About 27 percent of local epilepsy patients have drug-resistant epilepsy (DRE), and the nation needs to actively introduce new anti-epileptic drugs (AEDs) to treat them effectively, neurologists said. DRE refers to a condition when two AEDs have failed to control seizures.
Korean Epilepsy Society’s (KES) Drug Committee recently released a survey on 108 local epilepsy specialists who have prescribed AEDs.
Epilepsy is one of the three major brain diseases. Patients with epilepsy experience seizures repeatedly occurring from various causes and complex onset processes. Seizures occur suddenly when brain cells in a specific brain region are temporarily overexcited or when the brain loses inhibitory power, resulting in a loss of balance and control.
The local incidence and prevalence of epilepsy have continued to increase in the past eight years.
According to data from the National Health Insurance Service from 2009 to 2017, the incidence went up from 28.7 per 100,000 population in 2009 to 35.4 per 100,000 in 2017, and the prevalence, from 3.4 per 1,000 people in 2009 to 4.8 per 1,000 in 2017.
The problem is that a high proportion of epilepsy patients do not benefit from existing drugs.
Epilepsy is primarily treated with drugs, and seizures are controlled through anticonvulsants with a mechanism suitable for the patient. However, when two or more drugs do not control seizures, the disease is classified as DRE, a severe, intractable disease. About 30 percent of Korean epilepsy patients fall under this category.
The latest survey by the KEC also showed similar results. Neurologists said about 27 percent of their epilepsy patients failed to control seizures despite using two drugs.
The doctors picked “lack of efficacy” (57.4 percent), “adverse reactions” (20.4 percent), and “compliance” as the causes of failure to control seizures.
In particular, the “lack of efficacy” response came from all neurologists, regardless of the hospital type, clinical experience, region, or expertise. This shows that there was an unmet need among physicians for expanding AED options, the KES said.
Professor Seo Dae-won of neurology at the Samsung Medical Center, who conducted the poll, said over half of the respondents (54.5 percent) said adding a new AED to a DRE patient could control seizures.
“When specialists added drugs to patients who failed treatment despite taking five or more drugs, they considered the drug’s mechanism of action first. This suggests that we need to introduce new anticonvulsants actively,” he said.
According to the KES, AEDs are classified into four types depending on their mechanisms – inhibit ion channels to control the excitability of nerve cells, enhance the action of inhibitory neurotransmitters, weaken excitatory neurotransmission, or regulate the secretion of neurotransmitters.
Overseas guidelines also noted that physicians should make more delicate considerations when selecting drugs for patients with DRE.
The American Academy of Neurology made guidelines for DRE patients, separately from newly diagnosed epilepsy patients.
According to the guidelines, when selecting AEDs for DRE patients, neurologists should consider the seizure and syndrome type, patient age, concomitant medications, tolerability to anti-seizure drugs, safety, and efficacy.
“When treating DRE patients, we are worried about their adverse reactions and compliance with the increasing number of medications,” Seo said. “Thus, we should keep introducing new AED options, use them in parallel with existing drugs, and if it works, we could even reduce the number of drugs.”
In Korea, 18 AEDs are reimbursable. However, he added that patients do not have many treatment options, given the drug combination for each patient and the treatment tendency for epilepsy.