Amicus Therapeutics (FOLD.O) said its experimental drug to treat a rare, inherited disorder failed to meet the main goal of a late-stage study, sending its shares down 50 percent in extended trade on Wednesday.
The company is developing migalastat HCl in partnership with British drugmaker GlaxoSmithKline plc (GSK.L) to treat Fabry disease, a genetic condition in which a type of fat gets deposited in human tissue, particularly in the kidneys.
The disease is caused by the body's inability to produce the enzyme that helps breaks down the fat.
The six-month study found that 13 out of the 32 patients who were put on migalastat HCl reported a reduction of 50 percent or more in the fat deposits in their kidneys, compared to 9 of the 32 in the group that was given a placebo.
"This difference did not achieve statistical significance according to the pre-specified primary endpoint analysis," the company said.
Amicus said it expects to report results from 12 months of treatment in the first half of 2013, after which it plans to meet with the FDA to discuss a U.S. "approval pathway."
Fabry disease affects about 5,000 to 10,000 people worldwide and is believed to cause pain, kidney failure and increased risk of heart attack and stroke, according to the company.
Amicus shares closed at $5.77 on Wednesday on the Nasdaq, but fell as low as $2.80 after the bell.
(Reporting by Prateek Kumar and Zeba Siddiqui; Editing by Sreejiraj Eluvangal)