GSK asks FDA for new nod on restless legs drug

Fresh off an approval for restless leg syndrome in April, GlaxoSmithKline ($GSK) has asked the FDA to bless Horizant for use against shingles pain. A long-lasting version of the seizure drug gabapentin, Horizant was developed with partner XenoPort, and the two companies are studying it for other indications such as neuropathic pain.

If Horizant ends up getting the OK for broader use, it would be another score for a drug that once seemed like it was on life support; the FDA refused at first to approve the restless leg indication after some troubling safety signals in rats. But the agency changed its mind and allowed Horizant onto the market without the black-box warning some had feared. GSK is on the hook for some post-marketing safety studies, however, to make sure Horizant doesn't impair users' ability to drive.

Analysts are expecting Horizant to peak anywhere from $200 million to $500 million. GSK has U.S. rights to the drug, and XenoPort gets a 20% to 50% share of the profits for the first two years. After that, XenoPort can choose to co-promote the drug or accept a royalty.

- read the GSK release
- see the MedCity story