ABCL-170: Long-Term Outcomes from the Phase II L-MIND Study of Tafasitamab (MOR208) Plus Lenalidomide in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma

Context: Tafasitamab, a humanized anti-CD19 antibody, has demonstrated encouraging activity with durable responses with lenalidomide (LEN) in autologous stem cell transplant (ASCT)-ineligible patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) in the Phase II L-MIND study ( NCT02399085 ). In the primary analysis (cut-off November 30, 2018), the objective response rate (ORR) was 60.0%, median duration of response (DOR) was 21.7 months and median follow-up was 17.3 months. Objective: To report the long-term clinical efficacy and safety of tafasitamab + LEN in the L-MIND study after one additional year of follow-up (cut-off November 30, 2019). Design & Setting: An open-label, single-arm, Phase II study. Patients: Aged ≥18 years with R/R DLBCL (1–3 prior systemic therapies, including ≥1 CD20-targeting regimen), an ECOG performance status 0–2, and ASCT ineligible. Interventions: Tafasitamab (12 mg/kg intravenously, 28-day cycles) was administered once weekly during Cycles 1–3 with a loading dose on Cycle 1 Day 4, then every 2 weeks during Cycles 4–12. LEN (25 mg orally) was self-administered on Days 1–21 of Cycles 1–12. After Cycle 12, progression-free patients received tafasitamab every 2 weeks until disease progression. Main Outcome Measure(s): The primary endpoint was ORR (independent review committee). Secondary endpoints included DOR, progression-free survival (PFS), overall survival (OS), and safety. Results: In this long-term analysis, 80 of 81 enrolled patients received tafasitamab + LEN and were included in the efficacy analysis. ORR was 58.8% (n=47/80); 41.3% (n=33/80) with complete response; and 17.5% (n=14/80) with partial response. Median DOR was 34.6 months (95% confidence interval [CI]: 26.1–not reached [NR]). Median OS was 31.6 months (95% CI: 18.3–NR) with a median follow-up of 31.8 months. Median PFS was 16.2 months (95% CI: 6.3–NR) with a median follow-up of 22.6 months. No unexpected toxicities were reported. Conclusions: After a minimum of two years' follow-up, outcomes are consistent with the primary analysis and confirm the durability of response and meaningful OS of tafasitamab + LEN followed by tafasitamab in ASCT-ineligible patients with R/R DLBCL. Along with an acceptable safety profile, these data support a clinically relevant benefit with this immunological combination.