Encouraging findings for sitaxsentan from STRIDE trial

Encysive Pharmaceuticals (formerly Texas Biotechnology Corp) has released positive final results from the Sitaxsentan To Relieve ImpaireD Exercise in Pulmonary Arterial Hypertension (STRIDE) trial. The Phase IIb/III study, randomized, double-blind and placebo-controlled in design, evaluated the safety and efficacy of 100mg or 300mg sitaxsentan in 178 patients with New York Heart Association Class II, III and IV PAH. The subjects received the agent once a day for 12 weeks; patients successfully completing this part were eligible to enroll in a double-blind extension trial to obtain long-term safety data.

In the extension study, patients initially randomized to receive 100mg or 300mg remained on those doses, with those initially receiving placebo re-randomized to either of the two doses of sitaxsentan.

Data presented at the American Thoracic Society's International Conference in Seattle demonstrated that 100mg and 300mg sitaxsentan produced equivalent and statistically-significant improvements in six-minute walk distance (p<0.01 versus placebo), as well as an improvement in cardio-pulmonary parameters. Furthermore, the 300mg dose produced an increase in percent predicted peak oxygen uptake (VO2; a measure of metabolic and cardiorespiratory functional capacity), the primary endpoint in the trial. Sitaxsentan exhibited a good safety profile; no patients in the 100mg group discontinued as a result of adverse effects, compared with five from the placebo group and seven from the 300mg arm.