We evaluated the efficacy and safety of the investigational long-acting injectable antipsychotic agent paliperidone palmitate (PP) in the treatment of schizophrenia. Patients were randomized to receive gluteal injections of placebo or PP (50 or 100 mg eq., fixed doses), without oral supplementation, on days 1, 8, and 36 (9-wk, double-blind phase) in this phase 2b study. Patients (n=197, intent-to-treat analysis set) were 62% men, mean (s.d.) age 39 (10) yr, with a baseline mean (s.d.) Positive and Negative Syndrome Scale (PANSS) total score of 87.0 (12.5). Mean (s.d.) PANSS total scores showed significant improvement at endpoint (primary measure) for both the PP 50 mg eq. [-5.2 (21.5)] and PP 100 mg eq. [-7.8 (19.4)] groups, vs. placebo [6.2 (18.3)] (p0.001, each dose vs. placebo). This improvement was detected by day 8 and maintained to endpoint (p0.011) for both doses. In the safety analysis set (n=247), fewer PP-treated patients (2%) discontinued for treatment-emergent adverse events vs. placebo-treated (10%). Rates of treatment-emergent extrapyramidal syndrome-related adverse events were comparable between active treatment and placebo, with the exception of parkinsonism-related disorders (50 mg eq. 5%, 100 mg eq. 8%, placebo 1%). Results of other safety measures suggest PP to be generally well-tolerated. Throughout the study, investigators rated injection-site pain as absent (56-71%), mild (24-39%), moderate (2-12%), or severe (0-2%). PP (50 and 100 mg eq. doses) administered as a gluteal intramuscular injection was efficacious and generally tolerated in these patients with acute symptomatic schizophrenia.
Iloperidone is an atypical antipsychotic in development for the treatment of schizophrenia. This report examines efficacy results from three 6-week, randomized, double-blind, placebo- and active comparator-controlled studies in patients with schizophrenia or schizoaffective disorder. Multiple doses of iloperidone were studied. Active comparators (haloperidol 15 mg/d, or risperidone 4-8 mg/d) were included to confirm trial validity. The primary protocol-defined efficacy variable in Study 1 was change from baseline to end point in Positive and Negative Syndrome Scale total scores; in Studies 2 and 3, it was change in the Positive and Negative Syndrome Scale-derived Brief Psychiatric Rating Scale scores. Results were assessed through analysis of covariance using last observation carried forward in the intent-to-treat population. In total, 1943 patients were randomized. At least 1 iloperidone dosing group in each study demonstrated significantly better efficacy than placebo (Study 1, iloperidone 12 mg/d [P = 0.047]; Study 2, 4-8 mg/d [P = 0.012] and 10-16 mg/d [P = 0.001]; and Study 3, 20-24 mg/d [P = 0.010]). Active controls were also significantly more effective than placebo in each trial, thus validating the trials. Additional analysis in patients who received active treatment for at least 2 weeks indicated comparable efficacy score reductions at 6 weeks for patients receiving iloperidone 20 to 24 mg/d versus those receiving haloperidol or risperidone. Risk for motor-related adverse events (eg, akathisia and extrapyramidal symptoms) was lower with iloperidone than with risperidone and haloperidol and was generally similar to placebo. These trials indicate that iloperidone is effective for the treatment of schizophrenia.
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