Epcoritamab SC Monotherapy Leads to Deep and Durable Responses in Patients with Relapsed or Refractory Follicular Lymphoma: First Data Disclosure from the Epcore NHL-1 Follicular Lymphoma Dose-Expansion Cohort

Background: Despite recent therapeutic advances, an unmet need exists for efficacious, well-tolerated, and convenient treatment (tx) options for patients (pts) with relapsed/refractory (R/R) follicular lymphoma (FL). In particular, pts with high-risk disease, including those refractory to both anti-CD20 tx and an alkylating agent (double refractory) and those with disease progression within 2 y of first-line (1L) immunochemotherapy (POD24), require more effective options. Epcoritamab, a subcutaneous (SC) CD3xCD20 bispecific antibody, was recently approved by the US FDA for the tx of adults with R/R diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from indolent lymphoma, and high-grade B-cell lymphoma after ≥2 lines of systemic tx. Here we present initial results from the FL dose-expansion cohort of the EPCORE™ NHL-1 trial (NCT03625037; phase 1/2). Methods: Pts with CD20 + R/R FL (grade [G] 1-3A) who had received ≥2 prior lines of systemic tx received epcoritamab SC in step-up doses (SUD 1 and 2) in cycle (C) 1, followed by full doses of 48 mg in 28-d Cs: QW, C1-3; Q2W, C4-9; and Q4W, C≥10 until disease progression or unacceptable toxicity. The primary endpoint of overall response rate (ORR) was assessed per Lugano criteria by an independent review committee. As a secondary analysis, minimal residual disease (MRD) was assessed in peripheral blood using the clonoSEQ ® assay (Adaptive Biotechnologies, Seattle, WA). Results: Between Sep 2020 and Oct 2022, 128 pts with R/R FL G1-3A were enrolled to receive epcoritamab SC. As of Apr 21, 2023, the median follow-up was 17.4 mo. Median age was 65 y, 61% of pts had FLIPI 3-5, and 85% had stage III-IV disease. The median number of prior lines of tx was 3 (range, 2-9); 31% of pts had ≥4 prior lines of tx. Common prior therapies included anthracyclines (77%), lenalidomide (31%), and autologous stem cell transplant (19%). Most pts were primary refractory (54%), double refractory (70%), or refractory to their last prior tx (69%); 42% had POD24, and 52% progressed within 2 y of initiating any 1L tx. The ORR was 82%, with a complete response (CR) rate of 63% ( Figure). The median time to response and CR was 1.4 and 1.5 mo, respectively. ORRs/CR rates were generally consistent across prespecified high-risk subgroups: double refractory, 76%/56%; refractory to last prior tx, 74%/51%; POD24, 80%/61%; progression within 2 y of initiating any 1L tx, 79%/64%. High ORRs/CR rates were observed