Long-Term Outcomes of Autologous Transplantation in Multiple Myeloma: Prognostic Significance of Complete Response.

Autologous stem cell transplantation (ASCT) after high-dose melphalan 200mg/m2 has got an important role in the treatment of symptomatic multiple myeloma (MM). The prognostic significance of achieving complete response (CR) after ASCT was cause of great debate for a long time. Some studies have shown the strong prognostic significance of achieving CR in MM, but other studies have failed to correlation between strength of the response and outcome.

In this report we describe the long-term outcome of cohort 232 MM patients (pts) after ASCT with aim to establish the actual prognosis for the different response categories and to analyse other factors that might predict for long-term survival.

We evaluated 232 pts with newly diagnosed symptomatic MM who received ASCT as a part of the first-line treatment between 1995 and 2005, median follow-up from ASCT was 131 months (range 61–195).

Following ASCT, overall response rate was 90% (202/232), 23% (52/232) of pts were in complete remission (CR), very good partial response (VGPR) was achieved in 45% of pts (100/232), partial response (PR) in 22% of pts (50/232), minimal response (MR) or stable disease (SD) in 10% of pts (22/232). Median progression-free survival (PFS) and overall survival (OS) from ASCT were 30.8 and 71.9 months, respectively. Progression-free survival at 12 years after ASCT in different response categories was 41% for pts with CR, 11% for pts with VGPR and 10% for pts with PR. Overall survival at 12 years after ASCT was 51% for pts with CR, 22% for pts with VGPR and 20% for pts with PR. The achievement of CR after ASCT was independent factor for long-term survival, significance differences in OS and PFS were found between CR and non-CR groups (P under 0.001 and P under 0.001, respectively).

On multivariate analysis, the other factors associated with significantly better OS were ISS stage under III (P = 0.002), no presence of renal impairment (P = 0.008), age under 60 years (P = 0.001), no presence of deletion 1q21 (P = 0.029) and lenalidomide treatment in the post-transplant relapse (P = 0.002).

The achievement of complete response after ASCT in multiple myeloma is the most important prognostic factor, even after long-term follow-up. The relapse rate is low in patients who remained in CR after 12 years from ASCT. A long-term complete remission should be a goal of treatment.

Hajek:Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Cilag: Honoraria.