- Prior anticancer treatment (chemotherapy, radiotherapy, hormonal, immunotherapy, biological response modifiers, signal transduction inhibitors, etc) within 4 weeks prior to the first dose of AP23573; the interval is ≥ 2 weeks for signal transduction inhibitors with a half-life known to be <24 hours, and is ≥ 6 weeks for nitrosourea or mitomycin. Exception: Concurrent treatment with LHRH agonists is allowed for patients with prostate cancer.