This excerpt taken from the TPTX 8-K filed Oct 10, 2006.
Amendments in Writing, Integration.
All amendments to this Agreement must be in writing and signed by both Lenders and Borrower. This Agreement and the Loan Documents represent the entire agreement about this subject matter, and supersede prior negotiations or agreements. All prior agreements, understandings, representations, warranties, and negotiations between the parties about the subject matter of this Agreement and the Loan Documents merge into this Agreement and the Loan Documents.