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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)

    Analysis of infectious risk in the multiple myeloma patients treated with bispecific antibodies. Real world experience

    (PA-470) Analysis of Infectious Risk in the Multiple Myeloma Patients Treated with Bispecific Antibodies. Real World experience

    Friday, September 19, 2025

    Introduction:      The addition of bispecific antibodies (BsAbs) to the treatment of multiple myeloma (MM) has significantly improved its prognosis. However, an increase in infectious complications due to post-treatment immunodeficiency is also observed. The risk of infection also varies depending on the target of each bispecific antibody, suggesting individualized infection prevention strategies.
    The aim is to analyze the infectious risk of patients treated with BsAbs according to the target, to evaluate the differences in the degree of hypogammaglobulinemia (HG) and the immunoglobulin replacement in our series


    Methods:   A retrospective study was performed including patients treated with BsAbs in our center between July 2021 and April 2025. Three groups were considered according to the target received: 1) antiBCMA (teclistamab, elranatamab or linvoseltamab), 2) antiGPRc5d (talquetamab) and 3) antiFcRH5 (cevostamab). SPSS was used for the statistical analysis, the comparison of means was performed with Fisher's exact test due to the small sample size.

    Results:   A total of 28 patients were included of which 13 received antiBCMA, 13 antiGPRC5d and 2 antiFcRH. 22 patients (76%) were treated within the trial and, of these, 14 received AcBs in combination with other drugs. 41.3% of patients received at least 3 prior lines. 50.6% of patients achieved Complete Remission (CR) and 61.7% Partial Response (PR) or better and 5 patients died in the setting of progression (Table 1).  Regarding immune status, 52% had HG prior to treatment initiation. Patients with antiBCMA had lower IgG levels (not significant), the highest degree of HG was observed between the 2nd and 3rd treatment cycle. 67% of patients received IVIG replacement therapy. Patients with antiBCMA required IVIG more frequently (c 2/3m), although significance was not reached.  With respect to infectious risk, 64% of the patients presented some infectious event and 6 patients (21.4%) with 3 or more events. A total of 48% had severe infection, which required hospitalization. 78.6% of patients treated with antiBCMA presented infection vs 46.2% in the GPRC5d group (p 0.097). Serious infectious events were also more frequent with antiBCMA (50% vs. 30.8%, p 0.428).

    The frequency of respiratory infections was higher with antiBCMA (53.8 vs. 15.4, p 0.097); however, no differences were found between the two groups in the frequency or severity of pneumonia, diarrhea, UTI or other infections (Table 2). Only one patient discontinued treatment due to infectious cause in the antiBCMA group.

    Conclusions:   

    The results of our series reproduce the infectious toxicity data reported in published pivotal trials.
    Sixty-seven percent of the patients in our series received IVIG prophylaxis; patients with antiBCMA required replacement more frequently than those with talquetamab.