The US Food and Drug Administration (FDA) has approved brexpiprazole (Otsuka Pharmaceutical’s Rexulti) for the treatment of adults with schizophrenia. The antipsychotic is also approved as an add-on treatment for adults with major depressive disorder (MDD) who are already receiving antidepressant therapy.
Brexpiprazole was discovered by Tokyo-based Otsuka and co-developed with the Danish pharmaceutical company Lundbeck. The companies expect the drug to become available to patients in the United States in early August 2015.
The mechanism of action of brexpiprazole is unknown. However, Otsuka and Lundbeck say its efficacy may be mediated through partial agonist activity at serotonin 5-HT1A and dopamine D2 receptors, and antagonist activity at serotonin 5-HT2A receptors.
The FDA based its decision to approve brexpiprazole for use in schizophrenia on data from two six-week clinical trials, involving 1,310 participants. Brexpiprazole reduced the occurrence of symptoms associated with schizophrenia compared with placebo. The drug was also evaluated in combination with an antidepressant in two six-week trials involving 1,046 participants for whom an antidepressant alone did not adequately treat their symptoms. Patients taking brexpiprazole reported fewer symptoms of depression than those taking placebo.
The most common side effects reported by participants taking brexpiprazole in clinical trials included weight gain and restlessness.
Announcing its decision to approve brexpiprazole, the FDA highlighted that the drug carries a warning about an increased risk of death associated with off-label use to treat behavioural problems in older people with dementia-related psychosis. “No drug in this class is approved to treat patients with dementia-related psychosis,” the FDA states.