Impact of JC virus antibody testing in patients with Crohn's disease with loss of response to infliximab: a Markov model.

BACKGROUND: The optimal treatment strategy for patients with Crohn's disease who have loss of response to the anti-tumor necrosis factor α medication infliximab is uncertain. Natalizumab has an alternative mechanism of action, but its use has been limited by the risk of progressive multifocal leukoencephalopathy. In this study, we performed a decision analysis assessing the impact of JC virus (JCV) antibody testing and natalizumab utilization for loss of response to infliximab. METHODS: We constructed a Markov model to assess the difference between unscreened natalizumab use (option 1), JCV antibody testing with natalizumab when appropriate (option 2), and second anti-tumor necrosis factor α use (option 3). The base case was a 35-year-old man with severe Crohn's disease with loss of response to infliximab. The time horizon was 3 years. Results are reported in quality-adjusted life years (QALYs). Deterministic and probabilistic analyses were conducted. Markov analysis using a cohort of 5000 individuals was performed. The impact of JCV antibody status on outcomes in this model was assessed. RESULTS: Option 2 was the preferred strategy (2.0880 QALYs), followed by option 1 (2.0875 QALYs) and option 3 (2.0808 QALYs). Patients in option 2 required fewer surgeries compared with option 3. Previous JCV infection was associated with reduced QALYs with all options that allowed for natalizumab use. CONCLUSIONS: JCV antibody testing and subsequent treatment selection yield improved outcomes over natalizumab without testing or using only a second anti-tumor necrosis factor α in all patients.