PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior adjuvant immunotherapy and recovered No concurrent immunotherapy Chemotherapy: At least 4 weeks since prior adjuvant chemotherapy and recovered No other concurrent chemotherapy Endocrine therapy: No concurrent hormonal therapy Radiotherapy: At least 4 weeks since prior radiotherapy and recovered No more than 25% of total area of bone marrow irradiated No concurrent radiotherapy Surgery: At least 2 weeks since prior surgery and recovered Other: No concurrent proton pump inhibitors No other concurrent anticancer therapy