Spencer A, et al. - Researchers in this study analyzed marizomib (MRZ), pomalidomide (POM) and low-dose dexamethasone (Lo-DEX) [PMD] in relapsed/refractory multiple myeloma (RRMM) to assess safety and determined the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). As per observations, PMD was well tolerated and showed promising activity in heavily pre-treated, high-risk RRMM patients.

• Researchers administered intravenous MRZ (0.3–0.5 mg/m²) over 2 h on days 1, 4, 8, 11; POM (3–4 mg) on days 1–21; and Lo-DEX (5 or 10 mg) on days 1, 2, 4, 5, 8, 9, 11, 12, 15, 16, 22 and 23 of every 28-day cycle.
• They enrolled 38 patients that had received a median of 4 (range 1–10) prior lines of therapy; all patients received prior lenalidomide and bortezomib.
• They recognized no dose-limiting toxicities (DLTs) and determined 0.5 mg/m² MRZ to be the RP2D.
• In this study, the most common treatment-related ≥Grade 3 adverse events included: neutropenia (11/38 patients: 29%), pneumonia (4/38 patients 11%), anaemia (4/38 patients; 11%) and thrombocytopenia (4/38 patients; 11%).
• The overall response rate of 53% (19/36) and clinical benefit rate of 64% (23/36) were observed.