Detailed overview of incidence and management of cytokine release syndrome observed with teclistamab in the MajesTEC-1 study of patients with relapsed/refractory multiple myeloma

Background: Teclistamab, a B-cell maturation antigen × CD3 bispecific antibody, demonstrated an overall response rate of 63.0% in 165 heavily pretreated patients with relapsed or refractory multiple myeloma in the phase 1/2 MajesTEC-1 study. Cytokine release syndrome (CRS), a known manifestation of T-cell redirection, was observed in 119 of 165 patients (72.1%). Methods: Patients received once-weekly teclistamab 1.5 mg/kg subcutaneously after two step-up doses (0.06 and 0.3 mg/kg). CRS was graded according to American Society for Transplantation and Cellular Therapy criteria and managed according to the study protocol, including use of tocilizumab and/or steroids. Results: Most cases of CRS occurred during the step-up dosing schedule of teclistamab and were grade 1 (50.3% of patients) or grade 2 (21.2% of patients); a single case of grade 3 CRS was reported in a patient with concurrent grade 3 pneumonia. All CRS cases resolved and none led to treatment discontinuation. Overall, 33.3% of patients had >1 CRS event; CRS recurrence was reduced when tocilizumab was administered for the first CRS event compared with when it was not (20.0% vs. 62.2%, respectively). Baseline characteristics such as tumor burden and cytokine levels did not appear to predict CRS incidence or severity. Conclusions: Findings of this study support the need for preemptive planning and prompt management of CRS in patients treated with T-cell–engaging bispecific antibodies. Intervention with tocilizumab for CRS appears to decrease the likelihood of patients experiencing subsequent CRS events without compromising response to teclistamab. Plain language summary: Cytokine release syndrome (CRS), observed in 72.1% of patients treated with teclistamab in the MajesTEC-1 study, was mostly grade 1 or 2 and manageable, without requiring treatment discontinuation. Most CRS occurred during the step-up schedule, requiring vigilance during treatment initiation. Ensure fever is resolved and patients have no signs of infection before initiating the teclistamab step-up schedule or administering the next teclistamab dose, to avoid exacerbating CRS. Tocilizumab reduced the risk of subsequent CRS in patients receiving it for their first CRS event (20.0% vs. 62.2% in those not receiving it), without affecting response to teclistamab. No baseline characteristics, including tumor burden or cytokine levels, appeared to clearly predict for CRS occurrence or severity.