Bispecific antibodies (BsAbs), or antibodies that can bind to 2 antigens or 2 epitopes on the same antigen, are being used more often in heavily pretreated patients with relapsed or refractory (RR) multiple myeloma (MM). The BsAbs’ unique property allows them to bind to both a tumor cell and a T cell, which helps the T cell bind to the tumor cell. Though their use has been promising in early studies, a new study published in Blood Advances suggests they are associated with increased infection rates.
In the study, investigators studied the results of 11 trials comprising 1185 patients with RRMM undergoing BsAbs treatment for the first time. Most patients (71.6%) were treated with a special type of BsAbs, called a B cell maturation antigen (BCMA) BsAbs. Although the median follow-up was short (6.1 months), the results were staggering.
“Half of the patients treated with bispecific antibodies developed infection and a quarter of patients developed grade III/IV infections,” the study reported.
More specifically, the adverse events of interest were “all grade neutropenia in 38.6% (n=441/1143), all grade infections in 50% (n=542/1083), all grade cytokine release syndrome (CRS) in 59.6% (n=706/1185), grade III/IV neutropenia in 34.8% (n=372/1068), grade III/IV infections in 24.5% (n=272/1110), grade III/IV pneumonia in 10% (n=52.4/506), and grade III/IV coronavirus 2019 (COVID-19) in 11.4% (n45.4/395).”
Of interest, BCMA BsAbs were associated with higher grade III/IV neutropenia (39.2% vs 25.3%; P=.01) and higher grade III/IV infections (30% vs 11.9%; P=.01) than non-BCMA BsAbs, although the specific mechanism for the difference was not reported.
The investigators also noted that of 110 deaths reported in the 11 trials, 28 (25.5%) were secondary to infection. The authors recommend caution and advocate for developing infection-mitigation strategies when using BsAbs to treat RRMM.
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