First-in-Human (FIH) Trial in Patients With Relapsed, Progressive or Refractory B-Cell Lymphoma

The purpose of the dose-escalation part of the trial is to determine the maximum tolerated dose (MTD) and the recommended Phase 2 dose (RP2D), as well as to establish the safety profile of epcoritamab in participants with relapsed or refractory B-cell lymphoma. In the expansion part, additional participants will be treated with epcoritamab, at the RP2D and the purpose is to further explore and determine the safety and efficacy of epcoritamab. The dose-OPT part will evaluate alternative priming and intermediate dose regimens of epcoritamab in participants with: * Diffuse large B-cell lymphoma (DLBCL) * Follicular lymphoma (FL) * Mantle cell lymphoma (MCL) All participants will receive epcoritamab at the RP2D.