Tocilizumab prophylaxis for outpatient administration of teclistamab in relapsed/refractory multiple myeloma.

Abstract

e19504 Background: Teclistamab is the first BCMA-directed bispecific antibody approved for the treatment of relapsed and refractory multiple myeloma (RRMM). However, despite the deep and durable response rates achieved, concerns remain regarding the acute toxicity profile, particularly the risk of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). To date, a short hospitalization is still recommended for teclistamab initiation and data on the safety of outpatient treatment remains limited. Methods: We prospectively evaluated the safety of outpatient teclistamab initiation in subjects with triple-exposed RRMM. Subjects received the standard step-up dose (SUD) of 0.06 and 0.3 mg/kg and the first full dose (1.5 mg/kg) in the outpatient clinic on days 1, 3, and 5 of cycle 1, respectively, followed by weekly doses. All subjects received tocilizumab (8 mg/kg) on day 1 before first teclistamab dose. Other premedications consisted of dexamethasone (16 mg), acetaminophen (975 mg) and cetirizine (10 mg) for the SUD and first full dose. To receive outpatient SUD, patients were required to stay within 60 minutes of the hospital and have access to a 24-hour caregiver support. During the first 7 days, subjects were contacted by telephone or videoconference 4 times daily. Adverse events (AEs) were graded according to CTCAE v5.0. CRS and ICANS were graded according to ASTCT guidelines. Results: Between July 24, 2023, and January 6, 2025, 20 subjects received at least 3 doses of teclistamab. Cohort characteristics are presented in Table 1. Fourteen subjects (70%) met at least one exclusion criteria for the MAJESTEC-1 trial. With a median follow-up of 2.2 months (range 0.4-16.0), the ORR was 68%. To date, 16 subjects (80%) experienced at least 1 AE, with grade 3 in 70%. CRS occurred in 2 subjects (10%), all grade 1 (Table 1). One subject received 1 dose of tocilizumab, the other 1 dose of dexamethasone, both without requiring hospitalization. No case of ICANS was reported. Cytopenias were common, with grade 4 neutropenia occurring in 10 subjects (50%); G-CSF used in 9 subjects during SUD. Conclusions: Healthcare resource utilization is a major challenge in the evolving field of cellular immunotherapy. Prophylactic use of tocilizumab reduces both CRS incidence and severity with a very low rate of admission. Our results support that outpatient administration with tocilizumab prophylaxis is a safe and feasible option for teclistamab SUD. Baseline demographics. Characteristics Cohort (N=20) Median age in years (range) 72 (31-91) Male sex (%) 8 (40) Caucasians (%) 14 (70) >1 Extramedullary site of disease (%) 10 (50) High-risk cytogenetic profile - number/total number (%) 9/16 (56) International Staging System 3 number/total number (%) 6/17(35) Median time since diagnosis in years (range) 7.0 (1.5-20.9) Median number of previous lines of therapy (range) 4 (2-8)