Five monoclonal antibody (mAb) therapeutics have recently transitioned into late-stage clinical studies. Three (utomilumab, isatuximab, SHR-1210) are being evaluated as treatments for cancer, and the effects of two (crizanlizumab, olokizumab) are being studied in patients with other disorders. Utomilumab (PF-05082566) is a human IgG2 antibody agonist that targets the extracellular domain of 4-1BB (CD137), which is a co-stimulatory receptor expressed on activated T cells. In preclinical studies, Fisher et al (1) demonstrated that utomilumab can activate NF-κB and induce downstream cytokine production, promote leukocyte proliferation, and inhibit tumor growth in a xenograft tumor model. Utomilumab is included in a multi-center, international, randomized, open label, 2-component (Phase 1b followed by Phase 3), parallel-arm study (Javelin DLBCL; NCT02951156) of avelumab in combination with various agents for the treatment of relapsed/refractory diffuse large B-cell lymphoma. The study includes a total of 5 arms (A: avelumab/utomilumab/rituximab; B: avelumab/utomilumab/azacitidine; C: avelumab/rituximab/bendamustine; D: selected regimen from Phase 1b component, which may be the agents investigated in study arms A or B or C; E: investigator’s choice of either rituximab/bendamustine or rituximab/gemcitabine/oxaliplatin). Progression-free survival is the primary outcome measure of the Phase 3 component of the study, which has an estimated primary completion date of February 2021.