Epilepsy affects over 150,000 Australians, and 50 million globally, with one-third struggling to control their condition with currently available anti-seizure medications. These patients with drug-resistant epilepsy have high rates of disability, mental health and thinking problems, and injury and death rates.
Now, for the first time, a new drug has been discovered that is the first potentially curative drug for people with epilepsy who are resistant to control with current anti-seizure drugs. All currently available drugs used to treat people with epilepsy are symptomatic (only reducing seizure frequency in less than 70 per cent of cases), but without a sustained effect to mitigate or cure epilepsy or its associated conditions.
In a study published in the prestigious journal, eLife, and led by Dr Pablo Casillas-Espinosa and Professor Terry O'Brien from Monash Neuroscience and the Alfred, the researchers report that sodium selenate could be the first medical disease-modifying therapy for epilepsy.
According to Dr Casillas-Espinosa, current therapies target symptoms only, "so when a patient stops or misses the medication they are as likely to have a seizure as if they had been untreated, and importantly one-third of patients don't respond to any treatments so far," he said.
Drug-resistant epilepsy is associated with significantly increased morbidity, mortality and cost of care.
The study, conducted in animal models revealed sodium selenate to have a long-lasting effect (after months of stopping the medication) in reducing the frequency of seizures (and in 30 per cent of cases stopping them altogether) and improving other aspects of epilepsy such as memory, learning and sensor-motor functioning.
On the strength of these findings, the researchers have been awarded a $3 million Medical Research Future Fund (MRFF) grant to start a clinical trial of sodium selenate as a curative treatment in patients with drug-resistant epilepsy. This is one of 21 Monash University medical and health research projects that received funding from the Australian Government through the MRFF announced on Tuesday 14 March 2023.
The trial lead by Dr Lucy Vivash, Professor O'Brien and Dr Casillas-Espinosa – to start later this year will be the world's first to investigate the effect of 6 months of treatment with sodium selenate in patients with drug-resistant temporal lobe epilepsy (TLE) - to see whether, as in the pre-clinical animal studies, there is a sustained beneficial effect to reduce seizure frequency and neuropsychiatric comorbidities.
124 patients will be enrolled across at least 9 sites nationwide over 2.5 years. Following screening assessments, participants will be randomised to receive either sodium selenate or placebo for 6 months, and then followed for another 6 months and assessed for effects on (i) the number of seizures experienced (ii) measures of quality of life, (iii) presence and severity of adverse events, using a patient-designed desirability of outcome ranking (DOOR) scale.
Secondary outcomes measure other epilepsy-related outcomes, including cognitive deficits and depression and anxiety.
According to Professor O'Brien, epilepsy is one of the most common and serious disabling brain disorders which is costly to both individuals and their families, as well as the national health budget with an estimated annual economic cost in Australia of $12.3 billion. "Despite the cost of the disease – and the enormous amount of research into it, there has not been a single therapy developed to prevent the development of epilepsy, nor to mitigate its severity once established. Until now," he said.
"This Phase 2 clinical trial, if effective, has the potential to tackle a disease that is an enormous global burden as well as being truly transformative for people who are impacted by often daily seizures, with no respite."
The new study uses the DOOR scale, adapted for use in the trial by a focus group of people with epilepsy. The group from multiple states (NSW, VIC, SA, QLD) across Australia developed the scale according to the outcomes most important to them when trialling a new treatment for epilepsy.
The scale includes measures of seizure frequency, side effects and quality of life. "The scale we will be using is totally different to what we had initially planned. The consumer group were fantastic for helping us better understand their priorities when it comes to introducing a new medication into their lives" says Dr Lucy Vivash, lead scientist on the upcoming trial, "It absolutely shows the importance and benefit of involving patients in the planning of trials and research".
