PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy No prophylactic colony stimulating factors to prevent neutropenia Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy and recovered No other concurrent cytotoxic chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior major surgery and recovered No concurrent surgery Other: No other concurrent anticancer treatment At least 28 days since other prior investigational drugs, including analgesics or antiemetics No other investigational drugs during and for 28 days after study No concurrent drugs that induce or inhibit CYP3A enzyme