MM-252 A Retrospective Review of Relapsed Multiple Myeloma Post Autologous Stem Cell Transplant: Data From an Indian Tertiary Cancer Center

Abstract

Multiple myeloma (MM) relapsing post autologous stem cell transplant (ASCT) continues to have overall poor outcomes in low- to middle-income countries (LMICs), and the efficacy data on available salvage regimens is limited. Here, we report the treatment outcomes of such patients treated at an Indian tertiary cancer center. The primary objective was to determine the PFS with salvage treatment. Secondary objectives included objective response rates (ORR) and ≥ partial response (PR). Single-center retrospective study of MM patients relapsing post ASCT between January 2015 and October 2020, treated with salvage regimen and followed until January 2022. North Indian tertiary cancer referral center. Records of 51 relapsed MM patients were screened for the study. All of them received up-front ASCT followed by maintenance treatment and later relapsed. Six (8.5%) patients with incomplete treatment details were excluded. Forty-six patients were included in the study. PFS. Median age was 51 years (range 45-68 years); 67.8% were men. Thirteen (28.2%) patients had high-risk cytogenetics. An extramedullary pattern of relapse was seen in 7 (15.2%) patients. Pomalidomide-based salvage therapy (VPd, PCd) was used in 18 (39.2%) patients and VRd in 14 (30.5%) patients. ORR was 47.8% (24/46). CR was observed in 28.3% (13/46) of patients. After a median follow-up of 8.1 months (IQR 3.1-26.7 months), 30 patients progressed and the median PFS was 6.75 months (95% CI 0.7-27.5 months). Median PFS did not differ by type of salvage treatment, such as pomalidomide versus non-pomalidomide (hazard ratio [HR] 0.93; 95% CI 0.38-2.27; P-value 0.87). Multivariate Cox proportion analysis, however, suggested that extramedullary relapse (HR 2.63; 95% CI 1.04-6.65; P-value <0.001), presence of high-risk cytogenetics (HR 6.6; 95% CI 1.82-24; P-value <0.001), and poor response to salvage regimens (<PR) (HR 7.48; 95% CI 2.27-24.7; P-value <0.001) predicted poor PFS. In MM patients relapsing post ASCT, we suggest that extramedullary relapse, presence of high-risk cytogenetics, and poor response to a salvage regimen, irrespective of salvage used, predict a poor PFS. However, these findings require validation by a randomized control trial.