(Reuters) - Amicus Therapeutics Inc said it was unlikely to submit a U.S. marketing application for its lead drug, to treat Fabry disease, by the end of 2015 as expected, after U.S. health regulators asked for a more comprehensive analysis of trial data.
Amicus’s stock slumped as much as 59 percent to $5.69, at which point about $956 million had been wiped off the biotechnology company’s market capitalization on Friday.
The company is hoping to make the drug, migalastat, the first oral treatment for patients with a form of Fabry disease, a potentially fatal, inherited disorder that affects about 1 in 40,000 to 60,000 men and occurs less frequently in women.
Fabry disease is caused by the build up of a type of fat, most notably in the kidneys, due to the deficiency of the alpha-Gal A enzyme. The accumulation damages cells and could lead to kidney failure, heart attacks and strokes.
Migalastat, tailored to treat 30-50 percent of Fabry patients with a specific cellular mutation, is designed to be taken orally every other day.
That would potentially give it an edge over existing treatments such as Sanofi SA’s Fabrazyme and Shire Plc’s Replagal, which require bi-weekly infusions.
Amicus had planned to submit a marketing application for migalastat based on one 24-month late-stage study, which evaluated the drug against a placebo for six months, after which all subjects were given the drug.
This application was to be supplemented with data from another late-stage study testing migalastat against enzyme replacement therapies (ERTs), the current standard of care.
With that in mind, Amicus met with the FDA to discuss its application and, in September, said it was on track to file the application in the fourth quarter.
However, after reviewing of the minutes of that meeting, Amicus met the FDA again and was asked to integrate the data from both late-stage studies and conduct further analyses, the company said on Friday.
The United States, the European Union and Japan have granted migalastat orphan drug status, which gives Amicus certain incentives including a period of marketing exclusivity.
Amicus said on Friday it remained on track with regard to its marketing application for migalastat monotherapy in Europe, which represents about 70 percent of the drug’s commercial opportunity.
The company is also developing migalastat in combination with ERT’s for Fabry patients who do not have amenable mutations.
Reporting by Natalie Grover in Bengaluru; Editing by Savio D'Souza