Drug Interaction Report

GENERALLY AVOID: Coadministration of ritlecitinib with other immunosuppressive agents may potentiate the risk of infections as well as malignancies, including non-melanoma skin cancer (NMSC). Serious infections have been reported in patients who have received ritlecitinib. The most common serious infections reported with ritlecitinib included appendicitis, pneumonia, COVID-19, and sepsis. Herpes virus reactivation (e.g., herpes zoster) was also reported during clinical studies with ritlecitinib, as well as malignancies including NMSC.

MANAGEMENT: The safety and efficacy of ritlecitinib in combination with immunosuppressive agents has not been evaluated. It is recommended that the concomitant use of ritlecitinib with other Janus Kinase (JAK) inhibitors, biologic immunomodulators, cyclosporine, or other potent immunosuppressants be avoided. Some authorities recommend avoiding ritlecitinib with all systemic immunosuppressive agents. Patients receiving ritlecitinib should be closely monitored for the development of signs and symptoms of infection during and after treatment, including the possible development of tuberculosis in patients who tested negative for latent tuberculosis infection prior to initiating therapy. If a serious infection develops, ritlecitinib therapy should be interrupted until the infection is controlled.

ADJUST DOSING INTERVAL: Food may reduce the oral bioavailability of ixazomib. A food effect study found that administration of a single 4 mg dose of ixazomib with a high-fat meal decreased ixazomib peak plasma concentration (Cmax) by 69% and systemic exposure (AUC) by 28%.

MANAGEMENT: Ixazomib should be taken at least one hour before or two hours after eating. On days when both ixazomib and dexamethasone are administered, advise patients to separate dosing times, since dexamethasone should be taken with food while ixazomib should be taken on an empty stomach.