Acadia's pimavanserin fails to meet Ph III goals in schizophrenia

US biotech Acadia Pharmaceuticals (Nasdaq: ACAD) saw its shares fall 16% to $21.62 in after-hours trading on Monday, after it released disappointing top-line results from its Phase III ENHANCE study, which evaluated pimavanserin as an adjunctive treatment in adult schizophrenia patients with persistent inadequate response to their current antipsychotic therapy.

In the study, adding pimavanserin to existing antipsychotic treatment showed a consistent trend in improvement of psychotic symptoms, however the results did not achieve statistical significance on the primary endpoint, the Positive and Negative Syndrome Scale (PANSS) total score (p=0.0940).

A positive trend was also observed on the key secondary endpoint, the Clinical Global Impression-Severity (CGI-S) score (p=0.0543). The majority of patients in the study were enrolled in Europe (>80%), in this pre-specified subgroup analysis by region, consistent positive results were observed on both the primary endpoint, PANSS total score (unadjusted p=0.0234), and the key secondary endpoint, CGI-S score (unadjusted p=0.0214).