A case of hepatitis B virus reactivation after elranatamab therapy in a patient with multiple myeloma

Although elranatamab-specific information on HBV reactivation is limited, this case highlights a clinically relevant risk. Clinicians should remain vigilant for reactivation in patients receiving elranatamab, particularly those with resolved infection. Regular HBV DNA monitoring and prompt initiation of nucleos(t)ide analog therapy are essential to prevent severe complications, including fulminant hepatitis. Additionally, in the context of profound hypogammaglobulinemia during or after elranatamab, intravenous immunoglobulin may be considered to mitigate infection risk.