Comparative Efficacy and Safety of Bortezomib, Thalidomide, and Dexamethasone (VTd) without and with Daratumumab (D-VTd) from Cassiopeia Versus Vtd from Pethema/GEM in Patients with Newly Diagnosed Multiple Myeloma Using Propensity Score Matching (PSM)

Introduction: For patients (pts) with newly diagnosed multiple myeloma (NDMM) who are transplant-eligible, VTd with autologous stem-cell transplantation (ASCT) is a standard of care. In the PETHEMA/GEM study, pts in the VTd group received pre-ASCT induction therapy (six 28-day cycles) of bortezomib, thalidomide (ramp up to 200 mg daily, per label), and dexamethasone, followed by post-ASCT maintenance (up to 3 years) of interferon alfa-2b, thalidomide (100 mg daily), or thalidomide (100 mg daily) with bortezomib (1 cycle every 3 months; Rosiñol L, et al. Blood. 2012;120[8]:1589-96). Clinical practice has evolved and a modified thalidomide daily dose of 100 mg instead of 200 mg is now the standard of care (Mohty M, et al., presented at EBMT 2019, abstract OS12-3) and is reflected in treatment guidelines. In the phase 3 CASSIOPEIA study (part 1), pts received pre-ASCT induction (four 28-day cycles) and post-ASCT consolidation therapy (two 28-day cycles) of VTd (thalidomide 100 mg daily; VTd-mod) without or with daratumumab (D-VTd). In CASSIOPEIA part 2 (ongoing), pts with a partial response or better were re-randomized to maintenance therapy of daratumumab or observation (up to 2 years; Moreau P, et al. Lancet. 2019;394[10192]:29-38). Here, we used PSM to estimate the effect of treatments by controlling for differences in baseline covariates. We evaluated efficacy and safety in treatment groups from CASSIOPEIA versus the VTd group from PETHEMA/GEM (VTd-label).