Effect of CYP3A Inhibitors on Acalabrutinib: Co-administration with a strong CYP3A inhibitor (200 mg itraconazole once daily for 5 days) increased the Acalabrutinib Cmax by 3.9-fold and AUC by 5.1-fold in healthy subjects. Physiologically based pharmacokinetic (PBPK) simulations with Acalabrutinib and moderate CYP3A inhibitors (erythromycin, fluconazole, diltiazem) showed that co-administration increased Acalabrutinib Cmax and AUC by 2- to almost 3-fold.
Effect of CYP3A Inducers on Acalabrutinib: Co-administration with a strong CYP3A inducer (600 mg rifampin once daily for 9 days) decreased Acalabrutinib Cmax by 68% and AUC by 77% in healthy subjects.
Gastric Acid Reducing Agents: Acalabrutinib solubility decreases with increasing pH. Co-administration with an antacid (1 g calcium carbonate) decreased Acalabrutinib AUC by 53% in healthy subjects. Co-administration with a proton pump inhibitor (40 mg omeprazole for 5 days) decreased Acalabrutinib AUC by 43%.
In Vitro Studies -
Metabolic Pathways: Acalabrutinib is a weak inhibitor of CYP3A4/5, CYP2C8 and CYP2C9, but does not inhibit CYP1A2, CYP2B6, CYP2C19, and CYP2D6. The active metabolite (ACP-5862) is a weak inhibitor of CYP2C8, CYP2C9 and CYP2C19, but does not inhibit CYP1A2, CYP2B6, CYP2D6 and CYP3A4/5. Acalabrutinib is a weak inducer of CYP1A2, CYP2B6 and CYP3A4; the active metabolite (ACP-5862) weakly induces CYP3A4. Based on in vitro data and PBPK modeling, no interaction with CYP substrates is expected at clinically relevant concentrations.
Drug Transporter Systems: Acalabrutinib is a substrate of P-glycoprotein (P-gp) and BCRP. Acalabrutinib is not a substrate of renal uptake transporters OAT1, OAT3, and OCT2, or hepatic transporters OATP1B1 and OATP1B3. Acalabrutinib does not inhibit P-gp, OAT1, OAT3, OCT2, OATP1B1, and OATP1B3 at clinically relevant concentrations. Acalabrutinib may increase exposure to co-administered BCRP substrates (e.g., methotrexate) by inhibition of intestinal BCRP.