Monday, Acadia Pharmaceuticals Inc (NASDAQ:ACAD) released top-line results from the Phase 3 ADVANCE-2 trial evaluating pimavanserin for negative symptoms of schizophrenia. 

Pimavanserin did not demonstrate a statistically significant improvement over placebo on the study’s primary endpoint, the change from baseline to week 26 on the Negative Symptom Assessment-16 (NSA-16) total score (-11.8 vs. -11.1; p=0.4825; effect size=0.07). 

“We will continue to analyze these data with our scientific advisors, but we do not intend to conduct any further clinical trials with pimavanserin. We want to thank the patients, their families, and the investigators for their contributions in this important study,” said Steve Davis, Acadia’s Chief Executive Officer. 

ADVANCE-2 used the NSA-16 scale, designed to measure change on the wide range of predominant negative symptoms that patients experience, which looks at 16 items in five subscales and covers symptoms such as blunted affect, poor socialization and lack of motivation.​ 

The change from baseline observed in the pimavanserin arm of ADVANCE-2 was similar to the change from baseline observed at the 34 milligram dose in ADVANCE-1 (-11.8 vs. -11.6); however, the placebo effect in ADVANCE-2 was higher than the placebo effect observed in ADVANCE-1 (-11.1 vs. -8.5).

The safety and tolerability profile of pimavanserin was consistent with previous clinical trials, showing a low rate of adverse events.

In ADVANCE-2, pimavanserin was well-tolerated with an adverse event rate of 30.4% compared with 40.3% for the placebo arm.

Pimavanserin is already marketed as Nuplazid as the first and only prescription medication approved by the FDA for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis.

In the fourth quarter of 2023, Nuplazid’s net product sales were $143.9 million and $549.2 million for fiscal year 2023.

Price Action: ACAD shares are down 14.63% at $20.60 during the premarket session on the last check Tuesday.

Illustration of Phrama lab worker created with MidJourney.