Predictive Value of Leucine-Rich Alpha-2 Glycoprotein Levels in Crohn's Disease Treatment.

INTRODUCTION: Leucine-rich alpha-2 glycoprotein (LRG) is a novel serum biomarker that correlates with clinical activity of inflammatory bowel disease. It remains unclear whether LRG can predict treatment efficacy in Crohn's disease (CD). The aim of this study was to clarify the appropriate LRG cut-off value for predicting clinical remission of CD and whether pretreatment levels of LRG were associated with 52-week treatment persistence in patients treated with anti-tumor necrosis factor (anti-TNF) agents or ustekinumab. METHODS: We retrospectively analyzed correlations between LRG and CRP levels and clinical activity (Crohn's disease activity index [CDAI]). The rates of drug persistence at 52 weeks from the start of treatment were compared between the ustekinumab group and the anti-TNF agent group. RESULTS: The correlation between CDAI and LRG was statistically significant (r = 0.81, p < 0.01, respectively). The LRG cut-off value for predicting clinical remission was 15.3 µg/mL for the CDAI of <150 (AUC 0.90226, 95% CI: 0.815-0.989). There was a significant difference in drug continuance rate at 52 weeks between the anti-TNF agent group and ustekinumab group (100% [17/17] vs. 73.3% [11/15], respectively, p = 0.02). There was also a trend towards a lower LRG in the continuation group than in the discontinuation group in patients treated by ustekinumab. CONCLUSIONS: The LRG cut-off value for predicting clinical remission was 15.3 µg/mL for the CDAI of <150. Pretreatment levels of LRG may be a candidate marker for the prediction of efficacy in the use of ustekinumab.