A phase 1 (Ph1) trial of MK-3475 combined with lenalidomide (Len) and low-dose dexamethasone (Dex) in patients (pts) with relapsed/refractory multiple myeloma (RRMM).

TPS3117 Background: RRMM patients refractory to proteasome inhibitors and immunomodulatory drugs (IMiD) have a very poor outcome. PD-L1 expressed on most MM plasma cells is a potential mechanism of immune evasion. MK-3475 is a potent, highly selective, humanized IgG4/kappa isotype, anti-PD-1 monoclonal antibody designed to block PD-1 interaction with PD-L1 and PD-L2, enhancing lymphocytic activity, tumor regression and immune rejection. Methods: This is an open-label, Ph1 multicenter, non-randomized dose escalation trial of MK-3475 combined with Len/Low-dose Dex in RRMM patients failing two lines of prior therapy, including bortezomib and an IMiD, using a modified 3+3 design followed by a toxicity probability interval (TPI) for dose confirmation. Cohorts of 3-6 pts per dose level (DL) will be enrolled sequentially at escalating doses of MK-3475 (2, 5, 10 mg/kg) with Len (25mg) / Low-dose Dex (40mg) until a preliminary maximum tolerated dose (MTD) or maximum administered dose (MAD), is identified. Addition...