Document:

EX-10.2

 Exhibit 10.2 

EXECUTION VERSION 
 SHARE
PURCHASE AGREEMENT 
 This Share Purchase Agreement (“Agreement”) is made as of October 13, 2013 (the
“Effective Date”), by and among Aratana Therapeutics, Inc., a Delaware corporation (the “Company”), and each of those persons and entities listed as a Purchaser on the Schedule of Purchasers attached
as Exhibit A hereto (the “Schedule of Purchasers”). Such persons and entities are hereinafter collectively referred to as “Purchasers” and each individually as a
“Purchaser”. 
 AGREEMENT 

In consideration of the mutual covenants contained in this Agreement, and for other good and valuable consideration, the receipt of which is
hereby acknowledged, the Company and each Purchaser hereby agree as follows: 
 SECTION 1. AUTHORIZATION OF SALE OF SECURITIES. 

The Company has authorized the sale and issuance of 1,234,375 shares of its Common Stock, par value $0.001 per share (the “Common
Stock”), on the terms and subject to the conditions set forth in this Agreement. The shares of Common Stock sold hereunder at the Closing (as defined below) shall be referred to as the “Shares”. 

SECTION 2. AGREEMENT TO SELL AND PURCHASE THE SECURITIES. 

2.1 Sale of Shares. At the Closing (as defined in Section 3), the Company will sell to each Purchaser, and each Purchaser will
purchase from the Company, the number of Shares set forth opposite such Purchaser’s name on the Schedule of Purchasers at a purchase price of $16.00 per Share. 

2.2 Separate Agreement. Each Purchaser shall severally, and not jointly, be liable for only the purchase of the Shares that appear on
the Schedule of Purchasers that relate to such Purchaser. The Company’s agreement with each of the Purchasers is a separate agreement, and the sale of Shares to each of the Purchasers is a separate sale. The obligations of each Purchaser
hereunder are expressly not conditioned on the purchase by any or all of the other Purchasers of the Shares such other Purchasers have agreed to purchase. 

SECTION 3. CLOSING AND DELIVERY. 
 3.1
Closing. The closing of the purchase and sale of the Shares (which Shares are set forth in the Schedule of Purchasers) pursuant to this Agreement (the “Closing”) shall be held on October 17, 2013 at the offices of
Latham & Watkins LLP, John Hancock Tower, 20th Floor, 200 Clarendon Street, Boston, Massachusetts 02116, or on such other date and place as may be agreed to by the Company and the Purchasers. At or prior to the Closing, the Company and each
Purchaser shall execute any related agreements or other documents required to be executed hereunder, dated as of the date of the Closing (the “Closing Date”). 

3.2 Issuance of the Shares at the Closing. On or prior to the Closing, (i) the Company shall issue to each Purchaser a stock
certificate registered in the name of such 

 
Purchaser, or in such nominee name(s) as designated by such Purchaser, free and clear of all restrictive and other legends (except as provided in Section 5.3 hereof) representing the number
of Shares to be purchased by such Purchaser at the Closing as set forth in Schedule of Purchasers and (ii) upon confirmation that the stock certificate representing the number of Shares to be purchased by a Purchaser at the Closing as set forth
in Schedule of Purchasers has been received by such Purchaser or such Purchaser’s custodian, such Purchaser shall pay the purchase price to the Company for the Shares to be issued and sold to such Purchaser at the Closing, by wire transfer of
immediately available funds in accordance with the Company’s written wire instructions. The name(s) in which the stock certificates are to be issued to each Purchaser will be provided to the Company by each Purchaser in substance substantially
similar to the Stock Certificate Questionnaire and the information requested of each Purchaser on the Registration Statement Questionnaire will be provided to the Company by each Purchaser in substance substantially similar to the Registration
Statement Questionnaire, both attached hereto as Exhibits B and C (the “Stock Certificate Questionnaire” and the “Registration Statement Questionnaire,” respectively), and shall be
provided to the Company no later than the Closing Date. 
 SECTION 4. REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY. 

Except as otherwise expressly described in the Company’s filings with the Securities and Exchange Commission (the
“Commission”) available on EDGAR to the public since June 27, 2013 (the “Commission Documents”), or in the Company’s press releases, as posted on the website of the Company in the Investor
Relations – News Releases section, since June 27, 2013 (the “Press Releases,” and together with the Commission Documents, the “Company Information”), which qualify the following
representations and warranties in their entirety, the Company hereby represents and warrants to, and covenants with, each Purchaser, as follows: 

4.1 Organization and Standing; Subsidiaries. The Company has been duly organized 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 presently conducted, and to enter into and perform its obligations under this
Agreement and the other documents delivered by the Company pursuant hereto; and the Company is duly qualified as a foreign corporation to transact business and is in good standing in each other jurisdiction in which such qualification is required,
except where the failure so to qualify or to be in good standing, individually or in the aggregate, would not reasonably be expected to have a material adverse effect on the assets, liabilities, properties, condition, financial or otherwise, in the
results of operations or business of the Company, or materially impair the Company’s ability to perform its obligations under this Agreement (a “Company Material Adverse Effect”). The Company has no
subsidiaries which have incurred any material liabilities. 
 4.2 Corporate Power; Authorization. The Company has the
requisite power and authority to enter into and to consummate the transactions contemplated by this Agreement and the other documents delivered by the Company pursuant hereto and otherwise to carry out its obligations hereunder and thereunder. The
execution and delivery by the Company of this Agreement and the other documents delivered by the Company pursuant hereto and the consummation and performance by it of the transactions contemplated hereunder and thereunder

 
have been duly authorized by all necessary corporate action on the part of the Company, and no further consent or action is required by the Company, its Board of Directors or its stockholders.
This Agreement and the other documents delivered by the Company pursuant hereto have been duly executed by the Company and, when delivered in accordance with the terms hereof or thereof, will constitute the valid and binding obligation of the
Company, enforceable against the Company in accordance with their terms, except as may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting parties’ rights
generally and except as enforceability may be subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law). 

4.3 No Conflicts or Violations. The execution, delivery and performance by the Company of this Agreement and the other documents
delivered by the Company pursuant hereto and the consummation by the Company of the transactions contemplated hereby and thereby do not and will not (i) conflict with or violate any provision of the Company’s restated certificate of
incorporation or amended and restated bylaws, (ii) conflict with, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration
or cancellation (with or without notice, lapse of time or both) of, or give any rights to receipt of any portion of the proceeds from the sale of the Shares pursuant to, any agreement, credit facility, debt or other instrument (evidencing a Company
debt or otherwise) to which the Company is a party or by which any property or asset of the Company is bound or affected, or (iii) result in a violation of any law, rule, regulation, order, judgment, injunction, decree or other restriction of
any court or governmental authority to which the Company is subject (including federal and state securities laws and regulations) and the rules and regulations of any self-regulatory organization to which the Company or its securities are subject,
or by which any property or asset of the Company is bound or affected except in the case of clauses (ii) and (iii), such as would not, individually or in the aggregate, be reasonably expected to result in a Company Material Adverse Effect. 

4.4 Governmental Consents. No consent, approval, authorization, filing with or order of or registration with, any court or governmental
agency or body is required in connection with the transactions contemplated herein, except such as have been or will be obtained or made under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (the
“Securities Act”), or the Securities Exchange Act of 1934, as amended, and the rule and regulations promulgated thereunder (the “Exchange Act”), and such as may be required under the securities, or
blue sky, laws of any state or foreign jurisdiction in connection with the offer and sale of the Shares by the Company in the manner contemplated herein. 

4.5 Issuance and Delivery of the Shares. The Shares have been duly authorized and, when issued and paid for in compliance with
the provisions of this Agreement, will be validly issued, fully paid and nonassessable. Neither the issuance nor delivery of the Shares is subject to preemptive, co-sale or any other similar rights of the stockholders of the Company or any liens or
encumbrances (other than any liens or encumbrances created by or imposed by the Purchaser purchasing the applicable Shares pursuant to the terms of this Agreement). Assuming the accuracy of the representations made by each Purchaser in
Section 5, the offer and issuance by the Company of the Shares is exempt from registration under the Securities Act. 

 4.6 Capitalization. All of the Company’s outstanding shares of capital stock
have been duly authorized and validly issued and are fully paid and nonassessable, have been issued in compliance with all federal and state securities laws, and were not issued in violation of or subject to any preemptive, co-sale or other rights
to subscribe for or purchase securities. The authorized capital stock of the Company consists of 100,000,000 shares of Common Stock and 10,000,000 shares of Preferred Stock. As of October 10, 2013, there were 21,896,180 shares of Common Stock
issued and outstanding and zero shares of Preferred Stock issued or outstanding. There are no other shares of any other class or series of capital stock of the Company issued or outstanding. The Company has no capital stock reserved for issuance,
except that, as of the Effective Date, 347,782 shares of Common Stock are subject to outstanding stock options and 601,697 shares of Common Stock remain available for future issuance under the Company’s equity incentive plans. Except as stated
above, there are no outstanding options, warrants, or other rights to purchase, or equity or debt securities convertible into or exchangeable or exercisable for, any capital stock of the Company that have been granted by the Company. The issuance of
Common Stock or other securities pursuant to any provision of this Agreement will not give rise to any preemptive rights or rights of first refusal, co-sale rights or any other similar rights on behalf of any person or result in the triggering of
any anti-dilution or other similar rights. There are no securities or instruments containing anti-dilution provisions that will be triggered by the issuance of the Shares. 

4.7 Commission Documents; Financial Statements. Each document filed with the Commission by the Company complied in all material
respects with the Exchange Act. Except as otherwise disclosed in the Commission Documents, since December 31, 2012, (i) there have not been any changes in the assets, liabilities, financial condition or operations of the Company from that
reflected in the Company’s audited financial statements for the fiscal year ended December 31, 2012 included in the Company’s Registration Statement on Form S-1 (File No. 333-187372), except changes in the ordinary course of
business consistent with past practice that would not be reasonably expected, either individually or in the aggregate, to have a Company Material Adverse Effect, (ii) the Company has not incurred any liabilities (contingent or otherwise) other
than (A) trade payables, accrued expenses and other liabilities incurred in the ordinary course of business consistent with past practice and (B) liabilities not required to be reflected in the Company’s financial statements pursuant
to GAAP or required to be disclosed in filings made with the Commission, which would not, individually or in the aggregate, be reasonably expected to have a Company Material Adverse Effect, (iii) the Company has not altered its critical
accounting policies, and (iv) the Company has not declared or made any dividend or distribution of cash or other property to its stockholders or purchased, redeemed or made any agreements to purchase or redeem any shares of its capital stock.

 4.8 No Proceedings or Investigations. Except as disclosed in the Company Information, there is no proceeding, or, to the
Company’s knowledge, inquiry or investigation, before or by any court, public board, government agency, self-regulatory organization or body pending or, to the knowledge of the Company, threatened against or affecting the Company or any of its
subsidiaries that would be reasonably expected, individually or in the aggregate, to have a Company Material Adverse Effect. 
 4.9
NASDAQ Compliance. The Company has not, since June 26, 2013, received notice (written or oral) from the Financial Industry Regulatory Authority or NASDAQ to the 

 
effect that the Company is not in compliance with the listing or maintenance requirements of the NASDAQ Global Market. The Company is in compliance with all such listing and maintenance
requirements. The issuance and sale of the Shares under this Agreement does not contravene the rules and regulations of the NASDAQ Global Market, and no approval of the stockholders of the Company thereunder is required for the Company to issue and
deliver the Shares to the Purchasers. 
 4.10 Sarbanes-Oxley Act. Except as set forth in the second sentence of this
Section 4.10, the Company is in compliance in all material respects with applicable requirements of the Sarbanes-Oxley Act of 2002, as amended (the “Sarbanes-Oxley Act”), and applicable rules and regulations promulgated
by the Commission thereunder. Pursuant to the Jumpstart Our Business Startups Act (the “JOBS Act”), the Company is not required to comply, and therefore does not comply, with Section 404 of the Sarbanes-Oxley Act, until
it is no longer classified as an “emerging growth company” under the JOBS Act. 
 4.11 Disclosure Controls and Procedures.
The Company has established and maintains disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) that are effective in all material respects to ensure that material information relating to the Company,
including its subsidiaries, is made known to its chief executive officer and chief financial officer by others within those entities. The Company’s certifying officers have evaluated the effectiveness of the Company’s controls and
procedures as of June 30, 2013. The Company presented in its Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2013 the conclusions of the certifying officers about the effectiveness of the disclosure controls and
procedures based on their evaluations as of June 30, 2013. Since June 30, 2013, there have been no significant changes in the Company’s internal controls (as such term is defined in Item 307(b) of Regulation S-K under the
Exchange Act) or, to the Company’s knowledge, in other factors that could significantly affect the Company’s internal controls. 

4.12 No Integrated or Aggregated Offering. Neither the Company, nor any person acting on its behalf, has, directly or indirectly, made
any offers or sales of any security or solicited any offers to buy any security, under circumstances that would cause the offering of Shares contemplated by this Agreement to be (i) integrated with prior offerings by the Company for purposes of
the Securities Act or (ii) aggregated with prior offerings by the Company for the purposes of the rules and regulations of the NASDAQ Global Market. 

