GlaxoSmithKline and partner Valeant Pharmaceuticals International have filed their investigational epilepsy treatment retigabine.

The companies have submitted the compound to the US Food and Drug Administration and the European Medicines Agency and are hoping it will be used as adjunctive therapy to treat adult epilepsy patients with partial-onset seizures. Retigabine is a first-in-class neuronal potassium channel opener.

GSK and Valeant teamed up in August last year and Valeant received an initial payment of $125 million which covered the rights to retigabine, another epilepsy treatment VRX698 and other back-up compounds in its potassium channel opener programme. The deal could be worth a total of $820 million to Valeant depending on certain regulatory and commercial milestones, plus additional indications for retigabine.

News of the filings is also good news for Sweden’s Meda, which recently bought a chunk of Valeant’s European operations last year for $392 million and is entitled to receive “significant royalties and certain milestone payments” from the retigabine agreement.

Valeant, which announced net income from continuing operations for the third quarter of $37.6 million, compared with a loss of $7.3 million a year ago, and revenues of $220.3 million (+31%), says that three retigabine modified-release technologies will be assessed in a Phase I clinical study commencing in September.