Effects of Zibotentan Alone and in Combination with Dapagliflozin on Fluid Retention in Patients with CKD

Key Points Increasing doses of the endothelin receptor antagonist zibotentan and lower eGFR were associated with a higher risk of fluid retention. The higher risk of fluid retention could be attenuated by the combination of zibotentan with the sodium-glucose cotransporter 2 inhibitor dapagliflozin. Background Endothelin receptor antagonists (ERAs) reduce albuminuria but are limited by fluid retention risk, particularly in patients with CKD. Combining ERAs with sodium-glucose cotransporter 2 (SGLT2) inhibitors, which have diuretic effects, offers a promising strategy to mitigate fluid retention. In this post hoc analysis of the Zibotentan and Dapagliflozin for the Treatment of CKD (ZENITH-CKD) trial, we assessed fluid dynamics in patients with CKD treated with the ERA zibotentan alone and in combination with the SGLT2 inhibitor dapagliflozin. Methods In the ZENITH-CKD trial, 508 patients with CKD (eGFR ≥20 ml/min per 1.73 m 2 and a urinary albumin-creatinine ratio of 150–5000 mg/g) were randomized to treatment with placebo, dapagliflozin 10 mg plus placebo, zibotentan (0.25, 1.5, or 5 mg) plus dapagliflozin 10 mg, and zibotentan 5 mg plus placebo. We evaluated correlations between changes in fluid retention markers and bioimpedance-measured extracellular fluid in response to zibotentan treatment. We used Cox proportional hazards regression to assess the association between zibotentan/dapagliflozin treatment, baseline characteristics, and fluid retention and the relationship between zibotentan plasma exposure and fluid retention. Results After 3 weeks of treatment with zibotentan 0.25, 1.5, or 5 mg plus dapagliflozin 10 mg, changes in body weight ( β =0.36 [95% confidence interval (CI), 0.26 to 0.45]) per kg, B-type natriuretic peptide ( β =0.38 [95% CI, 0.22 to 0.54]) per doubling, and hemoglobin ( β =−0.29 [95% CI, −0.48 to −0.10]) per g/dl were independently associated with changes in extracellular fluid. Higher doses of zibotentan were associated with significantly higher risk of fluid retention compared with dapagliflozin alone (zibotentan 5 mg hazard ratio (HR) 8.50 [95% CI, 3.40 to 21.30]). The HR attenuated when zibotentan was combined with dapagliflozin (zibotentan/dapagliflozin 5/10 mg HR 3.09 [95% CI, 1.08 to 8.80], zibotentan/dapagliflozin 1.5/10 mg 2.70 [95% CI, 1.44 to 5.07], and zibotentan/dapagliflozin 0.25/10 mg HR 1.21 [95% CI, 0.50 to 2.91]). The risk of fluid retention was higher with higher zibotentan exposure and lower eGFR. Conclusions High doses of zibotentan were associated with a higher risk of fluid retention, which was attenuated with lower doses and the addition of dapagliflozin. Clinical Trial registry name and registration number: ZENITH-CKD Trial, NCT04724837.