Cost-Effectiveness of Adjunctive Therapy with Atypical Antipsychotics for Acute Treatment of Major Depressive Disorder

Abstract

Background: While the clinical utility of atypical antipsychotics has been established in patients with major depressive disorder (MDD) who are refractory to antidepressant therapy, their cost-effectiveness is unknown. Objective: To examine the cost-effectiveness of aripiprazole, quetiapine, and olanzapine/fluoxetine in adults with MDD who are refractory to antidepressant therapy. Methods: Using techniques of decision analysis, we estimated expected outcomes and costs over 6 weeks in adults with MDD receiving (1) aripiprazole 2-20 mg/day and antidepressant therapy; (2) quetiapine 150 mg/day or 300 mg/day and antidepressant therapy; (3) the fixed-dose combination of olanzapine 6, 12, or 18 mg/day with fluoxetine 50 mg/day; or (4) antidepressant therapy alone. Cost-effectiveness was assessed in terms of the cost per additional responder at 6 weeks, defined as the ratio of the difference in the cost of MDD-related care over 6 weeks versus antidepressant therapy afone to the difference in the number of patients achieving clinical response by 6 weeks. We estimated the model using data from Phase 3 clinical trials of atypical antipsychotics along with other secondary data sources. Results: With antidepressant therapy alone, the estimated clinical response rate at 6 weeks was 30%. Aripiprazole, quetiapine 150 mg/day, quetiapine 300 mg/day, and olanzapine/fluoxetine were estimated to increase clinical response at 6 weeks to 49%, 34%, 38%, and 45%. respectively. Costs of MDD-related care over 6 weeks were estimated to be $192 for antidepressant therapy, $847 for aripiprazole, $541 for quetiapine 150 mg/day, $672 for quetiapine 300 mg/day plus antidepressant therapy, and $791 for olanzapine/fluoxetine. Costs per additional responder (vs antidepressant therapy) over a 6-week period were estimated to be $3447 for aripiprazole, $8725 for quetiapine 150 mg/day, $6000 for quetiapine 300 mg/day, and $3993 for olanzapine/fluoxetine. Conclusions: Atypical antipsychotics substantially increase clinical response at 6 weeks. Cost per additional responder is lower for aripiprazole than for quetiapine or olanzapine/fluoxetine.