4.13 Price of Common Stock. The Company has not taken, nor will it take, directly or indirectly, any action designed to stabilize or
manipulate the price of the Common Stock or any security of the Company to facilitate the sale or resale of the Shares. 
 4.14 No
General Solicitation. Neither the Company, nor any of its affiliates, nor any person acting on its or their behalf, has engaged in any form of general solicitation or general advertising (within the meaning of Regulation D promulgated under the
Securities Act) in connection with the offer or sale of the Shares. 
 4.15 Environmental Laws. The Company (i) is in compliance
with any and all applicable foreign, federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants

 
or contaminants (“Environmental Laws”), (ii) has received all permits, licenses or other approvals required under applicable Environmental Laws to conduct its
business and (iii) is in compliance with all terms and conditions of any such permit, license or approval, except where such noncompliance with Environmental Laws, failure to receive required permits, licenses or other approvals or failure to
comply with the terms and conditions of such permits, licenses or approvals would not, individually or in the aggregate, be reasonably expected to have a Company Material Adverse Effect. There are no costs or liabilities associated with
Environmental Laws, including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating
activities and any potential liabilities to third parties, that would, individually or in the aggregate, be reasonably expected to have a Material Adverse Effect. 

4.16 No Registration Rights. No holder of any security of the Company has any right, which has not been waived, to have any security
owned by such holder included in the Registration Statement (as such term is defined in Section 8.1(a)(i)). 
 4.17 Shell Company
Status. The Company is not, and has never been, an issuer identified in, or subject to, Rule 144(i) of the Securities Act. 
 4.18
Investment Company Status. The Company is not, and upon consummation of the sale of the Shares will not be, an “investment company,” an affiliate of an “investment company,” a company controlled by an “investment
company” or an “affiliated person” of, or “promoter” or “principal underwriter” for, an “investment company” as such terms are defined in the Investment Company Act of 1940, as amended 

4.19 Title. The Company has good and marketable title to all personal property owned by it that is material to the business of the
Company, free and clear of all liens, encumbrances and defects except as described in the Commission Documents or such as do not materially affect the value of such property and do not interfere with the use made and proposed to be made of such
property by the Company. Any real property and buildings held under lease by the Company is held under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere with the use made and proposed to be made
of such property and buildings by the Company. The Company does not own any real property. 
 4.20 Intellectual Property. 

(a) All patents and patent applications filed by or on behalf of the Company (the “Owned Patents”) are owned or
co-owned by the Company free and clear of all liens, encumbrances, except with respect to licenses granted in the ordinary course of business as such licenses and business are described in the Commission Documents, defects or other restrictions,
except as would not, singly or in the aggregate, have a Material Adverse Effect; and the Company reasonably believes that the Owned Patents are (or will be upon their issuance) valid and enforceable, except as would not, singly or in the aggregate,
have a Material Adverse Effect. 
 (b) In connection with the Company’s Owned Patents, all known prior art references material to the
patentability of the Owned Patents have been disclosed or will be disclosed to the USPTO to the extent required by and in accordance with 37 C.F.R. Section 1.56; 

 
and neither the Company nor, to the Company’s knowledge, any other person has made any material misrepresentations or concealed any information material to the patentability of the Owned
Patents from the USPTO in such applications or in connection with the prosecution of such applications, in violation of 37 C.F.R. Section 1.56. 

(c) Except as set forth in the Commission Documents, to the Company’s knowledge, the Company owns or possesses rights to use, or can
acquire on commercially reasonable terms ownership of or rights to use, all patents, patent applications, patent rights, licenses, inventions, copyrights, know-how (including trade secrets and other unpatented and/or unpatentable proprietary or
confidential information, systems or procedures), trademarks, service marks, trade names and other intellectual property (collectively, “Intellectual Property”) necessary for the conduct of the Company’s business as now
conducted, and for the manufacture, use or sale of its presently proposed products, as described in the Commission Documents. 
 (d) The
Company has not received any written notice from a third party that the Company has infringed the Intellectual Property of such third party that, singly or in the aggregate, would be reasonably expected to have a Company Material Adverse Effect.

 (e) To the Company’s knowledge, and except as would not be reasonably expected to have a Company Material Adverse Effect, there are
no valid and enforceable rights of third parties to such Intellectual Property that are or would be infringed by the business currently conducted by the Company or in the manufacture, use, sale, offer for sale or import of its presently proposed
products, as described in the Commission Documents. 
 (f) Except as set forth in the Commission Documents, the Intellectual Property owned
by the Company is not subject to any judgment, order, writ, injunction or decree of any court or any federal, state, local, foreign or other governmental department, commission, board, bureau, agency or instrumentality, domestic or foreign, or any
arbitrator, except as would not be reasonably expected to have a Company Material Adverse Effect. 
 (g) To the Company’s knowledge,
there are no ongoing infringements by any third parties of any material Owned Patents in connection with the business currently conducted by the Company or its presently proposed products, as described in the Commission Documents, except as would
not be reasonably expected to have a Company Material Adverse Effect. 
 4.21 Regulatory Compliance. 

(a) The Company holds all necessary consents, authorizations, approvals, orders, certificates, registrations, exemptions, licenses, variances
and permits (“Permits”) of and from, and has made all required declarations and filings with, and complied with all formal recommendations of, all federal, state, local and other governmental authorities, including, without
limitation, the U.S. Food and Drug Administration (“FDA”) and comparable foreign regulatory agencies, and all self-regulatory organizations and all courts and other tribunals, to own, lease, license and use its properties and
assets and to conduct its business in the manner described in the Commission Documents, except as disclosed in the Commission Documents, and except to the extent that the failure to hold such permits, or to make such declarations or filings, or to
comply with such recommendations would not, individually or in the aggregate, be 

 
reasonably expected to have a Company Material Adverse Effect. All Permits are in full force and effect. The Company has fulfilled and performed all of its obligations with respect to the
Permits, and no event has occurred which allows, or after notice or lapse of time would allow, suspension, cancellation, revocation, or material adverse modification thereof or results in any other impairment of the rights of the holder of any
Permit, except as would not, individually or in the aggregate, be reasonably expected to have a Company Material Adverse Effect. The Company has not received any notice of any pending or threatened claims, suit, proceeding, hearing, enforcement,
audit, investigation, arbitration, or other action from any governmental entity relating to the suspension, cancellation, revocation or material adverse modification of any Permit which, individually or in the aggregate, if the subject of an
unfavorable decision, ruling or finding, would be reasonably expected to have a Company Material Adverse Effect, except as described in the Commission Documents. 

(b) None of the FDA or other governmental entity, including any applicable foreign regulatory agency, has recommended, commenced, or, to the
knowledge of the Company, threatened to initiate, any action to terminate, delay or suspend any proposed or ongoing clinical investigations conducted or proposed to be conducted by or on behalf of the Company. 

(c) To the best of the Company’s knowledge, all the operations of the Company and all the manufacturing facilities and operations of the
Company’s suppliers of products and product candidates and the components thereof manufactured in or imported into the United States are in compliance with applicable laws, rules, regulations and standards administered or enforced by the FDA
and any other governmental entity, and all the operations of the Company and all the manufacturing facilities and operations of the Company’s suppliers of products and product candidates manufactured outside, or exported from, the United States
are in compliance with applicable foreign regulatory requirements and standards, except to the extent that the failure to be in compliance with such laws, rules, regulations and standards would not, individually or in the aggregate, be reasonably
expected to have a Company Material Adverse Effect. 
 (d) Except as described in the Commission Documents, the preclinical studies and
clinical trials, including target animal studies, conducted by or on behalf of the Company are being or have been conducted in accordance in all material respects with all applicable rules, regulations and policies of the FDA and any other
governmental entity, including the current Good Clinical Practices and Good Laboratory Practices, and all applicable foreign regulatory requirements and standards. 

(e) The Company has operated its business and currently is in compliance in all material respects with all applicable rules, regulations and
policies of the FDA or any other governmental entity, including any applicable foreign regulatory organization. Since January 1, 2010, the Company has not had any product or manufacturing site subject to a governmental entity (including FDA)
shutdown or import or export prohibition, nor received any FDA Form 483 or other governmental entity notice of inspectional observations, “warning letters,” “untitled letters,” other requests or requirements from any
governmental entity to make changes to the Company’s products that if not complied with would reasonably be expected to result in a material liability to the Company, or similar notice from the FDA or other governmental entity

 
alleging or asserting noncompliance with any applicable laws, Permits, or such requests or requirements of a governmental entity. To the Knowledge of the Company, neither the FDA nor any other
governmental entity is considering any such action. 
 (f) Since January 1, 2010, the Company has not had any recalls, field
notifications, field corrections, market withdrawals or replacements, warnings, “dear doctor” letters, investigator notices, safety alerts or other notice of action relating to an alleged lack of safety, efficacy, or regulatory compliance
of the Company’s products. 
 SECTION 5. REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE PURCHASERS. 

5.1 Each Purchaser, severally and not jointly, represents and warrants to and covenants with the Company that: 

(a) Such Purchaser, taking into account the personnel and resources it can practically bring to bear on the purchase of the Shares
contemplated hereby, is knowledgeable, sophisticated and experienced in making, and is qualified to make, decisions with respect to investments in securities presenting an investment decision like that involved in the purchase of the Shares,
including investments in securities issued by the Company, and has requested, received, reviewed and considered all information such Purchaser deems relevant (including the Commission Documents) in making an informed decision to purchase the Shares.

 (b) Such Purchaser is acquiring the Shares pursuant to this Agreement for its own account for investment only and with no present
intention of distributing any of such Shares or any arrangement or understanding with any other persons regarding the distribution of such Shares. 

(c) Such Purchaser is an “accredited investor” within the meaning of Rule 501 of Regulation D promulgated under the Securities Act
or a Qualified Institutional Buyer within the meaning of Rule 144A promulgated under the Securities Act. 
 (d) (i) Such Purchaser is an
entity duly organized and validly existing in good standing (to the extent such concepts are applicable) under the laws of its jurisdiction of organization, (ii) such Purchaser has full right, power and authority to enter into this Agreement
and to consummate the transactions contemplated hereby and has taken all necessary action to authorize the execution, delivery and performance of this Agreement, and (iii) this Agreement constitutes a valid and binding obligation of such
Purchaser enforceable against such Purchaser in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors’ and contracting
parties’ rights generally and except as enforceability may be subject to general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law). 

(e) Such Purchaser is not a broker or dealer registered pursuant to Section 15 of the Exchange Act and is not affiliated with a
registered broker dealer. Such Purchaser is not party to any agreement for distribution of any of the Shares. 

 (f) Such Purchaser shall have delivered to the Company at no later than the Closing Date,
(i) the name(s) in which the stock certificate is to be issued to such Purchaser in substance substantially similar to the Stock Certificate Questionnaire and (ii) the Registration Statement Questionnaire for use in preparation of the
Registration Statement (in a substance substantially similar to Exhibit C), and such information is true and correct in all material respects as of the Effective Date and will be true and correct in all material respects as of the Closing
Date and the effective date of the Registration Statement; provided that such Purchaser shall be entitled to update such information by providing notice thereof to the Company at least two days before the effective date of such Registration
Statement. 
 (g) Such Purchaser (including any person controlling, controlled by, or under common control with such Purchaser, as the term
“control” is defined pursuant to the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and its implementing regulations (the “HSR Act”)) does not, and upon the consummation of the transactions
contemplated by this Agreement will not, hold voting securities of the Company exceeding an aggregate fair market value as of the Closing Date of seventy million nine hundred thousand dollars ($70,900,000), calculated pursuant to the HSR Act. 

5.2 Each Purchaser, severally and not jointly, understands that nothing in this Agreement or any other materials presented to such Purchaser
in connection with the purchase and sale of the Shares constitutes legal, tax or investment advice. Such Purchaser has consulted such legal, tax and investment advisors as it, in its sole discretion, has deemed necessary or appropriate in connection
with its purchase of the Shares. 
 5.3 Legends. Each Purchaser, severally and not jointly, understands that the Shares may bear one
or more legends in substantially the following form and substance: 
 “THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR ANY OTHER APPLICABLE SECURITIES LAWS AND HAVE BEEN ISSUED IN RELIANCE UPON AN EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND
SUCH OTHER SECURITIES LAWS. NEITHER THIS SECURITY NOR ANY INTEREST OR PARTICIPATION HEREIN MAY BE REOFFERED, SOLD, ASSIGNED, TRANSFERRED, PLEDGED, ENCUMBERED, HYPOTHECATED OR OTHERWISE DISPOSED OF, EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO A TRANSACTION WHICH IS EXEMPT FROM, OR NOT SUBJECT TO, SUCH REGISTRATION, IN EACH CASE IN ACCORDANCE WITH ALL APPLICABLE SECURITIES LAWS, AND IN THE CASE OF A TRANSACTION EXEMPT FROM, OR NOT SUBJECT
TO, SUCH REGISTRATION, UNLESS THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO IT THAT SUCH TRANSACTION DOES NOT REQUIRE REGISTRATION UNDER THE SECURITIES ACT AND SUCH OTHER APPLICABLE LAWS.” 

