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    Treatment of Relapsed/Refractory Myeloma (excluding T-cell redirection therapy)

    Category: Treatment of Relapsed/Refractory Myeloma (excluding T-cell redirection therapy)

    REAL-WORLD ANALYSIS OF TECLISTAMAB TREATMENT FOR RELAPSED REFRACTORY MULTIPLE MYELOMA IN THREE BELGIAN ACADEMIC HOSPITALS

    (PA-512) Real-world Analysis of Teclistamab Treatment for Relapsed Refractory Multiple Myeloma in Three Belgian Academic Hospitals

    Wednesday, September 17, 2025

    Introduction:      T-cell redirection therapies, including bispecific antibodies and CAR-T cells, are transforming the treatment landscape of relapsed/refractory multiple myeloma (RRMM), offering remarkable and durable responses. Teclistamab (Tec) is the first BCMA × CD3 bispecific antibody approved in this setting, based on the MajesTEC-1 phase 1/2 trial. Recently introduced in Belgium, we report on our real-world experience.



    Methods:   We conducted a retrospective analysis to assess the efficacy and tolerability of Tec in 36 patients treated at three Belgian academic centers, comparing real-world outcomes with those from clinical trials. Tec was administered weekly at 1.5 mg/kg after two step-up doses (0.06 and 0.3 mg/kg), following standard guidelines. High-risk (HR) cytogenetics were defined by t(4;14), t(14;16), and/or del(17p). Responses were evaluated according to IMWG 2016 criteria, with survival analyses performed using the Kaplan-Meier method. Adverse events (AEs) were graded per CTCAE v5.0, and CRS/ICANS were graded per ASTCT criteria.



    Results:   

    From December 2022 to January 2025, 53 patients received at least one dose of Tec. The median age was 68.5 years (range, 52–83), with 45% female patients. HR cytogenetics were observed in one-third, ISS stage III in 28%, circulating plasma cells in 8%, and extramedullary disease (EMD) in 28%. ECOG was 3-4 in 21% of patients.
    Patients had received a median of 4 prior lines of therapy (LOT) (range, 2–11); 55% had undergone at least one autologous stem cell transplantation. All were triple-class exposed; 50% were penta-exposed, and 34% were penta-refractory. All patients were refractory to their last LOT, with no prior exposure to BCMA-directed therapies.


    At a median follow-up of 10 months (range: 0.25–29.5), the ORR was 85%, with 79% achieving at least a VGPR. The median time to first and best response was 35 (range, 6-126) and 97 days (range, 12-363), respectively. Median progression-free survival (PFS) was over v2 years, but less than 6 months for patients with EMD. At the time of analysis, 15 patients (28%) had died, predominantly due to progressive disease. Median overall survival (OS) was not reached.

    All patients experienced at least one AE, with grade ≥3 events in 77%. CRS occurred in 50% of them with only one grade ≥3, all during step-up dosing. ICANS was observed in 7 patients (15%) with grade 3 in 1 case. Cytopenias were common: anemia (89%/39% grade ≥3), neutropenia (68%/43%), thrombocytopenia (60%/26%), and lymphopenia (87%/70%). Infectious episodes occurred in 32 patients (60%), with grade ≥3 infections in 37%. Immunoglobulin substitution was administered to 89% of patients.




    Conclusions:   

    Our real-world data demonstrate that teclistamab achieves comparable efficacy and safety outcomes to those reported in pivotal trials and other real-world studies. The toxicity profile was consistent with previous reports. These findings also underscore the urgent need for novel strategies to improve outcomes in patients with EMD.