Praxis Precision Medicines’ registrational trial of relutrigine in developmental and epileptic encephalopathies (DEEs) was stopped early for efficacy after a phase II readout, triggering a sharp rise in the company’s shares. The early halt indicates the study met predefined efficacy thresholds and could accelerate regulatory interactions and pivotal plans. Company disclosures and conference reporting noted consistent efficacy across severity spectra and durable responses, prompting investor optimism. Clarification: An early stop for efficacy occurs when interim data show treatment benefits sufficiently compelling to justify ending enrollment and proceeding to regulatory steps.