 In addition, stock certificates representing the Shares may contain any legend required by the
blue sky laws of any state to the extent such laws are applicable to the sale of such Shares hereunder. 
 5.4 Restricted Securities.
Purchaser understands that the Shares are characterized as “restricted securities” under the federal securities laws inasmuch as they are being acquired from the Company in a transaction not involving a public offering and that under such
laws and applicable regulations such Shares may be resold without registration under the Securities Act only in certain limited circumstances. In this connection, such Purchaser represents that it is familiar with Commission Rule 144, as presently
in effect, and understands the resale limitations imposed thereby and by the Securities Act. 
 5.5 Pending Acquisition and Resale
Registration. Purchaser understands that the Company intends to enter into an Agreement and Plan of Merger (the “Merger Agreement”) on or about the date hereof with respect to the acquisition of Vet Therapeutics, Inc., a
Delaware corporation, pursuant to which Vet Therapeutics, Inc. become a wholly owned subsidiary of the Company (the “Merger”). Purchaser also understands that, pursuant to the terms of the Merger Agreement, the Company shall
be obligated to register for resale the shares of Common Stock to be issued in connection with the completion of the Merger (the “Merger Shares”). Purchaser acknowledges and agrees that the Company may include the Merger
Shares and additional shares of Common Stock held by other shareholders of the Company in the Registration Statement (as defined below). 
 SECTION 6.
CONDITIONS TO COMPANY’S OBLIGATIONS AT THE CLOSING. 
 The Company’s obligation to complete the sale and issuance of the Shares
and deliver Shares to each Purchaser, individually, as set forth in the Schedule of Purchasers at the Closing shall be subject to the following conditions to the extent not waived by the Company: 

6.1 Receipt of Payment. Subject to confirmation of receipt of the stock certificates as set forth in Section 3.2 above, the
Company shall have received payment, by wire transfer of immediately available funds, in the full amount of the purchase price for the number of Shares being purchased by each Purchaser at the Closing as set forth in the Schedule of Purchasers. 

6.2 Representations and Warranties. The representations and warranties made by each Purchaser in Section 5 hereof shall be true
and correct in all material respects as of, and as if made on, the date of this Agreement and as of the Closing Date. 
 6.3 Receipt of
Executed Documents. Each Purchaser shall have executed and delivered to the Company (i) the name(s) in which the stock certificate is to be issued to each Purchaser in substance substantially similar to the Stock Certificate Questionnaire,
(ii) the Registration Statement Questionnaire (in substance substantially similar to that set forth in Exhibit C) and (iii) a Lock-Up Agreement in the form attached hereto as Exhibit D hereto. 

6.4 NASDAQ Approval. The Shares shall have been approved for listing on the NASDAQ Global Market, subject to official notice of
issuance 

 6.5 Securities Laws Disclosure; Publicity. On or before 9:00 a.m., New York City time, on
the business day immediately following the date hereof, the Company shall issue a press release (the “Press Release”) reasonably acceptable to the Purchasers disclosing all material terms of the transactions contemplated
hereby, or alternatively, the Company will file a Current Report on Form 8-K with the Commission describing the terms of this Agreement (and including this Agreement as an exhibit to such Current Report on Form 8-K). Notwithstanding the foregoing,
the Company shall not publicly disclose the name of any Purchaser, or include the name of any Purchaser in any press release, without the prior written consent of such Purchaser. From and after the issuance of the Press Release or such Form 8-K, no
Purchaser shall be in possession of any material, non-public information received from the Company or any of its officers, directors, employees or agents, that is not disclosed in the Press Release. 

SECTION 7. CONDITIONS TO PURCHASERS’ OBLIGATIONS AT THE CLOSING. 

Each Purchaser’s obligation to accept delivery of the Shares being purchased by such Purchaser at the Closing as set forth in the Schedule
of Purchasers and to pay for such Shares shall be subject to the following conditions to the extent not waived by such Purchaser: 
 7.1
Representations and Warranties Correct. The representations and warranties made by the Company in Section 4 hereof shall be true and correct in all material respects (except to the extent that such representations and warranties are
qualified by materiality, material adverse effect, or words of like effect, in which case such representations and warranties shall be true in all respects) as of, and as if made on, the date of this Agreement and as of the Closing Date. 

7.2 Legal Opinion. The Purchasers shall have received an opinion of Latham & Watkins LLP, special counsel to the Company, in a
customary form reasonably acceptable to the Purchasers. 
 7.3 Certificates. Each Purchaser shall have received: 

(a) A certificate signed by the Company’s Chief Executive Officer to the effect that the representations and warranties of the Company in
Section 4 hereof are true and correct in all material respects (except to the extent that such representations and warranties are qualified by materiality, material adverse effect, or words of like effect, in which case such representations and
warranties shall be true in all respects) as of, and as if made on, the date of this Agreement and as of the Closing Date and that the Company has satisfied in all material respects all of the conditions set forth in this Section 7. 

(b) A certificate signed by the Secretary of the Company to which is attached a true, complete and correct copy of each of the restated
certificate of incorporation of the Company, the amended and restated bylaws of the Company and certain resolutions of the Board of Directors of the Company, to the effect that (i) no document with respect to any amendment to the certificate of
incorporation of the Company has been filed in the office of the Secretary of State of the State of Delaware since July 2, 2013, and no action has been taken or, to the best knowledge of the Secretary of the Company, is contemplated by the
Board of Directors or the stockholders of the Company, for the purpose of effecting any such amendment or the 

 
dissolution, merger or consolidation of the Company, (ii) no proposal for any amendment, repeal or other modification to the amended and restated bylaws of the Company has been taken or is
currently pending before the Board of Directors or stockholders of the Company and (iii) the resolutions of the Board of Directors of the Company authorizing the execution, delivery and performance of this Agreement and the consummation of the
transactions contemplated by this Agreement have not been altered, amended or superseded and remain in full force and effect as of the date hereof. 

7.4 Good Standing. The Company shall be validly existing as a corporation in good standing under the laws of Delaware as of the
Effective Date and the Closing Date. 
 7.5 NASDAQ Approval. The Shares shall have been approved for listing on the NASDAQ Global
Market, subject to official notice of issuance. 
 7.6 Material Adverse Effect. No Company Material Adverse Effect shall have
occurred since the date of this Agreement or be reasonably expected to occur. 
 SECTION 8. REGISTRATION OF THE SECURITIES; COMPLIANCE WITH THE
SECURITIES ACT. 
 8.1 Registration Procedures and Expenses. 

(a) Except during a Suspension, the Company will, subject to receipt of necessary information from the Purchasers: 

(i) as soon as practicable, but in any event no later than 5:30 p.m., Eastern Time, on the 90th day after the Closing Date, to prepare and
file with the Commission a registration statement on Form S-1 or other applicable form available to the Company (the “Registration Statement”) covering the resale by each Purchaser of the Shares purchased by each Purchaser
hereunder that has complied with Section 8.5 (the “Registrable Securities”). 
 (ii) cause (A) the
Registration Statement, as may be amended from time to time, to become effective under the Securities Act as soon as practicable after the Registration Statement is filed by the Company, but in any event no later than 5:30 p.m., Eastern Time, on the
90th day after the Closing Date, or if the Registration Statement is reviewed by the Commission, on the 120th day after the Closing Date (its
“Required Effective Date”); 
 (iii) cause any prospectus used in connection with the Registration Statement (a
“Prospectus”) to be filed with the Commission pursuant to Rule 424(b) under the Securities Act as soon as practicable but in any event no later than 9:00 a.m., Eastern Time, on the next day that is not a weekend or holiday
and the NASDAQ Global Market is not closed (“Trading Day”) following the date the Registration Statement is declared effective by the Commission; 

(iv) promptly prepare and file with the Commission such amendments and supplements to the Registration Statement and any Prospectus used in
connection therewith as may be necessary to keep the Registration Statement continuously effective until the earliest of (1) such time as all Registrable Securities have been sold pursuant to such Registration Statement and (2) the first
anniversary of the Closing Date; 

 (v) so long as the Registration Statement is effective covering the resale of Registrable
Securities owned by the Purchasers, furnish to each Purchaser with respect to the Registrable Securities registered under such Registration Statement such reasonable number of copies of Prospectuses and such other documents as such Purchaser may
reasonably request in order to facilitate the public sale or other disposition of all or any of the Registrable Securities by such Purchaser; 

(vi) bear all expenses in connection with the procedures in paragraphs (i) through (v) of this Section 8.1(a) and the
registration of the Registrable Securities pursuant to the Registration Statement, other than fees and expenses, if any, of counsel or other advisers to the Purchasers or brokerage fees and commissions incurred by the Purchasers; and 

(vii) use commercially reasonable efforts to prevent the issuance of any stop order or other order suspending the effectiveness of the
Registration Statement and, if such an order is issued, to obtain the withdrawal thereof at the earliest possible time and to notify each Purchaser of the issuance of such order and the resolution thereof. 

(b) The Company shall be permitted to suspend or delay for one or more periods (each such period, a “Suspension”) the
actions required under Sections 8.1(a) and the use of a Prospectus forming a part of a Registration Statement in the event that (i) the Company is engaged in any activity or transaction or preparations or negotiations for any activity or
transaction that the Company desires to keep confidential for business reasons, if the Company determines in good faith that the public disclosure requirements imposed on the Company under the Securities Act in connection with the Registration
Statement would require disclosure of such activity, transaction, preparations or negotiations, (ii) any financial statements or other information required to be included or incorporated by reference in the Registration Statement are not
available, or (iii) the Company has timely filed a post-effective amendment to the Registration Statement to satisfy its undertakings under Item 512 of Regulation S-K promulgated under the Securities Act or to include any prospectus
required by Section 10(a)(3) of the Securities Act and such amendment shall have not yet been declared effective by the Commission. The Company agrees to file such amendment, supplement or report or otherwise disclose such additional
information as soon as practicable following such notice of such Suspension. Notwithstanding the foregoing, the Company agrees that no Suspension shall be for a period of longer than 45 days and no Suspension or Suspensions shall be for an aggregate
in any 365-day period of longer than 90 days; provided that any Suspension of up to 20 days pursuant to clause (iii) of this Section 8.1(b) shall not count toward the calculation of such periods. 

(c) With a view to making available to the Purchasers the benefits of Rule 144 (or its successor rule) and any other rule or regulation of the
Commission that may at any time permit the Purchaser to sell Registrable Securities to the public without registration, the Company covenants and agrees to: (A) make and keep public information available, as those terms are understood and
defined in Rule 144, until the earlier of (1) such date as all of the Purchasers’ Registrable Securities may be resold without volume or manner of sale limitations 

 
pursuant to Rule 144(b) or any other rule of similar effect or (2) such date as all of the Purchasers’ Registrable Securities shall have been resold; (B) file with the Commission
in a timely manner all reports and other documents required of the Company under the Exchange Act; and (C) furnish to the Purchaser upon request, as long as the Purchaser owns any Registrable Securities, (1) a written statement by the
Company that it has complied with the reporting requirements of the Exchange Act, (2) a copy of the Company’s most recent Annual Report on Form 10-K or Quarterly Report on Form 10-Q, if available, except to the extent that such documents
are available from the Commission on its EDGAR website, and (3) such other information as may be reasonably requested (including but not limited to, opinion of counsel) in order to avail the Purchaser of any rule or regulation of the Commission
that permits the selling of any such Registrable Securities without registration. 
 8.2 Delay in Effectiveness of Registration
Statement. If the Registration Statement is not declared effective by the Commission on or prior to its Required Effective Date (subject to any extension for a permissible Suspension), then, in addition to any other rights available to the
Purchasers, on such Required Effective Date and on each monthly anniversary of each such Required Effective Date (if the Registration Statement shall not have been declared effective by the Commission by such date) until the Registration Statement
has been declared effective by the Commission, the Company shall pay to each Purchaser, as liquidated damages and not as a penalty, a cash payment equal to 1.5% of the aggregate purchase price paid by such Purchaser to the Company with respect to
the Shares then held by such Purchaser that are Registrable Securities. The liquidated damages pursuant to the terms hereof shall apply on a pro rata basis for any portion of a month prior to the Registration Statement being declared effective by
the Commission; provided that the maximum aggregate liquidated damages payable to a Purchaser under this Section 8.2 shall not exceed 10% of the aggregate purchase price paid by such Purchaser to the Company with respect to the Shares
then held by such Purchaser that are Registrable Securities. The parties agree that such liquidated damages shall not be the exclusive damages under this Agreement with respect to the Registration Statement not being declared effective by the
Commission on or prior to its Required Effective Date. Notwithstanding the foregoing or anything to the contrary contained herein, no liquidated or other damages shall be due to a Purchaser in respect of (A) any limitation on the number of
Shares that may be registered imposed by the Commission following the Company’s reasonable best efforts not to have such limitation imposed, or (B) the failure to have any Registration Statement declared effective on the Required Effective
Date in the event that such failure results from a breach by such Purchaser of its obligations under this Agreement. 
 8.3 Maintenance
of Effectiveness of Registration Statement; Listing on Permitted Securities Exchange. If at any time after the Registration Statement is declared effective by the Commission, sales cannot be made thereunder due to the failure of the Company to
maintain the effectiveness of such Registration Statement (other than during a permissible Suspension), in each case for a period of longer than 10 days, or for an aggregate in any 365-day period of longer than 60 days (each such period, a
“Maintenance Period” and the final day of each such period, a “Maintenance Date”), then, in addition to any other rights available to the Purchasers, on each such Maintenance Date and on each
successive Maintenance Date, until the Registration Statement has been declared effective by the Commission (if the Registration Statement shall not have been declared effective by the Commission by such date), the Company shall pay to each
Purchaser, as liquidated damages and not as a penalty, a cash payment equal to 1.5% of the 

 
aggregate purchase price paid by such Purchaser to the Company with respect to the Shares then held by such Purchaser that are Registrable Securities. The liquidated damages pursuant to the terms
hereof shall apply on a pro rata basis for any portion of a Maintenance Period prior to the Registration Statement being declared effective by the Commission; provided that the maximum aggregate liquidated damages payable to a Purchaser under
this Section 8.3 shall not exceed 10% of the aggregate purchase price paid by such Purchaser to the Company with respect to the Shares then held by such Purchaser that are Registrable Securities. The parties agree that such liquidated damages
shall not be the exclusive damages under this Agreement with respect to the failure of the Company to maintain for any Maintenance Period the effectiveness of such Registration Statement (other than during a permissible Suspension). Notwithstanding
the foregoing or anything to the contrary contained herein, no liquidated or other damages shall be due to a Purchaser in respect of the failure to maintain the effectiveness of any Registration Statement for any Maintenance Period or the failure of
the Common Stock to be listed or included for quotation on a Permitted Securities Exchange for any Maintenance Period in the event that such failure results from a breach by such Purchaser of its obligations under this Agreement. 

