Amicus-GlaxoSmithkline Drug for Fabry Disease Fails Clinical Trial

Xconomy New York — 

Amicus Therapeutics (NASDAQ: FOLD) waited until late afternoon on Wednesday to announce that its lead drug, a treatment for rare Fabry disease, failed to meet its end point in a pivotal Phase III clinical trial, but that didn’t lessen the investor freakout. The Cranbury, NJ-based company’s stock dropped 50.65 percent in after hours trading, to $2.85.

The failure was a significant setback for the drug and the company, since a similar Amicus drug for Gaucher disease already failed in clinical trials in 2009. Britain’s GlaxoSmithkline (NYSE: GSK) is jointly developing the drug with Amicus and has to be pretty unhappy as well, given that in July the British pharma giant invested another $18.6 million in the Fabry program, after its initial upfront investment of $60 million in 2010. Glaxo holds a 19.9 percent stake in Amicus.

Fabry is a rare inherited disease that affects about 5,000 to 10,000 people worldwide. It is caused by a genetic flaw that stops a certain enzyme from breaking down a fatty substance called globotriaosylceramide (GL-3), that can build up in blood vessels and cause severe kidney damage. The Amicus drug, oral migalastat HCl (Amigal), is meant to prompt the faulty enzyme to clear the fat. In the trial, 13 out of 32 Fabry patients with severe disease who were randomized to the Amicus drug met the trial’s pre-established endpoint of a 50 percent or greater reduction in GL-3 in their kidneys after six months, compared with 9 out of 32 patients who met the 50 percent mark on placebo. The difference did not achieve statistical significance, marking a clear failure.

As Xconomy wrote last January, Amicus was founded in 2002 to commercialize a “pharmacological chaperone” platform developed at Mount Sinai Medical School in New York. The plan was to produce small molecules designed to attach themselves to defective enzymes, stabilize them, and then transport them to the part of the cell where they can break down whatever substance causes the disease.

Amicus CEO John Crowley said in the company’s press release that Amicus still plans to produce 12-month results from the Fabry study in the first half of 2013. “Once we have the 12-month data, we intend to meet with the FDA to discuss a U.S. approval pathway. We continue to believe that migalastat HCl may become an important treatment option as an oral monotherapy drug for both men and women with Fabry disease.”

GSK’s global head of rare diseases Marc Dunoyer also said in the statement that “GSK and Amicus are committed to advancing migalastat HCl as a monotherapy in Fabry patients.”