Levetiracetam, a new antiepileptic agent, has been launched in the United Kingdom
(see p736).
Levetiracetam (Keppra) is indicated as an adjunctive therapy in the treatment
of partial seizures in adults with epilepsy. Its manufacturer, UCB Pharma, says
that the drug has no known interactions with other drugs, which it says is an
advantage over other antiepileptics. It adds that levetiracetam can be used
in populations such as women who may be taking oral contraceptives and the elderly.
The drug is not licensed for children but studies are under way.
UCB Pharma says that levetiracetam does not directly interact with a neurotransmitter
or receptor but appears to have a stereo-specific binding site in the brain.
In addition, it has no activity in standard models of acute seizures but is
effective in animal models of chronic epilepsy.
Phase III clinical studies of levetiracetam were carried out in 904 patients
who had refractory partial onset seizures, with or without secondary generalisation,
for at least two years.
Response rate, measured as a greater than 50 per cent reduction in seizure frequency
over the trial period, was 21-37 per cent for a dose of 1,000mg a day, 35 per
cent for 2,000mg a day and 39 per cent for 3,000mg a day. The placebo response
rate was 7-14 per cent.
In two studies of 1,422 patients with refractory epilepsy who received 3,000mg
levetiracetam a day, 8 per cent became seizure-free compared with between 0
and 1 per cent of patients receiving placebo. The manufacturer says that this
result is impressive because seizure freedom is not often achieved in patients
with refractory epilepsy.
Levetiracetam was generally well tolerated in the clinical studies. When given
with other antiepileptics, the most frequently reported undesirable effects
were somnolence, asthenia and dizziness. The effects were mild to moderate in
intensity and occurred predominantly during the first four weeks of treatment,
after which severity decreased. The percentage of patients who discontinued
therapy or required a dose reduction because of an adverse event was 15 per
cent for levetiracetam and 12 per cent for placebo.