ASSUMPTION AGREEMENT

Exhibit 10.1

ASSUMPTION AGREEMENT

This ASSUMPTION AGREEMENT (this “Assumption Agreement”) is entered into as of June 29, 2012 (the “Effective Date”) by and between Amylin Pharmaceuticals, Inc., a corporation organized and existing under the laws of the State of Delaware (“Amylin”) and Bristol-Myers Squibb Company, a Delaware Corporation (the “Company”). Amylin and the Company are each referred to herein by name or as a “Party” or, collectively, as the “Parties.”

WHEREAS, Amylin and Eli Lilly and Company (“Lilly”) have entered into that certain Settlement and Termination Agreement dated November 7, 2011 (such agreement, as it may be amended or otherwise modified from time to time, the “Settlement Agreement”), pursuant to which, among other things, Amylin is obligated to pay certain amounts to Lilly;

WHEREAS, Amylin and the Company have entered into that certain Agreement And Plan of Merger, by and among the Company, B&R Acquisition Company, a Delaware corporation and a wholly-owned Subsidiary of the Company and Amylin, dated as of the Effective Date (the “Amylin/Company Agreement”);

WHEREAS, Section 13.17 of the Settlement and Termination Agreement provides that in the event of a Transfer Trigger Event referenced in subsections (i) or (ii) of the definition thereof, Amylin shall cause any successor, assignee or transferee to assume all of Amylin’s obligations to Lilly pursuant to the Settlement Agreement and the Note and the Security Agreement (each as defined in the Settlement Agreement); and

WHEREAS, as contemplated by the Settlement Agreement, Amylin now desires for the Company to assume, and the Company now desires to assume, in each case, with effect as of the Acceptance Time (as defined in the Amylin/Company Agreement), the obligations of Amylin under the Settlement Agreement, the Note and the Security Agreement, all on the terms set forth herein.

NOW, THEREFORE, in consideration of the premises and the mutual covenants herein contained and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties intending to be legally bound do hereby agree as follows:

if to Amylin, to: Amylin Pharmaceuticals, Inc.

9360 Towne Centre Drive

San Diego, California 92121

Attn: Chairman and Chief Executive Officer

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

Amylin Pharmaceuticals, Inc.

9360 Towne Centre Drive

San Diego, California 92121

Attn: General Counsel

and:                    Skadden, Arps, Slate, Meagher & Flom LLP

Four Times Square

New York, New York 10036-6522

        Attn: Nancy Lieberman, Esq.

         Ann Beth Stebbins, Esq.

E-mail: ***@***

              ***@***

if to the Company, to: Bristol-Myers Squibb Company

345 Park Avenue

New York, New York 10154

Attn: Senior Vice President, General Counsel and

          Corporate Secretary

E-mail: ***@***

with copies to (which shall not constitute notice):

Bristol-Myers Squibb Company

Route 206 and Province Line Road

Princeton, New Jersey 08543

Attn: Vice President and Assistant General Counsel,

Transactional Practice Group, Corporate Development

E-mail: ***@***

and:                   Kirkland & Ellis LLP

601 Lexington Avenue

New York, New York 10022

Attn: David Fox

         Daniel Wolf

E-mail: ***@***

              ***@***

in each case, with a copy to:

Eli Lilly and Company

Lilly Corporate Center

Indianapolis, IN 46285

Attention: General Counsel

and with a copy to:

Covington & Burling LLP

1201 Pennsylvania Ave., N.W.

Washington, D.C. 20004

Attn: John A. Hurvitz

or to such other address as the Party to whom notice is to be given may have furnished to the other Party in writing in accordance herewith. Any such notice will be deemed to have been given when delivered if personally delivered or on the Business Day after dispatch if

sent by nationally-recognized overnight courier (with confirmation of delivery).

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IN WITNESS THEREOF, the Parties have executed this Assumption Agreement as of the Effective Date.