Effects of PF-07901801,Tafasitamab, and Lenalidomide in People With Relapsed or Refractory Diffuse Large B-cell Lymphoma

The purpose of this study is to learn about the effects of three study medicines (PF-07901801, tafasitamab, and lenalidomide) when given together for the treatment of diffuse large B-cell lymphoma (DLBCL) that:is relapsed (has returned after last treatment) oris refractory (has not responded to last treatment)DLBCL is a type of non-Hodgkin lymphoma (NHL). NHL is a cancer of the lymphatic system. It develops when the body makes abnormal B lymphocytes. These lymphocytes are a type of white blood cell that normally help to fight infections.This study is seeking participants who are unable or unwilling to undergo a stem cell transplant. Stem cell transplant is when doctors put healthy blood cells back into your body.Everyone in this study will receive all three medicines. Participants will receive PF-07901801 and tafasitamab at the study clinic by intravenous (IV) infusion (given directly into a vein). Study interventions will be administered in 28-day cycles. PF-0791801 will be given weekly for the first three cycles and then every two weeks. Tafasitamab will administered on Days 1, 4, 8, 15 and 22 in cycle 1, weekly in cycles 2 and 3 and then every 2 weeks in cycle 4 and beyond. Lenalidomide will be taken by mouth at home every day for Days 1 to 21 of each 28-day cycle for the first 12 cycles.Participants can continue to take PF-07901801 and tafasitamab until their lymphoma is no longer responding. Lenalidomide is discontinued after 12 cycles.PF-07901801 will be given at different doses to different participants. Everyone taking part will receive approved doses of tafasitamab and lenalidomide. We will compare the experiences of people receiving different doses of PF-07901801. This will help us to determine what dose is safe and effective dose when combined with the other 2 study medicines.

Key Inclusion Criteria:Histologically confirmed diagnosis of DLBCLRelapsed or refractory diseaseParticipant is not be a candidate for or is unwilling to undergo high dose chemotherapy and subsequent stem cell transplant and/or is unable to receive chimeric antigen receptor (CAR) T-cell therapyPrevious treatment with at least one prior line of systemic therapy (for phase 2, at least 1 and no more than 2 prior lines of systemic therapy). Prior therapy must include an anti-CD20 antibody.Adequate bone marrow, hepatic and renal functionEastern Cooperative Oncology Group (ECOG) ≤2Must provide a tumor tissue sample (fresh or archival, collected prior to start of treatment) for biomarker analysisKey Exclusion Criteria:Prior treatment with an anti-CD47 or anti-CD19 (other than CAR T) or immunomodulatory agentsPrior allogeneic stem cell transplantation or autologous stem cell transplantation within 12 weeks prior to enrolmentParticipants with active, uncontrolled bacterial, fungal or viral infection.