Acadia Pharmaceuticals Inc. announced top-line results from its 298 patient Phase III CLARITY study which combined two identical, double-blind, placebo-controlled studies evaluating the efficacy, safety and tolerability of pimavanserin as an adjunctive treatment for major depressive disorder (MDD) .
The combined efficacy and safety analysis was pre-specified prior to data unblinding following feedback from the FDA. The study did not achieve statistical significance on the primary endpoint which was the 17-item Hamilton Depression Rating Scale (HAMD-17) total score change from baseline to week 5. Pimavanserin 34 mg, given once-daily as an adjunctive treatment to standard antidepressant therapy was associated with a mean reduction of 9.0 in HAMD-17 total score compared to 8.1 for placebo as an adjunctive treatment (p=0.296).
Positive results were observed on the key secondary endpoint, the Clinical Global Impression – Severity (CGI-S) score, a clinician assessment of a patient’s severity of depression (nominal p=0.042).
Acadia previously announced plans to combine its CLARITY-2 and CLARITY-3 Phase III studies evaluating pimavanserin for the adjunctive treatment of MDD with a pre-specified statistical analysis plan. The two Phase III studies concluded with slightly more than 50% enrollment..