Epilepsy treatment: Zorevunersen transforms lives of children with rare Dravet syndrome

An experimental new treatment is offering a beacon of hope for children suffering from a rare and severe form of epilepsy, with researchers suggesting it could enable them to “lead much healthier and happier lives”.

Early trials of the drug zorevunersen have demonstrated a dramatic reduction in seizures among young patients with Dravet syndrome.

Experts also believe that the treatment holds promise in mitigating the cognitive and behavioural challenges frequently associated with the condition.

One mother from Yorkshire, whose son participated in the trial, described the impact as having “completely changed” their lives.

Dravet syndrome is a rare genetic disorder characterised by the onset of seizures in the first year of life, evolving into a form of epilepsy which is resistant to conventional treatments.

It affects approximately one in 15,000 births across the UK. Patients often experience difficulties with speech and feeding, alongside intellectual disabilities and developmental delays.

The trial, a collaborative effort led by University College London (UCL) and Great Ormond Street Hospital (Gosh), involved 81 children aged between two and 18 years old with Dravet syndrome, spanning both the UK and the US.

Prior to the study, these patients endured an average of 17 seizures each month.

Children received either a single dose of zorevunersen, ranging from 10mg to 70mg, or multiple doses of between 20mg and 70mg over a three-month period, administered via a lumbar puncture.

The drug targets the underlying cause of Dravet syndrome – a faulty gene. Individuals typically possess two copies of the SCN1A gene, but in those with Dravet syndrome, one copy fails to produce sufficient protein for proper nerve cell function.

Zorevunersen works by binding to messenger RNA, boosting the production of this vital protein from the healthy gene to restore crucial levels.

In an extension study, 75 eligible patients continued to receive 45mg of the drug every four months.

Researchers observed that youngsters who had received 70mg of zorevunersen in the initial phase of the trial – whether in one, two, or three doses – experienced a significant reduction in seizures, ranging from 59 per cent to 91 per cent over the first 20 months of the extension studies.

Professor Helen Cross, lead author and director of childhood epilepsy at the UCL Institute of Child Health, as well as an honorary consultant in paediatric neurology at Gosh, said: “I regularly see patients with hard-to-treat genetic epilepsies with impacts that go beyond seizures and it’s heartbreaking when treatment options are limited. This new treatment could help children with Dravet syndrome lead much healthier and happier lives.”

Among the participants, 19 children were patients at UK hospitals, including Gosh, Sheffield Children’s Hospital, Evelina London Children’s Hospital, and The Royal Hospital for Children in Glasgow.

Eight-year-old Freddie Truelove, from Huddersfield, began taking zorevunersen in 2021. His mother, Lauren Truelove, said that Freddie, who once suffered more than a dozen seizures nightly, now experiences just one or two, lasting mere seconds, every three to five days.

Ms Truelove said: “The trial has completely changed our lives. We now have a life we didn’t ever think was possible and most importantly, it’s a life that Freddie can enjoy.”

The findings, published in the New England Journal of Medicine, are said to “support the continued development of zorevunersen as a potential disease-modifying treatment for Dravet syndrome”.

The trial also indicated that “most adverse events were mild or moderate”, with the most common being post-lumbar puncture syndrome, which can cause headaches.

Professor Cross added: “Overall, our findings showed that zorevunersen is safe to use and well tolerated by most patients and supports further evaluation in the ongoing phase three study.”

Galia Wilson, chairwoman of trustees at Dravet Syndrome UK, said: “We regularly see the devastating impact that this condition has on the lives of families. That’s why we’re so thrilled about these latest results from the initial zorevunersen clinical trials.

“We’re now looking forward to the phase three clinical trials taking place to see if the early promise we see here will translate into real hope for all those families currently affected by Dravet syndrome.”