Forest Laboratories and Cypress Bioscience are going to have to wait a bit longer to market milnacipran for fibromyalgia after US regulators said they need more time to evaluate the drug.

The US Food and Drug Administration has advised the companies that it was not able to take final action by the scheduled Prescription Drug User Fee Act action date of October 18, on their New Drug Application for milnacipran, a selective serotonin and norepinephrine reuptake inhibitor for the management of fibromyalgia. The treatment is already approved outside the USA for depression.

The FDA has not requested any additional information, Forest and Cypress said, but the agency has indicated that a clinical data question related to the NDA submission required confirmation. The FDA has also told the firm that its assessment could be completed in a matter of weeks, but could not confirm any specific timing.

The companies added that they continue to plan for a first-quarter 2009 launch of milnacipran, and noted that the FDA could not provide further information as to the reason for the delay.

However it would appear that the problem could be understaffing at the agency. Takeda has this month seen delays to the review of two of its key pipeline drugs (see the story on today’s elert) and the list of drugs that are waiting to be assessed is growing.

Prominent among them is Eli Lilly and Daiichi Sankyo’s anti-clotting drug prasugrel, which could be due to a labelling problem or simply a backlog at the FDA.