A Study to Learn About the Effects of Two Study Medicines (Maplirpacept [PF-07901801] And Glofitamab) When Given Together In People With Relapsed Or Refractory Diffuse Large B Cell Lymphoma.

This is a multicenter, open-label, Phase 1b/2 study to evaluate the safety, tolerability and potential clinical benefits of maplirpacept PF-07901801, an anti-CD47 molecule, in combination with fixed doses of glofitamab after a single dose of obinutuzumab in participants with relapsed/refractory (R/R) DLBCL not eligible for or unwilling to undergo high dose chemotherapy and subsequent autologous stem cell transplantation (ASCT) or unable to receive approved chimeric antigen receptor T-cell (CAR-T) therapy (for example, due to logistical limitations). For Phase 1b, participants must have previously received at least 2 prior systemic treatment regimen. For Phase 2, participants must have received at least 2 but no more than 4 prior systemic treatment regimens. All participants must have previously received an anti-CD20 containing regimen. Phase 1b will assess dose-limiting toxicities of PF-07901801 when administered in combination with glofitamab, to select doses for the Phase 2 part of the study. Phase 2 will evaluate safety and efficacy to determine the recommended Phase 3 dose of PF-07901801 to be administered in combination with glofitamab.