Teclistamab is an off-the-shelf, T cell-directing antibody binding to CD3 on T cells and BCMA on plasma cells. The open-label, multicentre, phase 1/2 MajesTEC-1 trial (NCT04557098) included patients with relapsed/refractory MM who received at least 3 prior lines of therapy and were triple-class exposed (n=165). The patients were treated with 1.5 mg/kg teclistamab, subcutaneously administered, once weekly. The primary endpoint was overall response rate.
Prof. Philippe Moreau (University Hospital of Nantes, France) presented the latest update of this trial. At a median follow-up of 7.8 months, the overall response rate was 62.0%. In addition, 58% of the patients achieved a very good partial response or better, and 29% of the patients reached a complete response or better. The median time to first response was 1.2 months and the median time to best response was approximately 3 months.
The results were consistent across subgroups, including older patients, patients with high-risk cytogenetics, and triple-class refractory patients. The 9-month event-free survival rate for responders was 85.9%. Prof. Moreau added that the responses were durable and tended to deepen over time. Teclistamab was generally well tolerated, with no patients requiring dose reduction.
The most common haematologic adverse events were neutropenia (65.5%), anaemia (49.7%), thrombocytopenia (38.2%), and lymphopenia (33.9%). Cytokine-release syndrome occurred in 71.5% of the patients; only 1 grade 3 case was reported, but this case resolved without treatment discontinuation. The grade 3 or 4 infection rate was 35.2%, which is not unexpected in this heavily pre-treated population. ICANS events were uncommon, all mild or moderate, and resolved without treatment discontinuation.
References:
1. Moreau P, et al. Updated Results From MajesTEC-1: Phase 1/2 Study of Teclistamab, a B-Cell Maturation Antigen x CD3 Bispecific Antibody, in Relapsed/Refractory Multiple Myeloma. O653, ASH 2021 Scientific Sessions, 11-14 December.