Gilead Sciences, Inc. (Nasdaq: GILD) announced that DAR-311 (DORADO), a Phase III clinical trial evaluating the company's endothelin receptor antagonist (ERA) darusentan for the treatment of resistant hypertension, met its co-primary efficacy endpoints of change from baseline to week 14 in trough sitting systolic blood pressure (SBP) and trough sitting diastolic blood pressure (DBP). DORADO is one of two ongoing Phase III clinical trials evaluating the safety, efficacy and tolerability of darusentan as an add-on treatment for resistant hypertension, defined as the failure to achieve goal blood pressure while adhering to full doses of an appropriate three-drug regimen that includes a diuretic. The second study, DAR-312 (DORADO-AC), is approximately 90 percent enrolled and is expected to be completed by the end of 2009.

In the DAR-311 study, reductions in mean trough sitting SBP from baseline of 8.6 mmHg, 16.5 mmHg, 18.1 mmHg and 18.1 mmHg were observed for the placebo, darusentan 50 mg, 100 mg and 300 mg groups, respectively, after 14 weeks of treatment. Reductions in mean trough sitting DBP from baseline of 5.3 mmHg, 10.1 mmHg, 9.9 mmHg and 10.7 mmHg were observed for the placebo, darusentan 50 mg, 100 mg and 300 mg groups, respectively, after 14 weeks of treatment. These results were statistically significant for all darusentan groups (p