The US Food and Drug Administration has extended approval of UCB's best-selling drug Keppra, allowing its use as an add-on therapy in the treatment of primary generalised tonic-clonic seizures in adults and children aged six and above with idiopathic generalised epilepsy.

Keppra (levetiracetam) has been on the market since 2000 as an adjunct treatment for partial onset seizures in patients aged four and above, and last summer the FDA backed its use in the in the treatment of myoclonic seizures in adults and adolescents over 12.

The extension was based on the results from a double-blind, randomised, placebo-controlled Phase III study of 164 patients with refractory IGE, whereby nearly a quarter (24.1%) achieved complete seizure freedom from all seizure types over the 20-week evaluation period. This compared with only 8.3% of those who received a placebo in addition to their usual treatment. Nearly three-quarters of those who took Keppra achieved a 50% reduction in weekly PGTC seizures, compared to 45.2% of those in the placebo group.

Dr Robert Knowlton of UAB Epilepsy Centre in Birmingham, Alabama, USA, noted that almost one in four people with epilepsy have tonic-clonic seizures, beginning with a sudden loss of consciousness and stiffening of the muscles, followed by rapid rhythmic jerking of the arms and legs. He added that “seizure freedom, with minimal side effects, is the ultimate goal for physicians and patients” and the trial supports “the growing evidence for Keppra as an effective adjunctive therapy across partial and generalised seizure types.”

The new approval should add to the already-considerable sales of Keppra which reached 761 million euros in 2006, a rise of 36% on the previous year.