Impact of Pre-Transplant Depth of Response on Outcomes in Patients With Multiple Myeloma: A Report on Behalf of Pakistan Blood and Marrow Transplant Group

Background: Depth of response prior to autologous stem cell transplantation (ASCT) has been associated with improved progression-free survival (PFS) in multiple myeloma (MM). This study aimed to evaluate the impact of pre-transplant response depth on post-transplant outcomes in patients with multiple myeloma. Subjects and methods: This retrospective multicenter analysis, conducted by the Pakistan Blood and Marrow Transplant group, included 223 MM patients treated over 18 years across six centers. Pre-transplant responses were classified using International Myeloma Working Group criteria. Overall survival (OS) and disease-free survival (DFS) were estimated using Kaplan-Meier methods. Results: The cohort had a mean age of 49 years, with 70.4% males. Back pain (56%) and pathological fractures (15%) were common presenting features. Anemia and renal impairment were noted in 45% and 26%, respectively. The predominant paraprotein subtype was IgG kappa (31%). ISS staging revealed that 33.3% of patients had stage I, 27.4% stage II, and 37.6% stage III disease. Induction therapy included RVd in 42% and CyBorD in 41% of patients. Post-induction responses showed complete stringent response (sCR) in 7.4%, complete response (CR) in 22%, very good partial response (VGPR) in 19%, and partial response (PR) in 18%. Age less than 50 years, favorable induction response, and achieving VGPR or more before ASCT were significantly associated with improved outcomes. At the time of transplant, 58.3% had sCR/CR and 20.2% had VGPR. Median OS was 72.4% at a median of 72 months, while DFS was 57% at a median of 47 months. Patients with sCR/CR prior to ASCT had significantly better OS and DFS. Conclusion: In resource-constrained settings, achieving a deeper response before ASCT is associated with superior survival outcomes in MM. Optimizing induction to attain at least VGPR may enhance the benefit of transplantation.