- You must have documented radiographic evidence of a tumor response of complete response (CR), partial response (PR), or stable disease (SD) according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines. Tumor assessment must occur between Cycle 4 (Day 1) of induction therapy and the date of randomization. This response does not have to be confirmed in order for the patient to be randomized to the maintenance phase.