A Phase 2b, Open-label, Multicenter, Randomized Parallel-Group, Two-Stage, Study of an Immunotherapeutic Treatment DPX-Survivac and Pembrolizumab, With and Without Intermittent Low-Dose Cyclophosphamide, in Subjects With Relapsed/Refractory Diffuse Large B-Cell Lymphoma (VITALIZE)

This is a Phase 2b, randomized, open label study to assess the safety and efficacy of DPX-Survivac and pembrolizumab, with and without low-dose cyclophosphamide (CPA) in subjects with relapsed or refractory DLBCL. The study will enroll up to 102 subjects. Eligible subjects will be randomized (1:1) to receive: * Arm 1: DPX-Survivac, pembrolizumab and intermittent, low-dose CPA; or, * Arm 2: DPX-Survivac and pembrolizumab All subjects will receive two 0.5 mL doses of DPX-Survivac 3 weeks apart on day 7 (D7) and D28 followed by up to twelve 0.1 mL doses of DPX-Survivac, 8 weeks apart (Q8W). A…