Extended-release risperidone may improve certain schizophrenia symptoms

Monthly extended-release risperidone demonstrated efficacy for improving various schizophrenia symptoms, according to study results published in Journal of Clinical Psychiatry.

“The efficacy of this subcutaneous injectable monthly risperidone (SMR) was established in a double-blind, placebo-controlled, 8-week phase 3 study in which patients hospitalized with moderate to severe exacerbations of schizophrenia were randomized to receive SMR 90 mg or 120 mg or matching placebo,” Anne Le Moigne, MS, of Global Research & Development at Indivior Inc. in Virginia, and colleagues wrote.

“After 8 weeks of treatment (2 injections of SMR or placebo), statistically significant improvements were observed vs. placebo on the [Positive and Negative Syndrome Scale (PANSS)] total score (the primary endpoint), as well as the exploratory endpoints PANSS positive scale score and PANSS general psychopathology scale score,” they said.

In a prior study, researchers used factor analysis to propose reorganizing PANSS items into five dimensions: positive symptoms, disorganized thoughts, uncontrolled hostility/excitement, anxiety/depression and negative symptoms. An analysis conducted with these dimensions showed significant improvement for oral risperidone 6 mg to 16 mg daily vs. placebo in total score effect size and the incorporated dimensions.

In the current study, Le Moigne and colleagues sought to further examine responses at SMR 90 mg and 120 mg via an analysis of PANSS item-level data from the SMR pivotal study, after which they examined effects of the five-dimension restructuring. They conducted these analyses among subgroups of patients who could benefit from the SMR 120 mg dose. A total of 111 participants received SMR 90 mg, 114 received SMR 120 mg and 112 received placebo.

Results showed dose-dependent responses in items from the study-specified PANSS positive and general psychopathology exploratory subscales. Le Moigne and colleagues noted dose-dependent responses across all five Marder dimensions. The largest effect sizes occurred with the 120 mg dose for the uncontrolled hostility/excitement and anxiety/depression dimensions. Participants with baseline uncontrolled hostility/excitement scores of nine or higher had greater improvement in PANSS total score at the 120 mg dose vs. the 90 mg dose.

“The improvements in the original PANSS negative symptoms subscale at the SMR 120 mg dose may have been at least partially attributable to improvements in positive symptoms,” Le Moigne and colleagues wrote. “These data suggest that patients with higher baseline scores on the Marder [uncontrolled hostility/excitement] dimension, as well as those with high negative symptoms scores, might benefit from initiating treatment with the 120 mg instead of the 90 mg dose.”