Upfront high-dose myeloablative chemotherapy followed by a single autologous stem cell transplantation (ASCT) is the standard therapy for patients under the age of 65 years with newly diagnosed multiple myeloma (MM). Because disease status after induction chemotherapy is variable, we evaluated the prognostic effect of disease status before ASCT, especially in patients who were initially chemosensitive. We retrospectively analyzed the initially chemosensitive MM patients (≥ partial remission [PR]) enrolled in the Korean Multiple Myeloma Working Party Web-based registration system (www.myeloma.or.kr). Between November 1996 and January 2007, 197 MM patients (median age 53 years) were treated with induction chemotherapy followed by a single ASCT. All patients received peripheral blood stem cell (PBSC) support after conditioning with melphalan (Mel) alone. We considered those patients with no detectable M-protein regardless of the result of immunofixation to be in complete remission (CR) in this study. The median follow-up times were 29.2 months (range, 5.4 to 103.8 months) from the day of diagnosis and 22.4 months (range, 0.4 to 96.0 months) from the day of ASCT. Before ASCT, 63 patients (32%) were in CR and 134 (68%) were in partial remission (PR). The patients in CR had significantly longer overall survival (OS) from the day of ASCT compared with those in PR (P = .0015). Among the patients who received induction chemotherapy with vincristine, adriamycin, and dexamethasone (n = 162), the same difference in OS was seen between those in CR and those in PR before ASCT (P = .0016). CR after ASCT also predicted longer OS (P = .0135); however, patients with continued CR after ASCT had significantly higher OS after ASCT compared with patient with induced CR after ASCT who were in PR before ASCT (P = .0178). Multivariate analysis indicated that remission status pre-ASCT (CR vs PR) is a significant prognostic factor for predicting OS after ASCT (P = .012, Cox proportional hazard analysis; odds ratio = 2.83; 95% confidence interval = 1.25 to 6.37). We conclude that patients with MM who are in CR before ASCT have a better OS than those in PR before ASCT. Continued CR after ASCT may be an important prognostic factor as well. Our findings suggest that the development of more effective induction regimens, including novel antimyeloma agents to improve initial response, should be pursued to enhance clinical benefits post-ASCT.
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