Exhibit 10.18 OMNIBUS ADDENDUM TO PROMISSORY NOTES AND RELATED AGREEMENTS THIS OMNIBUS ADDENDUM (the "Addendum") is made by and among GENITOPE CORPORATION ("Borrower"), STANFORD C. FINNEY, JR. ("Guarantor") and BANK ONE, N.A. ("Lender") as of August...Omnibus Addendum to Promissory Notes • September 11th, 2003 • Genitope Corp • Biological products, (no disgnostic substances) • Texas
