Drug Interaction Report

GENERALLY AVOID: The administration of live, attenuated virus or bacterial vaccines during immunosuppressant therapy may be associated with a risk of disseminated infection due to enhanced replication of vaccine virus or bacteria in the presence of diminished immune competence. Additionally, the safety of immunization with live or live-attenuated vaccines during or following the administration of ublituximab has not been studied. Ublituximab use causes a depletion of B-cells and can be expected to similarly increase the risk of a decreased or suboptimal immunologic vaccine response if immunization occurs before B-cells counts have recovered. Pharmacodynamic data has shown the median time to B-cell repletion following discontinuation of ublituximab is 70.3 weeks (range 0.1 to 75.1 weeks). For infants of mothers who have been exposed to ublituximab during pregnancy, there is a potential for depletion of B cells in their infants.

MANAGEMENT: Live virus or bacterial vaccines should not be administered to patients during therapy or after discontinuing ublituximab therapy until B-cell repletion occurs. Immunization status should be assessed prior to initiating ublituximab and recommended immunizations with live or attenuated live vaccines should be completed at least 4 weeks prior to ublituximab initiation. For infants of mothers exposed to ublituximab during pregnancy, live or live-attenuated vaccines should be delayed until B-cell levels have recovered; therefore, measuring CD19 positive B-cell levels prior to vaccination in these infants is recommended.