8.4 Restrictions on Transferability. 

(a) Each Purchaser agrees that it will not effect any disposition of the Shares or its right to purchase the Shares that would constitute a
sale within the meaning of the Securities Act or pursuant to any applicable state securities or Blue Sky laws of any state, except (i) as contemplated in the Registration Statement referred to in Section 8.1 above, (ii) pursuant to
the requirements of Rule 144 (in which case such Purchaser will provide the Company with reasonable evidence of such Purchaser’s compliance therewith) or (iii) pursuant to a written opinion of legal counsel reasonably satisfactory to the
Company and addressed to the Company to the effect that registration under Section 5 of the Securities Act is not required in connection with the proposed transfer; whereupon the holder of such securities shall be entitled to transfer such
securities. Each certificate evidencing the securities transferred as above provided shall bear the appropriate restrictive legends as may be required by Section 5.4. 

(b) Each Purchaser hereby covenants that such Purchaser will not sell any Shares pursuant to any Prospectus during a Suspension. 

(c) None of the Shares shall be transferable except upon the conditions specified in this Section 8, which are intended to ensure
compliance with the provisions of the Securities Act. Each Purchaser will cause any proposed transferee of the Shares held by such Purchaser to agree to take and hold such Shares subject to the provisions and upon the conditions specified in this
Section 8 if and to the extent that such Shares continue to be restricted securities in the hands of the transferee. In the case of a partnership distribution by any Purchaser, the foregoing agreement may be evidenced by a unilateral
instruction letter or similar notice provided by the Purchaser to each transferee referencing this Agreement and informing the transferee that, by accepting the distribution of the Shares, the transferee will be subject to the provisions and
conditions specified in this Section 8 if and to the extent that such Shares continue to be restricted securities in the hands of the transferee. 

(d) Subject to Section 10 hereof, each Purchaser covenants that such Purchaser will sell or transfer any Shares in accordance with the
applicable Registration 

 
Statement (to the extent such Purchaser is not relying on clauses (ii) or (iii) of Section 8.4(a) hereof), the Securities Act, applicable state securities laws and, to the extent
the exemption from prospectus delivery requirements in Rule 172 under the Securities Act is not available, the requirement of delivering a current prospectus in connection with any proposed transfer or sale of the Shares; provided, however,
notwithstanding anything to the contrary herein, in no event shall the Purchaser be liable for any violation of such laws, rules or regulations to the extent such violation results from a breach by the Company of any representation, warranty or
covenant of the Company in this Agreement or any document delivered hereunder or thereunder or the failure by such Purchaser is directly caused by the Company’s failure to provide written notice of a Suspension to such Purchaser. 

8.5 Furnish Information. It shall be a condition to the Company’s obligations to take any action under this Agreement with respect
to the registration of a Purchaser’s Registrable Securities that such Purchaser shall promptly furnish to the Company, upon request, such reasonable and customary information regarding itself, such Purchaser’s Registrable Securities, and
the intended method of disposition of such Registrable Securities. In connection therewith, each Purchaser shall be required to represent to the Company that all such information which is given is both complete and accurate in all material respects
when made. 
 SECTION 9. NOTICES. 
 All
notices, requests, consents and other communications hereunder shall be in writing, shall be sent by confirmed facsimile or electronic mail, or mailed by first-class registered or certified airmail, or nationally recognized overnight express
courier, postage prepaid, and shall be deemed given when so sent in the case of facsimile or electronic mail transmission, or when so received in the case of mail or courier, and addressed as follows: 

 

	 	(a)	if to the Company, to: 

 Aratana Therapeutics, Inc. 

1901 Olathe Boulevard 
 Kansas
City, Kansas 66103 
 Attention: Chief Executive Officer 

E-Mail: sstpeter@aratana.com 

with a copy to (which shall not constitute notice): 

Latham & Watkins LLP 

John Hancock Tower, 20th Floor 

200 Clarendon Street 
 Boston,
Massachusetts 02116 
 Attn: Peter N. Handrinos 

Fax: (617) 948-6060 

Email: peter.handrinos@lw.com 

or to such other person at such other place as the Company shall designate to the Purchasers in writing; and 

 (b) if to a Purchaser, at the address as set forth on such Purchaser’s signature page to
this Agreement, or at such other address or addresses as may have been furnished to the Company in writing. 
 SECTION 10. INDEMNIFICATION AND
CONTRIBUTION 
 10.1 For purposes of this Section 10 only: 

(a) the term “Purchaser” shall include the Purchaser and any affiliate (as such term is defined pursuant to Rule 12b-2
promulgated under the Exchange Act) of such Purchaser; 
 (b) the term “Prospectus” shall mean the prospectus and
any amendment or supplement thereto in the form first filed with the Commission pursuant to Rule 424(b) promulgated under the Securities Act or, if no Rule 424(b) filing is required, filed as part of the Registration Statement at the time of
effectiveness, as supplemented or amended from time to time; and 
 (c) the term “Registration Statement” shall
include any final prospectus, exhibit, supplement or amendment included in or relating to a Registration Statement. 
 10.2 The Company
agrees to indemnify and hold harmless each of the Purchasers and each person, if any, who controls each Purchaser within the meaning of the Securities Act against any losses, claims, damages, liabilities or expenses, joint or several, to which such
Purchasers may become subject, under the Securities Act, the Exchange Act, or any other federal or state statutory law or regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the
prior written consent of the Company), insofar as such losses, claims, damages, liabilities or expenses (or actions in respect thereof as contemplated below) arise out of or are based upon any untrue statement or alleged untrue statement of any
material fact contained in a Registration Statement or Prospectus, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in
light of the circumstances in which they were made, not misleading, and will reimburse each Purchaser and each person, if any, who controls each Purchaser within the meaning of the Securities Act for any legal and other expenses as such expenses are
reasonably incurred by such Purchaser or any person, if any, who controls such Purchaser within the meaning of the Securities Act in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability,
expense or action; provided, however, that the Company will not be liable to such Purchaser in any such case to the extent that any such loss, claim, damage, liability or expense arises out of or is based upon (i) an untrue statement or
alleged untrue statement or omission or alleged omission made in a Registration Statement or Prospectus in reliance upon (and prior to the furnishing by the Purchaser of corrective information to the Company) and in conformity with written
information furnished to the Company by or on behalf of such Purchaser expressly for use therein; (ii) the failure of such Purchaser to comply with the covenants and agreements contained herein unless such failure by such Purchaser results from
a breach by the Company of any representation, warranty or covenant of the Company in this Agreement or any other document delivered hereunder or thereunder or is caused by the Company’s failure to provide written notice of a Suspension to such
Purchaser; or (iii) the inaccuracy of any representations made by such Purchaser herein. 

 10.3 Each Purchaser shall severally, and not jointly, indemnify and hold harmless the other
Purchasers and the Company, each of its directors, each of its officers who signed a Registration Statement and each person, if any, who controls the Company within the meaning of the Securities Act, against any losses, claims, damages, liabilities
or expenses to which the Company, each of its directors, each of its officers who signed a Registration Statement or controlling person may become subject, under the Securities Act, the Exchange Act, or any other federal or state statutory law or
regulation, or at common law or otherwise (including in settlement of any litigation, if such settlement is effected with the prior written consent of such Purchaser) insofar as such losses, claims, damages, liabilities or expenses (or actions in
respect thereof as contemplated below) arise out of or are based upon any untrue statement or alleged untrue statement of any material fact contained in a Registration Statement or the Prospectus, or the omission or alleged omission to state therein
a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances in which they were made, not misleading, in each case to the extent, but only to the extent, that such untrue statement or
alleged untrue statement or omission or alleged omission was made in a Registration Statement or Prospectus in reliance upon and in conformity with written information furnished to the Company by or on behalf of such Purchaser expressly for use
therein, and will reimburse the Company, each of its directors, each of its officers who signed a Registration Statement or controlling persons for any legal and other expense reasonably incurred, as such expenses are reasonably incurred by the
Company, each of its directors, each of its officers who signed a Registration Statement or controlling persons in connection with investigating, defending, settling, compromising or paying any such loss, claim, damage, liability, expense or action.
No Purchaser shall be liable for the indemnification obligations of any other Purchaser. 
 10.4 Promptly after receipt by an indemnified
party under this Section 10 of notice of the threat or commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against an indemnifying party under this Section 10, promptly notify the
indemnifying party in writing thereof, but the omission so to notify the indemnifying party will not relieve it from any liability which it may have to any indemnified party hereunder or otherwise to the extent it is not prejudiced in any material
respect as a result of such failure. In case any such action is brought against any indemnified party and such indemnified party seeks or intends to seek indemnity from an indemnifying party, the indemnifying party will be entitled to participate
in, and, to the extent that it may wish, jointly with all other indemnifying parties similarly notified, to assume the defense thereof with counsel reasonably satisfactory to such indemnified party; provided, however, if the defendants in any
such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be a conflict between the positions of the indemnifying party and the indemnified party in conducting
the defense of any such action or that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, the indemnified party or parties shall have the
right to select separate counsel to assume such legal defenses and to otherwise participate in the defense of such action on behalf of such indemnified party or parties. Upon receipt of notice from the indemnifying party to such indemnified party of
its election to assume the defense of such action and approval by the indemnified party of counsel, the indemnifying party will not be liable to 

 
such indemnified party under this Section 10 for any legal or other expenses subsequently incurred by such indemnified party in connection with the defense thereof unless (i) the
indemnified party shall have employed such counsel in connection with the assumption of legal defenses in accordance with the proviso to the preceding sentence (it being understood, however, that the indemnifying party shall not be liable for the
expenses of more than one separate counsel, representing the indemnified parties who are parties to such action) or (ii) the indemnifying party shall not have employed counsel reasonably satisfactory to the indemnified party to represent the
indemnified party within a reasonable time after notice of commencement of action, in each of which cases the reasonable fees and expenses of counsel shall be at the expense of the indemnifying party. No indemnifying party, in the defense of any
claim covered by this Section 10, shall, except with the prior written consent of the indemnified party, consent to entry of any judgment or enter into any settlement which does not include as an unconditional term thereof the giving by the
claimant or plaintiff to such indemnified party of a release of the indemnified party and the indemnifying party from all liability in respect to such claim. An indemnified party shall not consent to entry of any judgment or enter into any
settlement without the prior written consent of the indemnifying party. 
 10.5 If the indemnification provided for in this Section 10
is unavailable to or insufficient to hold harmless an indemnified party under Section 10.2 or 10.3 above in respect of any losses, claims, damages, liabilities or expenses (or actions in respect thereof) referred to therein, then each
indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages, liabilities or expenses (or actions in respect thereof) in such proportion as is appropriate to reflect the
relative fault of the Company on the one hand and each Purchaser on the other in connection with the statements or omissions or other matters which resulted in such losses, claims, damages, liabilities or expenses (or actions in respect thereof), as
well as any other relevant equitable considerations. The relative fault shall be determined by reference to, among other things, in the case of an untrue statement, whether the untrue statement relates to information supplied by the Company on the
one hand or each Purchaser on the other and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such untrue statement. The Company and the Purchasers agree that it would not be just and equitable
if contribution pursuant to this Section 10.5 were determined by pro rata allocation (even if the Purchasers were treated as one entity for such purpose) or by any other method of allocation which does not take into account the equitable
considerations referred to above in this Section 10.5. The amount paid or payable by an indemnified party as a result of the losses, claims, damages, liabilities or expenses (or actions in respect thereof) referred to above in this
Section 10.5(e) shall be deemed to include any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. No person guilty of fraudulent misrepresentation
(within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The Purchasers’ obligations in this subsection to contribute are several
in proportion to their sales of Securities to which such loss relates and not joint. 
 10.6 Notwithstanding the foregoing or anything to
the contrary contained herein, no Purchaser will be liable for any losses, claims, damages, liabilities or expenses (or actions in respect thereof) in excess of the net amount received by such Purchaser from the sale of the Securities. 

