Tecvayli (teclistamab) continued to elicit what researchers described as deep and durable responses in patients with relapsed/refractory multiple myeloma, even among patients who had switched to less-frequent dosing, according to study findings.
Long-term follow-up data from the phase 1/2 MajesTEC-1 trial was presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting showing that, at a median follow-up of 30.4 months, among 165 patients treated with the phase 2 dose of 1.5 milligrams per kilogram subcutaneous weekly preceded by step-up dosing (where increasing doses of treatments are given over time) the objective response rate (the percentage of patients who responded partially or completely to treatment) was 63%.
Researchers noted that 46.1% of patients achieving a complete response (no evidence of disease) and 85.7% of minimal residual disease (MRD, small amounts of malignant cells remaining in a patient’s body following treatment)-evaluable patients were MRD negative at any point. MRD negativity was sustained for at least six months by 56.1% of patients and at least a year by 38.9%.
The median duration of response was 24 months. The median progression-free survival (the time a patient lives without their disease spreading or worsening) was 11.4 months, and overall survival (the time a patient lives following treatment, regardless of their disease status) was 22.2 months.
Patients treated with the phase 2 dose had the option to switch to every other week if they experienced a partial response or better after four cycles of therapy in phase 1 or complete response or better for six months in phase 2. Patients not in complete response could switch due to side effects. Patients who continued to demonstrate a response could also then switch to less-frequent dosing.
Thirty-eight patients are still being treated, with 37 having been switched to a less-frequent dosing schedule (every other week), maintaining their responses, researchers stated.
Hematologic side effects of any grade/grade 3 (severe) or 4 (life-threatening) included neutropenia (low count of neutrophils, a type of white blood cell, 71.5%/65.5%), anemia (low count of red blood cells, 55.2%/37.6%), thrombocytopenia (low platelet count, 41.8%/23%), and lymphopenia (low count of lymphocytes, a type of white blood cell, 36.4%/34.5%).
Nearly seventy nine percent (78.8%) of patients (55.2% grade 3 or 4) experienced infections. Eighteen of 22 grade 5 (deadly) infections were due to COVID-19, while new grade 3 or higher infections decreased over time. There was one case of side effects leading to dose reduction and eight cases of side effects leading to treatment discontinuation, with five of those being due to infection. Researchers stated that no new safety signals were reported.
Other than infections, other nonhematologic side effects experienced by at least 30% of patients included cytokine release syndrome (a systemic inflammatory response, 72.1% any grade/0.6% grade 3 or 4), diarrhea (34.5%/3.6%), pyrexia (fever, 30.9%/0.6%) and fatigue (30.3%/2.4%).
Based on the findings of MajesTEC-1, Tecvayli received accelerated approval from the Food and Drug Administration in 2022 for the treatment of adult patients with pretreated, relapsed or refractory multiple myeloma, with the agency reporting that it was the first BCMA-directed CD3 T-cell engager approved for members of this patient population.
According to the National Cancer Institute, Tecvayli works by binding to the CD3 protein on healthy T cells, part of the immune system, and to the BCMA protein on multiple myeloma cells. By bringing healthy T cells and myeloma cells near each other, the goal of the treatment is to help T cells kill myeloma cells.
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