Response to induction chemotherapy is not essential to obtain survival benefit from high-dose melphalan and autotransplantation in myeloma

Two hundred and twenty-two myeloma patients autografted after 200 mg/m² melphalan were studied to examine the relationship between response to induction chemotherapy and outcome. Induction comprised cyclophosphamide, vincristine, doxorubicin and methylprednisolone (C-VAMP) every 3 weeks for one cycle beyond maximum response. 81% responded to C-VAMP (chemosensitive) with 40 complete (CR) and 139 partial (PR) remissions, and 43 did not respond (NR; <50% reduction in paraprotein; primary refractory). Overall, 130 patients (59%) attained or remained in CR post-transplant; including 40% of NR, 53% of PR, and 97% of CR after C-VAMP (P < 0.0001). Amongst these 130 patients, the 5-year OS was independent of response to C-VAMP (NR 79%, PR 74%, CR 60%; P = 0.69). Similarly, among the 69 patients in PR post-transplant, the 5-year OS was independent of response to C-VAMP. In Cox analysis, lack of response to C-VAMP did not affect outcome significantly. These data show that lack of response to induction therapy does not automatically predict poor long-term outcome in myeloma, since a substantial proportion of these patients attain CR after autograft and enjoy extended survival. Myeloma patients should not be disqualified from an autograft based upon lack of response to induction chemotherapy.