US ONCOLOGY HOLDINGS, INC. $250,000,000 Senior Unsecured Floating Rate Notes Due 2015 Registration Rights AgreementUS Oncology Holdings, Inc. • July 27th, 2005 • New York
US Oncology Holdings, Inc., a corporation organized under the laws of Delaware (the “Issuer”), which is the parent of US Oncology, Inc., a corporation organized under the laws of Delaware, proposes to issue and sell to certain purchasers (the “Initial Purchasers”), for whom you (the “Representatives”) are acting as representatives, $250,000,000 principal amount of its Senior Unsecured Floating Rate Notes Due 2015 (the “Securities”), upon the terms set forth in the Purchase Agreement between the Issuer and the Representatives, dated March 15, 2005 (the “Purchase Agreement”), relating to the initial placement (the “Initial Placement”) of the Securities. To induce the Initial Purchasers to enter into the Purchase Agreement and to satisfy a condition to your obligations thereunder, the Issuer agrees with you for your benefit and the benefit of the holders from time to time of the Securities (including the Initial Purchasers) (each a “Holder” and, collectively, the “Holders”), as follows:
