- Interval from prior treatment to time of study drug administration should be at least 2 weeks for cytotoxic agents, or at least 5 half-lives for noncytotoxic agents and adequate recovery from prior toxicities. If the patient had a transplant, at least 6 months must have passed before initiation of treatment on this protocol and stable graft versus host disease (no change in severity) for 4 weeks preceding study entry (if applicable).