RAPP Stock Soars 62% in a Week on Meeting Phase II Epilepsy Study Goal

Shares of Rapport Therapeutics RAPP surged 61.6% in a week after the company reported positive top-line data from a mid-stage study of its lead candidate, RAP-219, in patients with drug-resistant focal onset seizures (FOS), a type of epileptic seizure. RAP-219 is a potential first-in-class, investigational TARPγ8-specific AMPAR negative allosteric modulator.

The phase IIa RAP-219-FOS-201 study of RAP-219 is evaluating the candidate’s efficacy, safety, and tolerability in adults with drug-resistant FOS. The study enrolled thirty FOS patients, who received 0.75 mg of RAP-219 daily for the first five days, followed by 1.25 mg daily for the remainder of the eight-week treatment period. The study also entails another 8-week follow-up period, which is currently ongoing.

RAPP’s Phase II FOS Study Data in Detail

Rapport Therapeutics reported that the phase IIa FOS study met its primary endpoint, showing a statistically significant reduction in long episodes (LEs) — an electrographic biomarker tied to seizure activity — compared with baseline, over the eight-week treatment period. RAP-219 also delivered a statistically significant and clinically meaningful reduction in clinical seizures during the study.

Across the eight-week treatment period, 85.2% of patients achieved a ≥30% reduction in LEs, 72% achieved a ≥50% reduction in clinical seizures, and 24% of patients reached seizure freedom. RAP-219 was also found to be well-tolerated in the mid-stage study. Most adverse events related to treatment with the candidate were mild to moderate in severity. This further supports RAP-219’s potential advancement as a new anti-seizure medication.

Year to date, RAPP stock has gained 30.8% compared with the industry’s 5.6% growth. 

Per Rapport Therapeutics, as many as 40% of focal epilepsy patients continue to experience seizures despite a range of available therapies, underscoring the need for more effective treatments. Management believes that the magnitude of clinical seizure reduction and the corroborating biomarker data support RAP-219’s potential as a highly effective new therapy for patients with drug-resistant FOS.

RAPP’s Next Steps in the Development of its FOS Drug

Rapport Therapeutics plans to meet with the FDA in late 2025 to discuss the phase IIa FOS study top-line data and is targeting the launch of pivotal studies for RAP-219 in the third quarter of 2026. The company expects to share further efficacy analyses and eight-week follow-up data in 2026.

Rapport Therapeutics is also preparing to launch a long-term safety study of RAP-219 by the end of 2025, to enable FOS patients from the RAP-219-FOS-201 study to continue treatment with the candidate. Preliminary data from this open-label study are expected in the second half of 2026. In parallel, the company is advancing development of a long-acting injectable formulation of RAP-219, aimed at addressing patient nonadherence to oral anti-seizure medications, a key barrier to sustained treatment benefit.

Beyond epilepsy, Rapport Therapeutics is broadening RAP-219’s clinical program into additional indications. A separate phase II study evaluating the candidate in bipolar mania is currently underway, with top-line results anticipated in the first half of 2027. The company also plans to provide an update later in 2025 on the timeline for starting yet another mid-stage study of RAP-219 for diabetic peripheral neuropathic pain.

Rapport Therapeutics, Inc. Price and Consensus

Rapport Therapeutics, Inc. price-consensus-chart | Rapport Therapeutics, Inc. Quote

RAPP’s Zacks Rank & Stocks to Consider

Rapport Therapeutics currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are CorMedix CRMD, Pharming Group PHAR and Kiniksa Pharmaceuticals KNSA, each sporting a Zacks Rank #1 (Strong Buy) at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

In the past 60 days, estimates for CorMedix’s earnings per share have increased from $1.10 to $1.52 for 2025. During the same time, earnings per share estimates for 2026 have increased from $1.46 to $2.12. Year to date, shares of CRMD have surged 61.6%.

CorMedix’s earnings beat estimates in each of the trailing four quarters, delivering an average surprise of 34.85%.

In the past 60 days, estimates for Pharming Group’s 2025 loss per share have narrowed from 40 cents to 10 cents. For 2026, PHAR’s earnings per share estimate has improved from 7 cents to 27 cents. PHAR stock has risen 47% year to date.

Pharming Group’s earnings beat estimates in two of the trailing four quarters and missed on the remaining two occasions, delivering an average negative surprise of 39.14%.

In the past 60 days, estimates for Kiniksa Pharmaceuticals’ 2025 earnings per share have increased from 74 cents to $1.03. Earnings per share estimate for 2026 has increased from $1.19 to $1.60 during the same period. KNSA stock has surged 87.1% year to date.

Kiniksa Pharmaceuticals’ earnings beat estimates in two of the trailing four quarters and missed on the remaining two occasions, delivering an average negative surprise of 330.56%.

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