Talquetamab plus Teclistamab in Relapsed or Refractory Multiple Myeloma.

Background: Talquetamab (anti-G protein-coupled receptor family C group 5 member D) and teclistamab (anti-B-cell maturation antigen) are bispecific antibodies that activate T cells by targeting CD3 and that have been approved for the treatment of triple-class-exposed relapsed or refractory multiple myeloma.

Methods: We conducted a phase 1b-2 study of talquetamab plus teclistamab in patients with relapsed or refractory multiple myeloma. In phase 1, we investigated five dose levels in a dose-escalation study. Talquetamab at a dose of 0.8 mg per kilogram of body weight plus teclistamab at a dose of 3.0 mg per kilogram every other week was selected as the recommended phase 2 regimen. The primary objective was to evaluate adverse events and dose-limiting toxic effects.

Results: A total of 94 patients received treatment, with the recommended phase 2 regimen used in 44. The median follow-up was 20.3 months. Three patients had dose-limiting toxic effects (including grade 4 thrombocytopenia in 1 patient with the recommended phase 2 regimen). Across all dose levels, the most common adverse events were cytokine release syndrome, neutropenia, taste changes, and nonrash skin events. Grade 3 or 4 adverse events, most commonly hematologic events, occurred in 96% of the patients. Grade 3 or 4 infections occurred in 64% of the patients. With the recommended phase 2 regimen, a response occurred in 80% of the patients (including in 61% of those with extramedullary disease); across all dose levels, a response occurred in 78%. The likelihood of patients continuing in response at 18 months was 86% with the recommended phase 2 regimen (82% among those with extramedullary disease) and 77% across all dose levels.

Conclusions: The incidence of grade 3 or 4 infections with talquetamab plus teclistamab was higher than has been observed with either therapy alone. A response was observed in a high percentage of patients across all dose levels, with durable responses with the recommended phase 2 regimen. (Funded by Janssen Research and Development; RedirecTT-1 ClinicalTrials.gov number, NCT04586426.).