Multiple myeloma: VMCP/VBAP alternating combination chemotherapy is not superior to melphalan and prednisone even in high-risk patients. The efficacy of alternating vincristine, melphalan (M), cyclophosphamide, prednisone/vincristine, carmustine, doxorubicin, and prednisone (VMCP/VBAP) polychemotherapy was compared with the M and prednisone (MP) regimen as induction treatment in multiple myeloma (MM). Three hundred four MM patients entered this study between March 1983 and July 1986; the analysis was performed in December 1989. The treatment groups did not show significant differences with respect to major prognostic factors. Median overall survival was 33.8 months. In the VMCP/VBAP and MP arms, after 12 induction chemotherapy cycles, 59.0% and 47.3% (P less than .068) of the patients achieved an M component reduction greater than 50%. No significant difference was observed in the two treatment arms in terms of remission duration (21.3 v 19.6 months, P less than .66) and survival (31.6 v 37.0 months, P less than .28). Patients younger than 65 years did not show any advantage from the alternating polychemotherapy. At diagnosis, the plasma cell labeling index (LI) and serum beta-2 microglobulin (beta 2-m) were evaluated in 173 and 183 patients, respectively. A significantly reduced survival was observed for patients with LI greater than or equal to 2% (16.4 months) or beta 2-m greater than or equal to 6 mg/L (20.4 months). Even in these poor-risk subgroups, VMCP/VBAP was not superior to MP. 