Efficacy and safety of epcoritamab in Japanese patients with relapsed or refractory diffuse large B-cell lymphoma: 3-year follow-up from the EPCORE NHL-3 trial.

Background: Primary results from the EPCORE NHL-3 trial (NCT04542824) showed deep, durable responses in Japanese patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) treated with single-agent epcoritamab, a subcutaneous CD3xCD20 bispecific antibody. Here, we report 3-year follow-up of safety and efficacy.

Methods: Japanese patients with R/R CD20⁺ DLBCL and  ≥ 2 prior systemic therapies received epcoritamab (0.16/0.8-mg step-up doses, then 48-mg full doses) according to the approved label. The primary endpoint was overall response rate per independent review committee.

Results: As of July 12, 2024, 36 patients received epcoritamab (median follow-up, 36.7 months). Overall/complete response rates were 56%/47%. Median duration of response was 15.2 months. Median duration of complete response was not reached; an estimated 53% of complete responders remained in complete response at 3 years. Median progression-free/overall survival (PFS/OS) were 4.1/14.9 months overall; neither was reached among complete responders. Three-year PFS/OS estimates were 25%/39% overall and 53%/71% in complete responders. Among 30 evaluable patients, 17 (57%) became minimal residual disease (MRD) negative, which was associated with longer PFS (cycle 3 day 1 landmark analysis). The most common treatment-emergent adverse events (TEAEs) were cytokine release syndrome (83%), injection-site reaction (69%), and neutropenia (39%), consistent with previous reports. No fatal TEAEs occurred.

Conclusions: With  > 3 years of follow-up, epcoritamab treatment has consistently shown durable responses and high rates of MRD negativity in Japanese patients with R/R DLBCL. Safety was similar to previous reports. These long-term remissions reaffirm encouraging outcomes with epcoritamab for this challenging-to-treat population.