AN INCREMENTAL RESPONSE TO HIGH-DOSE THERAPY IN MULTIPLE-MYELOMA

Results of conventional chemotherapy for multiple myeloma are disappoi nting. High-dose chemoradiotherapy with auto-transplantation is increa singly reported and some results are encouraging. We report the result s of peripheral blood stem cell transplantation (PBSCT) for multiple m yeloma at a single institution over a 6-year period. Forty patients, i ncluding 18 de novo patients, received debulking chemotherapy consisti ng of vincristine, adriamycin, and dexamethasone or methylprednisolone followed by stem cell mobilization with high-dose cyclophosphamide. T wenty-nine patients received PBSCT following high-dose chemoradiothera py. Following PBSCT 92% of evaluable patients obtained at least a part ial remission and 29% reached complete remission. Objective treatment responses, defined as at least a 50% reduction in serum paraprotein or marrow plasma cells, were observed following each treatment step of d ebulking chemotherapy, mobilization and PBSCT in 50, 42 and 71% of pat ients, respectively. The median overall survival from diagnosis in pat ients transplanted was 50 months and the median overall and progressio n-free survivals following transplant were 26 and 18 months, respectiv ely. Median follow-up was 28 months. Overall treatment-related mortali ty was 20% but was significantly lower in de novo vs previously treate d patients at 6 and 33% respectively (P = 0.027). De novo patients wer e more likely to obtain complete remission and had a longer overall su rvival following transplant but overall survival from diagnosis was si milar to previously treated patients. A low serum B2M before mobilizat ion predicted a longer progression-free survival. PBSCT needs to be co nsidered early following diagnosis to maximise treatment response and reduce the high treatment-related mortality seen in heavily pretreated patients. In this treatment program a dose response effect in multipl e myeloma was observed possibly suggesting that more intensive therapy than a single transplant may effect greater disease response.