PF610 OUTCOMES FOR TRANSPLANT‐INELIGIBLE PATIENTS WITH NEWLY DIAGNOSED MULTIPLE MYELOMA RECEIVING LENALIDOMIDE, BORTEZOMIB, AND DEXAMETHASONE, OR BORTEZOMIB AND DEXAMETHASONE: AN ENHANCED DATABASE ANALYSIS

Background: For transplant‐ineligible patients with newly diagnosed multiple myeloma (NDMM), US clinical guidelines recommend lenalidomide and dexamethasone (Rd)‐based regimens, including triplet therapy with lenalidomide, bortezomib, and dexamethasone (RVd). Other doublet regimens, such as bortezomib and dexamethasone (Vd), are still a first‐line option for these patients, particularly the elderly and/or frail. Aims: To compare real‐world outcomes of RVd or Vd treatment in transplant‐ineligible patients with NDMM overall and in subgroups of patients who are frail, have poor performance status, or have multiple comorbidities. Methods: A retrospective observational study of patients with NDMM was conducted using the nationally representative Flatiron Network database, an enhanced oncology electronic health record (EHR) database comprising 265 clinics throughout the USA. Eligible patients were diagnosed with multiple myeloma, ICD‐9 (203.0x) or ICD‐10 (C90.xx), between Jan 2011 and May 2018 and were treated with RVd or Vd without stem cell transplantation. The primary comparison was time to next therapy (TTNT) in the overall population and in subgroups of frail patients based on age (>80 years), as well as Eastern Cooperative Oncology Group performance status (ECOG PS) score (≥2), and Charlson Comorbidity Index (CCI) (>2). Overall and progression‐free survival (PFS) data were limited as patient data prior to database adoption were incomplete. Treatment‐free interval (TFI) for patients who initiated a second‐line therapy was defined as time from start of first‐line to start of second‐line therapy minus the duration of therapy (DOT). The Kaplan–Meier and Cox proportional hazard methods were used to calculate TTNT after adjusting for baseline demographic and clinical characteristics. Results: Of the 8,470 eligible patients, 2,369 were treated with RVd (n = 1,309) or Vd (n = 1,060). Patients treated with Vd were more likely to be older (median age 75 vs 70 years; P  < 0.0001), have creatinine clearance <30 mL/min (23.9% vs 10.7%, P  < 0.0001), have ECOG PS score ≥2 ( P  = 0.0031), and have International Staging System stage III disease (45.1% vs 28.8%; P  < 0.0001). There were no significant differences in baseline neutropenia, anemia, or thrombocytopenia, or in median CCI. Patients were less likely to have high‐risk cytogenetics in the Vd group (19.7% vs 26.0%; P  < 0.0001). Mean DOT was longer for RVd (11.4 ± standard deviation [SD] 13.3 months) than for Vd (7.7 ± SD 9.7 months). However, the median adjusted TTNT was significantly longer with RVd than Vd (40.9 vs 14.8 months; hazard ratio [HR] 0.43; 95% CI 0.33–0.55; P  < 0.0001). Patients were less likely to initiate a new treatment in the RVd group (24.8% vs 40.6%; P  < 0.0001). Of those starting a new line of treatment, the mean TFI for RVd versus Vd was 42.6 versus 39.3 days, respectively ( P  = 0.2214). Median TTNT was significantly longer with RVd for all defined subgroups (Table). There were no significant differences in TFI in days, but the proportion of patients initiating a new treatment was lower (age >80 years, 14.4% vs 28.3%; ECOG PS ≥2, 19.7% vs 31.6%; CCI >2, 23.0% vs 36.3%) for RVd versus Vd patients, respectively. Summary/Conclusion: In this study, one of the largest real‐world studies of transplant‐ineligible patients, triplet therapy with RVd significantly prolonged TTNT vs Vd by 26.1 months in the overall patient population, and by between 21.1 and 25.2 months in subgroups of NDMM patients with poor performance status or multiple comorbidities.