Negoescu DM¹, Enns EA², Swanhorst B¹, Baumgartner B¹, Campbell JP³, Osterman MT⁴, Papamichael K⁵, Cheifetz AS⁵, Vaughn BP³. Inflamm Bowel Dis. 2019 Jun 10. pii: izz113. doi: 10.1093/ibd/izz113. [Epub ahead of print]

Author information

1 Department of Industrial and Systems Engineering, University of Minnesota College of Science and Engineering, Minneapolis, MN.

2 Division of Health Policy and Management, University of Minnesota School of Public Health, Minneapolis, MN.

3 Division of Gastroenterology, Hepatology and Nutrition, University of Minnesota Medical School, Minneapolis, MN.

4 Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA.

5 Center for Inflammatory Bowel Disease, Beth-Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.

Abstract

BACKGROUND: Therapeutic drug monitoring (TDM) is increasingly performed for Infliximab (IFX) in patients with Crohn's disease(CD). Reactive TDM is a cost-effective strategy to empiric IFX dose escalation. The cost-effectiveness of proactive TDM is unknown. The aim of this study is to assess the cost-effectiveness of proactive vs reactive TDM in a simulated population of CD patients on IFX.

METHODS: We developed a stochastic simulation model of CD patients on IFX and evaluated the expected health costs and outcomes of a proactive TDM strategy compared with a reactive strategy. The proactive strategy measured IFX concentration and antibody status every 6 months, or at the time of a flare, and dosed IFX to a therapeutic window. The reactive strategy only did so at the time of a flare.

RESULTS: The proactive strategy led to fewer flares than the reactive strategy. More patients stayed on IFX in the proactive vs reactive strategy (63.4% vs 58.8% at year 5). From a health sector perspective, a proactive strategy was marginally cost-effective compared with a reactive strategy (incremental cost-effectiveness ratio of $146,494 per quality-adjusted life year), assuming a 40% of the wholesale price of IFX. The results were most sensitive to risk of flaring with a low IFX concentration and the cost of IFX.

CONCLUSIONS: Assuming 40% of the average wholesale acquisition cost of biologic therapies, proactive TDM for IFX is marginally cost-effective compared with a reactive TDM strategy. As the cost of infliximab decreases, a proactive monitoring strategy is more cost-effective.