Rapport reports 3.1-point improvement over placebo in mania treatment trial
Key Facts
Rapport Therapeutics announced on October 20 that its experimental treatment for bipolar mania delivered a placebo-adjusted improvement of 3.1 points on the Young Mania Rating Scale. The company said in a results statement attached to a U.S. Securities and Exchange Commission filing that the trial met its primary and secondary endpoints with statistical significance. The Phase 2 clinical study was conducted in the United States and enrolled 253 adult participants. Participants were experiencing an acute manic episode associated with bipolar I disorder, according to the filing. The trial used a randomized, double-blind, placebo-controlled design, and the company plans to discuss its results with regulators as part of the treatment's development.
The primary endpoint had a p-value of 0.045, according to the company's statement, which reported the adjusted difference in total Young Mania Rating Scale scores between the drug and placebo. The secondary endpoint, measuring mania severity on the Clinical Global Impression scale for bipolar disorder, showed an adjusted improvement of 0.4 points. That endpoint had a p-value of 0.024, according to the same statement. Rapport had amended the trial's statistical analysis plan before announcing the results, according to an earlier business update filed with the Securities and Exchange Commission. It also increased the target enrollment to allow the study to be considered potential confirmatory evidence of the drug's efficacy as part of its development for mania.
On safety, Rapport said in its statement that "all treatment-emergent adverse events were mild or moderate in severity." Overall treatment discontinuation was 24.6% in the drug group, compared with 11.8% in the placebo group, according to the regulatory filing. Withdrawal of consent was the most common reason for discontinuation, the company said. The trial used a maintenance dose of 0.75 mg, according to the presentation Rapport released with the study results. Among refinements for the upcoming program, the company presented a higher dose of 1.25 mg, intended to achieve receptor occupancy levels more quickly.
The drug's scientific approach, according to Rapport's presentation, relies on selective modulation of AMPA receptor activity associated with the protein TARP gamma 8. The approach aims to reduce excitatory activity associated with mania, according to the scientific description the company provided with the trial results. On commercial development, Rapport has a collaboration and licensing agreement with Tenacia Biotechnology, according to an earlier business update. The agreement covers development and commercialization of the drug in Greater China across its targeted indications, including the bipolar mania addressed by the new results. It also includes focal epilepsy within the scope of the companies' announced collaboration and licensing arrangement to develop and commercialize the treatment in that region.
On finances, Rapport's net loss in the second quarter of 2026 was about $56.6 million, compared with $26.7 million in the same period a year earlier, according to its financial results. Research and development expenses for the three months ended June 2026 were about $51.4 million. That compared with $22.7 million in the corresponding period, according to the quarterly report filed with the Securities and Exchange Commission. The company ended the second quarter with cash, cash equivalents and short-term investments of $436.1 million, excluding restricted cash. In its trial results presentation, Rapport projected that its resources would fund operations into the second half of 2029.
Rapport plans to meet with the U.S. Food and Drug Administration in the first quarter of 2027, according to the filing accompanying the study results. The company plans to discuss the clinical data and the design of trials required for registration at the meeting, the program's next regulatory step. Its presentation on trial development includes expanding the geographic scope beyond the United States, where the Phase 2 study was conducted. Rapport listed that expansion among the design refinements presented for the upcoming program, alongside the proposed dose adjustment. The company expects to begin its Phase 3 program for bipolar mania in the second half of 2027, according to the timeline in the results presentation.