Antiseizure Medications in Development: Novel Mechanisms, Precision Therapy, and the Move Towards Disease Modification.

Background

Despite more than 30 licenced antiseizure medications (ASMs), approximately one third of people with epilepsy remain drug-resistant, and developmental and epileptic encephalopathies represent one of the greatest unmet needs in epilepsy therapeutics. The past decade has produced a substantial reorientation of ASM discovery, driven by epilepsy genetics, new disease models, advances in drug screening, and innovative therapeutic modalities.

Objective

The objective of this study was to review the contemporary clinical-stage pipeline of ASMs with novel or differentiated mechanisms of action, organized by molecular target, while placing recent regulatory successes and instructive failures within the broader transition toward mechanism-based, precision, and potentially disease-modifying therapies. Findings: A 2024 pipeline analysis identified more than 200 epilepsy therapies in preclinical or clinical development; at the cutoff of the present literature search (30 June 2026), over 40 compounds had reached phase II or III, with the majority directed at DEEs. Functional-state-selective sodium channel modulation has emerged as a leading conceptual advance supported by converging mechanistic and early clinical evidence, exemplified by relutrigine (PRAX-562), a preferential persistent-current inhibitor for which a regulatory decision is pending in SCN2A/SCN8A-DEEs, and vormatrigine (PRAX-628), whose large open-label effect was not reproduced in a controlled (blinded) trial. Several of the efficacy figures summarized here derive from congress presentations, interim analyses, or open-label extensions and await full peer-reviewed publication. Parallel advances include the selective Kv7 opener azetukalner; the dual-mechanism benchmark cenobamate; cholesterol-24-hydroxylase inhibition (soticlestat); selective serotonergic agonism (bexicaserin); glutamatergic precision agents (radiprodil); subtype-selective GABAA modulators (darigabat, ganaxolone); and gene-directed therapies (zorevunersen, elsunersen). Pre-symptomatic intervention in tuberous sclerosis complex provides an early, single-trial clinical proof of principle for delaying and reducing the incidence of epilepsy in a genetically defined population; this should not yet be equated with established disease prevention.

Conclusions

The pipeline reflects an ongoing shift from broad symptomatic agents toward mechanism-led, genotype-matched, and potentially disease-modifying treatments. This shift is tempered by a persistent translational gap between early signals and randomized-trial confirmation, and by the preliminary status of much of the supporting evidence.