Rapport Therapeutics, Inc. (RAPP) · Oct 20, 2026 · Other events

Rapport Therapeutics bipolar trial clears Phase 2 bar, caveats remain

Above the bar — YMRS benefit 3.1 points, p=0.045; CGI-BP benefit 0.4 points, p=0.024

Rapport Therapeutics’ bipolar mania trial met both endpoints and supports Phase 3, but high overall discontinuations and incomplete follow-up temper the read.

Rapport is a clinical-stage neuroscience company building its lead drug, RAP-219, across epilepsy and bipolar mania; its epilepsy Phase 3 program is already enrolling, while bipolar mania data had been pulled forward to October 2026 from earlier 2027 timing.

The efficacy readout clears the trial’s bar, but only narrowly on the primary endpoint. RAP-219 beat placebo by 3.1 points on the Young Mania Rating Scale at Week 3, with a p-value of 0.045, and also produced a statistically significant 0.4-point improvement on the prespecified CGI-BP mania-severity endpoint at p=0.024. That is a genuine proof-of-concept result and supports moving into Phase 3, but the primary result is close to the conventional significance threshold rather than an overwhelming efficacy signal.

MeasureRAP-219Placebo / comparisonRead
Week 3 YMRS change from baseline-15.4 points-12.3 points3.1-point placebo-adjusted advantage (Financial Highlights)
Week 3 CGI-BP mania-severity improvement——0.4-point placebo-adjusted advantage; p=0.024 (Efficacy results)
Any treatment-emergent adverse event51.6%52.8%Broadly balanced (Treatment Period TEAE Summary)
Discontinuation due to treatment-emergent adverse event3.2%0.8%Higher on RAP-219 (Treatment Period TEAE Summary)
Overall treatment discontinuation24.6%11.8%Mainly withdrawal of consent (Patient disposition)

The tolerability profile looks differentiated, but the headline “low discontinuation” omits a meaningful operational wrinkle. Treatment-emergent adverse events were similar to placebo, all were mild or moderate, and no serious or severe events were reported. 〔0〕 However, 24.6% of RAP-219 patients discontinued treatment versus 11.8% on placebo, driven primarily by withdrawal of consent rather than adverse events. That does not invalidate the efficacy result, but it complicates confidence in adherence and makes the larger Phase 3 population especially important.

The result advances RAP-219 into a credible second indication, not toward approval. The company plans an FDA End-of-Phase 2 meeting in the first quarter of 2027 and two bipolar-mania Phase 3 trials in the second half of 2027. 〔1〕 The evidence is also incomplete: the reported safety window covers only the three-week treatment period, with eight-week post-treatment safety data still to come. 〔2〕

The timing was largely expected; the clinical confirmation is the new information. Rapport had already guided to October 2026 topline results, so this is not a surprise on timing. What changed is that the bipolar program now joins the company’s epilepsy portfolio as a Phase 3 opportunity, strengthening the “pipeline-in-a-product” story while leaving dose selection, longer-term safety, and reproducibility for the next stage.

Bottom line: RAP-219 passed its bipolar mania Phase 2 efficacy test and supports Phase 3, making this a meaningful advance for Rapport’s pipeline. The signal is positive but not definitive: the modest primary-endpoint margin, elevated overall discontinuation rate, and incomplete follow-up keep the result from being a clean home run.

What to watch next

FDA End-of-Phase 2 meeting, first quarter 2027

Original filing on SEC EDGAR

More Rapport Therapeutics, Inc. news

Rapport Therapeutics bipolar trial clears Phase 2 bar, caveats remain | RAPP Stock News
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