What this means for patients
Research stage: not yet standard treatment.
This report describes side effects seen in 41 Chinese patients with relapsed or refractory multiple myeloma who received talquetamab, an experimental bispecific antibody, in an early-phase study. The GPRC5D-related side effects, mainly taste changes, dry mouth, skin rash and nail problems, were mostly mild and often improved with supportive care. Because this is a small study of a treatment still under investigation, these results do not show that talquetamab is approved or suitable for every patient.
OBJECTIVES: Talquetamab (G-protein-coupled receptor class C group 5 member D [GPRC5D] × CD3 bispecific antibody) demonstrated antitumor activity in relapsed/recurrent multiple myeloma (RRMM) in the phase I/II MonumenTAL-1 study. We report the safety profile of talquetamab in Chinese patients from MonumenTAL-1, focusing on GPRC5D-associated on-target/off-tumor adverse events (AEs).
METHODS: Adult Chinese patients with heavily pretreated RRMM and measurable disease received subcutaneous talquetamab 0.4 mg/kg once weekly (QW) or 0.8 mg/kg biweekly (Q2W). Incidence, time to onset, duration, and recovery status of GPRC5D-associated AEs were reported. Data cutoffs: 29 February 2024 (QW cohort); 26 August 2024 (Q2W cohort).
RESULTS: A total of 41 adult Chinese patients were included in this study (QW cohort, n = 29; Q2W cohort n = 12). Median treatment duration was 7.7 months (QW cohort) and 7.1 months (Q2W cohort); median follow-up was 16.3 and 13.9 months, respectively. GPRC5D on-target/off-tumor AEs, predominantly grade 1-2 (one grade 3 non-rash skin toxicity; QW cohort), were most commonly oral AEs (dysgeusia, dry mouth), skin AEs (rash, non-rash skin toxicity), and nail disorders; 50%-100% resolved by data cutoff. AEs were managed with supportive therapies. Talquetamab dose modification was needed in one case (grade 2 weight decrease).
DISCUSSION: The generally mild GPRC5D-associated AEs were well tolerated and consistent with the known safety profile of talquetamab. Supportive management of these AEs without need for dose modification enabled prolonged treatment.
CONCLUSIONS: Education of patients with RRMM on potential GPRC5D-associated AEs before starting treatment, and timely management upon experience, may ensure optimum exposure and thus maximum benefit with talquetamab.
Original publication: PubMed. This is the published abstract of the study, in its original English.