Outcome of Patients with Multiple Myeloma (MM) After 1st Relapse Following Front-Line Treatment with Autologous Stem Cell Transplantation (ASCT): Impact of Early Reduced Intensity Allogeneic Transplantation (RICALLO)

Abstract 4533

The aim of this single center study was to assess the outcome of pts with MM following the first relapse after autologous transplantation, according to whether or not a RICALLO was performed early in 2d response.

Records of the patients were reviewed and the criteria for entering the study were: Symptomatic MM treated frontline with a program including single or double ASCT, relapse at any time following ASCT, response (CR, VGPR or PR) to a second line treatment. RICALLO was proposed to pts with no significant co-morbidities, having a suitable donor (either sibling or 10/10 MUD) and who gave their consent after precise information on the risk of the RICALLO.

One hundred and seven pts treated between 01/2004 and 02/2011 fulfilling the inclusion criteria were identified. The initial treatment for relapse consisted of VD (37 pts), RD (29 pts), TD (36 pts), VTD (4 pts) or autologous SCT (1 pt). 22 pts received a RICALLO (allo group) while in 2d response, a median 7.7 months (2–36) after relapse. The RIC consisted of fludarabine plus either 2Gy ICT or busulfan and ATG (according to ongoing available protocols in the centre). The graft was PBSC from sibling (N: 8) or MUD (N: 14). 85 pts (CT group) received therapies according to ongoing protocols or available standard of cares. Following further relapses, 11 pts received a RICALLO while in ≥ 3d response in the CT group. The main characteristics of the patients in each group: age, MM prognostic factors at diagnosis, type of 1^st line therapy (VAD or bortezomib containing regimens), single or double ASCT, time to relapse after ASCT and 2d line treatment were similar between the 2 groups. The response achieved with 2d line treatment was different between 2 groups (CR + VGPR/other: 8/14 and 7/76 in allo and CT group respectively, p= 0.01)

The 3y OS from the time of relapse for the entire cohort was: 47% (CI95%, 41–53). It was of 45% (CI95% 34–56) and of 48% (CI95% 41–55) for the allo group and the CT group respectively (p= ns). The median time from 1^st relapse to death was 31 mo in the entire cohort and 20 and 34 mo in the allo group and CT group respectively (p= ns). The causes of death were, relapse in 5 and 33 pts, or treatment toxicity in 8 and 3 pts in the allo group and CT group respectively.

Three 3 y EFS (event = 2d relapse or death) was 16% (CI95%, 11–21) for the whole cohort and 16% (CI95%, 6–26) and 19% (CI95%, 13–25) for the allo group and CT group respectively (p= ns).