Zibotentan Can Be Co-administered with Contraceptives Containing Ethinyl Estradiol and Levonorgestrel: A Pharmacokinetic Drug-Drug Interaction Study.

The endothelin A receptor antagonist zibotentan, combined with the sodium-glucose co-transporter-2 inhibitor dapagliflozin, is being investigated for the treatment of chronic kidney disease with high proteinuria. To allow women of childbearing potential access to this treatment, highly effective contraception is required and drug interactions compromising contraception reliability must be avoided. This study investigated the risk of pharmacokinetic (PK) interaction between zibotentan and the contraceptives ethinyl estradiol and levonorgestrel. A single-sequence, within-participant comparison study was conducted in 24 healthy women of non-childbearing potential, comparing the PK of ethinyl estradiol/levonorgestrel alone and with zibotentan. Single oral doses of 0.06 mg ethinyl estradiol/0.3 mg levonorgestrel were administered on Days 1 and 15; zibotentan 10 mg was dosed orally, once-daily through Days 6-19. PK profiles were determined and ethinyl estradiol/levonorgestrel PK was compared between Day 1 and 15 based on geometric least-squares mean ratios of PK parameters, including maximum observed concentration (Cmax) and area under the plasma concentration-time curve from zero to infinity (AUCinf). Co-administration with zibotentan did not affect ethinyl estradiol PK (geometric mean ratio [90% confidence interval] Cmax 1.05 [0.99-1.11], AUCinf 1.00 [0.96-1.05]), while a weak interaction (increased exposure) was observed for levonorgestrel (Cmax 1.12 [1.02-1.23], AUCinf 1.30 [1.21-1.39]), which was regarded as without clinical relevance. Plasma exposure of ethinyl estradiol/levonorgestrel was not reduced by multiple-dose zibotentan. In conclusion, contraception containing ethinyl estradiol/levonorgestrel is regarded possible under zibotentan-containing treatments. This expands choices for women of childbearing potential, supporting diversity in the ZENITH High Proteinuria trial.

A comprehensive analysis of liver safety across zibotentan oncology trials: knowledge of the past offers new perspectives on the present.

BACKGROUND: Endothelin receptor antagonists (ERAs) are associated with liver injury. We used data from previous oncology clinical trials to determine the liver safety profile of zibotentan, which is currently in clinical development (in combination with dapagliflozin) for chronic kidney disease and cirrhosis. RESEARCH DESIGN AND METHODS: Six global, double-blinded, phase 2b and 3 clinical trials from the zibotentan oncology development program were pooled to analyze liver safety. Descriptive statistics, proportion of liver-related adverse events, liver biochemistry parameter elevation, and shifts from baseline were analyzed, with individual case assessment. RESULTS: A total of 1532 patients received zibotentan for 285 days (mean), and 1486 patients received placebo for 320 days (mean). The frequency of any hepatic disorder preferred term was similar across zibotentan monotherapy (22/947 patients, 2.3%) and placebo monotherapy arms (30/881 patients, 3.4%). A total of 4 (0.4%) patients receiving zibotentan monotherapy experienced ALT elevations >5× ULN versus 8 (0.9%) receiving placebo. Of the seven patients receiving zibotentan who met criteria for potential Hy's Law, there were no cases of drug-induced liver injury. CONCLUSIONS: We found no evidence of zibotentan-related liver biochemistry changes among cancer-treated patients, suggesting that hepatotoxicity of ERAs is molecule-dependent, and allowing exploration of zibotentan for new indications.

Pharmacokinetics and Tolerability of Zibotentan in Patients with Concurrent Moderate Renal and Moderate Hepatic Impairment.

BACKGROUND AND OBJECTIVE: Zibotentan, a selective endothelin A receptor antagonist, is in development for chronic liver and kidney disease. The pharmacokinetics (PK) of zibotentan were previously investigated in patients with either renal impairment or hepatic impairment, but the impact of both pathologies on PK was not evaluated. This study evaluated the PK and tolerability of a single oral dose of zibotentan in participants with concurrent moderate renal impairment and moderate hepatic impairment versus control participants. METHODS: Twelve participants with moderate renal and hepatic impairment and 11 healthy matched control participants with no clinically significant liver or kidney disease were enrolled in an open-label, parallel-group study design. After administration of a single oral dose of zibotentan 5 mg, blood and urine sampling was performed. Pharmacokinetic parameters were determined for each of the two cohorts and compared. Comparisons between the cohorts were based on the geometric least squares mean ratio for the primary endpoints, which were area under the plasma concentration-time curve (AUC) from time zero to infinity (AUC∞) and from time zero to the time of the last measurable concentration (AUClast), and maximum plasma drug concentration (Cmax) on Day 1 through 120 h post-dose. Secondary endpoints included apparent total body clearance (CL/F) on Day 1 through 120 h post-dose. Safety endpoints were assessed up to discharge. RESULTS: In total, 11 participants with concurrent moderate renal and hepatic impairment, and 11 controls, completed the study. Zibotentan was generally well tolerated, and no new clinically significant safety findings were observed. Total exposure (AUC∞ and AUClast) was approximately 2.10-fold higher in participants with concurrent moderate renal and hepatic impairment versus controls, while Cmax and total nonrenal body clearance were similar among all groups. A regression-based post hoc analysis, comparing exposure and CL/F in patients with concurrent impairment to patients with either renal or hepatic impairment alone, showed that CL/F with concurrent impairment was approximately half of that in controls and was positively correlated with reduction of renal function. Inclusion of the data on concurrent moderate renal and hepatic impairment in the regression analysis led to a narrower confidence interval for the predicted mean CL/F in participants with moderate hepatic impairment. CONCLUSION: The presented findings advance the understanding of the PK of zibotentan in both renal impairment and hepatic impairment, with and without overlapping pathologies, and will thus increase the confidence of dose selection in future studies, particularly in vulnerable patient populations with concurrent renal and hepatic impairment. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05112419.