Introduction: Schizoaffective disorder (SCA) presents with mixed symptoms of psychosis, depression, and mania, and is associated with significant functional impairment. Once-monthly monotherapy or adjunctive paliperidone palmitate (PP) significantly reduced relapse risk in the first placebo (PBO)-controlled, relapse-prevention SCA study (NCT01193153). Exploratory analysis examined whether patients early in their illness were more responsive to treatment than those with a longer duration of SCA.
Method: Subjects who stabilized (via psychotic and mood symptom scores) in a 25-week open-label (OL)-phase could enter the 15-month double-blind (DB) relapse-prevention phase. Exploratory analyses compared early- (diagnosis <5 years) and chronic-illness (≥5 years) subgroups for OL changes in PANSS, HAMD, YMRS, and PSP (t-test); adverse events; percent meeting OL-stabilization criteria and entering DB-phase (Chi-square test); and DB time-to-relapse and relapse rates (Kaplan-Meier estimates, Hazard Ratios [HR] from Cox proportional hazards models).
Results: 667 (206 early; 461 chronic) subjects enrolled in the OL PP treatment phase. Mean symptom and functioning scores improved more in early- versus chronic-illness groups: PANSS, HAMD, YMRS, and PSP, all P<0.05. Most common adverse events: weight increased (8.7%), insomnia (6.9%), injection site pain (6.5%), parkinsonism (6.5%), akathisia (5.2%). A higher percentage of early- than chronic-illness patients met OL-stabilization criteria (70.4%[143/203] versus 60.0%[270/450], respectively; P=0.010) and entered DB randomization (57.8%[119/206] versus 46.6%[215/461]; P=0.008). DB-relapse rates: Early-illness, PP=10.2% versus PBO=30.0% (P=0.014), HR=2.8 (95%CI=1.11, 7.12; P=0.029); Chronic-illness, PP=18.1% versus PBO=35.5% (P=0.001), HR=2.38 (95%CI=1.37, 4.12; P=0.002).
Conclusion: Exploratory data-analyses suggest that early versus later treatment with PP in SCA results in greater symptom improvement and lower relapse rates.