NEW YORK (Reuters) - The U.S. Food and Drug Administration declined to approve an experimental epilepsy drug from GlaxoSmithKline and Valeant Pharmaceuticals International, the companies said on Wednesday, marking another delay for the anti-seizure medicine.
The drugmakers received a so-called complete response letter from the agency for the drug ezogabine, meaning the FDA will not approve the medicine until certain concerns are addressed.
The FDA cited non-clinical reasons for putting off approval of the medicine, the companies said. That would suggest that further clinical trials would not be required, but that details about the product's eventual label or a requirement for post-marketing studies might be under consideration.
Britain-based Glaxo and Canadian drugmaker Valeant said they believe the issues cited by the agency can be addressed and that they are working for a timely response to the FDA as soon as possible in 2011.
Ezogabine, with a proposed brand name of Potiga, appeared on its way to approval in August after an FDA expert advisory panel voted 13-0 that it was effective for use with other epilepsy drugs in patients who still have seizures with current therapy, and 11-0 that monitoring for urinary problems would help minimize side effects.
The FDA had been expected to make an approval decision on ezogabine by the end of August, but instead delayed its action date by three months to Nov 30 -- a date that has now slipped away without a final decision.
The medicine is aimed at controlling seizures when other treatments fail.
Analysts have forecast peak annual sales ranging from $200 million to $800 million.
About 3 million Americans have epilepsy, a brain disorder that causes seizures. But an estimated 30 percent of patients do not find adequate relief with current drugs.
In clinical studies ezogabine cut partial-onset seizures by 23 percent to 44 percent depending on the dose. That compared with a reduction for placebo patients of 13 percent to 18 percent. Partial-onset seizures are the most common type and start in a part of the brain rather than the entire brain.
(Reporting by Bill Berkrot; editing by Gunna Dickson)