Exhibit 10.53 WAIVER This Waiver is made into as of October 5, 2004 (the "Waiver"), by and between COMERICA BANK ("Bank"), and GENAISSANCE PHARMACEUTICALS, INC. ("Borrower"). RECITALS Borrower and Bank are parties to that certain Loan and Security Agreement dated as of September 30, 2003, as amended by a First Amendment to Loan and Security Agreement dated as of March 16, 2004 (collectively, the "Agreement"). At the request of Borrower, Bank desires to waive compliance by Borrower of a provision of the Agreement, to the extent set forth in this Waiver. NOW, THEREFORE, the parties agree as follows: 1. Bank waives compliance by Borrower of Section 6.9 of the Agreement for the period from August 31, 2004 through October 5, 2004. This is not a continuing waiver, and Borrower shall comply with such Section from and after October 6, 2004, and all other provisions of the Agreement. 2. Unless otherwise defined, all initially capitalized terms in this Waiver shall be as defined in the Agreement. The Agreement, as amended hereby, shall be and remain in full force and effect in accordance with its respective terms and hereby is ratified and confirmed in all respects. Except as expressly set forth herein, the execution, delivery, and performance of this Waiver shall not operate as a waiver of, or as an amendment of, any right, power, or remedy of Bank under the Agreement, as in effect prior to the date hereof. 3. Borrower represents and warrants that the representations and warranties contained in the Agreement are true and correct as of the date of this Waiver, and that no Event of Default has occurred and is continuing. This Waiver may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one instrument. IN WITNESS WHEREOF, the undersigned have executed this Waiver as of the first date above written. GENAISSANCE PHARMACEUTICALS, INC. By: /s/ Ben D. Kaplan ----------------------------- Title: SVP & CFO COMERICA BANK By: /s/ Ron W. Homa ----------------------------- Title: Vice President