Pharmacokinetic Interactions Between Bazedoxifene and Cholecalciferol: An Open-Label, Randomized, Crossover Study in Healthy Male Volunteers

Moon Hee Lee,1 Seok-Kyu Yoon,1 Hyungsub Kim,2 Yong-Soon Cho,3 Sungpil Han,4 Shi Hyang Lee,1 Kyun-Seop Bae,1 Jina Jung,5 Sung Hee Hong,5 Hyeong-Seok Lim1 1Department of Clinical Pharmacology and Therapeutics, Asan Medical Center, University of Ulsan, Seoul, Republic of Korea; 2Department of Emergency Medical Services, College of Health Sciences, Eulji University, Seongnam, Republic of Korea; 3Department of Pharmacology and Clinical Pharmacology, Inje University College of Medicine, Busan, Republic of Korea; 4Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; 5Hanmi Pharmaceutical Co. Ltd., Seoul, Republic of KoreaCorrespondence: Hyeong-Seok Lim, Department of Clinical Pharmacology and Therapeutics, Asan Medical Center, University of Ulsan, 88 Olympic-Ro 43-Gil, Songpa-Gu, Seoul, 05505, Republic of Korea, Tel +82-2-3010-4613, Fax +82-2-3010-4623, Email mdlhs@amc.seoul.krPurpose: The combined administration of bazedoxifene, a tissue-selective estrogen receptor modulator, and cholecalciferol can be a promising therapeutic option for postmenopausal osteoporosis patients. This study aimed to examine the pharmacokinetic interactions between these two drugs and the tolerability of their combined administration in healthy male subjects.Patients and Methods: Thirty male volunteers were randomly assigned to one of the six sequences comprised of three treatments: bazedoxifene 20 mg monotherapy, cholecalciferol 1600 IU monotherapy, and combined bazedoxifene and cholecalciferol therapy. For each treatment, a single dose of the investigational drug(s) was administered orally, and serial blood samples were collected to measure the plasma concentrations of bazedoxifene and cholecalciferol. Pharmacokinetic parameters were calculated using the non-compartmental method. The point estimate and 90% confidence interval (CI) of the geometric mean ratio (GMR) were obtained to compare the exposures of combined therapy and monotherapy. The pharmacokinetic parameters compared were the maximum plasma concentration (Cmax) and the area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast). The safety and tolerability of the combined therapy were assessed in terms of the frequency and severity of adverse events (AEs).Results: For bazedoxifene, the GMR (90% CI) of the combined therapy to monotherapy was 1.044 (0.9263– 1.1765) for Cmax and 1.1329 (1.0232– 1.2544) for AUClast. For baseline-adjusted cholecalciferol, the GMR (90% CI) of the combined therapy to monotherapy was 0.8543 (0.8005– 0.9117) for Cmax and 0.8056 (0.7445– 0.8717) for AUClast. The frequency of AEs observed was not significantly different between the combined therapy and monotherapy, and their severity was mild in all cases.Conclusion: A mild degree of pharmacokinetic interaction was observed when bazedoxifene and cholecalciferol were administered concomitantly to healthy male volunteers. This combined therapy was well tolerated at the dose levels used in the present study.Keywords: bazedoxifene, cholecalciferol, drug-drug interaction, pharmacokinetics, tolerability