Luc Dirix1, Helen Swaisland2, Henk M W Verheul3, Sylvie Rottey4, Karin Leunen5, Guy Jerusalem6, Christian Rolfo7, Dorte Nielsen8, L Rhoda Molife9, Rebecca Kristeleit10, Judith de Vos-Geelen11, Morten Mau-Sørensen12, Patricia Soetekouw11, Carla van Herpen13, Anitra Fielding2, Karen So14, Wendy Bannister15, Ruth Plummer16. 1. Medical Oncology, Sint-Augustinus-University of Antwerp, Antwerp, Belgium. Electronic address: luc.dirix@telenet.be. 2. AstraZeneca, Macclesfield, United Kingdom. 3. Department of Medical Oncology, VU Medisch Centrum, Amsterdam, the Netherlands. 4. Department of Medical Oncology, Ghent University Hospital and Heymans Institute of Pharmacology, Ghent, Belgium. 5. Universitair Ziekenhuizen Leuven, Leuven, Belgium. 6. CHU Sart-Tilman and Liege University, Liege, Belgium. 7. Oncology Department, Universitair Ziekenhuis Antwerpen, Antwerp, Belgium. 8. Department of Oncology, Herlev and Gentofte Hospital, Herlev, Denmark. 9. The Royal Marsden and Institute of Cancer Research, Sutton, United Kingdom. 10. University College London Cancer Institute, London, United Kingdom. 11. Division of Medical Oncology, Maastricht University Medical Center, Maastricht, the Netherlands. 12. Department of Oncology, University Hospital, Rigshospitalet, Copenhagen, Denmark. 13. Radboud University Medical Center, Nijmegen, the Netherlands. 14. AstraZeneca, Cambridge, United Kingdom. 15. PHASTAR, London, United Kingdom. 16. Northern Centre for Cancer Care, Newcastle upon Tyne, United Kingdom.
Abstract
PURPOSE: The metabolism of olaparib, a potent inhibitor of poly(ADP-ribose) polymerase (PARP) with demonstrated efficacy in patients with BRCA-mutated ovarian cancer, is mediated by cytochrome P450 (CYP) enzymes (predominantly CYP3A4/5). We assessed the potential of a CYP3A4 inhibitor (itraconazole) and inducer (rifampin) to alter the pharmacokinetic (PK) profile of olaparib following single oral tablet doses. METHODS: Two Phase I, open-label, non-randomized trials were conducted in patients with advanced solid tumors. In Study 7, patients received olaparib alone and co-administered with itraconazole; in Study 8, a separate group of patients received olaparib alone and co-administered with rifampin. No interaction between itraconazole and olaparib was concluded if two-sided 90% CIs for the treatment ratios of AUC and/or AUC0-t and Cmax fell within the bioequivalence range of 0.80-1.25. An interaction between rifampin and olaparib was concluded if the lower limit of the 90% CI for the treatment ratios was <0.5 (ie, >50% decrease in olaparib AUC or Cmax in the presence of rifampin compared with olaparib alone). FINDINGS: In Study 7 (N = 59; 17 male, 42 female), 56 and 53 patients were evaluable for PK analysis following treatment with olaparib alone and olaparib plus itraconazole, respectively; in Study 8 (N = 22; 4 male, 18 female), all patients were evaluable. Co-administration of olaparib with itraconazole resulted in a statistically significant increase in the relative bioavailability of olaparib: Cmax treatment ratio, 1.42 (90% CI, 1.33-1.52); mean AUC treatment ratio, 2.70 (90% CI, 2.44-2.97). Mean CL/F and Vz/F were reduced (8.16 vs 3.05 L/h and 192 vs 75.1 L), although mean t½ was unchanged (15.0 vs 15.6 hours). Co-administration of olaparib with rifampin resulted in a statistically significant decrease in the relative bioavailability of olaparib: Cmax treatment ratio, 0.29 (90% CI, 0.24-0.33); mean AUC treatment ratio, 0.13 (90% CI, 0.11-0.16). CL/F and Vz/F were increased when olaparib and rifampin were co-administered (6.36 vs 48.3 L/h and 112 vs 1076 L); however, mean t½ was unchanged (13.0 vs 15.8 hours). Safety data for olaparib following tablet dosing were consistent with the known safety profile. IMPLICATIONS: Exposure to olaparib was significantly increased when co-administered with the potent CYP3A4 inhibitor itraconazole, and significantly decreased when co-administered with the potent CYP3A4 inducer rifampin, compared with olaparib alone. Potent CYP3A4 enzyme inhibitors and inducers should be avoided during olaparib treatment. ClinicalTrials.gov identifiers: NCT01900028 (Study 7) and NCT01929603 (Study 8).
