In a sequential nonrandomized study, 204 consecutive unselected patients aged < 70 years received induction chemotherapy with infusional vincristine and adriamycin with oral methyl prednisolone (VAMP: n = 75) or with additional cyclophosphamide, C-VAMP (n = 129). 38/129 C-VAMP patients also received verapamil during induction as part of a controlled trial with the aim to overcome drug resistance. A median of five courses (range 1-11) of chemotherapy were required before maximal response was attained and this was similar in both groups. An over-all response rate of 71% was noted at the end of induction. The complete remission (CR) rate with C-VAMP was 24%, which was significantly higher (P = 0.04) than the CR rate with VAMP alone (8%). The addition of verapamil did not alter the response rate of C-VAMP. Compliance to VAMP was overall 83% and not affected by the addition of cyclophosphamide. The proportion of patients going on to receive high-dose chemotherapy and an autograft was the same for VAMP and C-VAMP treated patients (71%). The median overall survival (OS) and progression-free survival (PFS) for the whole group were 4.4 years and 2.0 years and no difference in outcome was observed between the different treatment groups. Therefore the addition of weekly cyclophosphamide to VAMP induction therapy has significantly improved the response rates of previously untreated myeloma patients. C-VAMP was not more toxic and did not compromise the chances of receiving an autograft. Verapamil was without influence on any parameters in this study.