Aryx shares in meltdown after comparison trial disappoints

Shares of Aryx Therapeutics were pummeled in premarket trading after the company announced that its trial comparing the experimental blood clotting drug tecarfarin failed to demonstrate superiority over warfarin, a standard treatment.

The data was positive for both treatments. Tecarfarin stayed in its target therapeutic range 74 percent of the time while warfarin hit a nearly identical 73.2 percent mark. That's not what investors were looking for, though. Shares plunged 51 percent. Aryx CEO Paul Goddard said he plans to continue partnership talks after the company fully analyzes the numbers.

Researchers say that tecarfarin performed much as it had in earlier trials. The nasty surprise in the data appeared in the warfarin arm.

"Warfarin patients did much better than we had reason to expect and as a result we did not achieve statistical significance," said Goddard. "This appears to be due in no small part to the central dose control center that we established for the trial, and to the ability of the center to anticipate the potential daily pitfalls of warfarin use."

- here's Aryx's release
- read the story from Dow Jones