Two new anti-seizure medicines with novel mechanisms move forward

Two new anti-seizure drugs have moved forward in the testing and approval process. Potiva, known generically as ezogabine or retigabine was recommended for approval by an FDA advisory panel, although with cautions to monitor for bladder retention as a side effect. Retigabine acts on a potassium channel in brain cells. Excitability of brain cells is controlled by ion channels, which are proteins that act as passageways for sodium, potassium, calcium and chloride ions into and out of the cells. Existing anti-seizure drugs work on sodium, calcium and chloride channels. Retigabine is the first clinically available drug to affect potassium channels. Potiva, sponsored jointly by Valeant and Glaxo Pharmaceuticals, will presumably be available soon after FDA final approval.

A second drug, called perampanel, works by blocking the excitatory neurotransmitter glutamate at the so-called AMPA receptor site. No currently available anti-seizure drug uses this mechanism. The drug’s sponsor, Eisai, reported favorable results from a mainly European and Asian trial in 706 patients who received 2, 4 or 8 mg of perampanel. Seizures were reduced when the drug was added to existing drug regimens. Side effects typically included dizziness, sleepiness or headache, but the medication usually was well-tolerated. The sponsor plans to submit the drug for FDA approval.