IPM Take
The sharp signal is that genetic epilepsy is moving beyond better seizure control. Zorevunersen is designed to increase expression from the functioning SCN1A copy, putting genetic diagnosis at the centre of future access. If later trials confirm benefit, the pathway will need fast genetic testing, specialist referral, lumbar-puncture delivery capacity, long-term monitoring and reimbursement models that recognise developmental outcomes, not only seizure counts.
Executive Summary
A 2026 New England Journal of Medicine study evaluated zorevunersen in children and adolescents with Dravet syndrome, a severe developmental and epileptic encephalopathy caused primarily by SCN1A haploinsufficiency. The published data came from Phase 1/2a and open-label extension studies involving 81 patients aged 2 to 18 years. The studies were designed primarily to assess safety and tolerability, while also evaluating seizure frequency, clinical status, quality of life and neurodevelopmental measures. Zorevunersen was generally well tolerated, and seizure reductions were observed, especially in patients receiving the highest initial dose. A Phase 3 EMPEROR study is underway to test efficacy, safety and tolerability in a controlled design.
Why it matters
- Researchers / academia: Need to test whether genetically targeted epilepsy therapies can improve outcomes beyond seizure reduction, including cognition, behaviour and daily functioning.
- Clinicians: Will need pathways for early genetic confirmation, specialist counselling and referral if disease-modifying approaches move closer to practice.
- Patients / advocates: Should watch whether promising early data are confirmed in Phase 3 and whether access planning includes diagnosis, delivery and follow-up capacity.
Previously, Dravet syndrome care focused mainly on reducing seizure frequency and managing developmental, behavioural and safety risks. Existing treatments can help, but they do not fully address the underlying genetic cause.
What has changed is the emergence of a treatment strategy aimed at the disease mechanism itself. Zorevunersen is an antisense oligonucleotide designed to increase functional NaV1.1 protein production from the unaffected SCN1A copy. This makes the relevant population more precise: children and adolescents with Dravet syndrome whose disease biology matches the target.
The evidence is promising, but still early. The published studies were not designed as definitive access evidence. They were primarily safety and tolerability studies, with seizure and developmental outcomes assessed in early-phase and extension settings. That makes the ongoing Phase 3 study critical before the therapy can be treated as routine-ready.
For IPM, the implication is clear: precision epilepsy will require a pathway that starts with early genetic diagnosis. Without that, disease-modifying approaches may exist scientifically but arrive too late for the children most likely to benefit.
