Paliperidone Palmitate Delays Relapse in Patients with Schizoaffective Disorder

Patients suffering from schizoaffective disorder usually need an assortment of medications to treat the multiple and complex symptoms associated with this condition. The treatment “cocktail” can include antidepressants, antipsychotics, mood stabilizers, or any combination of the three.

But the need for multi-drug therapy might be reduced, according to the results of a trial presented on May 6, 2014, at the 167th annual meeting of the American Psychiatric Association, held in New York City, NY.

Researchers conducted a randomized, double-blind, placebo-controlled trial (which, in all its phases, lasted nearly two years) to test the antipsychotic paliperidone palmitate (brand name: Invega Sustenna) both as a monotherapy and as an adjunct to antidepressants and to mood stabilizers in patients schizoaffective disorder. That’s significant, because if paliperidone palmitate merely replaced an antipsychotic — but patients still needed the rest of the cocktail – it might not constitute much of an improvement.

Paliperidone palmitate is currently approved as a once-monthly injection for treating schizophrenia, which shares some of the symptoms of schizoaffective disorder.

The 334 study participants began with a two-part stabilization period, totaling 25 weeks, during which they were stabilized on paliperidone palmitate at doses ranging from 78 mg to 234 mg. After that, they were randomized to placebo, and the actual trial lasted another 15 months.

The key endpoint was time to relapse, with relapse defined as psychiatric hospitalization, any intervention to prevent hospitalization because of worsened symptoms, clinically significant self-injury, suicidal or homicidal ideation, violent behaviors, or a worsening of schizoaffective symptoms,

Judging by that endpoint, there were some dramatic findings. The researchers reported 33.5% of the patients in the placebo group suffered a relapse during the trial period, more than double the 15.2% rate of those taking the medication. That made the risk of relapse 2.49-fold higher for the placebo group.

Breaking down the causes of relapse, the risks were highest for manic symptoms (3.62 times higher than on medication), depressive symptoms (3.12), any mood symptoms (2.93) and mixed symptoms (1.93).

Interestingly, the risks of relapse were actually higher for patients taking paliperidone palmitate as an adjunct in combination with other medication rather than as a monotherapy. For instance, the risk of relapse in the placebo group was 3.38 times higher than paliperidone palmitate as a monotherapy, but only 2.03 times higher when the drug was combined with antidepressants or mood stabilizers.

Shouldn’t the combination have actually enhanced the effectiveness of paliperidone palmitate? Not necessarily, said Dong-Jing Fu, PhD, director of clinical development at Janssen Scientific Affairs. Only the placebo component was randomized, so that those getting the mood stabilizer or antidepressant medications in addition to the paliperidone palmitate “could be a bit more difficult to treat.”

The improvements did not come without cost. Participants who received the study medication exhibited significantly higher (though still low) levels of weight gain, headaches, colds, and akathisia (or restlessness), compared with the control group. For instance, 8.5% of patienst treated with paliperidone palmitate gained weight, versus 7% of patients who received placebo. More than 3% of those on the study medication, and 5.9% of the placebo group, actually exhibited a worsening of their schizoaffective disorder.