Rapport Therapeutics (RAPP) Study Result summary

Study background and rationale

• RAP-219 targets drug-resistant focal onset seizures, addressing a significant unmet need as 30-40% of epilepsy patients do not respond to current medications.

• Preclinical models showed robust, dose-dependent seizure protection and high target expression in seizure-initiating brain regions.

• RAP-219 offers once-daily dosing, low risk of drug-drug interactions, and a long half-life, supporting ease of use and broad adoption.

Study design and patient population

• Phase II-A/2a trial enrolled 30 adults with drug-resistant focal onset seizures and implanted RNS devices; 26 completed the 8-week open-label treatment.

• Patients had long-standing epilepsy, median of three background anti-seizure medications, and stable RNS and medication regimens prior to enrollment.

• Study included a 12-week pre-treatment, 8-week treatment, and 8-week follow-up period; key entry criteria included ≥16 long episodes during baseline.

• Three analysis populations were defined: safety, mITT, and mITT-CS for efficacy assessments.

Efficacy results

• RAP-219 achieved a 71% median reduction in long episode frequency and a 77.8% median reduction in clinical seizure frequency.

• 85.2% of patients had ≥30% reduction in long episodes; 72% had ≥50% reduction in clinical seizures.

• 24% of patients were seizure-free during the full eight-week treatment period.

• Efficacy was robust regardless of background anti-seizure medication regimen and supported by both clinical and electrographic biomarker data.

• Rapid onset of efficacy was observed, with effects seen within days of starting treatment.