Acadia Pharmaceuticals reported that its Phase 2 Alzheimer’s disease psychosis study with remlifanserin missed the primary endpoint, but the company said the signal supports moving into Phase 3 “with a caveat.” The update follows scrutiny around competing mechanisms in the indication. In the trial’s primary endpoint—change from baseline on the Scale for the Assessment of Positive Symptoms–Hallucinations and Delusions subscales—60 mg of the 5HT2A inverse agonist did not meet the target effect versus placebo at week six, with a p-value just above the conventional threshold. Shares fell after the disclosure as the interpretation of the remaining signal became the market focus. Acadia’s decision effectively keeps the program alive while acknowledging uncertainty in statistical confidence, setting up the next phase as the test of whether the Phase 2 read-through translates into robust efficacy.