Assessing the efficacy of 2 years of maintenance treatment with venlafaxine extended release 75-225 mg/day in patients with recurrent major depression: a secondary analysis of data from the PREVENT study.

The objective of this study was to evaluate the long-term efficacy of venlafaxine extended release (ER) < or =225 mg/day in patients with recurrent major depressive disorder (MDD). In this double-blind trial, outpatients with recurrent MDD (N=1096) were randomized to 10 weeks of acute-phase treatment with venlafaxine ER (75-300 mg/day) or fluoxetine (20-60 mg/day) followed by a 6-month continuation phase and two consecutive 12-month maintenance phases. At the start of each maintenance period, venlafaxine ER responders were randomized to double-blind venlafaxine ER or placebo. In this analysis, data from responders to acute and continuation treatment were analyzed during the combined maintenance phases while receiving venlafaxine ER < or =225 mg/day. Failure to maintain response was defined as an increase in maintenance dose to 300 mg/day or recurrence. Differences were calculated using Kaplan-Meier methods and compared using log-rank tests. Continuation-phase responders (n=114) receiving venlafaxine ER < or =225 mg/day comprised the analysis population (venlafaxine ER: n=55; placebo: n=59). The estimated probability for remaining well across 24 months of maintenance treatment was 67% for venlafaxine ER and 41% for placebo (P=0.007). Venlafaxine ER effectively maintained response at doses < or =225 mg/day for up to 2.5 years in patients with recurrent MDD. The findings are consistent with those of the full data set.