 SECTION 11. MISCELLANEOUS. 

11.1 Waivers and Amendments. Neither this Agreement nor any provision hereof may be changed, waived, discharged, terminated, modified or
amended except upon the written consent of the Company and each Purchaser. 
 11.2 Headings. The headings of the various sections of
this Agreement have been inserted for convenience of reference only and shall not be deemed to be part of this Agreement. 
 11.3
Severability. In case any provision contained in this Agreement should be deemed invalid, illegal or unenforceable by a court of competent jurisdiction in any respect, the validity, legality and enforceability of the remaining provisions
contained herein shall not in any way be affected or impaired thereby and any such invalid, illegal or unenforceable provision of this Agreement shall be replaced with a valid, legal and enforceable provision that will achieve, to the extent
possible, the same economic, business and other purposes of the invalid, illegal or unenforceable provision. 
 11.4 Governing Law.
This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York, without regard to any principles of conflict of laws that would result in the application of any law other than the laws of the State of
New York. 
 11.5 Counterparts. This Agreement may be executed in two or more counterparts, each of which shall constitute an
original, but all of which, when taken together, shall constitute but one instrument, and shall become effective when one or more counterparts have been signed by each party hereto and delivered to the other parties. 

11.6 Successors and Assigns. Except as otherwise expressly provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of the parties hereto. 
 11.7 Entire Agreement. This
Agreement and other documents delivered pursuant hereto, including the exhibits, constitute the full and entire understanding and agreement between the parties with regard to the subjects hereof and thereof. 

11.8 Expenses. Each party hereto shall pay all costs and expenses incurred by it in connection with the execution and delivery of this
Agreement, and all the transactions contemplated thereby. 
 [signature pages follow] 

 IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed by their
duly authorized representatives as of the day and year first above written. 
  

			
	ARATANA THERAPEUTICS, INC.
		
	By:	 	 /s/ Steven St. Peter

	Steven St. Peter
	President and Chief Executive Officer

 SIGNATURE PAGE TO 

SECURITIES PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 ADAGE CAPITAL PARTNERS, LP

		
	By:	 	 /s/ Dan Lehan

	 Name: Dan Lehan

	 Title:   Chief Operating Officer

  

			
	Address:	 	200 Clarendon St., 52nd Floor
		 	Boston, MA 02116

 Telephone: 617-867-2855

Telecopier: 617-867-2801
 e-mail: djl@adagecapital.com 

 

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 375,000
	  	$	16	  	  	$	6,000,000	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	FIDELITY ADVISOR SERIES VII: FIDELITY ADVISOR HEALTH CARE FUND
		
	By:	 	 /s/ Adrien Deberghes

	Name: Adrian Deberghes
	Title:   Deputy Treasurer

  

			
	Address:	 	M. Gardiner & Co
		 	c/o JPMorgan Chase Bank, N.A.
		 	P.O. Box 35308
		 	Newark, NJ 07101-8006

 Telephone:
                                        

 Telecopier:
                                        

 e-mail: Fidelity.crcs@jpmorgan.com 
  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 113,365
	  	$	16	  	  	$	1,813,840	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	FIDELITY CENTRAL INVESTMENT PORTFOLIOS LLC: FIDELITY HEALTH CARE CENTRAL
FUND
		
	By:	 	 /s/ Adrien Deberghes

	Name: Adrian Deberghes
	Title:   Deputy Treasurer

  

			
	Address:	 	M. Gardiner & Co
		 	c/o JPMorgan Chase Bank, N.A.
		 	P.O. Box 35308
		 	Newark, NJ 07101-8006

 Telephone:
                                        

 Telecopier:
                                        

 e-mail: Fidelity.crcs@jpmorgan.com 
  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 196,710
	  	$	16	  	  	$	3,147,360	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 HUTCHIN HILL CAPITAL PRIMARY FUND,
LTD.

		
	By:	 	 /s/ Gregory N. Racz

	Name: Gregory N. Racz
	Title:   President

  

			
	Address:	 	c/o Hutchin Hill Capital, LP
		 	142 W. 57th Street, 15th Floor
		 	New York, NY 10019

 Telephone: 212-757-2212 

Telecopier: 212-757-9298 
 e-mail: greg.racz@hutchinhill.com

  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 62,500
	  	$	16	  	  	$	1,000,000	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	JENNISON GLOBAL HEALTHCARE MASTER FUND, LTD.
	
	 By: Jennison Associates LLC

	Its: Investment Manager to Jennison Global Healthcare Master Fund, Ltd.

			
		
	By:	 	 /s/ David Chan

	Name: David Chan
	Title:   Managing Director

  

			
	Address:	 	c/o Jennison Associates LLC
		 	466 Lexington Avenue
		 	New York, NY 10017

 Telephone: 212-833-0476 

Telecopier: 212-986-6138 
 e-mail: dchan@jennison.com 

 

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 188,408
	  	$	16	  	  	$	3,014,528.00	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 JENOP GLOBAL HEALTHCARE FUND
LIMITED

	
	 By: Jennison Associates LLC

	Its: Investment Adviser to Jenop Global Healthcare Fund Limited
		
	By:	 	 /s/ David Chan

	Name: David Chan
	Title:   Managing Director

  

			
	Address:	 	c/o Jennison Associates LLC
		 	466 Lexington Avenue
		 	New York, NY 10017

 Telephone: 212-833-0476 

Telecopier: 212-986-6138 
 e-mail: dchan@jennison.com 

 

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 61,592
	  	$	16	  	  	$	985,472.00	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 SIO PARTNERS, LP

		
	By:	 	 /s/ Albert Vigneau

	Name: Albert Vigneau
	Title:   Chief Financial Officer

  

			
	Address:	 	535 Fifth Avenue, Suite 910
		 	New York, NY 10017

 Telephone: 212-601-9786 

Telecopier: 212-257-7046 
 e-mail: albert.vigneau@siocapital.com

  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 103,967
	  	$	16	  	  	$	1,663,472	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 SIO PARTNERS OFFSHORE, LTD.

		
	By:	 	 /s/ Albert Vigneau

	Name: Albert Vigneau
	Title:   Chief Financial Officer

  

			
	Address:	 	535 Fifth Avenue, Suite 910
		 	New York, NY 10017

 Telephone: 212-601-9786 

Telecopier: 212-257-7046 
 e-mail: albert.vigneau@siocapital.com

  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 49,792
	  	$	16	  	  	$	796,672	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	 SIO PARTNERS QP, LP

		
	By:	 	 /s/ Albert Vigneau

	Name: Albert Vigneau
	Title:   Chief Financial Officer

  

			
	Address:	 	535 Fifth Avenue, Suite 910
		 	New York, NY 10017

 Telephone: 212-601-9786 

Telecopier: 212-257-7046 
 e-mail: albert.vigneau@siocapital.com

  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 18,116
	  	$	16	  	  	$	289,856	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

			
	 PURCHASER:

	
	
VARIABLE INSURANCE PRODUCTS FUND IV: HEALTH 
CARE PORTFOLIO

			
		
	By:	 	 /s/ Adrien Deberghes

	Name: Adrian Deberghes
	Title:   Deputy Treasurer

  

			
	Address:	 	M. Gardiner & Co
		 	c/o JP Morgan Chase Bank, N.A.
		 	P.O. Box 35308
		 	Newark, NJ 07101-8006

 Telephone:
                                        

 Telecopier:
                                        

 e-mail: Fidelity.crcs@jpmorgan.com 
  

									
	 Shares to be Purchased
	  	Price Per Share in
Dollars	 	  	Aggregate Price	 
	 64,925
	  	$	16	  	  	$	1,038,800	  

  
 SIGNATURE PAGE TO 

SHARE PURCHASE AGREEMENT 

 EXHIBIT A 

SCHEDULE OF PURCHASERS 
  

									
	 Name and Address
	  	Number of
Shares	 	  	Aggregate
Purchase Price of
Shares	 
	 ADAGE CAPITAL LP

200 Clarendon St., 52nd Floor

Boston, MA 02116
	  	 	375,000	  	  	$	6,000,000	  
		  	  
	  
	 	  	  
	  
	 
	 FIDELITY ADVISOR SERIES VII: FIDELITY
ADVISOR HEALTH CARE FUND
 M. Gardiner & Co.

c/o JPMorgan Chase Bank, N.A.

P.O. 35308

Newark, NJ 07101-8006
	  	 	113,365	  	  	$	1,813,840	  
		  	  
	  
	 	  	  
	  
	 
	 FIDELITY CENTRAL INVESTMENT PORTFOLIOS
LLC: FIDELITY HEALTH CARE CENTRAL FUND

M. Gardiner & Co.

c/o JPMorgan Chase Bank, N.A.

P.O. 35308

Newark, NJ 07101-8006
	  	 	196,710	  	  	$	3,147,360	  
		  	  
	  
	 	  	  
	  
	 
	 HUTCHIN HILL CAPITAL PRIMARY
FUND,LTD.
 c/o Hutchin Hill Capital, LP

142 W. 57th Street, 15th Floor
 New York, NY 10019
	  	 	62,500	  	  	$	1,000,000	  
		  	  
	  
	 	  	  
	  
	 
	 JENNISON GLOBAL HEALTHCARE MASTER
FUND, LTD.
 c/o Jennison Associates LLC

466 Lexington Avenue

New York, NY 10017
	  	 	188,408	  	  	$	3,014,528	  
		  	  
	  
	 	  	  
	  
	 
	 JENOP GLOBAL HEALTHCARE FUND
LIMITED
 c/o Jennison Associates LLC

466 Lexington Avenue

New York, NY 10017
	  	 	61,592	  	  	$	985,472	  
		  	  
	  
	 	  	  
	  
	 
	 SIO PARTNERS, LP

535 Fifth Avenue, Suite 910

New York, NY 10017
	  	 	103,967	  	  	$	1,663,472	  
		  	  
	  
	 	  	  
	  
	 
	 SIO PARTNERS OFFSHORE, LTD.

535 Fifth Avenue, Suite 910

New York, NY 10017
	  	 	49,792	  	  	$	796,672	  
		  	  
	  
	 	  	  
	  
	 
	 SIO PARTNERS QP, LP

535 Fifth Avenue, Suite 910

New York, NY 10017
	  	 	18,116	  	  	$	289,856	  
		  	  
	  
	 	  	  
	  
	 
	 VARIABLE INSURANCE PRODUCTS FUND IV:
HEALTH CARE PORTFOLIO
 M. Gardiner & Co.

c/o JPMorgan Chase Bank, N.A.

P.O. 35308

Newark, NJ 07101-8006
	  	 	64,925	  	  	$	1,038,800	  
		  	  
	  
	 	  	  
	  
	 
		  	 	1,234,375	  	  	$	19,750,000	  
		  	  
	  
	 	  	  
	  
	 

 EXHIBIT B 

STOCK CERTIFICATE QUESTIONNAIRE 
 Pursuant
to Section 5 of the Agreement, please provide us with the following information: 
  

					
	1.	  	The exact name that your Shares are to be registered in (this is the name that will appear on your stock certificate(s)). You may use a nominee name if appropriate:	  	  

			
	2.	  	The relationship between the Purchasers and the registered holder listed in response to item 1 above:	  	  

			
	3.	  	The mailing address of the registered holder listed in response to item 1 above:	  	  

			
	4.	  	The Social Security Number or Tax Identification Number of the registered holder listed in the response to item 1 above:	  	  

			
	5.	  	The number of shares that you or your organization will own immediately after the Closing, including those Shares purchased by you or your organization pursuant to this Purchase Agreement and those shares purchased by you or your
organization through other transactions:	  	  

 EXHIBIT C 

REGISTRATION STATEMENT QUESTIONNAIRE 
 In
connection with the preparation of the Registration Statement, please provide us with the following information: 
 Plan of Distribution 

Attached as Exhibit C-I hereto is a draft of the “Plan of Distribution” section of the Registration Statement. Do you propose to offer or sell any
Shares of Common Stock to be registered on the Registration Statement by means other than those described in Exhibit C-I? 
  ̈  Yes             ̈  No 

If “yes”, please describe the manner in which you propose to offer or sell such Shares of Common Stock: 

 

	
	  

	
	  

	
	  

 Selling Stockholders 

Pursuant to the “Selling Stockholder” section of the Registration Statement, please state your or your organization’s name exactly as it should
appear in the Registration Statement: 
  

	
	  

 Please provide the number of shares that you or your organization will own immediately after Closing, including those Shares
purchased by you or your organization pursuant to this Purchase Agreement and those shares purchased by you or your organization through other transactions: 
  

	
	  

  
 C-1 

 Have you or your organization had any position, office or other material relationship within the past three years
with the Company or its affiliates? 

