Amicus Therapeutics (FOLD)

Amicus Therapeutics Inc. lost more than half its market value Friday after the drug maker said it has delayed plans to seek U.S. approval of its treatment for a rare genetic disorder because of questions from regulators.

The Cranbury, N.J., company was expected to submit a new drug application for its migalastat monotherapy, known as Galafold, by the end of the year to the U.S. Food and Drug Administration. However, Amicus said Friday that following recent meetings with the FDA, more time will be needed to complete the application.

The monotherapy treats Fabry disease, a genetic disorder that affects about 5,000 to 10,000 people across the world, and possibly more, according to Amicus’s website. The disease is caused by deficiency of an enzyme that is intended to degrade a specific lipid, the company said. Buildup of the lipid results in symptoms such as pain, kidney failure and higher risk for heart disorders and stroke.

Amicus said Friday that U.S. regulators had questions about the treatment’s gastrointestinal effects and requested the drug maker to combine two studies in its application. The company said making the changes could take several months but didn’t offer specific details.

Shares of the drug fell 53% to $6.39 Friday, giving the company a market value of about $760 million.