Rapport's RAP-219 narrowly clears Phase 2 bipolar mania trial, plans FDA meeting

Rapport Therapeutics' experimental pill RAP-219 narrowly met statistical significance in a mid-stage bipolar mania study, an unexpected result analysts said could unlock a billion-dollar-plus market. The Boston-based company plans to meet with the FDA in the first quarter of next year to discuss the data and late-stage trial design, with two Phase 3 studies in acute bipolar mania slated to begin in the second half of 2027. In the roughly 250-patient trial, RAP-219 reduced scores on a 0-to-60 symptom scale by an average of 15.4 points after three weeks versus 12.3 points for placebo — a 3.1-point difference just sufficient for significance. Drug-treated patients improved across all 11 scale components, and RAP-219 also beat placebo on a secondary mania measure. Adverse events were mild to moderate and comparable between arms, with agitation most common in the treatment group. Jefferies analyst Andrew Tsai said the drug's safety appears "clean" and efficacy in line with approved bipolar medicines, noting continued success could add over $1 billion to peak sales forecasts. Stifel's Paul Matteis called the win a "clear positive" despite efficacy near the threshold of significance. An estimated 3% of U.S. adults, or more than 7 million people, have bipolar disorder.