ABCL-388 L-MIND: Safety and Efficacy of Tafasitamab in Patients With Relapsed/Refractory Diffuse Large B-Cell Lymphoma on Treatment for at Least 2 Years

Abstract

Durable responses with the immunotherapy tafasitamab+lenalidomide were previously reported in ASCT-ineligible patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) in the Phase II L-MIND trial (NCT02399085). Based on L-MIND, tafasitamab+lenalidomide received accelerated approval (US) and conditional approval (EU and other countries) in this setting. To describe the long-term efficacy and safety of tafasitamab+lenalidomide in L-MIND patients who received treatment for ≥2 years. Ongoing, multicenter, open-label, single-arm Phase II study. Eligibility: ≥18 years old, histologically confirmed DLBCL, and 1-3 prior systemic therapies for DLBCL, including ≥1 anti-CD20 therapy. Tafasitamab: twelve 28-day cycles (12 mg/kg IV) QW during Cycles 1-3, with a loading dose on Cycle 1 Day 4; Q2W Cycles 4-12. Lenalidomide: 25 mg PO Cycles 1-12 Days 1-21. Cycle 13+ tafasitamab monotherapy Q2W until disease progression. Time-to-event, treatment response, and safety endpoints were assessed. Of 80 patients in the full analysis set, 27 (34%) received treatment for ≥2 years (median: 4.3 years). At data cut-off (February 15, 2022), 23 of 27 patients were confirmed alive, one was lost to follow-up, one died with unknown cause, and two died following adverse events (AEs) unrelated to study treatment. Thirteen patients remained on treatment, including six with treatment ≥5 years. Fourteen patients discontinued tafasitamab after ≥2 years due to progressive disease (n=4), patient/physician's decision (n=8), and non-treatment-related fatal AEs (n=2: one each, COVID-19 and cardiovascular AE). Among the 27 patients who received treatment for ≥2 years, the AE analysis for patients receiving tafasitamab+lenalidomide combination therapy (Cycles 1-12) and tafasitamab monotherapy (Cycles 13-24) by exposure-adjusted incidence revealed lower incidence of AEs during tafasitamab monotherapy compared with combination therapy. The majority of AEs were Grade 1-2. The most common AEs (≥1 event/patient-year) were neutropenia and diarrhea during combination (incidence, all-grade/Grade ≥3 AEs: 3.87/1.91 and 1.04/0.04, respectively) and following monotherapy (incidence, all-grade/Grade ≥3 AEs: 0.87/0.45 and 0.32/0.0, respectively). Tafasitamab+lenalidomide followed by tafasitamab monotherapy provided durable responses, with long-term treatment efficacy in those patients who received tafasitamab for up to 5 years. The adverse event burden decreased as patients transitioned from combination therapy to tafasitamab monotherapy. MorphoSys AG.