Efficacy of the serotonin 5ht-2a inverse agonist pimavanserin in treatment-resistant schizophrenia

We present ten cases of patients with schizophrenia and schizoaffective disorder with refractory hallucinations and delusions who received a trial of pimavanserin when clozapine or multiple antipsychotics failed. Four of ten patients had not responded to a clozapine trial. The subjects’ ages ranged between 21 and 77 years and were followed up for several months with clinical assessments of their psychotic symptoms as well as their negative symptoms and social cognition.
All 10 patients with refractory hallucinations and delusions showed marked response to pimavanserin 34 mg/day within 4–8 weeks, with continuation of the response for several months of follow-up. Improvements in negative symptoms and social functioning were also observed in several patients.
This series of 10 cases of patients with refractory psychosis who responded to pimavanserin is an important new finding that has never been reported before. It may herald a new direction in the treatment of patients who have either failed to respond to clozapine or even as an option before resorting to clozapine with its many adverse events and the need for frequent blood draws to measure white blood counts which many patients decline to do. Controlled studies comparing clozapine and pimavanserin in refractory schizophrenia are warranted to confirm these clinical observations.