- Patients are eligible for enrollment if they have not had prior investigational or approved cytotoxic chemotherapy within 28 days prior to the first dose (week 1, day 1); 42 days in the case of alkylating agents; 28 days or 5 half-lives (whichever is less; but not less than 14 days) in case of investigational or approved molecularly targeted agent; 14 days in the case of radiotherapy; any number of prior therapies is allowable