Usmani SZ, Garfall AL, Nahi H, et al. - Good tolerability and promising efficacy, with durable responses that deepened over time, were shown by teclistamab at the recommended phase 2 dose in patients with relapsed or refractory multiple myeloma. For such patients, teclistamab affords a novel treatment strategy.

• Open-label, single-arm, phase 1 study (MajesTEC-1 study) with multiple myeloma patients who were relapsed, refractory, or intolerant to established therapies.

• 157 patients (median six previous therapy lines) were given at least one dose of teclistamab (intravenous n = 84; subcutaneous n = 73).

• Recommended phase 2 dose was defined as once per week subcutaneous administration of teclistamab at 1500 μg/kg.

• In part one, no dose-limiting toxicities occurred at the recommended phase 2 dose.

• Cytokine release syndrome occurred in 28 (70%) and neutropenia in 26 (65%) as the most common treatment-emergent adverse events, among 40 patients treated at the recommended phase 2 dose.

• In these 40 patients, the overall response rate was 65%; 58% showed a very good partial response or better.

• Maintained teclistamab exposure above target exposure levels, and consistent T-cell activation, were noted at recommended phase 2 dose.