Epcoritamab and Tazemetostat for the Treatment of Relapsed or Refractory Grade I-IIIa Follicular Lymphoma

This phase II trial tests the safety, side effects and effectiveness of epcoritamab and tazemetostat in treating patients with grade I-IIIa follicular lymphoma that has come back after a period of improvement (relapsed) or that has not responded to previous treatment (refractory). Epcoritamab is a bispecific monoclonal antibody that binds to two different antigens on the surface of cancer cells that may help the body's immune system attack the cancer and may interfere with the ability of the cancer cells to grow and spread. Tazemetostat, a EZH2 inhibitor, may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving epcoritamab and tazemetostat may be safe, tolerable and/or effective in treating patients with relapsed or refractory grade I-IIIa follicular lymphoma.

PRIMARY OBJECTIVES: I. To assess the safety/tolerability of epcoritamab in combination with tazemetostat in patients with relapsed/refractory follicular lymphoma (FL). (Safety lead-In) II. To evaluate the anti-tumor activity of epcoritamab in combination with tazemetostat in patients with relapsed/refractory FL by complete response rate. (Phase II) SECONDARY OBJECTIVES: I. To estimate overall response rate (ORR) duration of response (DOR) of the combination of epcoritamab and tazemetostat. II. To estimate progression-free survival, and overall survival of the combination of epcoritamab and tazemetostat. III. To assess the toxicities of the combination of epcoritamab and tazemetostat. EXPLORATORY OBJECTIVES: I. To characterize the T-cell population balance in patients treated with epcoritamab and tazemetostat in different compartments (peripheral blood, tumor). II. To explore correlation between response and presence of EZH2 mutations. III. To evaluate minimal residual disease (MRD) dynamics during treatment and explore the correlation of MRD kinetics with response. OUTLINE: Patients receive tazemetostat orally (PO) twice daily (BID) on days 1-28 of each cycle. Patients also receive epcoritamab subcutaneously (SC) on days 1, 8, 15, and 22 of cycles 2-4 then on day 1 of remaining cycles. Cycles repeat every 28 days for up to 13 cycles in the absence of disease progression or unacceptable toxicity. Patients also undergo collection of blood samples on study and undergo bone marrow biopsy and computed tomography (CT) or positron emission tomography (PET)/CT throughout the study. After completion of study treatment, patients are followed up at 30 and 60 days then for up to 2 years.