Acadia Pharmaceuticals has commenced the Phase III CLARITY programme of pimavanserin with the initiation of the CLARITY-2 clinical trial.
Intended for major depressive disorder (MDD) patients, the programme also includes the CLARITY-3 trial, which will be launched in the coming months.
Pimavanserin is a selective serotonin inverse agonist that targets 5-HT2A receptors, which are believed to be involved in depression.
The Phase III trials are designed to assess the safety and efficacy of the therapeutic as adjunctive treatment in patients who did not achieve an adequate response to standard antidepressant therapy.
Both the six-week, randomised, double-blind, placebo-controlled, multi-centre trials will enrol around 280 patients each. CLARITY-2 will be conducted in the US, while CLARITY-3 will involve international sites.
The primary endpoint of the trials is a change from baseline on the 17-item Hamilton Depression Rating Scale (HAMD-17) total score.
Participants completing the studies can choose to enrol into a 52-week open-label extension study that will track pimavanserin’s long-term safety and tolerability.
Acadia Pharmaceuticals president Serge Stankovic said: “We believe pimavanserin has the potential to be a very important treatment option for the millions of MDD patients where there remains unmet medical need.
“Based on feedback we received from the US FDA, if we’re successful in the Phase III programme, we plan to use the Phase II CLARITY study and positive study results from at least one of these two Phase III studies to support a supplemental NDA submission.”
The company is further studying the therapeutic in a variety of indications, including dementia-related psychosis, schizophrenia inadequate response and schizophrenia-negative symptoms.
In 2016, the US Food and Drug Administration (FDA) approved pimavanserin to treat hallucinations and delusions linked to Parkinson’s disease psychosis.