Acadia to end Nuplazid testing after schizophrenia trial flop and years of failed expansion efforts

Acadia Pharmaceuticals is calling it quits on future testing of Nuplazid after a string of expansion efforts have come up short.

Most recently, the drug couldn’t meet the mark in a phase 3 trial evaluating its potential for treating negative symptoms of schizophrenia, the company said in a Monday press release.

The 26-week study was comprised of 454 adult patients with mostly negative symptoms who had gained control of their positive symptoms through ongoing antipsychotic treatment. Negative symptoms of schizophrenia include poor socialization and lack of motivation, while positive symptoms include hallucinations or delusions.

In the study, Nuplazid (pimavanserin) didn't provide a significant improvement versus placebo when measured on the Negative Symptom Assessment-16 (NSA-16) scale.

Acadia is “disappointed the trial did not meet its primary endpoint given the significant unmet need in patients with negative symptoms of schizophrenia,” CEO Steve Davis said in the release. “We will continue to analyze these data with our scientific advisors, but we do not intend to conduct any further clinical trials with pimavanserin.”

It’s the end of a long chapter of futile efforts to expand the med after its 2016 FDA approval to treat Parkinson’s disease psychosis.

The company long pushed for a nod in dementia-related psychosis, which resulted in a 2021 complete response letter that Acadia described as “very disappointing." The FDA took issue with the design of the company's pivotal trial used to support the application, while Acadia said it has a go-ahead from the agency to run the study.

Acadia later pivoted to the smaller subgroup of patients with Alzheimer’s disease psychosis, but that bid was rejected in 2022. In its rejection, the agency recommended another trial due to “limitations in the interpretability” of the initial study's results in that subset.

Meanwhile, as Acadia moves past efforts to expand Nuplazid's label, it’s focusing on its newer offering, Daybue.

Last year, Daybue scored FDA approval as the first approved treatment for neurodevelopmental disorder Rett syndrome. The drug generated $177 million in sales during 2023, while Nuplazid picked up $549 million.