PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy Greater than 4 weeks since prior chemotherapy Endocrine therapy: At least 4 months since prior long acting somatostatin analogue Concurrent hormonal therapy (except somatostatin analogues) allowed if started at least 2 months previously Radiotherapy: Greater than 4 weeks since prior radiotherapy No prior radiotherapy to at least 25% of bone marrow Surgery: Greater than 4 weeks since prior surgery Other: Greater than 4 weeks since prior investigational drugs No other concurrent investigational drug therapy No other concurrent antineoplastic therapy Concurrent bisphosphonates allowed