Banerjee, Rahul

Summary Functional high‐risk (FHR) multiple myeloma (FHRMM) is often defined as progression within 12–24 months of front‐line autologous hematopoietic stem cell transplantation (AHSCT). For patients with early progression after suboptimal front‐line therapies, it is challenging to assign the disease progression to a true FHR phenotype versus less effective front‐line therapy. In this study, we combined data from three Center for International Blood and Marrow Transplant Research studies (MM18‐02, MM19‐01 and MM20‐03). We included patients who received front‐line AHSCT between 2008 and 2018 and had progression <12 (FHR12, n = 465), <18 (FHR18, n = 672) or <24 months (FHR24, n = 853) after AHSCT. We classified induction therapy as standard lenalidomide‐containing triplets (bortezomib, lenalidomide, dexamethasone [VRD]/carfilzomib, lenalidomide, dexamethasone [KRD]) versus other (bortezomib, thalidomide, dexamethasone [VTD]/bortezomib, cyclophosphamide, dexamethasone [VCD]/bortezomib, dexamethasone [VD]/lenalidomide, dexamethasone [RD]) and studied the impact of front‐line therapy on post‐FHR overall survival (OS). In the FHR12 cohort (follow‐up 48 months), the OS after VRD/KRD ( n = 238) was 21 versus 17 months with other regimens ( n = 227, hazard ratio [HR] = 1.2, 95% confidence interval [CI]: 0.6–1.06). In a multivariable model, the HR for OS was 0.94 (95% CI: 0.7–1.3, p = 0.69) for VRD/KRD versus other regimens. There was no significant interaction between type of first‐line (1L) therapy and time from 1L AHSCT to first relapse in predicting OS. Similar results were seen for FHR18 and FHR24. FHRMM remains a negative prognostic factor irrespective of front‐line therapy and warrants consideration of T‐cell engagers' second‐line therapy.