Cost-Effectiveness of a Pharmacogenetic Test to Guide Treatment for Major Depressive Disorder

BACKGROUND: Recent clinical trials indicate that pharmacogenetic-guided treatment of major depressive disorder (MDD) results in higher treatment response rates by genetically matching patients to medications and avoiding a trial-and-error process. OBJECTIVE: To evaluate the cost-effectiveness of a pharmacogenetic test (IDGx) that has demonstrated effectiveness compared with standard of care (SOC) medication management among patients with varied MDD severity. METHODS: Data from a large prospective, randomized controlled trial of treatment-naive patients or patients with inadequately controlled MDD in general practice and psychiatric treatment settings were used to build a Markov state-transition probability model. Analyses were conducted from the societal perspective. Treatment response rates, mortality rates, direct and indirect medical costs, and utility inputs were derived from the reference study and published scientific literature. The cost of the pharmacogenetic test was $2,000. A 3% discount rate was used to discount costs and effects. Univariate one-way sensitivity analyses were performed to determine the effect of input parameters on net monetary benefit. RESULTS: For moderate to severe MDD, the model estimated a cumulative effect over 3 years of 2.07 quality-adjusted life-years (QALYs) for the pharmacogenetic-guided treatment group and 1.97 QALYs for the SOC group, including a lower probability of death from suicide (0.328% and 0.351%, respectively). Total costs over 3 years were $44,697 (IDGx) and $47,295 (SOC). This difference includes a savings of $2,918 in direct medical costs and $1,680 in indirect costs. Results were more pronounced when only severely depressed patients were evaluated. CONCLUSIONS: Pharmacogenetic testing among moderate to severe MDD patients improved QALYs and resulted in cost savings. Sensitivity analyses supported the robust nature of the current findings of the dominant IDGx test to guide treatment.