ACADIA Pharmaceuticals Inc. Securities Lawsuit Investigation

Shamis & Gentile P.A., a law firm that advocates for investors who are victims of securities fraud, is investigating potential claims against ACADIA Pharmaceuticals Inc. (ACAD)

If you purchased or held ACADIA Pharmaceuticals securities and suffered losses, you may be eligible to join this securities investigation and seek compensation.

About ACADIA Pharmaceuticals

ACADIA Pharmaceuticals is a biopharmaceutical company focused on developing and commercializing innovative medicines to address unmet medical needs in central nervous system disorders.

Its portfolio has included candidates such as intranasal carbetocin (ACP-101) for Prader-Willi syndrome (PWS) and pimavanserin for schizophrenia, as well as Nuplazid for Parkinson’s disease psychosis.

Potential Concerns Under Investigation

Lawyers are investigating whether ACADIA Pharmaceuticals and certain executives may have made misleading statements or omitted material information regarding its drug development programs between November 30, 2023, and late-September 2025. The investigation centers on whether the company adequately disclosed the risks and status of its lead drug candidates, particularly ACP-101 and pimavanserin.

On November 30, 2023, ACADIA Pharmaceuticals announced the start of its pivotal Phase 3 COMPASS PWS trial for ACP-101, emphasizing the unmet need for PWS treatments and presenting ACP-101 as a promising candidate. 

The company's Chief Medical Officer stated that prior Phase 3 trials had shown carbetocin nasal spray ‘was observed to reduce hyperphagia-related behaviors,’ although those studies did not reach statistical significance on primary endpoints. Attorneys may examine whether earlier statements downplayed the severity of prior trial failures or failed to disclose that earlier studies had not reached statistical significance on their primary endpoints.

Questions have been raised as to whether the company's public statements gave an overly optimistic impression without adequately disclosing known risks.

Throughout the investigation period, ACADIA Pharmaceuticals allegedly highlighted its drug pipeline and development plans, including positive commentary on ACP-101 and pimavanserin in press releases, SEC filings, and analyst calls. Public communications may have failed to disclose significant risks and adverse information about the challenges in its clinical trials.

The alleged corrective disclosure occurred on March 11, 2024, when ACADIA Pharmaceuticals revealed that its late-stage pimavanserin trial for schizophrenia had failed to show efficacy, and the company would discontinue further clinical trials for this indication. Shares dropped approximately 16% on this news, causing substantial losses for investors.

On September 24, 2025, ACADIA Pharmaceuticals announced that the Phase 3 COMPASS PWS trial for ACP-101 "did not demonstrate a statistically significant improvement" over placebo on the primary or secondary endpoints. Management expressed disappointment and stated the company would not continue development of ACP-101.

Following this announcement, the stock fell about $2.34 per share, or 9.9%, from $23.60 to $21.26. With approximately 168 million shares outstanding, the $2.34 per-share drop on September 24, 2025, implies approximate aggregate losses of about $390 million.

Legal professionals might consider whether ACADIA Pharmaceuticals’ leadership had motives to keep the stock price high, given the company’s reliance on its drug pipeline for revenue. For instance, Nuplazid accounted for approximately 72% of 2023 sales, and the success of ACP-101 and pimavanserin was critical to the company’s growth strategy.

The abrupt discontinuation of both ACP-101 and pimavanserin programs, after extensive promotion, could be viewed as a red flag suggesting that executives may have known more about the clinical challenges than was publicly disclosed.

Your Rights and Next Steps

Investors who purchased or acquired ACADIA Pharmaceuticals securities between November 30, 2023, and late-September 2025, and suffered financial losses may have important legal rights. This is an active investigation, not a filed lawsuit, but it could lead to a securities class action if sufficient evidence of wrongdoing is uncovered.

Lawyers are ready to help investors understand their options. By joining the investigation, investors may help strengthen the case and increase the likelihood of recovering losses. If the investigation develops into a class action, eligible investors may have the opportunity to participate and seek compensation for their damages.

It is important for investors to act promptly, as securities investigations and potential class actions are time-sensitive. Gathering documentation of stock purchases, sales, and losses during the class period can help support any future claims.

You May Be Entitled to Compensation

If you purchased or acquired ACADIA Pharmaceuticals securities and experienced losses during the proposed class period, you may be eligible to join this investigation and seek financial recovery. Securities investigations move quickly, and there may be deadlines for participating in any future class action.

To protect your rights and explore your options, complete the form below to join the investigation. Lawyers are ready to help evaluate your claim and guide you through the next steps.