Adverse Event Management with Bispecifics

Adverse Event Management with Bispecifics

Infection prophylaxis for bispecific therapy differs significantly from anti-CD38 antibody approaches. Universal IVIG administration from treatment initiation, regardless of baseline IgG levels, has successfully reduced infection rates well below the 80%+ rates observed in clinical trials. This proactive strategy, combined with acyclovir and trimethoprim-sulfamethoxazole, represents a comprehensive prophylactic approach based on the recognition that infections will occur without aggressive prevention.

Cytopenias, particularly neutropenia, commonly occur with bispecific antibodies, especially with significant marrow involvement. These cytopenias reflect on-target inflammation suppressing normal hematopoiesis rather than direct myelosuppression. Liberal use of growth factors, preferably longer-acting formulations like pegfilgrastim rather than daily filgrastim, helps manage neutropenia more effectively with reduced administration burden and more stable neutrophil counts.

Additional antibiotic prophylaxis beyond trimethoprim-sulfamethoxazole, such as fluoroquinolones for enhanced pneumonia coverage, is under consideration but not yet universally implemented. The combination of IVIG, acyclovir, and trimethoprim-sulfamethoxazole represents the current standard prophylactic approach, with trimethoprim-sulfamethoxazole providing superior Pneumocystis coverage compared to alternatives. Growth factor support allows continuation of effective therapy despite developing cytopenias in the setting of active BCMA-targeted treatment.