Rapport Therapeutics Plans to Initiate Its Phase 3 Program for RAP-219 in Focal Onset Seizures in Q2 of 2026 and Expand Its Epilepsy Portfolio With New Program in Primary Generalized Tonic-Clonic Seizures

CLINICAL AND PIPELINE UPDATES

Rapport is prioritizing programs it believes have the greatest potential to deliver meaningful impact for patients and long-term value for the Company. This disciplined approach positions the Company for a strong cadence of milestones throughout 2026 and beyond as it advances its pipeline.

RAP-219 Epilepsy Portfolio

• Robust Phase 2a Data in FOS Supports a Multi-Billion Market Opportunity, if Approved. Market research indicates epileptologists and neurologists view RAP-219's potential best-in-class profile as highly favorable, suggesting a greater than $2B commercial opportunity in the U.S., if approved.
• Updating Guidance on Start of Phase 3 Program in FOS. Following Rapport's End-of-Phase-2 meeting with the FDA in December, the Company is accelerating the initiation of its Phase 3 program in FOS to begin in the second quarter of 2026, updated from its previous guidance of initiation in the third quarter of 2026.
• Open-label Trial Initiated. The Company has begun enrolling patients into an open-label, long-term safety trial, enabling participants from its recently completed Phase 2a FOS trial to resume RAP-219 treatment. Initial data from the trial is expected to be shared in the second half of 2026.
• Expansion into PGTCS. Building on the robust clinical data from RAP-219's Phase 2a clinical trial in FOS, Rapport is expanding its epilepsy portfolio into PGTCS, the most common type of generalized seizure and an important next step in addressing unmet need across the epilepsy spectrum. With proof-of-concept established in FOS, Rapport plans to initiate a Phase 3 trial of RAP-219 in PGTCS in the first half of 2027.

Additional RAP-219 Updates

• Bipolar Mania Phase 2 Trial Progress. The Company's Phase 2 trial of RAP-219 in bipolar mania continues to enroll patients and remains on track to report topline results in the first half of 2027.
• Long-Acting Injectable Development. Development of a long-acting injectable for RAP-219, a key potential differentiator in the epilepsy space, continues to progress. Investigational New Drug (IND)-enabling activities are expected to start in the first quarter of 2026 to support a Phase 1 clinical study in healthy volunteers, with initial pharmacokinetic results expected in 2027.
• DPNP Trial Clinical Hold Lifted. Following further discussions with the FDA in December, the FDA removed its clinical hold on the DPNP IND. The Company is deferring further investment in the RAP-219 DPNP program as it prioritizes its α6β4 program, which it believes has significant potential in chronic pain and migraine.

Other Pipeline Updates

• α6β4 Investigational New Drug (IND)-Enabling Activities Underway. Rapport has initiated IND-enabling activities for its development candidate agonist of the α6β4 nAChR, a clinically-validated target the Company is pursuing as a potential novel non-opioid, non-CNS approach for chronic pain and migraine.

BUSINESS UPDATES

• Presentation at the 44th Annual J.P. Morgan Healthcare Conference. Rapport Therapeutics will present at the 44th Annual J.P. Morgan Healthcare Conference, being held next week in San Francisco, CA. 
• Cash Position. The Company ended the third quarter with $513.0 million in cash, cash equivalents and short-term investments. Management expects this will be sufficient to fund the Company's planned operations into the second half of 2029.