Aripiprazole in combination with lamotrigine for the long-term treatment of patients with bipolar I disorder (manic or mixed): a randomized, multicenter, double-blind study (CN138-392).

OBJECTIVES: To evaluate the efficacy and safety of aripiprazole (ARI) plus lamotrigine (LTG) compared with placebo (PBO) plus LTG, for long-term treatment in bipolar I disorder patients with a recent manic/mixed episode. METHODS: After a 9-24 week stabilization phase receiving single-blind ARI (10-30 mg/day) plus open-label LTG (100 or 200 mg/day), patients maintaining stability (Young Mania Rating Scale/Montgomery-Åsberg Depression Rating Scale total scores ≤ 12) with ARI+LTG for eight consecutive weeks were randomized to continue on double-blind ARI + LTG or to receive PBO + LTG, after removing ARI from ARI + LTG treatment, and followed up for 52 weeks. The primary outcome measure was time from randomization to relapse into a manic/mixed episode. RESULTS: A total of 787 patients entered the stabilization phase, and 351 were randomized to ARI + LTG (n = 178) or PBO + LTG (n = 173). ARI + LTG yielded a numerically longer time to manic/mixed relapse than PBO + LTG, but it was not statistically significant [hazard ratio (HR) = 0.55; 95% confidence interval (CI): 0.30-1.03; p = 0.058]. The estimated relapse rates at Week 52 were 11% for ARI + LTG and 23% for PBO + LTG, yielding a number needed-to-treat of nine (95% CI: 5-121). The three most common adverse events were akathisia [10.8%, 6.1% for ARI + LTG and PBO + LTG, respectively; number needed-to-harm (NNH) = 22], insomnia (7.4%, 11.5%), and anxiety (7.4%, 3.6%). Mean weight change was 0.43 kg and -1.81 kg, respectively (last observation carried forward, p = 0.001). Rates of ≥ 7% weight gain with ARI + LTG and PBO + LTG were 11.9% and 3.5%, respectively (NNH = 12). CONCLUSIONS: ARI + LTG delayed the time to manic/mixed relapse but did not reach statistical significance. Safety and tolerability results revealed no unexpected adverse events for ARI combination with LTG.