S0865 Simultaneous Monitoring of the Inverse Relationship Between Endoscopic Healing Index Scores and Therapeutic Drug Monitoring Across Biologics in Crohn's Disease

Abstract

INTRODUCTION: Endoscopic healing index (EHI): MONITR (Prometheus, San Diego, CA) scoring is a proprietary, non-invasive serologic test which compares favorably with the Crohn’s disease (CD) endoscopic scoring system, SES-CD, often considered a gold standard in clinical assessment. The relationship between same day EHI testing performance and therapeutic drug monitoring across multiple biologic agents in the CD patient population is not fully understood. Given the pressing need for non-invasive remote monitoring and optimization of clinical status in the CD patient population, we explored the relationship between simultaneous serum patient clinical monitoring and therapeutic drug monitoring (TDM) as part of standard of care practice. METHODS: Adult patients (N = 25) were evaluated retrospectively from a cohort of samples seen in an inflammatory bowel disease clinic. The relationship between EHI and TDM concentration was assessed via numeric score for EHI from 0 to 100 and multiple concentrations of different biologics at a single lab. The analysis was done on multiple biologic agents as part of standard of care practice and the deidentified data compiled. RESULTS: There were 25 CD patients who formed the study population (5 infliximab, 3 adalimumab, 3 vedolizumab and 14 ustekinumab). Across all biologics, increased drug levels were associated with EHI scores < 50. Additionally, within the ustekinumab group (N = 14) the average drug levels for the patients with an EHI score >50 and considered to have moderate to severe disease was 1.98 ug/mL (n = 4) vs 5.17 ug/mL (n = 7) in patients with a score < 40 and considered to have mild to moderate disease. CONCLUSION: Amongst the biologic treated CD patients, there was evidence of lower drug levels across all biologics in patients with higher EHI scores (>50). Additional studies are necessary to determine if biologic therapy guided by home EHI will improve longterm clinical trajectories in CD patients and this study will serve as a baseline for prospective analysis of EHI scoring serially and changes in disease status with adjustment of biologics.Table 1Figure 1Figure 2