WAIVER

<PAGE>

                                                                   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