 ̈  Yes             ̈  No 
 If yes, please indicate the nature of any such relationships below: 

 

	
	  

	
	  

	
	  

 Are you (i) an NASD Member (see definition), (ii) a Controlling (see definition) shareholder of an NASD Member,
(iii) a Person Associated with a Member of the NASD (see definition), (iv) an Underwriter or a Related Person (see definition) with respect to the proposed offering; (v) do you own any shares or other securities of any NASD Member not
purchased in the open market; or (vi) have you made any outstanding subordinated loans to any NASD Member? 
 Answer:  ̈ Yes  ̈ No If “yes” to any of such questions, please identify the question and describe below: 

 

	
	  

	
	  

	
	  

 NASD Member. The term “NASD member” means either any broker or dealer admitted to membership in the National
Association of Securities Dealers, Inc. (“NASD”). (NASD Manual, By-laws Article I, Definitions) 
 Control. The term “control”
(including the terms “controlling,” “controlled by” and “under common control with”) means the possession, direct or indirect, of the power, either individually or with others, to direct or cause the direction of the
management and policies of a person, whether through the ownership of voting securities, by contract, or otherwise. (Rule 405 under the Securities Act of 1933, as amended) 

Person Associated with a member of the NASD. The term “person associated with a member of the NASD” means every sole proprietor, partner, officer,
director, branch manager or executive representative of any NASD Member, or any natural person occupying a similar status or performing similar functions, or any natural person engaged in the investment banking or securities business who is directly
or indirectly controlling or controlled by a NASD Member, whether or not such person is registered or exempt from registration with the NASD pursuant to its by-laws. (NASD Manual, By-laws Article I, Definitions) 

  
 C-2 

 Underwriter or a Related Person. The term “underwriter or a related person” means, with respect to a
proposed offering, underwriters, underwriters’ counsel, financial consultants and advisors, finders, members of the selling or distribution group, and any and all other persons associated with or related to any of such persons. (NASD
Interpretation) 

  
 C-3 

 EXHIBIT C-I 

FORM OF PLAN OF DISTRIBUTION 

The selling stockholders, which as used herein includes donees, pledgees, transferees or other successors–in–interest selling shares
received after the date of this prospectus from a selling stockholder as a gift, pledge, partnership distribution or other transfer, may, from time to time, sell, transfer or otherwise dispose of any or all of their shares on any stock exchange,
market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices
determined at the time of sale, or at negotiated prices. 
 The selling stockholders may use any one or more of the following methods when
disposing of shares: 
  

	 	•	 	ordinary brokerage transactions and transactions in which the broker-dealer solicits purchasers; 

  

	 	•	 	block trades in which the broker-dealer will attempt to sell the shares as agent, but may position and resell a portion of the block as principal to facilitate the transaction; 

 

	 	•	 	purchases by a broker-dealer as principal and resale by the broker-dealer for its account; 

  

	 	•	 	an exchange distribution in accordance with the rules of the applicable exchange; 

  

	 	•	 	privately negotiated transactions; 

  

	 	•	 	short sales effected after the date the registration statement of which this prospectus is a part is declared effective by the SEC; 

  

	 	•	 	through the writing or settlement of options or other hedging transactions, whether through an options exchange or otherwise; 

  

	 	•	 	broker-dealers may agree with the selling stockholders to sell a specified number of such shares at a stipulated price per share; 

  

	 	•	 	a combination of any such methods of sale; or 

  

	 	•	 	any other method permitted pursuant to applicable law. 

 The selling stockholders may also sell
shares under Rule 144 under the Securities Act, if available, rather than under this prospectus. The selling stockholders are not obligated to, and there is no assurance that the selling stockholders will, sell all or any of the shares we are
registering. The selling stockholders may transfer, devise or gift such shares by other means not described in this prospectus. 

 In connection with the sale of our shares, the selling stockholders may enter into hedging
transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the common stock in the course of hedging the positions they assume. The selling stockholders may also sell shares of our common stock short
and deliver these securities to close out their short positions, or loan or pledge the common stock to broker-dealers that in turn may sell these securities. The selling stockholders may also enter into option or other transactions with
broker-dealers or other financial institutions or create one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus,
which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction to the extent required by law). 

The aggregate proceeds to the selling stockholders from the sale of the common stock offered by them will be the purchase price of the common
stock less discounts or commissions, if any. Each of the selling stockholders reserves the right to accept and, together with their agents from time to time, to reject, in whole or in part, any proposed purchase of common stock to be made directly
or through agents. We will not receive any of the proceeds from this offering. 
 Broker-dealers engaged by the selling stockholders may
arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the selling stockholders (or, if any broker-dealer acts as agent for the purchaser of shares, from the purchaser) in amounts to be
negotiated. The selling stockholders do not expect these commissions and discounts to exceed what is customary in the types of transactions involved. Any profits on the resale of shares by a broker-dealer acting as principal might be deemed to be
underwriting discounts or commissions under the Securities Act. Discounts, concessions, commissions and similar selling expenses, if any, attributable to the sale of shares will be borne by a selling stockholder. The selling stockholders may agree
to indemnify any agent, dealer or broker-dealer that participates in transactions involving sales of the shares against certain liabilities, including liabilities arising under the Securities Act. 

The Company is required to pay certain fees and expenses incurred by the Company incident to the registration of the shares. The Company
has agreed to indemnify the selling stockholders against certain losses, claims, damages and liabilities, including liabilities under the Securities Act. 

The selling stockholders, broker-dealers or agents that participate in the sale of the common stock may be “underwriters” within the
meaning of Section 2(11) of the Securities Act. Any discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions under the Securities Act. Selling stockholders who are
“underwriters” within the meaning of Section 2(11) of the Securities Act will be subject to the prospectus delivery requirements of the Securities Act. There is no underwriter or coordinating broker acting in connection with the
proposed sale of the resale shares by the selling stockholders. 

 The selling stockholders may from time to time pledge or grant a security interest in some or all
of the shares owned by them and, if they default in the performance of any of their secured obligations, the pledgees or secured parties may offer and sell the shares from time to time under this prospectus as it may be supplemented from time to
time, or under an amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act amending the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling
stockholders under this prospectus. 
 To the extent required, the shares to be sold, the names of the selling stockholders, the respective
purchase prices and public offering prices, the names of any agents, dealers or underwriters, any applicable commissions or discounts with respect to a particular offer will be set forth in an accompanying prospectus supplement or, if appropriate, a
post-effective amendment to the registration statement that includes this prospectus. 
 In order to comply with the securities laws of some
states, if applicable, the common stock may be sold in these jurisdictions only through registered or licensed brokers or dealers. In addition, in some states the common stock may not be sold unless it has been registered or qualified for sale or an
exemption from registration or qualification requirements is available and is complied with. 
 The anti-manipulation rules of Regulation M
under the Exchange Act may apply to sales of shares in the market and to the activities of the selling stockholders and their affiliates. In addition, we will make copies of this prospectus (as it may be supplemented or amended from time to time)
available to the selling stockholders for the purpose of satisfying the prospectus delivery requirements of the Securities Act. 
 We have
agreed with the selling stockholders to keep the registration statement of which this prospectus constitutes a part effective until the earlier of (1) such time as all of the shares covered by this prospectus have been disposed of pursuant to
and in accordance with the registration statement, or (2) the date on which the shares may be sold pursuant to Rule 144 of the Securities Act without volume or manner of sale restrictions. 

 EXHIBIT D 

FORM OF LOCK-UP AGREEMENT 

 LOCK-UP AGREEMENT 

October 13, 2013 
 Aratana Therapeutics, Inc. 

1901 Olathe Boulevard 
 Kansas City, Kansas 66103 

Ladies & Gentlemen: 
 This Lock-Up
Agreement is being delivered to you in connection with the Share Purchase Agreement (the “Purchase Agreement”), dated as of October 13, 2013 by and among Aratana Therapeutics, Inc. (the “Company”) and the
investors party thereto (the “Investors”), providing for the purchase by the Investor of shares (the “Shares”) of Common Stock, par value $0.001 per share (the “Common Stock”) of the Company (the
“Financing”). 
 In consideration of the execution of the Purchase Agreement by the Investors, and for other good and
valuable consideration, the undersigned hereby irrevocably agrees that, without the prior written consent of the Company, the undersigned will not, directly or indirectly, (1) offer for sale, sell, pledge, or otherwise dispose of (or enter into
any transaction or device that is designed to, or could be expected to, result in the disposition by any person at any time in the future of) any shares of Common Stock acquired in the Financing (including, without limitation, shares of Common Stock
that may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and shares of Common Stock that may be issued upon exercise of any
option or warrant) or securities convertible into or exchangeable for Common Stock, or (2) enter into any swap or other derivatives transaction that transfers to another, in whole or in part, any of the economic benefits or risks of ownership
of shares of Common Stock acquired in the Financing, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or other securities, in cash or otherwise, during the period beginning on
the date hereof and ending on the date that is 90 days after the date that is the Closing Date, as defined in that certain Agreement and Plan of Merger, dated as of the date hereof, by and among the Company, Jayhawk Acquisition Corporation and Vet
Therapeutics, Inc. (such 90-day period, the “Lock-Up Period”).
 The foregoing paragraph shall not apply to
(1) transfers of Common Stock or securities convertible into or exchangeable or exercisable for any shares of Common Stock made as a bona fide gift or gifts, provided that the donee or donees thereof agree in writing to be bound by the
terms of this Lock-Up Agreement prior to such transfer, (2) transfers of Common Stock or securities convertible into or exchangeable or exercisable for any shares of Common Stock to an immediate family member of the undersigned or to any trust
for the direct or indirect benefit of the undersigned or an immediate family member of the undersigned, provided that the transferee agrees in writing to be bound by the terms of this Lock-Up Agreement prior to such transfer, (3) distributions
to partners, members, shareholders or affiliates of the undersigned, provided that the undersigned is a limited partnership, limited liability company or corporation and the distributees thereof agree in writing to be bound by the terms of this
Lock-Up Letter Agreement 

 
prior to such distribution, (4) if multiple funds with the same strategy and managed by a single investment advisor have purchased Shares in the Financing, transfers of Common Stock between
such funds for the purpose of redistribution and/or rebalancing, (5) transfers of Common Stock owned by the undersigned prior to the Financing and (6) transfers of Common Stock acquired in open market transactions after the Financing. 

In furtherance of the foregoing, the Company and its transfer agent are hereby authorized to decline to make any transfer of securities if
such transfer would constitute a violation or breach of this Lock-Up Letter Agreement. 
 The undersigned understands that the Company and
the Investors will proceed with the Financing in reliance on this Lock-Up Agreement. 
 The terms of this Lock-Up Letter Agreement
shall be construed in accordance with the laws of the State of New York. 
 [Signature Page Follows] 

 The undersigned hereby represents and warrants that the undersigned has full power and authority
to enter into this Lock-Up Agreement and that, upon request, the undersigned will execute any additional documents necessary in connection with the enforcement hereof. Any obligations of the undersigned shall be binding upon the heirs, personal
representatives, successors and assigns of the undersigned. 
  

	
	Very truly yours,
	
	   

	(Name of Stockholder—Please Print)
	
	   

	(Signature)
	
	   

	 (Name of Signatory if Stockholder is an

entity—Please Print)

	
	   

	 (Title of Signatory if Stockholder is an

entity—Please Print)EX-10.3

 Exhibit 10.3 

CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT (INDICATED BY ASTERISKS) HAS BEEN OMITTED AND FILED SEPARATELY WITH THE
SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT. 
 FIRST AMENDMENT AND JOINDER 

TO 
 LOAN AND SECURITY
AGREEMENT 
 This First Amendment and Joinder to Loan and Security Agreement (this “First Amendment and Joinder”),
dated as of October 11, 2013, is executed and delivered by VET THERAPEUTICS, INC., a Delaware corporation (“New Borrower”), ARATANA THERAPEUTICS, INC. (“Borrower”), and SQUARE 1 BANK
(“Bank”). Capitalized terms used herein but not otherwise defined herein shall have the meanings ascribed to those terms in the Loan Agreement (as defined below). 

RECITALS 
 a.
Borrower and Bank are parties to that certain Loan and Security Agreement dated as of March 4, 2013 (as amended from time to time, the “Original Loan Agreement”). 

b. From and after the date hereof (the “Effective Date”), New Borrower, Borrower, and Bank desire to amend and supplement the
terms and provisions of the Original Loan Agreement as provided herein, and the Original Loan Agreement as supplemented by this First Amendment and Joinder, and as may be hereafter further supplemented, amended, modified or restated from time to
time, shall be referred to collectively as the “Loan Agreement.” 
 c. Bank desires that New Borrower execute this First
Amendment and Joinder for the purpose of acknowledging that it is and shall be a Borrower under the Loan Agreement and the other Loan Documents. 

d. New Borrower has read and approved the Loan Documents and has asked Bank to agree to allow New Borrower to become a party to the Loan
Documents in order to facilitate its ability to continue to operate its business by achieving a stronger financial base for itself and its affiliated companies. 

