PARIS (AP) -- The U.S. Food and Drug Administration has notified drug maker Genzyme that its treatment for multiple sclerosis is not ready for approval for the American market.
The French pharmaceutical company Sanofi, which is the parent of Genzyme, said in a statement Monday that the FDA said the companies had not submitted sufficient evidence to show the benefits of Lemtrada. The drug was approved by the European Medicines Agency for use in the EU earlier this year.
It also has been approved in Canada and Australia. Sanofi said it "strongly disagrees" with the FDA decision, and it plans to appeal.
Sanofi wants to market Lemtrada as a treatment for relapsing multiple sclerosis, a disease in which the immune system attacks healthy nerves. It can cause pain, numbness, slurred speech, impaired vision, muscle weakness and neurological problems.
The French drugmaker is eager to bring new drugs to the market at a time when it is suffering from generic competition after patents on some of its best-selling drugs lapsed.
U.S.-traded shares of Sanofi slipped 39 cents to $52.41 in Monday morning trading.
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.