Genmab A/S today announced results from the Phase 1b/2 EPCORE® CLL-1 clinical trial evaluating epcoritamab (Abstract #883), a T-cell engaging bispecific antibody administered subcutaneously, demonstrated an overall response rate (ORR) of 61 percent and a complete response (CR) rate of 39 percent in difficult-to-treat adult patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) treated with epcoritamab monotherapy. These results, from the monotherapy expansion (EXP) cohort (n=23) of the trial, along with the first safety data from the optimization (OPT) cohort, were presented at the 66th Annual Meeting and Exposition of the American Society of Hematology (ASH), during the ASH Annual Meeting Press Program. The data will be presented during an oral session on December 9, 2024.

In the EXP cohort, the median time to response was two (2.0) months and the median time to CR was 5.6 months. Among all patients in the cohort, median progression-free survival (PFS) was 12.8 months and median overall survival (OS) was not reached (median follow-up was 22.8 months). An estimated 65 percent of patients were alive at 15 months. Among 12 responders evaluable for minimal residual disease (MRD) by next-generation sequencing in peripheral blood, nine patients (75 percent) had undetectable MRD.

The most frequent non-hematologic treatment-emergent adverse events (TEAEs) in the EXP cohort were cytokine release syndrome (CRS; 96 percent), diarrhea (48 percent), peripheral edema (48 percent), fatigue (43 percent), and injection-site reaction (43 percent). Cytopenias were common (anemia, 65 percent; thrombocytopenia, 65 percent; neutropenia, 48 percent); however, most patients had baseline anemia and thrombocytopenia, suggesting that these events were largely disease-related. Three cases of immune effector cell-associated neurotoxicity syndrome (ICANS) were reported (one Grade 1; two Grade 2), and there was one clinical tumor lysis syndrome (CTLS) case (Grade 2). These cases did not lead to treatment discontinuation. Four fatal TEAEs occurred - two cases of pneumonia, one case of sepsis and one case of squamous cell carcinoma of the skin.

The EXP cohort followed a 2-step step-up dose regimen, and CRS was manageable and primarily low grade (9 percent Grade 1, 70 percent Grade 2, 17 percent Grade 3). In the first data from the separate OPT cohort, which followed a 3-step step-up dose regimen, CRS severity was substantially reduced with only low-grade events (71 percent Grade 1, 12 percent Grade 2). In both cohorts, CRS events primarily occurred following the first full dose, and none led to treatment discontinuation. No ICANS or CTLS cases were reported in the OPT cohort.

“These EPCORE CLL-1 data are encouraging, especially as the majority of patients were heavily pre-treated with at least four lines of therapy,” said Alexey Danilov, MD, PhD, Marianne and Gerhard Pinkus, Professor and Director of Early Clinical Therapeutics and Associate Director of the Toni Stephenson Lymphoma Center, Department of Hematology and Hematopoietic Cell Transplantation, City of Hope. “Despite progress in treating chronic lymphocytic leukemia, there remains a tremendous need for additional therapeutic options for high-risk patients whose disease has progressed following standard chemoimmunotherapy and targeted therapies.”

Additional data from the EXP cohort showed high response rates in patients with high-risk factors treated with epcoritamab, including TP53 aberrations, IGHV-unmutated disease and double-exposed disease – prognostic markers that are associated with disease progression and decreased survival.i,ii,iii In patients with TP53 aberrations (n=15), the ORR was 67 percent with a CR of 33 percent. Among patients with IGHV-unmutated disease (n=16), the ORR was 63 percent, and the CR was 44 percent. In double-refractory patients, the ORR was 53 percent, and the CR was 37 percent.

All patients in the trial had prior chemoimmunotherapy, and most patients had previously received targeted therapies such as BTK and BCL2 inhibitors (double-exposed) and had high-risk disease characteristics.

“Chronic lymphocytic leukemia is incurable, and patients often need a variety of treatments throughout their lifetime, especially if their disease has high-risk prognostic factors, has relapsed or has become refractory to the current standard-of-care, including targeted therapies,” said Dr. Judith Klimovsky, Executive Vice President & Chief Development Officer, Genmab. “These early data show the potential therapeutic applicability of epcoritamab in relapsed or refractory chronic lymphocytic leukemia, and further reinforce the potential of epcoritamab as a core therapy for the treatment of B-cell malignancies.”

Use of epcoritamab in CLL is not approved in the U.S. or in the EU or in any other territory. The safety and efficacy of epcoritamab for use in CLL have not been established.

 

Source: genmab.com

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