Achievement of CR and nCR Before and After First High-Dose Therapy Followed by Autologous Stem Cell Transplantation Is a Major Marker for Long-Term Survival in Multiple Myeloma Patients.

Abstract 3400

Poster Board III-288

To analyse the impact of complete response (CR), near CR (nCR) and very good partial response (VGPR) before and after first high-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) on overall survival (OS) and progression-free survival (PFS), we evaluated all patients with multiple myeloma (MM) who underwent an ASCT in frontline treatment at our centre. The transplantations were performed between June 1992 and February 2009 giving a minimum follow up of 5 months after ASCT. The retrospective analysis included a total of 994 patients (579 males and 415 females) with a median age of 58 years at time of first ASCT (range 25 - 76 years). Median follow-up after first ASCT was 5.8 years. All patients suffered from symptomatic MM. Before induction treatment 48%, 31% and 21% of patients were in ISS-stage I, II and III, respectively. The following induction regimes were applied prior to HDT: VAD (n=683), TAD (n=74), PAD (n=64), and other regimes (n= 173). The patients were treated with HDT once (n= 460), twice (n=437) or thrice (n=97). 91 patients received an allogeneic SCT, 30 of these before first progression after ASCT. These were censored for PFS at time of allogeneic SCT. Maintenance therapy (interferon n=332, thalidomide n=203, bortezomib n=48 or others n=13) was administered in 596 patients. Overall survival and progression-free survival were calculated from the time of first ASCT. The median OS time was 5.7 years and the median PFS was 2.2 years. Log-rank test, univariate and multivariate Cox PH regression as well as landmark analyses were utilized to assess the prognostic impact of response. We analysed the effect of achievement of CR, of nCR or CR and of VGPR or CR or nCR before and after HDT, respectively. Achieving CR or nCR is a highly significant prognostic factor for PFS and OS before (p<0.001 and p=0.01, respectively) and after first HDT (both p<0.001). The group including VGPR showed superior outcome when assessed after HDT, driven by the effect of CR/nCR. When adjusting for the effect of age, beta-2 microglobulin before ASCT, albumin before ASCT, new drugs before ASCT (thalidomide and bortezomib; yes/no), second ASCT within 9 months (yes/no), maintenance therapy (yes/no), and date of first ASCT, achieving CR or nCR remained a significant prognostic factor (PFS after ASCT: HR=0.66 [0.54;0.80], p<0.001; OS after ASCT: HR=0.65 [0.51;0.83], p=0.001). In addition, we analyzed the effect of duration of response compared to response achievement per se. Patients who sustained their remission (overall response = PR and better) at 3 yrs after first ASCT had a favourable prognosis with respect to OS compared to patients losing remission.