Economic Evaluation of Implementing a Novel Pharmacogenomic Test (IDgenetix®) to Guide Treatment of Patients with Depression and/or Anxiety

Mehdi Najafzadeh, Jorge A. Garces, Alejandra Maciel

The response to therapeutics varies widely in patients with depression and anxiety, making selection of an optimal treatment choice challenging. IDgenetix(®), a novel pharmacogenomic test, has been shown to improve outcomes by predicting the likelihood of response to different psychotherapeutic medications. The objective of this study was to estimate the cost effectiveness of implementing a novel pharmacogenomic test (IDgenetix(®)) to guide treatment choices in patients with depression and/or anxiety compared with treatment as usual from the US societal perspective. We developed a discrete event simulation to compare clinical events, quality-adjusted life-years, and costs of the two treatment strategies. Target patients had a Hamilton Rating Scale for Depression Score ≥ 20 and/or a Hamilton Rating Scale for Anxiety score ≥ 18 at baseline. Remission, response, and no response were simulated based on the observed rates in the IDgenetix(®) randomized controlled trial. Quality-adjusted life-years and direct and indirect costs attributable to depression and anxiety were estimated and compared over a 3-year time horizon. We conducted extensive deterministic and probabilistic sensitivity analyses to assess the robustness of the results. The model predicted cumulative remission rates of 78 and 66% in IDgenetix(®) and treatment as usual groups, respectively. Estimated discounted quality-adjusted life-years were 2.09 and 1.94 per patient for IDgenetix(®) and treatment as usual, respectively, which resulted in 0.15 incremental quality-adjusted life-years (95% credible interval 0.04-0.28). The total costs after accounting for a US$2000 test cost were US$14,124 for IDgenetix(®) compared with US$14,659 for treatment as usual, suggesting a US$535 (95% credible interval - 2902 to 1692) cost saving per patient in the IDgenetix(®) group. Incremental quality-adjusted life-year gain (0.49) and cost savings (US$6800) were substantially larger in patients with severe depression (Hamilton Rating Scale for Depression score ≥ 25). Using the IDgenetix(®) test to guide the treatment of patients with depression and anxiety may be a dominant strategy, as it improves quality-adjusted life-years and decreases overall costs over a 3-year time horizon.