Infection Prophylaxis in Myeloma Patients Receiving Bispecific Antibodies Therapies

Authored by Samer Al Hadidi, published on 2026-09-04 20:24:53.0

The algorithm is broadly aligned with current supportive-care practice for relapsed/refractory multiple myeloma patients receiving BCMA- and GPRC5D-directed bispecific antibodies, which are associated with high rates of infections, hypogammaglobulinemia, and cytopenias. Routine HSV/VZV prophylaxis, PJP prophylaxis, immunoglobulin replacement for significant/recurrent infections with hypogammaglobulinemia, and risk-adapted antibacterial/antifungal strategies are supported by contemporary expert guidance and emerging trial safety data. The main area of variability is the threshold/strategy for IVIG (prophylactic for all vs infection/IgG-driven) and the details of antibacterial prophylaxis during early cycles or neutropenia, which are not fully standardized across guidelines.

  1. Infection prophylaxis for BsAb recipients
    Important to be part of initial planning and treatment Bispecific antibody therapy in multiple myeloma has a high infection burden and commonly causes hypogammaglobulinemia and cytopenias, supporting proactive, up-front infection prevention planning. Contemporary expert consensus and major myeloma guidance outline baseline screening, vaccination, and antimicrobial/IVIG prophylaxis considerations for BsAb recipients.
    • Throughout treatment
      • Antiviral (VZV/HSV)
        Until 3-6 months post-BsAb
        • Pneumocystis (PJP)
          TMP-SMX until CD4 greater than 200 (or while on treatment)
          • CMV and hepatitis B
            Entecavir if HBV risk
            • Hypogammaglobulinemia
              IVIG until IgG greater than 400 (preferably regardless of level)
    • During neutropenia
      • Antibacterial
        Highest risk early cycles Consider G-CSF support
        • Antifungal
          Overall risk is low (limit use to prolonged neutropenia)
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