Background: This was the first controlled continuation phase study (up to 1-year total treatment) to evaluate the safety and efficacy of bupropion SR for decreasing the risk for relapse of depression in patients who responded to bupropion SR.
Methods: Patients with recurrent major depression were treated with bupropion SR 300 mg/day during an 8-week open-label phase. Responders (based on Clinical Global Impressions Scale for Improvement of Illness scores) entered a randomized, double-blind phase where they received bupropion SR 300 mg/day or placebo for up to 44 weeks. After randomization, relapse was defined as the point at which the investigator intervened by withdrawing the patient from the study to treat depression.
Results: Four hundred twenty-three patients were randomized. A statistically significant difference in favor of bupropion SR over placebo was seen in the time to treatment intervention for depression when survival curves were compared (log-rank test, p =.003). Statistically significant separation between bupropion SR and placebo began at double-blind week 12 (p <.05). Adverse events in bupropion SR-treated patients accounted for 9% and 4% of discontinuations from the open-label and double-blind phases, respectively.
Conclusions: Bupropion SR was shown to be effective and well tolerated in decreasing the risk for relapse of depression for up to 44 weeks.