UPDATED: Lilly's failed Alzheimer's drug raises troubling questions for drug class

One of the most popular sessions at the Alzheimer's Association International Conference in Paris this week was directed by Eli Lilly's Eric Siemers, who offered a detailed look at the experiences of Alzheimer's patients followed after the failure of its high-profile, late-stage study for semagacestat. The study was halted about a year ago after researchers determined that patients taking the drug scored worse on cognitive skills compared to the placebo arm. They also demonstrated an increased rate of skin cancer.

In the follow-up, Siemers said that the semagacestat patients continued to fare badly on cognitive skills, failing to recover and return to baseline after they stopped taking the treatment, a gamma secretase inhibitor. And as the Wall Street Journal notes, that could have serious consequences for researchers at Bristol-Myers Squibb and EnVivo Pharmaceuticals, who have been studying similar types of Alzheimer's drugs.

BMS says it is closely looking to see if its drug triggers a similar effect in clinical trials. A spokesperson for EnVivo contacted FierceBiotech today to note that its Alzheimer's program is a modulator of gamma secretase rather than a direct inhibitor, which it believes will steer clear of the same safety concerns raised by semagacestat. And other experts say that the jury is still out on that class of drug.

"I don't think it's dead," Marc Cantillon, executive director of the Coalition Against Major Diseases, tells the WSJ. But anyone operating in the same development field would have to study the Lilly data closely.

- here's the WSJ story