. The Company and Cowen agree that it would not be just and equitable if contributions pursuant to this Section 9(d) were to be determined
by pro rata allocation or by any other method of allocation that does not take into account the equitable considerations referred to herein. The amount paid or payable by an indemnified party as a result of the loss, claim, liability, expense, or
damage, or action in respect thereof, referred to above in this Section 9(d) shall be deemed to include, for the purpose of this Section 9(d), any legal or other expenses reasonably incurred by such indemnified party in
connection with investigating or defending any such action or claim to the extent consistent with Section 9(c) hereof. Notwithstanding the foregoing provisions of this Section 9(d), Cowen shall not be required to contribute
any amount in excess of the commissions received by it under this Agreement and no person found guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) will be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation. For purposes of this Section 9(d), any person who 

  
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controls a party to this Agreement within the meaning of the Securities Act, and any officers, directors, partners, employees or agents of Cowen, will have the same rights to contribution as that
party, and each officer of the Company who signed the Registration Statement will have the same rights to contribution as the Company, subject in each case to the provisions hereof. Any party entitled to contribution, promptly after receipt of
notice of commencement of any action against such party in respect of which a claim for contribution may be made under this Section 9(d), will notify any such party or parties from whom contribution may be sought, but the omission to so
notify will not relieve that party or parties from whom contribution may be sought from any other obligation it or they may have under this Section 9(d) except to the extent that the failure to so notify such other party materially
prejudiced the substantive rights or defenses of the party from whom contribution is sought. Except for a settlement entered into pursuant to the last sentence of Section 9(c) hereof, no party will be liable for contribution with respect
to any action or claim settled without its written consent if such consent is required pursuant to Section 9(c) hereof. 

10. Representations and Agreements to Survive Delivery. The indemnity and contribution agreements contained in
Section 9 of this Agreement and all representations and warranties of the Company herein or in certificates delivered pursuant hereto shall survive, as of their respective dates, regardless of (i) any investigation made by or on
behalf of Cowen, any controlling persons, or the Company (or any of their respective officers, directors or controlling persons), (ii) delivery and acceptance of the Placement Shares and payment therefor or (iii) any termination of this
Agreement. 
 11. Termination. 

(a) Cowen shall have the right by giving written notice as hereinafter specified at any time to terminate this Agreement if (i) any
Material Adverse Change, or any development that would reasonably be expected to result in a Material Adverse Change has occurred that, in the reasonable judgment of Cowen, would materially impair the ability of Cowen to sell the Placement Shares
hereunder, (ii) the Company shall have failed, refused or been unable to perform any agreement on its part to be performed hereunder; provided, however, in the case of any failure of the Company to deliver (or cause another person to
deliver) any certification, opinion, or letter required under Sections 7(m), 7(n), or 7(o), Cowen’s right to terminate shall not arise unless such failure to deliver (or cause to be delivered) continues for more than thirty
(30) days from the date such delivery was required; or (iii) any other condition of Cowen’s obligations hereunder is not fulfilled, or (iv), any suspension or limitation of trading in the Placement Shares or in securities generally on
the Exchange shall have occurred. Any such termination shall be without liability of any party to any other party except that the provisions of Section 7(g) (Expenses), Section 9 (Indemnification and Contribution),
Section 10 (Representations and Agreements to Survive Delivery), Section 16 (Applicable Law; Consent to Jurisdiction) and Section 17 (Waiver of Jury Trial) hereof shall remain in full force and effect
notwithstanding such termination. If Cowen elects to terminate this Agreement as provided in this Section 11(a), Cowen shall provide the required notice as specified in Section 12 (Notices). 

(b) The Company shall have the right, by giving ten (10) days notice as hereinafter specified to terminate this Agreement in its
sole discretion at any time after the date of this Agreement. Any such termination shall be without liability of any party to any other party except that the provisions of Section 7(g), Section 9, Section 10,
Section 16 and Section 17 hereof shall remain in full force and effect notwithstanding such termination. 

  
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 (c) Cowen shall have the right, by giving ten (10) days notice as hereinafter specified
to terminate this Agreement in its sole discretion at any time after the date of this Agreement. Any such termination shall be without liability of any party to any other party except that the provisions of Section 7(g),
Section 9, Section 10, Section 16 and Section 17 hereof shall remain in full force and effect notwithstanding such termination. 

(d) Unless earlier terminated pursuant to this Section 11, this Agreement shall automatically terminate upon the issuance and
sale of all of the Placement Shares through Cowen on the terms and subject to the conditions set forth herein; provided that the provisions of Section 7(g), Section 9, Section 10, Section 16 and
Section 17 hereof shall remain in full force and effect notwithstanding such termination. 
 (e) This Agreement shall
remain in full force and effect unless terminated pursuant to Sections 11(a), (b), (c), or (d) above or otherwise by mutual agreement of the parties; provided, however, that any such termination by mutual agreement
shall in all cases be deemed to provide that Section 7(g), Section 9, Section 10, Section 16 and Section 17 shall remain in full force and effect. 

