Introduction: Bispecific antibodies (BsAbs) are a newly approved treatment for relapsed and refractory Multiple Myeloma (MM) in Brazil. They are expected to be widely used among patients previously exposed to anti-CD38, proteasome inhibitors, and immunomodulatory agents (triple class-exposed), as access and cost hinder the use of CAR-T cells for most of the population. Brazil’s unique label for teclistamab and talquetamab allows for the possibility of prescription in the second line of treatment for triple-class exposed patients, even though data is lacking in this setting. Here, we present initial data on twelve patients treated with commercially available BsAbs in our hospital.
Methods: We collected data for patients treated with BsAbs at our Oncology Center (AC Camargo Cancer Center) in São Paulo, Brazil, between June 2023 and May 2024. Baseline characteristics were collected at baseline, and response and toxicity parameters were updated based on the last day of follow-up.
Results: Twelve patients were identified, most were male (58%), and the median age was 67.5 years (CI 44-77), with 33.3% expressing IgG/Kappa and 33.3% expressing IgG/Lambda. ISS 1 was the most common staging (41.6%), followed by ISS 3 (33.3%). FISH was unavailable for most (66.6%). All patients were triple class exposed, with the majority having received lenalidomide and thalidomide as IMiDs (66.6%). The mean number of previous lines of treatment was 3 (CI 1-5), with one patient receiving treatment as a second line. The median follow-up was 4 months [CI 1-7]. Teclistamab was the most common BsAb (83.3%, n=10), followed by talquetamab (16.7%, n=2). Response was achieved in 10 patients, with 16% (2/12 pts) in stringent complete response, 33.3% (4/12 pts) in VGPR, and 25% (3/12 pts) in partial response. The median hospital stay for step-up dosing was 12 days [CI 9-56]. Cytokine release syndrome (CRS) occurred in most patients (83%, 10/12 pts), with most being grade 1 (50%, 6/12 pts). Tocilizumab was used in 41% (5/12 pts) of patients, and dipyrone was the most used antipyretic for CRS management (83%, 10/12 pts). Immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in two patients (16%), and both had dialytic renal dysfunction due to MM activity. Infections were common (66.6%, 8/12 pts), with most being grade 3-4 (66.6%, 8/12pts) and lower respiratory tract infections (37.5%, 4/12 pts). Hypogammaglobulinemia occurred in 91.6% (n=11) of patients, and only one patient had not yet received intravenous human immunoglobulin. One patient died during the in-hospital stay for the step-up dosing due to infectious complications and renal dysfunction.
Conclusions: BsAbs will be used as a mainstay treatment for most of the Brazilian patients for whom it is available. Responses and the toxicity profile seem to be in line with what was previously observed in pivotal studies, although more data and follow-up are necessary for definitive conclusions.