Vernalis and partner Endo Pharmaceuticals have reported the results of a second, confirmatory Phase III trial showing the benefits of their Frova product in menstrual migraine.

The two companies say they now plan to file the data with the US Food and Drug Administration (FDA) in the middle of this year, seeking approval for a regimen of six treatment days each month. If approved, Frova (frovatriptan) would be the first drug in the triptan class to be given a green light in menstrual migraine.

Analysts at Piper Jaffray suggest that the new indication could help Frova achieve $280 million in peak annual sales for Frova – a good performance for a drug that was a relatively-late entrant into the triptan market.

US sales of the drug reached $38 million last year, following a re-launch in the year by Endo and co-promotion by Vernalis. In Europe, frova is licensed to menarini, and Vernalis booked £3 million in royalties on the product’s sales during 2005.

According to a deal signed with Endo in 2004, Vernalis stands to receive $40 million if Frova is cleared for menstrual migraine, as well as up to $255 million in sales milestones.

Last year, Vernalis reported data from a first Phase III study showing that 59% of patients taking 2.5mg of frovatriptan twice daily were headache free during their menstrual period, compared to only 33% of placebo patients.

In the confirmatory trial both once and twice-daily dose regimens of Frova 2.5mg demonstrated efficacy, with statistical significance compared to placebo. In addition, both dose regimens achieved statistical significance in other measures, including increased number of menstrual periods with one or no days of mild headache, reduction in headache intensity and a reduction in the use of rescue medication.

All the women in the study had tried and failed to manage their menstrual migraine using other triptans or non-steroidal anti-inflammatory drugs (NSAIDs). Piper Jaffry estimates that there are around 2 million women in the USA alone who suffer from migraine only during menstrual periods.