(f) Any termination of this Agreement shall be effective on the date specified in such notice of termination; provided, however,
that such termination shall not be effective until the close of business on the date of receipt of such notice by Cowen or the Company, as the case may be. If such termination shall occur prior to the Settlement Date for any sale of Placement
Shares, such Placement Shares shall settle in accordance with the provisions of this Agreement. 
 (g) Subject to the additional
limitations set forth in Section 7 of the Agreement, in the event of termination of this Agreement prior to the sale of any Placement Shares, Cowen shall be entitled only to reimbursement of its out-of-pocket expenses actually incurred.

 12. Notices. All notices or other communications required or permitted to be given by any party to any other party pursuant
to the terms of this Agreement shall be in writing, unless otherwise specified in this Agreement, and if sent to Cowen, shall be delivered to Cowen at Cowen and Company, LLC, 599 Lexington Avenue, New York, NY 10022, fax no. 646-562-1124, Attention:
General Counsel, with a copy to LeClairRyan, 885 Third Avenue, New York, NY 10022, Attention: James T. Seery. Email:james.seery@leclairryan.com; or if sent to the Company, shall be delivered to Mast Therapeutics, Inc., 12390 El Comino Real, Suite
150, San Diego, CA 92130, Attention: Chief Financial Officer, with a copy to DLA Piper LLP (US), 4365 Executive Drive, Suite 1100, San Diego, CA 92121, Attention: Michael S. Kagnoff. Email:Michael.kagnoff@dlapiper.com. Each party to this Agreement
may change such address for notices by sending to the parties to this Agreement written notice of a new address for such purpose. Each such notice or other communication shall be deemed given (i) when delivered personally or by verifiable
facsimile transmission (with an original to follow) on or before 4:30 p.m., New York City time, on a Business Day (as defined below), or, if such day is not a Business Day on the next succeeding Business Day, (ii) on the next Business Day after
timely delivery to a nationally-recognized overnight courier and (iii) on the Business Day actually received if deposited in the U.S. mail (certified or registered mail, return receipt requested, postage prepaid). For purposes of this
Agreement, “Business Day” shall mean any day on which the Exchange and commercial banks in the City of New York are open for business. 

  
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 13. Successors and Assigns. This Agreement shall inure to the benefit of and be
binding upon the Company and Cowen and their respective successors and the affiliates, controlling persons, officers and directors referred to in Section 9 hereof. References to any of the parties contained in this Agreement shall be
deemed to include the successors and permitted assigns of such party. Nothing in this Agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors and permitted assigns any rights,
remedies, obligations or liabilities under or by reason of this Agreement, except as expressly provided in this Agreement. Neither party may assign its rights or obligations under this Agreement without the prior written consent of the other party;
provided, however, that Cowen may assign its rights and obligations hereunder to an affiliate of Cowen without obtaining the Company’s consent. 

14. Adjustments for Share Splits. The parties acknowledge and agree that all share-related numbers contained in this Agreement
shall be adjusted to take into account any share split, share dividend or similar event effected with respect to the Common Stock. 

15. Entire Agreement; Amendment; Severability. This Agreement (including all schedules and exhibits attached hereto and Placement
Notices issued pursuant hereto) constitutes the entire agreement and supersedes all other prior and contemporaneous agreements and undertakings, both written and oral, among the parties hereto with regard to the subject matter hereof. Neither this
Agreement nor any term hereof may be amended except pursuant to a written instrument executed by the Company and Cowen. In the event that any one or more of the provisions contained herein, or the application thereof in any circumstance, is held
invalid, illegal or unenforceable as written by a court of competent jurisdiction, then such provision shall be given full force and effect to the fullest possible extent that it is valid, legal and enforceable, and the remainder of the terms and
provisions herein shall be construed as if such invalid, illegal or unenforceable term or provision was not contained herein, but only to the extent that giving effect to such provision and the remainder of the terms and provisions hereof shall be
in accordance with the intent of the parties as reflected in this Agreement. 
 16. Applicable Law; Consent to Jurisdiction.
This Agreement shall be governed by, and construed in accordance with, the internal laws of the State of New York without regard to the principles of conflicts of laws. Each party hereby irrevocably submits to the non-exclusive jurisdiction of the
state and federal courts sitting in the City of New York, borough of Manhattan, for the adjudication of any dispute hereunder or in connection with any transaction contemplated hereby, and hereby irrevocably waives, and agrees not to assert in any
suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is brought in an inconvenient forum or that the venue of such suit, action or proceeding is improper.
Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof (certified or registered mail, return receipt requested) to such party at the
address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process
in any manner permitted by law. 

  
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 17. Waiver of Jury Trial. The Company and Cowen each hereby irrevocably waives any
right it may have to a trial by jury in respect of any claim based upon or arising out of this Agreement or any transaction contemplated hereby. 

