Praxis Precision Medicines, Inc. provided an update on its Phase 2a proof of concept study evaluating PRAX-628 in epilepsy patients with PPR. PPR studies measure electroencephalogram (EEG) signatures after intermittent photic stimulation and are used as an indicator of anti-seizure efficacy. About the Phase 2a PPR Study: Patient EEG signatures were assessed at defined measurement points over a 24-hour period after receiving placebo or PRAX-628, and results were compared to baseline.

Patients must have demonstrated PPR during screening and baseline to be evaluable. A total of six patients were baselined in the 15 mg cohort, of whom five were evaluable. One patient in the 15 mg cohort did not present adequate PPR at baseline to be evaluated.

Four patients were baselined in the 45 mg cohort, of whom three were evaluable. One patient in the 45 mg cohort was not evaluable due to lack of eligibility. Three patients from the 15mg cohort participated in the 45mg cohort after a washout period of >100 days.

Three patients were on background anti-seizure medications (ASMs). Response Assessment: Complete: Reduction to zero in the number of generalized PPR events at any assessment period vs. baseline.

Partial: Reduction, other than to zero, in the number of generalized PPR events at any assessment period vs. baseline. Safety and PK samples were collected during the entire observation period.

PRAX-628 for Focal Epilepsy: The Phase 2a study builds on positive results from animal studies and the Phase 1 dose escalation study in healthy volunteers. PRAX-628 demonstrated unprecedented pre-clinical efficacy in the maximal electroshock seizure (MES) model. PRAX-628 was generally well-tolerated at all tested doses in the Phase 1 study.

Pharmacokinetic data from the Phase 1 study demonstrated dose-dependent exposure supporting once-daily dosing without titration to achieve potentially therapeutically effective drug concentration levels. Further analysis of patients in the Phase 1 study using quantitative EEG data showed a pharmacodynamic effect at all dose levels and was significantly different from placebo.