PURPOSE: The metabolism of olaparib, a potent inhibitor of poly(ADP-ribose) polymerase (PARP) with demonstrated efficacy in patients with BRCA-mutated ovarian cancer, is mediated by cytochrome P450 (CYP) enzymes (predominantly CYP3A4/5). We assessed the potential of a CYP3A4 inhibitor (itraconazole) and inducer (rifampin) to alter the pharmacokinetic (PK) profile of olaparib following single oral tablet doses. METHODS: Two Phase I, open-label, non-randomized trials were conducted in patients with advanced solid tumors. In Study 7, patients received olaparib alone and co-administered with itraconazole; in Study 8, a separate group of patients received olaparib alone and co-administered with rifampin. No interaction between itraconazole and olaparib was concluded if two-sided 90% CIs for the treatment ratios of AUC and/or AUC0-t and Cmax fell within the bioequivalence range of 0.80-1.25. An interaction between rifampin and olaparib was concluded if the lower limit of the 90% CI for the treatment ratios was <0.5 (ie, >50% decrease in olaparib AUC or Cmax in the presence of rifampin compared with olaparib alone). FINDINGS: In Study 7 (N = 59; 17 male, 42 female), 56 and 53 patients were evaluable for PK analysis following treatment with olaparib alone and olaparib plus itraconazole, respectively; in Study 8 (N = 22; 4 male, 18 female), all patients were evaluable. Co-administration of olaparib with itraconazole resulted in a statistically significant increase in the relative bioavailability of olaparib: Cmax treatment ratio, 1.42 (90% CI, 1.33-1.52); mean AUC treatment ratio, 2.70 (90% CI, 2.44-2.97). Mean CL/F and Vz/F were reduced (8.16 vs 3.05 L/h and 192 vs 75.1 L), although mean t½ was unchanged (15.0 vs 15.6 hours). Co-administration of olaparib with rifampin resulted in a statistically significant decrease in the relative bioavailability of olaparib: Cmax treatment ratio, 0.29 (90% CI, 0.24-0.33); mean AUC treatment ratio, 0.13 (90% CI, 0.11-0.16). CL/F and Vz/F were increased when olaparib and rifampin were co-administered (6.36 vs 48.3 L/h and 112 vs 1076 L); however, mean t½ was unchanged (13.0 vs 15.8 hours). Safety data for olaparib following tablet dosing were consistent with the known safety profile. IMPLICATIONS: Exposure to olaparib was significantly increased when co-administered with the potent CYP3A4 inhibitor itraconazole, and significantly decreased when co-administered with the potent CYP3A4 inducer rifampin, compared with olaparib alone. Potent CYP3A4 enzyme inhibitors and inducers should be avoided during olaparib treatment. ClinicalTrials.gov identifiers: NCT01900028 (Study 7) and NCT01929603 (Study 8).
Authors: Christian Rolfo; Nicolas Isambert; Antoine Italiano; L Rhoda Molife; Jan H M Schellens; Jean-Yves Blay; Thomas Decaens; Rebecca Kristeleit; Olivier Rosmorduc; Regina Demlova; Myung-Ah Lee; Alain Ravaud; Katerina Kopeckova; Maria Learoyd; Wendy Bannister; Gershon Locker; Judith de Vos-Geelen Journal: Br J Clin Pharmacol Date: 2020-04-05 Impact factor: 4.335