Clinical assessment of mocravimod as a victim of drug–drug interactions via CYP3A4 metabolism and transporters

Mocravimod, a novel immunomodulator targeting sphingosine-1-phosphate receptor (S1PR), is being developed as a maintenance treatment for patients with acute myeloid leukemia undergoing allogeneic hematopoietic cell transplantation. Preclinical data suggested that cytochrome (CYP) 3A4 is the primary enzyme involved in mocravimod metabolism. In vitro data showed that both mocravimod and its active metabolite mocravimod-phosphate are substrates for breast cancer resistance protein (BCRP) and P-glycoprotein (P-gp) but not for organic-anion-transporting polypeptides (OATP1B1 and OATP1B3). As mocravimod is co-administered with CYP3A4 inhibitors such as azoles or cyclosporin, the potential for drug-drug interactions (DDIs) was evaluated. In addition, the effect of BCRP, P-gp, and OATP via cyclosporin co-administration was assessed. Two open-label, two-period, fixed-sequence studies were conducted in healthy subjects to evaluate the DDI potential of mocravimod and 1) itraconazole, a dual CYP3A4/P-gP inhibitor, or 2) cyclosporin, a moderate inhibitor of CYP3A4 and P-gp, BCRP, OATP1B1, and OATP1B3. Safety and tolerability were also monitored. The PK of mocravimod and mocravimod-phosphate were bioequivalent with or without co-administration of multiple doses of itraconazole and a moderate interaction is observed when co-administered with cyclosporin. The most commonly-reported treatment-emergent adverse events were bradycardia and decreased lymphocyte count, which are expected side effects for S1PR modulators.