Belantamab Mafodotin in Combination with Lenalidomide Plus Dexamethasone in Patients with Relapsed/Refractory Multiple Myeloma: Safety and Efficacy Analysis of DREAMM-6 Trial Arm-a

Introduction: Belantamab mafodotin (belamaf) is a first-in-class, antibody-drug conjugate that targets B-cell maturation antigen. In the recent ALGONQUIN study, clinical activity associated with belamaf in combination with the immunomodulatory drug pomalidomide were increased in triple-class exposed/refractory multiple myeloma (MM) patients, highlighting the potential for belamaf-based combinations in this population (Trudel, et al. Blood. 2022;140 (Suppl 1):7306-07). Preclinical data indicate that belamaf combined with other immunomodulatory agents, such as lenalidomide (Len) may also provide additional benefit. Arm A of the Phase I/II DREAMM-6 (NCT03544281) study aimed to assess the safety and clinical activity of belamaf doses/schedules in combination with the standard of care (SOC) of Len plus dexamethasone (Dex) in patients with relapsed/refractory MM (RRMM). Methods: Patients were eligible to participate if they had received ≥1 prior line of therapy (LOT). In Part 1 (dose escalation), up to two dose levels of belamaf (1.9 mg/kg [dose level -1 Q4W]; 2.5 mg/kg Q4W [dose level 1]) and alternative dosing schedules were administered in combination with the fixed SOC dose. In Part 2 (dose expansion), patients received belamaf at the following doses/schedules: 1.9 mg/kg Q8W, 1.9 mg/kg Q4W, 2.5 mg/kg Q4W, or 2.5 mg/kg Q4W split dose (50% on Days 1 and 8 of a given cycle). For this study, Len 25 mg was administered orally (10 mg if estimated glomerular filtration rate 75 years old, patients with BMI