GlaxoSmithKline PLC and Valeant Pharmaceuticals International say they may have to wait an extra three months for the U.S. regulatory review of their potential epilepsy treatment ezogabine.
The two companies said Tuesday that the U.S. Food and Drug Administration has extended its target date under the Prescription Drug User Act to review ezogabine to Nov. 30 from Aug. 30.
Ezogabine is designed for patients already taking one to three other anti-epileptic drugs.
London-based Glaxo and Valeant, which is based in Aliso Viejo, California, have already submitted an evaluation of the risks of the drug that was requested in August by the FDA.
Glaxo shares are down 1.3 percent at 1,209 pence ($18.65) on the London Stock Exchange.