The efficacy of Xeplion was established in four double-blind, placebo-controlled studies in patients with an acute exacerbation of schizophrenia, and a longer-term double-blind relapse prevention/maintenance study. Xeplion was superior to placebo in improving symptoms of schizophrenia as measured by the change in the positive and negative syndrome scale (PANSS) total scores from baseline to endpoint in the acute treatment trials and significantly delayed time to relapse vs. placebo in the longer-term maintenance study.
The most recent acute symptom control study was a multi-centre, randomized, placebo-controlled, double-blind, parallel-group study (n=636). All patients received a dose of 150 mg eq. on day one in the deltoid muscle. From Day eight and monthly thereafter, patients were assigned to one of three fixed doses of Xeplion (25, 100 and 150 mg eq) administered into either the deltoid or gluteal muscle for 13 weeks. All three doses of Xeplion were superior to placebo in improving the PANSS total score at endpoint (the primary measure of efficacy). The results support efficacy across the entire duration of treatment, with onset of efficacy and significant improvement in PANSS compared to placebo observed from day 8 in some patients. The results of the other studies also yielded significant results in favor of Xeplion.