BERLIN (FRONTLINE MEDICAL NEWS) – Switching patients with schizophrenia from various oral antipsychotics to long-acting injectable aripiprazole at 400 mg once monthly resulted in a dramatic reduction in their psychiatric hospitalization rate in a phase IIIb study.

This robust 90% reduction in psychiatric hospitalizations during the first 3 months on long-acting aripiprazole, compared with participants’ last 3 months prior to making the switch, suggests that injectable aripiprazole might offer significant cost savings to the health care system, Dr. Timothy S. Peters-Strickland observed at the annual congress of the European College of Neuropsychopharmacology.

He presented the findings of a phase IIIb, multicenter, open-label, mirror-image clinical trial involving 433 schizophrenia patients. The study, conducted in a naturalistic community setting, was dubbed a mirror-image study, because it retrospectively looked back at the psychiatric hospitalization rate of participants when they were on oral antipsychotics as well as conducting a prospective assessment of participants’ psychiatric hospitalizations after they made the switch to once-monthly injectable aripiprazole. Thus, patients served as their own controls.

Of note, at enrollment all participants required a change away from their current oral antipsychotic for various reasons, including lack of efficacy, side effects, or poor compliance. This might well have been a factor in some of the psychiatric hospitalizations occurring during the period before the switch.

As part of the study protocol, all participants on an oral antipsychotic other than aripiprazole (Abilify) were converted to oral aripiprazole over the course of 1-4 weeks of cross titration before making the switch to injectable aripiprazole. The duration of the cross-titration period was left to physician discretion.

A key observation regarding this cross-titration phase is that longer proved to be better. That is, the rate of discontinuation because of adverse events during the conversion process was substantially higher – 10.4% – in patients whose cross-titration period lasted 1 week than the 2.9% rate in patients whose cross-titration continued for more than 1 week and up to 4 weeks before introducing long-acting injectable therapy, reported Dr. Peters-Strickland of Otsuka in Princeton, N.J.

The primary study endpoint was the psychiatric hospitalization rate during the last 3 months on oral antipsychotic therapy prior to cross titration, compared with the rate during the first 3 months after the switch to long-acting aripiprazole. The rate on oral therapy was 27.1%, an order of magnitude greater than the 2.7% rate once the same patients had made the switch.

A hefty 32% of patients discontinued long-acting aripiprazole within the first 6 months. A total of 9% of subjects did so because of adverse events, 8% were lost to follow-up, and 2% quit because of lack of efficacy. The most common treatment-emergent adverse events were insomnia, akathisia, and emergence of a psychotic disorder.

The psychiatric hospitalization rate during the last 6 months that patients were on oral antipsychotic therapy was 38.1%, compared with an 8.8% rate during the first 6 months after they started on injectable aripiprazole, whether they stayed on the long-acting medication for the full 6 months or not.

This mirror-image study was sponsored by Lundbeck and Otsuka. Dr. Peters-Strickland is an Otsuka employee.


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