Exhibit 10.1

FIRST AMENDMENT TO AMENDED AND RESTATED EXCLUSIVE LICENSE,

DEVELOPMENT AND COMMERCIALIZATION AGREEMENT

This FIRST AMENDMENT TO THE AMENDED AND RESTATED EXCLUSIVE LICENSE, DEVELOPMENT
AND COMMERCIALIZATION AGREEMENT (this “Amendment”), is entered into and
effective as of April 26, 2019 (the “Amendment Date”) by and between ARATANA
THERAPEUTICS, INC., a Delaware corporation (“Aratana”), and PACIRA
PHARMACEUTICALS, INC., a California corporation (“Pacira”, together with
Aratana, the “Parties”), for the purpose of amending that certain Amended and
Restated Exclusive License, Development and Commercialization Agreement between
Aratana and Pacira effective as of July 5, 2018 (the “Agreement”). Capitalized
terms used but not otherwise defined herein shall have the meanings provided in
the Agreement, as amended.

WHEREAS, the Parties wish to amend Section 4.5 of the Agreement; and

WHEREAS, Section 12.5 of the Agreement states that the Agreement may only be
modified in writing with specific reference to this Agreement and signed by the
Parties to the Agreement.

NOW, THEREFORE, in consideration of the premises and the mutual promises and
covenants contained herein, the Parties hereby agree as follows:

1.    Amendment and Restatement of Section 4.5. Section 4.5 of the Agreement is
hereby amended and restated to read in its entirety as follows:

“4.5 No Competing Products. During the Term, neither Aratana nor any of its
Affiliates shall Commercialize in the territories where Aratana or any of its
Affiliates has initiated the registration of the Licensed Product, a product
other than the Licensed Product that directly competes with NOCITA®, where
“directly competes” is defined to mean meeting all of the following three
criteria: (i) having the same mode of action, that is, as locally-acting
analgesia; (ii) having the same indication, that is, control of post-operative
pain for surgical veterinary use for at least 48 to 72 hours post-surgery for
the indications contained in the approved label; and (iii) having the same mode
of administration, that is, tissue infiltration through local administration;
provided, however, that this restriction shall not apply to the grant of a
license or sublicense by Aratana to a Third Party approved by Pacira either
pursuant to Section 2.2.1 or 2.2.2 above. Notwithstanding anything herein to the
contrary, Aratana shall not grant any Third Party (other than Pacira) a right of
reference to any Drug Approval Application.”

2.    No Other Amendment. Except as specifically amended by this Amendment, the
terms and conditions of the Agreement shall remain unchanged and in full force
and effect.

3.    Counterparts. This Amendment may be executed in counterparts, each of
which shall be deemed an original document, and all of which, together with this
writing, shall be deemed one instrument. This Amendment may be executed by
facsimile or PDF signatures, which signatures shall have the same force and
effect as original signatures.

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IN WITNESS WHEREOF, the Parties hereto have caused this Amendment to be executed
in their respective names by their duly authorized representatives as of the
date first set forth above.

 

PACIRA PHARMACEUTICALS, INC. By:          /s/ David Stack Name:   David Stack
Title:   Chief Executive Officer and Chairman

 

ARATANA THERAPEUTICS, INC. By:          /s/ Craig Tooman Name:   Craig Tooman
Title:   President and Chief Executive Officer

 

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