Why drugs do not help some epileptics

Around one third of people with epilepsy are not helped by any of the available treatments. New research offers a reason why and suggests new ways to treat drug resistance in epileptic patients. People with drug-resistant epilepsy are more than twice as likely as epileptics who respond to medication to carry a particular variation in a gene that may transport epilepsy drugs in the body. Increased levels of the protein encoded by the gene, known as ABCB1, are already known to appear in cancer cells that have become resistant to many cancer drugs. Researchers at the University College London, UK sequenced the ABCB1 gene in 315 people with epilepsy, 200 of whom were resistant to medications. ABCB1 gene belongs to a family of genes known as transporters, which move substances around the body. Since the genetic pattern in ABCB1 did not appear in all cases of drug-resistance, other genetic patterns in other transporter genes could also play a role in some patients who do not respond to drugs. The precise role of ABCB1 in the body remains unclear. The protein may prevent epilepsy drugs from crossing over the blood-brain barrier and achieving their effects. Research also suggests that during seizures, levels of the ABCB1 protein increases, relative to when seizures are not taking place. Overall, 27.5 percent of the drug-resistant epileptics had the genetic variation, compared with 16 percent of those who responded to medication and 18.5 percent of people without epilepsy. However, the fact that the one genetic pattern in the ABCB1 gene appears more commonly among epileptics resistant to drugs suggests that the genetic pattern is somehow linked to whatever is causing the problem. Discovering the cause of a patient's inability to respond to epilepsy drugs may enable doctors to treat the patient's resistance and allowing them to be helped by epilepsy drugs.