The bispecific antibody teclistamab continued to demonstrate deep and durable responses in patients with relapsed or refractory multiple myeloma (MM) after approximately a two-year median follow-up, according to long-term follow-up results from the MajesTEC-1 study.
Niels WCJ van de Donk, MD, PhD, of the Amsterdam University Medical Center in the Netherlands, presented the updated results with extended follow-up as a poster at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting.
Teclistamab gained US Food and Drug Administration approval in October 2022 for treatment of patients with relapsed or refractory MM based on data from the phase I/II MajesTEC-1 study, which showed rapid, deep, and durable responses. The overall response rate was 63%, with 39% of patients achieving complete response (CR) or better.
In the trial, patients received teclistamab 1.5 mg/kg once per week with an option to switch to every two-week dosing if they achieved partial response or better after at least four weeks of therapy in phase I or CR or better after six months in phase II.
At the meeting, Dr. van de Donk presented results of the trial with 22 months of follow-up.
At this longer follow-up, 43% of patients achieved CR or better. Overall, the median duration of response was two years, but for those patients who achieved CR, the median duration of response was not yet reached.
Median progression-free survival was 12.5 months and median overall survival was 21.9 months. These data support “teclistamab as a safe and effective off-the-shelf BCMA bispecific therapy for patients with relapsed or refractory MM”, the study researchers wrote.
Infections occurred in the majority of patients (78%). Key infections included respiratory infections (56%), COVID-19 (27%), other viral (10%), gastrointestinal (8%), fungal (5%), pneumocystis jiroveci pneumonia (4%), and hepatitis B (0.6%).
Cytokine release syndrome also occurred in the majority of patients (72%), but only 0.6% were grade 3 and there were no grade 4/5 CRS events. ICANS was reported in 3% of patients.
Of the 49 patients who remain on study, more than 90% have moved to every two-week dosing.
Van de Donk NWCJ, Moreau P, Garfall LA, et al. Long-term follow-up from MajesTEC-1 of teclistamab, a B-cell maturation antigen (BCMA) x CD3 bispecific antibody, in patients with relapsed/refractory multiple myeloma (RRMM). Abstract# 8011. Presented at the 2023 American Society of Clinical Oncology Annual Meeting; June 2-6, 2023; Chicago, Illinois.