How Encysive Botched the FDA Game

When Encysive(ENCY Quote) recently struck out in its third attempt to win U.S. approval of its most promising drug, the company immediately cried foul.

In a nutshell, Encysive claimed that the Food and Drug Administration had changed the rules of the game in the final inning and, in a seemingly desperate move, the company vowed to seek a formal review that could raise its final score.

However, based on a play-by-play analysis of events, Encysive hasn't always stuck close to the rules itself.

Go back to the beginning, when Encysive first announced results of its pivotal trial (popularly known as Stride) of Thelin, a treatment of pulmonary arterial hypertension, in 2002. Notably, Encysive admitted at the time that its preferred 100-milligram dose of Thelin had failed to meet its chief goal of significantly raising peak oxygen uptake, or VO2, among PAH sufferers.

Rather than dwelling on this setback, Encysive chose to focus on a secondary endpoint -- which the drug had met -- in future trials instead.

"While percent predicted peak VO2 was the primary endpoint in the Stride trial, the six-minute-walk distance has been the regulatory standard," Encysive stated as it geared up for a new study the following year. Thus, "the soon-to-initiate second pivotal trial, Stride II, will utilize six-minute-walk distance as the primary endpoint and will not include VO2 testing."