Acadia Halts Work on Depression Drug After Late-Stage Trial Failure

Acadia Pharmaceuticals received the FDA’s OK for pimavanserin (Nuplazid), the first drug approved to treat hallucinations and delusions associated with Parkinson’s disease, in 2016. Since then, the San Diego company has looked to expand its use into other indications, with mixed results.

That trend continued Monday when Acadia (NASDAQ: [[ticker:ACAD]]) reported it would end its efforts to advance the drug as an adjunctive treatment for major depressive disorder (MDD) after preliminary data from a Phase 3 trial indicated it failed to meet the study’s main goal.

The trial combined two studies that collectively enrolled about 300 patients with MDD. While the group that received pimavanserin once daily along with a standard antidepressant saw improvement in their depression after five weeks compared to those who received a placebo as an adjunct therapy, as measured by a rating scale used to track the disorder’s severity. But the difference between the two groups wasn’t enough to be statistically significant.

On a Monday afternoon conference call CEO Steve Davis called the company’s decision to end its development of the drug as a potential adjunctive depression treatment “primarily a commercial consideration,” though he noted that the company hadn’t yet finished its analysis of the full dataset.

“We’re not saying that the drug doesn’t have an antidepressant effect—we believe it does—it’s really a function of, what do we think the prospects are for getting that highly differentiated profile … in the jump to the MDD space, where there are approved generic drugs, and, particularly, given the position we have in [Parkinson’s-related psychosis] (PRP) and [dementia-related psychosis] (DRP), where there was no drug approved in PDP before us and there’s no drug approved in DRP,” he said. “So it’s a little bit of a different situation, and we just feel like this is a function of making prudent appropriate investments and being disciplined about them.”

The company also announced Monday that the FDA set a deadline of April 3 for its review of the drug as a DRP treatment. However, the agency didn’t grant the company’s request for priority review, a designation intended to speed the review of drugs that have the potential to significantly improve the treatment of a serious condition. Davis, on the call, said the company hasn’t been able to determine why it wasn’t granted an accelerated review given the lack of existing treatments for the condition. Priority review would have shortened the review timeline from 10 months to six.

SVBLeerink analyst Marc Goodman, in a research note, called both the agency’s decision—and Acadia’s late-stage miss in depression—“somewhat disappointing and surprising.” Goodman had pegged the business opportunity for pimavanserin as an adjunctive treatment for depression at about $500 million. However, Acadia faces little to no competition in the indications it continues to pursue, he wrote.

In addition to DRP, the company is studying pimavanserin in patients diagnosed with schizophrenia who exhibit “negative” symptoms, such as a flat affect and a seeming lack of interest in the world or other people, patients for whom no FDA-approved therapies exist. About a year ago, Acadia ended its study of the drug as a treatment for patients with schizophrenia whose hallucinations and delusions weren’t responding adequately to antipsychotic treatment after it failed to meet the main goal of a Phase 3 trial.

In after-hours trading, Acadia shares fell 12 percent to about $49 apiece.

Image: iStock/Mathisa_s