18. Absence of Fiduciary Relationship. The Company acknowledges and agrees that: 

(a) Cowen has been retained solely to act as sales agent in connection with the sale of the Common Stock and that no fiduciary, advisory
or agency relationship between the Company and Cowen has been created in respect of any of the transactions contemplated by this Agreement, irrespective of whether Cowen has advised or is advising the Company on other matters; 

(b) the Company is capable of evaluating and understanding and understands and accepts the terms, risks and conditions of the
transactions contemplated by this Agreement; 
 (c) the Company has been advised that Cowen and its affiliates are engaged in a broad
range of transactions which may involve interests that differ from those of the Company and that Cowen has no obligation to disclose such interests and transactions to the Company by virtue of any fiduciary, advisory or agency relationship; and 

(d) the Company waives, to the fullest extent permitted by law, any claims it may have against Cowen, for breach of fiduciary duty or
alleged breach of fiduciary duty and agrees that Cowen shall have no liability (whether direct or indirect) to the Company in respect of such a fiduciary claim or to any person asserting a fiduciary duty claim on behalf of or in right of the
Company, including stockholders, partners, employees or creditors of the Company. 
 19. Counterparts. This Agreement may be
executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. Delivery of an executed Agreement by one party to the other may be made by facsimile or
electronic transmission. 
 20. Definitions. As used in this Agreement, the following term has the meaning set forth below: 

(a) “Applicable Time” means the date of this Agreement, each Representation Date, the date on which a Placement Notice
is given, and any date on which Placement Shares are sold hereunder. 
 [Remainder of Page Intentionally Blank] 

  
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 If the foregoing correctly sets forth the understanding between the Company and Cowen, please so
indicate in the space provided below for that purpose, whereupon this letter shall constitute a binding agreement between the Company and Cowen. 
  

			
	Very truly yours,
	
	COWEN AND COMPANY, LLC
		
	By:	 	 /s/ Grant Miller

		 	Name: Grant Miller
		 	Title: Head of Equity Capital Markets
	
	ACCEPTED as of the date first-above written:
	
	MAST THERAPEUTICS, INC.
		
	By:	 	 /s/ Brandi Roberts

	Name:	 	Brandi Roberts
	Title:	 	CFO









 SCHEDULE 1 

FORM OF PLACEMENT NOTICE 
  

			
	From:	    	[                                ]
	Cc:	    	[                                ]
	To:	    	[                                ]
	Subject:	    	Cowen at the Market Offering—Placement Notice

 Ladies and Gentlemen: 
 Pursuant
to the terms and subject to the conditions contained in the Sales Agreement between Mast Therapeutics, Inc. (the “Company”), and Cowen and Company, LLC (“Cowen”) dated February 10, 2014 (the
“Agreement”), I hereby request on behalf of the Company that Cowen sell up to [     ] shares of the Company’s common stock, par value 0.001 per share, at a minimum market price of
$             per share. Sales should begin on the date of this Notice and shall continue until [DATE] [all shares are sold]. 







 SCHEDULE 2 
  


			
	 The Company
	  	
		
	 Brian Culley
	  	Chief Executive Officer
		
	 Brandi Roberts
	  	Chief Financial Officer
		
	Cowen	  	
		
	 Robert Sine
	  	Director
		
	 William Follis
	  	Director








 SCHEDULE 3 

Compensation 
 Cowen shall be paid
compensation, or allowed a discount, in an amount agreed to in writing by the parties up to 3.0% of the gross proceeds from the sales of Common Stock pursuant to the terms of this Agreement. 







 Exhibit 7(m) 

OFFICER CERTIFICATE 
 The
undersigned, the duly qualified and elected                             , of Mast Therapeutics, Inc.
(“Company”), a Delaware corporation, does hereby certify in such capacity and on behalf of the Company, pursuant to Section 7(m) of the Sales Agreement dated February 10, 2014 (the “Sales
Agreement”) between the Company and Cowen and Company, LLC, that to the knowledge of the undersigned. 
 (i) The
representations and warranties of the Company in Section 6 of the Sales Agreement (A) to the extent such representations and warranties are subject to qualifications and exceptions contained therein relating to materiality or
Material Adverse Change, are true and correct on and as of the date hereof with the same force and effect as if expressly made on and as of the date hereof, except for those representations and warranties that speak solely as of a specific date and
which were true and correct as of such date, and (B) to the extent such representations and warranties are not subject to any qualifications or exceptions, are true and correct in all material respects as of the date hereof as if made on and as
of the date hereof with the same force and effect as if expressly made on and as of the date hereof except for those representations and warranties that speak solely as of a specific date and which were true and correct as of such date; and 

(ii) The Company has complied with all agreements and satisfied all conditions on its part to be performed or satisfied pursuant to the Sales
Agreement at or prior to the date hereof. 
 Capitalized terms used but not defined herein shall have the meanings ascribed to them in the
Sales Agreement. 
  

			
	MAST THERAPEUTICS, INC.
		
	 By:
	 	  

		 	Name:
		 	Title:



Date: