A Long-term Study of the Safety and Effectiveness of RAP-219 in Adults With Focal Onset Seizures

January 22, 2026 updated by: Rapport Therapeutics Inc.

An Open-label, Long-term Study Evaluating RAP-219 in Adult Participants With Refractory Onset Seizures

This is a clinical research study for an investigational drug called RAP-219 in patients with Refractory Focal Epilepsy. This study is being conducted to determine RAP-219 Long- term safety and open-label antiseizure activity in patients with Refractory Focal Epilepsy.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This is a multi-center, open-label study to evaluate the long-term safety, tolerability, pharmacokinetics, pharmacodynamics and antiseizure activity of RAP-219 in adult participants with refractory focal seizures

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Idaho
      • Boise, Idaho, United States, 83702
        • Recruiting
        • Consultants in Epilepsy and Neurology, PLLC
    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Recruiting
        • Mayo Clinic
    • New York
      • New York, New York, United States, 10016
        • Recruiting
        • NYU Langone Comprehensive Epilepsy Center
    • Ohio
      • Cleveland, Ohio, United States, 44195
        • Recruiting
        • Cleveland Clinic Foundation
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • University of Pennsylvania - Department of Neurology
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Recruiting
        • Vanderbilt University Medical Center
    • Texas
      • Houston, Texas, United States, 770300
        • Recruiting
        • Baylor College of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Completion of the associated parent study (RAP-219-FOS-201) treatment period with acceptable tolerability, per Investigator.
  • Diagnosis of refractory focal epilepsy
  • Stable RNS(c) system settings
  • A demonstrated history of compliance with RNS(c) system data interrogation and upload
  • Good overall health other than focal epilepsy, per Investigator.
  • BMI ≥ 18 kg/m^2 and ≤ 45 kg/m^2
  • Willing and able to adhere to all aspects of the protocol.

Exclusion Criteria:

  • Known of hypersensitivity to RAP-219
  • Any clinically unstable or serious medical, neurological (other than epilepsy), psychological, or behavioral problem; laboratory or ECG finding that would increase participant risk or should otherwise exclude the patient from participation, as assessed by Investigator
  • Pregnancy, lactation, or individuals of reproductive potential who do not agree to simultaneously use two effective birth-control methods

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: RAP-219
Drug: RAP-219
Participants will receive one RAP-219 0.125 mg capsule daily for 3 days followed by one 0.25mg tablet RAP-219 daily for 28 days, then one 0.75mg tablet daily for the remainder of the treatment period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Incidence of treatment-emergent adverse events (TEAEs)
Time Frame: From the start of RAP-219 treatment through 8 weeks after last dose, up to Week 112
From the start of RAP-219 treatment through 8 weeks after last dose, up to Week 112

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percent change in clinical seizure frequency
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Group median percent change in clinical seizure frequency per 28-day period as reported in a clinical seizure diary
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Clinical seizure 25%, 50%, 75%, and 100% responder proportions
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Proportion of participants with at least 25%, 50%, 75%, or with 100% reduction in clinical seizure frequency per 28-day period as reported in a clinical seizure diary
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Change in clinical seizure-free day frequency
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Group median change in clinical seizure-free day frequency per 28-day period as reported in a clinical seizure diary
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Longest clinical seizure-free interval
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Duration, in days, of the longest continuous period of clinical seizure-free days per period as reported in a clinical seizure diary
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Time to pre-randomization clinical seizure count
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Duration, in days, between the beginning of the open-label treatment period and the nth clinical seizure, where n is the number of clinical seizures per 28-day period during the prospective pre-treatment baseline period, as reported in a clinical seizure diary
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
RNS long episode 30%, 50%, 75% or with 100% responder proportions
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Proportion of participants with at least 30%, 50%, 75%, and 100% reduction in long episodes per 28-day period as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Percent change in RNS long episode frequency
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Group median percent change in long episode frequency per 28-day period as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Change in RNS long episode-free day frequency
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Group median change in long episode-free day frequency per 28-day period as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Longest RNS long episode-free interval
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Duration, in days, of the longest continuous period of long episode-free days per period as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Time to pre-randomization long episode count
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Duration, in days, between the beginning of the open-label treatment period and the mth long episode, where m is the number of long episodes per 28-day period during the pre-treatment baseline period, as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Percent change in RNS estimated electrographic seizure frequency
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Group median percent change in estimated electrographic seizure frequency per 28-day period as recorded by the RNS® System
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Clinical Global Impression of Change (CGI-C) responder count and proportions
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Count and proportion of participants with any improvement (minimally improved, much improved, or very much improved) or clinically meaningful improvement (much improved or very much improved) as reported on the Clinical Global Impression of Change (CGI-C) scale
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Patient Global Impression of Change [PGI-C] responder count and proportions
Time Frame: Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.
Count and proportion of participants with any improvement (minimally improved, much improved, or very much improved) or clinically meaningful improvement (much improved or very much improved) as reported on the Patient Global Impression of Change (PGI-C) scale
Throughout the open-label period until 8 weeks after the last dose, up to Week 112, compared to the pre-treatment baseline period.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Rapport Therapeutics Inc.

Investigators

  • Principal Investigator: Imran Quraishi, MD, Yale University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 15, 2025

Primary Completion (Estimated)

February 3, 2028

Study Completion (Estimated)

February 3, 2028

Study Registration Dates

First Submitted

October 8, 2025

First Submitted That Met QC Criteria

October 17, 2025

First Posted (Actual)

October 21, 2025

Study Record Updates

Last Update Posted (Actual)

January 23, 2026

Last Update Submitted That Met QC Criteria

January 22, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RAP-219-FOS-901

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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