How Encysive Botched the FDA Game

"This letter is not intended to be an all-inclusive list of deficiencies with your clinical study of an investigational drug," the FDA stated. But "failure to adequately and promptly explain the violations noted above may result in regulatory action without further notice."

For its part, Encysive has since portrayed that complaint as a "red herring" that cannot explain the FDA's treatment of Thelin. Even without the results collected by the test site in question, the company claims, Thelin would have still hit its targets and should have therefore gained regulatory approval.

Still, just two months after the test site tried -- but failed -- to satisfy the FDA with a written response, the agency issued its first "approvable" letter for Thelin instead of the full-blown blessing so many had expected. Encysive soon won an expedited review, however, and seemed poised to overcome that temporary setback.

Then, in a devastating blow, Encysive last summer fielded a second approvable letter suggesting that one major concern remained.

The FDA's own analysis, employing a formula that reportedly deviated from the SPA, left Thelin coming up short of its goals without further clinical trials. Encysive first threatened to fight the FDA, using a formal dispute-resolution process, but quietly agreed to negotiate with the agency instead.

In the months that followed, three foreign regulatory agencies approved Thelin as a safe and effective new treatment for PAH. But after that, the FDA once again blocked Thelin while blessing Gilead's competing PAH treatment -- which is still seeking its first approval elsewhere -- on the very same day.