Key Highlights

  • Rapport Therapeutics (NASDAQ:RAPP) traded at USD 22.55, down 18.12%, in pre-market trading on Wednesday, October 28, 2026. No company announcement dated that day or the day before was identified, and the latest release covered bipolar mania data from Tuesday, October 20, 2026.
  • In the Phase 2 trial of RAP-219 in 253 adults with acute bipolar mania, the drug improved the Young Mania Rating Scale by 3.1 points more than placebo at Week 3, with a p-value of 0.045.
  • For the second quarter of 2026 the company reported a net loss of USD 56.6 million and cash of USD 436.1 million, which it expects will fund operations into the second half of 2029.
  • Pre-market trading is thin and prices can change before the 9:30 a.m. ET open. The Federal Reserve decision is due later on Wednesday, October 28, 2026.

Pre-Market Move and Its Trigger

Rapport Therapeutics (NASDAQ:RAPP) is a clinical-stage company developing RAP-219 for focal onset seizures and acute bipolar mania. Its USD 22.55 pre-market price, down 18.12%, appeared on Wednesday, October 28, 2026. Working back from that quote puts the prior close near USD 27.54, a simple calculation. No company announcement dated on or just before that day accompanied the move. The latest release, dated Tuesday, October 20, 2026 at 6:00 a.m. ET, reported topline results from the Phase 2 bipolar mania trial. The pre-market slide appears to reflect continued repricing of those data and thin trading, which is an inference rather than a company statement.

Why the Bipolar Data and Balance Sheet Frame the Move

RAP-219 lowered Young Mania Rating Scale scores by 15.4 points against 12.3 points on placebo, a placebo-adjusted gain of 3.1 points with a p-value of 0.045, according to the release of Tuesday, October 20, 2026. A secondary clinician-rated severity measure improved by 0.4 points versus placebo, with a p-value of 0.024. Every adverse event in the treatment period was mild or moderate, and discontinuations for adverse events were 3.2% on RAP-219 against 0.8% on placebo. Two Phase 3 bipolar mania trials are expected to start in the second half of 2027. The Wednesday, August 5, 2026 release reported a net loss of USD 56.6 million, research and development expense of USD 51.4 million and a loss of USD 1.19 per share.

Risks and Signals to Track

Positives: the primary endpoint was met, safety was described as mild or moderate, and cash of USD 436.1 million at Tuesday, June 30, 2026 funds operations into the second half of 2029, while Phase 3 trials in focal onset seizures are enrolling. Negatives: a p-value of 0.045 is close to the conventional 0.05 threshold, and the Phase 3 bipolar mania start is not expected until the second half of 2027. Risks named include trial outcomes, higher discontinuation rates, rising expenses and future dilution. Items to watch: open-label safety data and the start of China recruitment, both expected in the fourth quarter of 2026, the third quarter report and the Federal Reserve decision later on Wednesday, October 28, 2026.

Where Things Stand

In short, Rapport Therapeutics (NASDAQ:RAPP) dropped 18.12% to USD 22.55 before the open, with no company announcement dated on or just before Wednesday, October 28, 2026. The move seems linked to the data of Tuesday, October 20, 2026 and to thin trading. The headline figure is the 3.1-point placebo-adjusted improvement, with a p-value of 0.045. Catalysts ahead include the fourth quarter 2026 open-label safety data, the start of China Phase 3 recruitment and the Federal Reserve decision due later on Wednesday, October 28, 2026. Pre-market prices are snapshots that can change, and this is not investment advice.