Amendment To Collaboration And License Agreement Dated July 31, 2006

EXHIBIT 10.8.1

AMENDMENT

This Amendment (hereinafter referred to as " Amendment" ) is made and entered into July 31, 2006 by and between Toray Industries, Inc., a Japanese corporation, having its principal place of business at Nihonbashi Mitsui Tower, 1-1, Nihonbashi-Muromachi 2-chome,Chuo-ku, Tokyo 103-8666, Japan (hereinafter referred to as " Toray" ), and Acologix, Inc., a Delaware corporation, having its principal place of business at 3960 Point Eden Way, Hayward, CA 94545, U.S.A. (hereinafter referred to as " Acologix" ) (each a " Party ," together the " Parties" ).

BACKGROUND WHEREAS, Toray and Acologix have entered into a Collaboration and License Agreement dated June 9, 2005 (hereinafter referred to as the " License Agreement" ); and

WHEREAS, Toray and Acologix desire to amend the License Agreement and to document the Parties' mutual understanding of issues addressed since the execution of the License Agreement;

NOW, THEREFORE, for and in consideration of the covenants, conditions and undertakings hereinafter set forth, it is agreed by and between the Parties as follows:

1. For the purpose of this Amendment, the words and terms which are defined in the License Agreement shall have the same meanings when used in this Amendment.

2. Section 2.4.1 of the License Agreement shall be amended to read as follows:

2.4.1 European Development Cost Sharing .

(a) On or before the [***] of the [***] of each calendar quarter (March 10 th , June 10 th , September 10 th , or December 10 th ), each Party shall submit to the other Party a written report including supporting documentation setting forth in reasonable detail an accounting of any authorized European Development Costs, as set forth in the European Co-Development Plan and Budget, that have been actually paid by that Party during the three (3) month period ending on the last day of the immediately prior month (the " Payment Period" ), together with an invoice for fifty percent (50%) of the total amounts paid by that Party during the Payment Period. Within [***] after receipt of such notice, each Party shall pay to the other Party the invoiced amount, less any amounts related to expenses for which there is no direct evidence of these expenses having been authorized as European Development Costs. The Parties agree to resolve any questions regarding European Development Cost invoices diligently.

*** Confidential treatment request pursuant to a request for confidential treatment filed with the Securities and Exchange Commission. Omitted portions have been filed separately with the Commission.


(b) On or before the [***] of the first month of any calendar quarter (January 10 th , April 10 th , July 10 th , or October 10th), each Party shall submit to the other Party a written report setting forth in reasonable detail an estimate of any European Development Costs that it estimates will have been paid by that Party during the one (1) month period ending on the last day of the immediately prior month.

(c) Each Party shall furnish to the other Party copies of any contracts or other documentation outlining the nature and scope of its relationships with any Third Parties engaged in Development under the European Development Plan & Budget for which it may seek reimbursement under this amended Section 2.4.1. (d) Notwithstanding the foregoing, the portion of the mass balance study described in the Plan & Budget Summary which has been performed prior to the Effective Date of this Agreement shall be deemed to be performed during the Co-Development Term for the purposes of Section 1.15, and the European Development Costs related thereto authorized in the Plan & Budget Summary actually paid by Toray prior to the Effective Date shall be deemed actually paid by Toray during the first Payment Period for the purposes of this amended Section 2.4.1. (e) For clarity, both the amounts paid by Acologix to Toray and the amounts paid by Acologix to Third Parties shall be considered " borne by Acologix" for the purposes of the maximum total payment set forth above.

3. Notwithstanding Section 8.2 and 8.3 of the License Agreement, reimbursement of European Development Costs by Acologix under the amended Section 2.4.1 of the License Agreement shall be paid in Japanese yen. In any report submitted by Toray pursuant to the amended Section 2.4.1 of the License Agreement, any authorized European Development Costs that have been paid in a currency other than Japanese yen shall be expressed in such currency, together with the Japanese yen equivalent, calculated using the telegraphic transfer selling rate of Bank of Tokyo-Mitsubishi UFJ, Ltd. prevailing on the date such authorized European Development Costs were actually paid by Toray. Reimbursement of European Development Costs by Toray under the amended Section 2.4.1 of the License Agreement shall be paid in United States dollar. In any report submitted by Acologix pursuant to the amended Section 2.4.1 of the License Agreement, any authorized European Development Costs that have been paid in a currency other than United States dollar shall be expressed in such currency, together with the United States dollar equivalent, calculated using the selling rate obtained by Silicon Valley Bank on the date such authorized European Development Costs were actually paid by Acologix.

4. Section 12.4 of the License Agreement shall be amended to exclude the obligation for either Party to name the other Party as an additional insured on any insurance policy procured under the License Agreement. Section 12.4 of the License Agreement shall be amended to read as follows:

12.4 Insurance . Within [***] after the Effective Date, each Party shall at its own expense procure and maintain during the Term and for a period of [***] thereafter an insurance policy/policies, adequate to cover *** Confidential treatment request pursuant to a request for confidential treatment filed with the Securities and Exchange Commission. Omitted portions have been filed separately with the Commission.


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