Acadia Pharmaceuticals reported a Phase 2 failure in Alzheimer’s disease psychosis but said the company has enough signal to continue into Phase 3 with modifications. The company framed the decision as a path forward after identifying activity signal despite missing the primary endpoint. For trials in psychiatric symptoms associated with neurodegeneration, this kind of outcome typically forces protocol renegotiations around enrichment, endpoint selection, and dose or duration. Analysts also highlighted debate on the safety language in the readout, which can influence confidence in the risk-benefit profile as development moves into a larger, longer Phase 3. The update reinforces how quickly Alzheimer’s development programs must adapt after mid-stage readouts in order to protect timelines and investor expectations.