GlaxoSmithKline's recently-licensed Trobalt (retigabine) should be prescribed as an add-on treatment for adults with epilepsy if other medicines have been ineffective or produced unmanageable side effects, says new final guidance from the National Institute for Health and Clinical Excellence (NICE).

People with epilepsy often need to take a combination of drugs to control their seizures. In its final guidance, NICE recommends Trobalt as an add-on (adjunctive) treatment for adults with partial-onset seizures (which are caused by too much electrical activity in one part of the brain), with or without secondary generalisation (when this excess activity reaches the whole brain), if they have not responded well to the following drugs: Novartis' Tegretol (carbamazepine), Sanofi's Frisium (clobazam), Pfizer's Neurontin (gabapentin), GSK's Lamictal (lamotrigine), UCB's Keppra (levetiracetam), Novartis' Trileptal (oxcarbazepine), Sanofi's Depakine (sodium valproate) and Johnson & Johnson's Topamax topiramate).

Epilepsy is estimated to affect 260,000-416,000 people in England and Wales, 55% of whom will experience partial-onset seizures.  Moreover, around 30% of people diagnosed with epilepsy do not respond to initial drug treatments.

"Seizures can be extremely debilitating as they can interfere with a person's social life, employment and other daily activities," said Professor Carole Longson, director of the Institute's health technology evaluation centre. "While there are a number of effective anti-epileptic drugs already widely available on the NHS, people can have different responses to them. It's therefore very important for doctors to have a broad range of options so that they can find the right combination for their patients," she said.

GSK launched the drug in the UK in May, following the granting of a marketing authorisation by the European Commission at the end of March.  NICE is "very pleased to able to issue these recommendations for the NHS so soon after retigabine's regulatory approval. We hope that this guidance will lead to even more people having greater control of the condition," added Prof Longson.

The drug, which is known as Potiga (ezogabine) in the US and is co-marketed globally by GSK and Valeant Pharmaceuticals, received approval from the Food and Drug Administration (FDA) on June 13 as adjunctive treatment of partial-onset seizures in patients aged 18 and older. It is expected to be available in US pharmacies by the end of the year, says GSK.

Applications for marketing authorisation for the drug have been submitted in five other countries including Switzerland, where the Agency for Therapeutic Products granted it preliminary authorisation in December 2010.