UCB’s stock has soared on the news that the Belgian firm’s epilepsy drug Vimpat has been given the green light by US regulators.

The US Food and Drug Administration has approved Vimpat (lacosamide) for use as an add-on therapy for the treatment of partial-onset seizures in people with epilepsy who are 17 and older. The approval is based on one Phase II and two Phase III trials of 1,300 people and before adding Vimpat, patients experienced a median baseline seizure frequency ranging from 10 to 17 seizures per month, despite being on one to three other antiepileptics; 45.2% of patients had previously tried seven or more AEDs to control their seizures.

In the studies, patients randomised to Vimpat had their seizures reduced by half and experienced reductions in median seizure frequency at rates that were significantly greater than those in placebo groups. In preclinical studies, Vimpat has been shown to bind to the collapsin response mediator protein-2, an important target that affects the way that nerves differentiate and grow. However, the precise nature of the interaction between the drug and CRMP-2 and between the latter and seizure control is not known.

Lead investigator Steven Chung at the Barrow Neurological Institute in Phoenix said that “Vimpat is unique because it works unlike any other antiepileptic drug that is currently available”. He added that it should be considered for patients who have uncontrolled seizures with their current treatment regimen, “no matter how many previous AEDS they've tried”.

Vimpat, which is approved in Europe and was recently launched in the UK and Germany, is seen as a vital element in plugging the gap in sales facing UCB from the loss of patent protection on the allergy drug Zyrtec (cetirizine) last year and the antiepileptic Keppra (levetiracetam) in the near future.

However hopes are high that Vimpat could follow Keppra and become a blockbuster. The scientific community is also impressed with the compound according to its reaction to data presented at the European Congress on Epileptology in Berlin last month.

At the meeting in Germany, Elinor Ben-Menachem at the Institute for Clinical Neurosciences at the Sahlgrenska Academy in Gothenburg, Sweden, said that the pharmacokinetic profile of Vimpat is excellent. Lacosamide was completely absorbed in trials and can also be used with a wide range of other drugs patients may be taking for other conditions, such as metformin for diabetes, digoxin for herart failure and oral contraceptives.

Prof Menachem told PharmaTimes World News that the side effect profile of Vimpat is excellent and another advantage is that Vimpat will be available in three formulations – tablets, syrup and an intravenous injection. This is important especially in a hospital setting where patients in seizure need alternatives for administration.