Drug Interaction Report

ADJUST DOSING INTERVAL: The immunogenicity and efficacy of vaccines during treatment with a neonatal Fc receptor (FcRn) blocker like efgartigimod alfa or rozanolixizumab have not been evaluated. FcRn blockers can cause a transient reduction in IgG levels. In addition, efgartigimod alfa may decrease white blood cell, lymphocyte, and neutrophil counts. In general, the administration of inactivated, killed, or otherwise noninfectious vaccines to immunosuppressed patients is generally safe but may be associated with a diminished or suboptimal immunologic response due to antibody inhibition.

MANAGEMENT: The need to administer age-appropriate vaccines according to immunization guidelines should be assessed prior to initiation of a new treatment cycle with FcRn blockers. It is advisable to complete recommended vaccinations before starting FcRn blockers to avoid potential effects of the medication on immunologic response to vaccines. For efgartigimod alfa, some authorities advise that administration of inactivated, killed, or otherwise noninfectious vaccines may occur at any time during treatment. However, other authorities recommend that, for patients currently being treated, vaccination should occur at least 2 weeks after the last infusion of a treatment cycle and 4 weeks before starting the next cycle of either efgartigimod alfa or rozanolixizumab. Individual product labeling should be consulted for specific guidance.