How well does Vimpat work?

Vimpat (lacosamide) is generally used as add-on (adjunctive) therapy for partial seizures in individuals age 17 years and older whose seizures are not well controlled by other medications.

Before being approved for marketing in most countries, regulatory authorities (the FDA in the US) review results of clinical trials that must document that the medication is effective for the purpose stated and is reasonably safe. Clinical trials of seizure medicines, including Vimpat, usually are done by adding on the medicine to regimens that are not working well. Therefore, the benefit of a new drug seen in tests usually is incremental, and in people who have seizures that are proven to be difficult to control. A drug might be expected to show greater degrees of benefit in people whose seizures are not so severe, though data on this point usually are lacking.

Studies of Vimpat were performed on patients who had an average of 10-17 partial seizures per month, and usually were taking 2 or 3 other seizure medicines. At a dose of 200 mg per day, median seizure frequency reduction was in the range of 21-26%. At a dose of 400 mg per day, median seizure frequency reduction was in the range of 35-40%. About 40% of the patients taking 400 mg per day had seizure frequency cut in half or better. Little additional benefit occurred at 600 mg per day.