U.S. Markets closed

Amicus treatment for Fabry disease fails in study

NEW YORK (AP) -- A potential treatment from Amicus Therapeutics and GlaxoSmithKline for Fabry disease, a rare disorder, missed its goals in late-stage testing, triggering a sell-off in Amicus' stock in after-hours trading.

Fabry disease is an enzyme disorder caused by the buildup of a type of fat in the body's cells. The fat can cause pain and damage the kidneys and nervous system, among other problems.

Amicus said Wednesday that six-month results from a late-stage study of migalastat missed the primary endpoint, but Amicus and its partner will continue to analyze the data and look forward to receiving 12-month results in the first half of next year. They intend to meet with the Food and Drug Administration once they have those additional results.

No drug-related serious adverse events related to the drug were observed.

The companies are also testing migalastat in a second late-stage clinical trial.

In July, Amicus of Cranbury, N.J., and GlaxoSmithKline, based in London, announced they were expanding their partnership for the drug, giving Amicus commercial rights to market any migalastat products in the U.S., while GlaxoSmithKline will market the drugs in all other countries. GlaxoSmithKline then agreed to pay Amicus $30 million upfront and up to $170 million if the drug advanced through clinical development, was approved, and reached sales targets.

Amicus Therapeutics shares plunged in late-trading, shedding half their value to $2.85, after closing at $5.77.