NOW, THEREFORE, in consideration of the premises herein contained, and for other good and valuable consideration (the receipt,
sufficiency and adequacy of which are hereby acknowledged), the parties hereto (intending to be legally bound) hereby agree as follows: 

1. Incorporation. The foregoing preamble and recitals are incorporated herein by this reference. 

2. Joinder and Assumption. From and after the Effective Date, New Borrower hereby absolutely and unconditionally: 

(a) (i) joins as and becomes a party to the Loan Agreement as a Borrower thereunder, (ii) assumes, as a joint and several obligor
thereunder, all of the obligations, liabilities and indemnities of a Borrower under the Loan Agreement and all other Loan Documents, and (iii) covenants and agrees to be bound by and adhere to all of the terms, covenants, waivers, releases,
agreements and conditions of or respecting a Borrower with respect to the Loan Agreement and the other Loan Documents and all of the representations and warranties contained in the Loan Agreement (in the manner set forth in Section 5 of this
First Amendment and Joinder) and the other Loan Documents with respect to New Borrower; and 
 (b) collaterally assigns and transfers to
Bank, and hereby grants to Bank, a continuing security interest in all of New Borrower’s now owned and existing and hereafter acquired and 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 
arising assets and Collateral, as collateral security for the prompt and complete payment and performance when due (whether at the stated maturity, by acceleration or otherwise) of all of the
Obligations. New Borrower hereby authorizes Bank to file at any time uniform commercial code financing statements in such jurisdictions and offices as Bank deems necessary in connection with the perfection of a security interest in all of New
Borrower’s now owned or hereafter arising or acquired assets and property, including, without limitation, accounts receivable, deposit accounts, equipment, general intangibles, inventory, and any and all other personal property of New Borrower,
and all products, substitutions, replacements, and proceeds of such property and assets. New Borrower has read the Loan Agreement and affirmatively grants to Bank all rights to New Borrower’s assets as set forth in said Loan Agreement and the
Loan Documents. 
 From and after the Effective Date, any reference to the term “Borrower” in the Loan Agreement shall also
include New Borrower. Except as expressly provided herein, the Loan Agreement remains in full force and effect and is hereby ratified and confirmed in all respects. 

3. Amendments to Loan Agreement. 

(a) Section 2.1(b) of the Loan Agreement is hereby amended and restated, as follows: 

(b) Term Loans 

(i) Bank has heretofore made a term loan to Borrower in an amount equal to $5,000,000 (the “Tranche A Term
Loan”). The proceeds of the Tranche A Term Loan shall be used to supplement the growth capital needs of Borrower and for general corporate purposes and working capital needs. Subject to and upon the terms and conditions of this Agreement, Bank
agrees to make one (1) or more term loans to Borrower in an aggregate principal amount not to exceed Ten Million Dollars ($10,000,000) (each a “Tranche B Term Loan” and collectively the “Tranche B Term Loans”, and together
with the Tranche A Term Loan, each a “Term Loan” and collectively the “Term Loans”). Borrower may request Tranche B Term Loans at any time from October 11, 2013 through the Availability End Date. The proceeds of Tranche B
Term Loans shall be used to finance Borrower’s acquisition of Vet Therapeutics, Inc., a Delaware corporation. 

(ii) Interest shall accrue from the date of each Term Loan at the rate specified in Section 2.3(a), and prior to
the Availability End Date shall be payable monthly in arrears beginning on the first date of the month next following the date such Term Loan was funded, and continuing on the same day of each month thereafter. Any Term Loans that are outstanding on
the Availability End Date shall be payable in 24 equal monthly installments of principal, plus all accrued interest, beginning on April 1, 2014 and continuing on the same day of each month thereafter through the Term Loan Maturity Date, at
which time all amounts due in connection with the Term Loans and any other amounts due under this Agreement shall be immediately due and payable. Term Loans, once repaid, may not be reborrowed. Borrower may prepay any Term Loans without penalty or
premium. 
 (iii) When Borrower desires to obtain a Tranche B Term Loan, Borrower shall notify Bank (which notice
shall be irrevocable) by facsimile transmission to be received no later than 3:30 p.m. Eastern time on the Business Day prior to the date on which the Term Loan is to be made. Such notice shall be substantially in the form of Exhibit C. The notice
shall be signed by an Authorized Officer. 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 (b) Section 2.5(c) of the Loan Agreement is hereby amended and restated, as
follows: 
 (c) Success Fee. Immediately upon consummation of an Acquisition, (i) if Bank has advanced at least
$5,000,000 of the Tranche B Term Loans, Borrower shall pay a success fee to Bank of $250,000 and (ii) if Bank has not advanced at least $5,000,000 of the Tranche B Term Loans, Borrower shall pay a success fee to Bank of $125,000. 

(c) Section 5.10 of the Loan Agreement is hereby amended and restated, as follows: 

5.10 Subsidiaries. Borrower does not own any stock, partnership interest or other equity securities of any Person,
except (i) Aratana Therapeutics, Inc. owns 100 percent of the stock of Vet Therapeutics, Inc. and (ii) Permitted Investments. 

(d) Section 6.7(b) of the Loan Agreement is hereby amended and restated, as follows: 

(b) Liquidity Ratio. Beginning January 1, 2014, a Liquidity Ratio of at least 1.00:1.00; provided, however, that
if Bank receives evidence in form and substance satisfactory to it that Borrower has two products that have received either (i) FDA approval or (ii) a USDA Biologic License, the required Liquidity Ratio shall be lowered to 0.50:1.00. 

(e) Section 7.4 of the Loan Agreement is hereby amended and restated, as follows: 

7.4 Indebtedness. Create, incur, assume, guarantee or be or remain liable with respect to any Indebtedness, or permit
any Subsidiary so to do, other than Permitted Indebtedness, or prepay any Indebtedness or take any actions which impose on Borrower an obligation to prepay any Indebtedness, except (i) Indebtedness to Bank, (ii) as permitted under any
subordination agreement in connection with Subordinated Debt, or (iii) payments pursuant to the Seller’s Note. 

(f) A new Article 13 is hereby added to the Loan Agreement, as follows: 

13. CO-BORROWER PROVISIONS. 

13.1 Primary Obligation. This Agreement is a primary and original obligation of each Borrower and shall remain in effect
notwithstanding future changes in conditions, including any change of law or any invalidity or irregularity in the creation or acquisition of any Obligations or in the execution or delivery of any agreement between Bank and any Borrower. Each
Borrower shall be liable for existing and future Obligations as fully as if all Credit Extensions were advanced to such Borrower. Bank may rely on any certificate or representation made by any Borrower as made on behalf of, and binding on, such
Borrower and each other Borrower, including without limitation Loan Advance / Paydown Request Forms, Borrowing Base Certificates and Compliance Certificates. 

13.2 Enforcement of Rights. Each Borrower is jointly and severally liable for the Obligations, and Bank may proceed
against any Borrower to enforce the Obligations without waiving its right to proceed against any other Borrower. 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 13.3 Borrowers as Agents. Each Borrower appoints each other Borrower as
its agent with all necessary power and authority to give and receive notices, certificates or demands for and on behalf of each Borrower, to act as disbursing agent for receipt of any Credit Extensions on behalf of each Borrower and to apply to Bank
on behalf of each Borrower for Credit Extensions, any waivers and any consents. This authorization cannot be revoked, and Bank need not inquire as to each Borrower’s authority to act for or on behalf of a Borrower. 

13.4 Subrogation and Similar Rights. Notwithstanding any other provision of this Agreement or any other Loan Document,
each Borrower irrevocably waives all rights that it may have at law or in equity (including, without limitation, any law subrogating such Borrower to the rights of Bank under the Loan Documents) to seek contribution, indemnification, or any other
form of reimbursement from any other Borrower, or any other Person now or hereafter primarily or secondarily liable for any of the Obligations, for any payment made by such Borrower with respect to the Obligations in connection with the Loan
Documents or otherwise and all rights that it might have to benefit from, or to participate in, any security for the Obligations as a result of any payment made by the Borrower with respect to the Obligations in connection with the Loan Documents or
otherwise. Any agreement providing for indemnification, reimbursement or any other arrangement prohibited under this Section 13.4 shall be null and void. If any payment is made to a Borrower in contravention of this Section 13.4, such
Borrower shall hold such payment in trust for Bank and such payment shall be promptly delivered to Bank for application to the Obligations, whether matured or unmatured. 

13.5 Waivers of Notice. Except as otherwise provided in this Agreement, each Borrower waives notice of acceptance
hereof; notice of the existence, creation or acquisition of any of the Obligations; notice of an Event of Default; notice of the amount of the Obligations outstanding at any time; notice of intent to accelerate; notice of acceleration; notice of any
adverse change in the financial condition of any other Borrower or of any other fact that might increase the Borrower’s risk; presentment for payment; demand; protest and notice thereof as to any instrument; default; and all other notices and
demands to which the Borrower would otherwise be entitled. Each Borrower waives any defense arising from any defense of any other Borrower, or by reason of the cessation from any cause whatsoever of the liability of any other Borrower. Bank’s
failure at any time to require strict performance by any Borrower of any provision of the Loan Documents shall not waive, alter or diminish any right of Bank thereafter to demand strict compliance and performance therewith. Nothing contained herein
shall prevent Bank from foreclosing on the Lien of any deed of trust, mortgage or other security instrument, or exercising any rights available thereunder, and the exercise of any such rights shall not constitute a legal or equitable discharge of
any Borrower. Each Borrower also waives any defense arising from any act or omission of Bank that changes the scope of the Borrower’s risks hereunder. 

13.6 Subrogation Defenses. Each Borrower hereby waives any defense based on impairment or destruction of its subrogation
or other rights against any other Borrower and waives all benefits which might otherwise be available to it under any statutory or common law suretyship defenses or marshalling rights, now and hereafter in effect. 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 13.7 Right to Settle, Release. 

(a) The liability of each Borrower hereunder shall not be diminished by (i) any agreement, understanding or
representation that any of the Obligations is or was to be guaranteed by another Person or secured by other property, or (ii) any release or unenforceability, whether partial or total, of rights, if any, which Bank may now or hereafter have
against any other Person, including another Borrower, or property with respect to any of the Obligations. 
 (b)
Without affecting the liability of any Borrower hereunder, Bank may (i) compromise, settle, renew, extend the time for payment, change the manner or terms of payment, discharge the performance of, decline to enforce, or release all or any
of the Obligations with respect to a Borrower, (ii) grant other indulgences to a Borrower in respect of the Obligations, (iii) modify in any manner any documents relating to the Obligations with respect to a Borrower, (iv) release,
surrender or exchange any deposits or other property securing the Obligations, whether pledged by a Borrower or any other Person, or (v) compromise, settle, renew, or extend the time for payment, discharge the performance of, decline to
enforce, or release all or any obligations of any guarantor, endorser or other Person who is now or may hereafter be liable with respect to any of the Obligations. 

13.8 Subordination. All indebtedness of a Borrower now or hereafter arising held by another Borrower is subordinated to
the Obligations and the Borrower holding the indebtedness shall take all actions reasonably requested by Bank to effect, to enforce and to give notice of such subordination. 

(g) The following definitions in Exhibit A to the Loan Agreement are hereby amended and restated, as follows: 

“Cash Burn” means an amount equal to the prior period’s Cash minus the current period’s ending Cash that
has been adjusted for any changes to Cash as a result of borrowings and repayments of borrowings, proceeds from the sale of equity and the exercise of stock options or warrants, paid-in-capital and minority interest, and capital expenditures
financed under a capital lease. Notwithstanding the foregoing, the calculation of Cash Burn shall exclude the cash outflow for Borrower’s acquisition of Vet Therapeutics, Inc. to the extent that such cash outflow is offset by concurrent cash
inflows from the issuance of Borrower’s equity securities. 
 “Collateral States” means the states where the
Collateral is located, which are California and Kansas. 
 (h) The following new clause (g) is hereby added to the
definition of “Permitted Indebtedness” in Exhibit A to the Loan Agreement: 
 (g) The Seller’s Note.

 (i) The following new clause (m) is hereby added to the definition of “Permitted Investment” in Exhibit A
to the Loan Agreement: 
 (m) Investments by Aratana Therapeutics, Inc. in Vet Therapeutics, Inc. 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 (j) The following new definition is hereby added in alphabetical order to Exhibit
A to the Loan Agreement: 
 “Seller’s Note” means that certain Promissory Note, dated October 15, 2013,
issued by Vet Therapeutics, Inc. to Jeffrey Miles, on behalf of the Company Stockholders as the Stockholders’ Representative (as each is defined in the Seller’s Note). 

(k) Exhibit B-1 is hereby added to the Loan Agreement in the form attached hereto as Appendix I. 

(l) Exhibit E to the Loan Agreement is hereby supplemented with respect to New Borrower pursuant to the attached Appendix II.

