US regulators have extended approval of Belgian drugmaker UCB’s flagship drug Keppra, allowing its use as an add-on therapy for the treatment of seizures in patients with juvenile myoclonic epilepsy.

Keppra (levetiracetam) has been on the market since 2000 as an adjunct treatment for partial onset seizures in patients aged four and above, but this new indication represents the first US approval for the agent for a generalized seizure type in patients.

Clearance was based on the results from a double-blind, randomised, placebo-controlled Phase III study which showed that 15.1% of patients receiving Keppra were free of myoclonic seizures during the treatment period compared to just 3.4% of placebo patients.

The new approval should add to the already-considerable momentum behind the product. UCB reported Keppra sales of 365 million euros in the first half of 2006, a rise of 42% that puts it in sight of surpassing antihistamine Zyrtec (cetirizine) as the firm's top product.

Since the start of the year, UCB has won approvals in the USA and Europe for an intravenous formulation of Keppra that should expand its use into emergency-room settings, as well as EU clearance of the drug in juvenile myoclonic epilepsy.

And, earlier this month, Keppra was also approved in Europe as a monotherapy for newly diagnosed epilepsy patients with partial onset seizures, a milestone achievement for the product.