A clinical trial investigating the use of Gilead Sciences' endothelin receptor antagonist darusentan as therapy for resistant hypertension found that the treatment missed its co-primary efficacy endpoints of change from baseline to week 14 in trough sitting systolic blood pressure (BP) and diastolic BP when compared to a placebo.
According to the pharmaceutical company, darusentan is an add-on oral therapy that is designed to block the endothelin type-A receptor, which activated by endothelin-1 produces vasoconstriction and cell proliferation.
In the double-blind placebo study of 849 patients, participants were split into three randomized groups who received a dosage of darusentan, a comparator guanfacine (Tenex; Shire Pharmaceuticals) or a placebo. Gilead said the study was meant to detect an 8 mm Hg improvement in systolic BP and diastolic BP between patients who received darusentan and the placebo.
While results showed darusentan fared better in sitting systolic BP and diastolic BP rates compared to guanfacine after 14 weeks, according to the company, reductions in mean trough sitting systolic BP and diastolic BP rates were not statistically different between darusentan and the placebo.
According to the Forest City, Calif.-based company, this was the second Phase III clinical trial positioned to evaluate the drug.
“We think it would be challenging to define an expedient path forward. We would likely be required to initiate another Phase III study and would rather allocate our resources to other promising research and development opportunities in our pipeline,” said Norbert Bischofberger, PhD, Gilead's executive vice president of research and development and chief scientific officer.