 4. Consent to Acquisition. Borrower has informed Bank that Borrower wishes to enter into an Agreement and Plan of Merger (the
“Merger Agreement”), pursuant to which New Borrower will become a wholly owned subsidiary of Borrower (the “New Borrower Acquisition”). Bank hereby consents to the New Borrower Acquisition, subject to the conditions
that (i) Bank has been provided with a copy of the final Merger Agreement, along with all accompanying exhibits and schedules, and approved the terms and conditions of the New Borrower Acquisition, (ii) Bank has confirmed, to its
satisfaction, that there are no security interests, liens, or other encumbrances of record on any of New Borrower’s assets, and (iii) Borrower and New Borrower execute this First Amendment and Joinder simultaneously with the closing of the
New Borrower Acquisition. 
 5. Representations and Warranties. New Borrower hereby represents and warrants to Bank, which
representations and warranties shall survive the execution and delivery hereof, that: (a) this First Amendment and Joinder is the legally valid and binding obligation of New Borrower, enforceable against New Borrower in accordance with its
terms, and (b) except as otherwise set forth below, each of the representations and warranties contained in the Original Loan Agreement, as well as all other representations and warranties contained in the other Loan Documents, are true and
correct in all respects to the extent required under the Original Loan Agreement. 
 6. Successors and Assigns. This First Amendment
and Joinder shall be binding upon New Borrower, Borrower, and Bank and Bank’s successors and assigns, and shall inure to the benefit of New Borrower, Borrower, Bank and Bank’s successors and assigns. No other person or entity shall be a
direct or indirect legal beneficiary of, or have any direct or indirect cause of action or claim in connection with, this First Amendment and Joinder. New Borrower may not assign or transfer any of its rights or obligations under this First
Amendment and Joinder without the prior written consent of Bank. 
 7. Severability; Construction. Wherever possible, each provision
of this First Amendment and Joinder shall be interpreted in such a manner so as to be effective and valid under applicable law, but if any provision of this First Amendment and Joinder shall be prohibited by or invalid under applicable law, such
provision shall be ineffective to the extent of such provision or invalidity, without invalidating the remainder of such provision or the remaining provisions of this First Amendment and Joinder. All obligations of Borrower and New Borrower and
rights of Bank expressed herein shall be in addition to and not in limitation of those provided by applicable law. 
 8. Counterparts;
Facsimile and other Electronic Transmission. This First Amendment and Joinder may be executed in any number of counterparts and by the different parties hereto on separate counterparts and each such counterpart shall be deemed to be an original,
but all such counterparts shall together constitute but one and the same First Amendment and Joinder. Receipt of an executed signature page to this First Amendment and Joinder by facsimile or other electronic transmission shall constitute for all
purposes effective delivery thereof. Electronic records of this executed First Amendment and Joinder maintained by Bank shall be deemed to be originals. 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 9. GOVERNING LAW. THIS FIRST AMENDMENT AND JOINDER SHALL BE A CONTRACT MADE UNDER AND
BE CONSTRUED, ENFORCED AND GOVERNED BY THE LAWS OF THE STATE OF NORTH CAROLINA APPLICABLE TO CONTRACTS MADE AND TO BE PERFORMED ENTIRELY WITHIN SUCH STATE, WITHOUT REGARD TO CONFLICT OF LAW PRINCIPLES. 

10. WAIVER OF JURY TRIAL. BANK, NEW BORROWER, AND BORROWER EACH WAIVE ANY RIGHT TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION
BASED UPON OR ARISING OUT OF THIS FIRST AMENDMENT AND JOINDER OR ANY TRANSACTION CONTEMPLATED HEREIN, INCLUDING CLAIMS BASED ON CONTRACT, TORT, BREACH OF DUTY AND ALL OTHER COMMON LAW OR STATUTORY BASES. ALL DISPUTES, CONTROVERSIES, CLAIMS, ACTIONS
AND SIMILAR PROCEEDINGS ARISING WITH RESPECT TO BORROWER’S OR NEW BORROWER’S ACCOUNTS OR ANY RELATED AGREEMENT OR TRANSACTION SHALL BE BROUGHT IN THE GENERAL COURT OF JUSTICE OF NORTH CAROLINA SITTING IN DURHAM COUNTY, NORTH CAROLINA OR
THE UNITED STATES DISTRICT COURT FOR THE MIDDLE DISTRICT OF NORTH CAROLINA, EXCEPT AS PROVIDED BELOW WITH RESPECT TO ARBITRATION OF SUCH MATTERS. IF THE JURY WAIVER SET FORTH IN THIS SECTION IS NOT ENFORCEABLE, THEN ANY DISPUTE, CONTROVERSY OR CLAIM
ARISING OUT OF OR RELATING TO THIS FIRST AMENDMENT AND JOINDER OR ANY OF THE TRANSACTIONS CONTEMPLATED HEREIN WILL BE FINALLY SETTLED BY BINDING ARBITRATION IN DURHAM COUNTY, NORTH CAROLINA IN ACCORDANCE WITH THE THEN-CURRENT COMMERCIAL ARBITRATION
RULES OF THE AMERICAN ARBITRATION ASSOCIATION BY ONE ARBITRATOR APPOINTED IN ACCORDANCE WITH SAID RULES. THE ARBITRATOR SHALL APPLY NORTH CAROLINA LAW TO THE RESOLUTION OF ANY DISPUTE, WITHOUT REFERENCE TO RULES OF CONFLICTS OF LAW OR RULES OF
STATUTORY ARBITRATION. JUDGMENT ON THE AWARD RENDERED BY THE ARBITRATOR MAY BE ENTERED IN ANY COURT HAVING JURISDICTION THEREOF. NOTWITHSTANDING THE FOREGOING, THE PARTIES MAY APPLY TO ANY COURT OF COMPETENT JURISDICTION FOR PRELIMINARY OR INTERIM
EQUITABLE RELIEF, OR TO COMPEL ARBITRATION IN ACCORDANCE WITH THIS PARAGRAPH. THE EXPENSES OF THE ARBITRATION, INCLUDING THE ARBITRATOR’S FEES, REASONABLE ATTORNEYS’ FEES AND EXPERT WITNESS FEES, INCURRED BY THE PARTIES TO THE ARBITRATION,
MAY BE AWARDED TO THE PREVAILING PARTY, IN THE DISCRETION OF THE ARBITRATOR, OR MAY BE APPORTIONED BETWEEN THE PARTIES IN ANY MANNER DEEMED APPROPRIATE BY THE ARBITRATOR. UNLESS AND UNTIL THE ARBITRATOR DECIDES THAT ONE PARTY IS TO PAY FOR ALL (OR A
SHARE) OF SUCH EXPENSES, THE PARTIES SHALL SHARE EQUALLY IN THE PAYMENT OF THE ARBITRATOR’S FEES AS AND WHEN BILLED BY THE ARBITRATOR. 

11. Conditions Precedent to Effectiveness of First Amendment and Joinder. The agreement of Bank to enter into this First Amendment and
Joinder on the date hereof is subject to the condition precedent that Bank shall have received, in form and substance satisfactory to Bank, each the following items and completed each of the following requirements: 

(c) this First Amendment and Joinder, duly executed by New Borrower and Borrower; 

(d) all conditions precedent to the consummation of the acquisition of New Borrower by Borrower and any related transactions, each as
specified in the Merger Agreement, have been satisfied or will be satisfied simultaneously with the initial funding of Tranche B Term Loans, in each case as determined by Bank in Bank’s sole discretion; 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 (e) an officer’s certificate of each of Borrower and New Borrower with respect to
incumbency and resolutions authorizing the execution and delivery of this First Amendment and Joinder; 
 (f) a financing statement
(Form UCC-1) with respect to New Borrower; 
 (g) payment of a $10,000 facility fee, which may be debited from any of
Borrower’s or New Borrower’s accounts with Bank; 
 (h) payment of the fees and Bank Expenses in connection with the
documentation of this First Amendment and Joinder and any other related documentation, which may be debited from any of Borrower’s or New Borrower’s accounts with Bank; 

(i) current SOS Reports indicating that, as to New Borrower, except for Permitted Liens, there are no other security interests or
Liens of record in the Collateral; 
 (j) a Borrower Information Certificate from New Borrower; and 

(k) such other documents or certificates, and completion of such other matters, as Bank may reasonably deem necessary or appropriate.

 12. Notices. The address for notices to be sent to Bank and for the payment of all sums due under the Loan Agreement is correctly
set forth therein, and Bank confirms said address is: 
 Square 1 Bank 

406 Blackwell Street, Suite 240 

Durham, NC 27701 
 Attn: Loan
Operations Manager 
 FAX: 919-314-3080 
 For
purposes hereof, the address for notices to be sent to New Borrower is: 
 Vet Therapeutics, Inc. 

1901 Olathe Blvd. 
 Kansas City,
Kansas 66103 
 Attn: Louise Mawhinney 

FAX: (913) 904-9641 
 13.
Effectiveness of Joinder. Notwithstanding anything to the contrary in this First Amendment and Joinder, Bank, New Borrower, and Borrower hereby agree that New Borrower will be deemed to have entered into this First Amendment and Joinder
simultaneously with consummation of the New Borrower Acquisition. 
 [Signature Page Follows] 

  
 Aratana Therapeutics – First
Amendment and Joinder to Loan and Security Agreement 

 IN WITNESS WHEREOF, the undersigned have caused this First Amendment and Joinder to Loan
and Security Agreement to be duly executed and delivered as of the date first above written. 
  

			
	NEW BORROWER:
	
	VET THERAPEUTICS, INC.
		
	By:	 	 /s/ Steven St. Peter

	Name:	 	 Steven St. Peter

	Title:	 	 President

	
	BANK:
	
	SQUARE 1 BANK
		
	By:	 	 /s/ Zach Robbins

	Name:	 	 Zach Robbins

	Title:	 	 AVP

  

			
	Acknowledged and Agreed:
	
	BORROWER:
	
	ARATANA THERAPEUTICS, INC.
		
	By:	 	 /s/ Steven St. Peter

	Name:	 	 Steven St. Peter

	Title:	 	 President & CEO

 [Signature Page to First Amendment and Joinder to Loan and Security Agreement] 

 APPENDIX I 
  

			
	DEBTOR:	  	VET THERAPEUTICS, INC.
		
	SECURED PARTY:	  	SQUARE 1 BANK

 EXHIBIT B-1 

COLLATERAL DESCRIPTION ATTACHMENT TO LOAN AND SECURITY AGREEMENT 

All personal property of Borrower (herein referred to as “Borrower” or “Debtor”) whether presently existing or hereafter created or
acquired, and wherever located, including, but not limited to: 
 (a) all accounts (including health-care-insurance receivables),
chattel paper (including tangible and electronic chattel paper), deposit accounts, documents (including negotiable documents), equipment (including all accessions and additions thereto), financial assets, general intangibles (including patents,
trademarks, copyrights, goodwill, payment intangibles, domain names and software), goods (including fixtures), instruments (including promissory notes), inventory (including all goods held for sale or lease or to be furnished under a contract of
service, and including returns and repossessions), investment property (including securities and securities entitlements), letter of credit rights, money, and all of Debtor’s books and records with respect to any of the foregoing, and the
computers and equipment containing said books and records; 
 (b) any and all cash proceeds and/or noncash proceeds of any of the
foregoing, including, without limitation, insurance proceeds, and all supporting obligations and the security therefor or for any right to payment. All terms above have the meanings given to them in the North Carolina Uniform Commercial Code, as
amended or supplemented from time to time, including revised Division 9 of the Uniform Commercial Code-Secured Transactions. 

Notwithstanding the foregoing, the Collateral shall not include any of the intellectual property, in any medium, of any kind or nature
whatsoever, now or hereafter owned or acquired or received by Borrower, or in which Borrower now holds or hereafter acquires or receives any right or interest (collectively, the “Intellectual Property”); provided, however, that the
Collateral shall include all accounts and general intangibles that consist of rights to payment and proceeds from the sale, licensing or disposition of all or any part, or rights in, the foregoing (the “Rights to Payment”). 

Notwithstanding the foregoing, if a judicial authority (including a U.S. Bankruptcy Court) holds that a security interest in the underlying
Intellectual Property is necessary to have a security interest in the Rights to Payment, then the Collateral shall automatically, and effective as of October 11, 2013, include the Intellectual Property to the extent and only to the extent
necessary to permit perfection of Bank’s security interest in the Rights to Payment, and further provided, however, that Bank’s enforcement rights with respect to any security interest in the Intellectual Property shall be absolutely
limited to the Rights to Payment only, and Bank shall have no recourse whatsoever with respect to the underlying Intellectual Property. 

 APPENDIX II 

EXHIBIT E 
 SCHEDULE OF
EXCEPTIONS 
 Permitted Indebtedness (Exhibit A) – 

The Seller’s Note. 
 Permitted
Investments (Exhibit A) – None. 
 Permitted Liens (Exhibit A) – None. 

Intellectual Property (Section 5.4) – 

See attached. 
 Prior Names (Section 5.5)
– None. 
 Litigation (Section 5.6) – None. 

Inbound Licenses (Section 5.12) – 

Exclusive Commercial License Agreement by and between [***] and Vet Therapeutics, Inc., dated November 28, 2012, including the Side
Letter by and between [***] and Vet Therapeutics, Inc., November 21, 2012. 
 Commercial License Agreement by and between Crucell
Holland B.V. and Vet Therapeutics, Inc., dated April 2, 2013. 
 Collaboration Agreement by and between Inverness Medical Innovations,
Inc. and Vet Therapeutics, Inc., dated April 2, 2009. 
  

	*	Confidential Treatment Requested 

  
 11

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