GlaxoSmithKline’s good week in terms of approvals ended with another thumbs-up from regulators, this time in the USA, for Requip XL to be marketed as a treatment for Parkinson’s disease.

The US Food and Drug Administration has backed Requip XL(ropinirole extended-release tablets) to treat the signs and symptoms of idiopathic Parkinson's disease. GSK noted that the product, the first oral once-daily non-ergot dopamine agonist indicated for the disease, should be available by mid-July in the USA.

The approval was primarily based on data from a 393-patient which showed that adding Requip XL to existing levodopa therapy delayed the return of symptoms, or ‘off-time’ by 2.1 hours a day. Specifically, comparing the experience of the group treated with extended-release ropinirole versus placebo, the adjusted mean difference in the reduction of ‘off’ time was 1.7 hours, which was statistically significant.

Rajesh Pahwa, professor of neurology at the University of Kansas Medical Center, noted that Requip XL provides continuous delivery of ropinirole over 24 hours to provide “smoother blood levels without the peaks and troughs that multiple daily doses typically deliver”. The formulation uses fellow UK firm SkyePharma’s Geomatrix technology and has already beenapproved in Europe.

GSK, which was granted European marketing authorisation a couple of days earlier for its breast cancer compound Tyverb (lapatinib), recently lost patent protection on the original formulation of Requip for the treatment of moderate to severe restless legs syndrome last month.