AMENDMENT TO INTERNATIONAL DISTRIBUTOR AGREEMENT

EXHIBIT 10.15(b)

AMENDMENT TO

INTERNATIONAL DISTRIBUTOR AGREEMENT

THIS AMENDMENT TO INTERNATIONAL DISTRIBUTOR AGREEMENT (the “Amendment”) is entered into effective January 1, 2003 (the “Amendment Effective Date”) by and between TheraSense, Inc., a Delaware corporation with a principal place of business at 1360 South Loop Road, Alameda, California 94502, USA (“TheraSense”), and Disetronic Medical Systems AG, with a principal place of business at Kirchbergstrasse 190, CH-3401 Burgdorf, Switzerland, and Disetronic Injection Systems AG, with a principal place of business at Brunnmattstrasse 6, CH-3401 Burgdorf, Switzerland, both corporations organized under the laws of Switzerland (the latter corporation referred to hereinafter as “Disetronic”). Unless otherwise defined herein, all capitalized terms used in this Amendment shall have the meaning given to them in the International Distributor Agreement dated September 13, 2000, as amended (the “Agreement”).

WHEREAS, the parties hereto entered into the Agreement pursuant to which, among other things, Disetronic distributes TheraSense’s FreeStyle Products.

WHEREAS, the parties desire to amend the Agreement pursuant to this Amendment.

NOW, THEREFORE, in consideration of the mutual promises contained herein, the parties agree as follows:

***Confidential Treatment Requested

“Prior to the first day of the [***] of the Minimum Purchase Obligations for such calendar year shall be purchased. Prior to the first day of the [***], Disetronic shall purchase [***] System Kits. “

“13.1 Initial Term. The initial term of this Agreement shall commence on the Effective Date and shall continue in force until December 31, 2006, unless terminated earlier under the provisions of this Article 13 (the “Initial Term”).”

“13.6 Permissive Termination. The parties agree that notwithstanding Section 15.3 below, Disetronic may, upon three (3) months prior written notice to TheraSense, terminate this Agreement if an entity acquires all or substantially all of TheraSense’s business assets to which this Agreement pertains, whether by merger, acquisition, sale or otherwise and such entity sells or offers for sale insulin pumps, infusion sets or pens. The parties further agree that TheraSense may, upon [***] prior written notice to Disetronic, terminate this Agreement. Without limiting the foregoing, each party shall provide prompt written notice to the other party in the event that such party has been acquired. Within ninety (90) days of such acquisition notice from TheraSense, Disetronic shall elect whether to terminate this Agreement as set forth above. Commencing upon receipt of any notice of termination, delivered by either party, under this Section 13.6 and continuing until the effective date of termination, Disetronic’s rights under Section 2.1.1 shall be converted to non-exclusive and Disetronic’s Minimum Purchase Obligations under Section 7.3 shall be void and have no effect. Upon termination of the Agreement by either party under this Section 13.6, Disetronic shall have satisfied its Minimum Purchase Obligations if it has made all [***] purchases required by Section 7.3.1 which arose prior to receipt of the notice of termination.”

“13.7.4 Products. In the event of termination of this Agreement for any reason other than by (i) expiration pursuant to Section 13.1, (ii) Disetronic pursuant to

***Confidential Treatment Requested

2

Section 13.2,13.3 or 13.6 or (iii) TheraSense pursuant to Section 13.6, Disetronic shall cease selling any FreeStyle Products and shall destroy all remaining inventory at the time of such termination. In the event of termination by expiration pursuant to Section 13.1 or by Disetronic pursuant to Section 13.2, 13.3, or 13.6, Disetronic may continue selling in the FreeStyle Territory any FreeStyle Products which were in Disetronic’s inventory at the time of such termination of the Agreement. In the event of termination by TheraSense pursuant to Section 13.6, Disetronic may, for six months following the effective date of termination, continue selling in the FreeStyle Territory any FreeStyle Products which were in Disetronic’s inventory at the time of such termination of the Agreement.”

IN WITNESS WHEREOF, Disetronic and TheraSense have executed this Amendment by their respective duly authorized representatives.

***Confidential Treatment Requested

3

EXHIBIT C

ANNUAL MINIMUM PURCHASE OBLIGATION FOR THE EUROPEAN TERRITORY

***Confidential Treatement Requested

4