FDA Requests Additional Thelin Study In “Approvable” Letter
This article was originally published in The Pink Sheet Daily
Executive Summary
Encysive hopes to answer the agency’s questions without further clinical work, however.
|
FDA's "approvable" letter for Encysive's pulmonary arterial hypertension drug Thelin (sitaxsentan) is requesting additional clinical trial work, the firm announced. The company hopes to respond to FDA's questions without more clinical work. CEO Bruce Given noted during a March 27 investor call that the original trial was large, with 1,500 original subjects, from which 899 PAH patients were drawn. The company is in the midst of another long-term safety study, called STRIDE 3, which could provide pertinent data on safety and tolerability. The company said it does not know when it will submit its response to FDA, but will meet with the agency in a matter of days about it. Given declined to describe why the agency did not approve the drug outright, saying that could interfere with negotiations with the agency. Despite the setback, the company does not plan to alter its sales strategy. Encysive recently completed hiring its sales force for Thelin, but now says that the reps will benefit from the extra time to prepare for launch. "They'll continue to learn their territories, familiarize themselves with the disease state and the needs of their customers and they'll continue to improve their ability to be in a position that when we're approved they'll be ready to go," Given said. While there are several PAH products on the market, Encysive has said that the main competitor for Thelin will be Actelion's Tracleer (bosentan), which is also an endothelin receptor antagonist. The company's STRIDE-2 trial compared Thelin to Tracleer. In the 226-patient international trial, 100 mg Thelin increased a six-minute walk test by 31.4 meters over placebo. In an open-label arm of the study, Tracleer improved patient performance in the walk test by 29.5 meters over placebo, Encysive reported. Encysive's intent is to distinguish Thelin from Tracleer in terms of safety, which the company maintains is of more concern than efficacy for the category. In the STRIDE-2 trial, Thelin was associated with a 3% rate of liver abnormalities compared to 11% for Tracleer; placebo had a 6% rate. -Todd Leeuwenburgh |