Updated version: Acadia's drug for the treatment of Alzheimer’s disease-related psychosis failed to meet the primary endpoint in a mid-stage trial.

Full rewrite, updated stock price performance, added executive comments in the 6th paragraph and analyst comments in the 7th paragraph.

Sahil Pandey

Reuters, September 24 - Acadia Pharmaceuticals (ACAD.O) said on Thursday that its experimental drug for treating psychosis related to Alzheimer's disease failed to meet the main goal in a mid-stage trial, sending the company’s shares down about 11%.

Patients receiving the 60mg once-daily dose of remlifanserin showed greater improvement in reducing hallucinations and delusions compared to those taking a placebo, but the difference was not substantial enough for the study to achieve its primary endpoint.

The lower 30mg dose group did not show significant efficacy across the study measures, while the higher dose group met the key secondary endpoint assessing overall severity of Alzheimer’s disease psychosis symptoms.

Despite the setback, Acadia said it will continue recruiting patients for two ongoing late-stage clinical trials and discontinue the 30mg dose group. The company still expects peak sales for remlifanserin to reach around $4 billion in Alzheimer’s disease psychosis and Lewy body dementia psychosis.

Additionally, analysis indicated that patients with more severe psychosis symptoms may benefit more from the drug, so the company is considering moderate adjustments to patient screening criteria.

“I don’t think we are likely to take further measures that would narrow the eligible trial patient population much further,” Acadia’s head of R&D, Elizabeth H.Z. Thompson, said when discussing potential adjustments being considered for the late-stage clinical program.

BMO Capital Markets analyst Evan Seigerman said that while the trial narrowly missed its main objective, the positive results on key secondary measures suggest potential avenues for Acadia as it refines the ongoing late-stage study design.

Acadia said the incidences of adverse events, serious adverse events, and treatment discontinuation rates for the drug were comparable to the placebo group, with no evident negative impact on motor or cognitive function and no deaths among treated patients.

Psychosis associated with Alzheimer’s disease affects about 30% of patients diagnosed with the condition, can cause hallucinations and delusions, increase the burden on caregivers and raise the need for nursing home care. There is currently no approved treatment for this disorder.

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