Optimizing Anti-TNF-a Therapy: Serum Levels of Infliximab and  Adalimumab Are Associated With Mucosal Healing in @entity1 With XXXX .

@entity1 @entity32 @entity39 @entity5 @entity33 @entity29
BACKGROUND _ AIMS: It is not clear what serum levels of anti- @entity5 @entity39 factor are associated with reduced intestinal @entity32 in @entity1 with @entity29 ( @entity29 ). We aimed to identify serum levels of infliximab and adalimumab associated with @entity33 in @entity1 with @entity29 and to evaluate the putative gain in control of @entity32 by incremental increases in drug levels. METHODS: We performed a retrospective cross-sectional study of 145 @entity1 with @entity29 treated with infliximab (n  = 78) or adalimumab (n  = 67) at a medical center in Israel from 2009 through 2014. We collected data from colonoscopy examinations; @entity33 was defined as simple endoscopic score of <3 or a Mayo score  <=1. These data were compared with serum levels of anti- @entity5 @entity39 factor agents, clinical scores, and levels of C-reactive protein. RESULTS: Median serum levels of infliximab and adalimumab were significantly higher in @entity1 with @entity33 than @entity1 with active disease (based on endoscopy) (for infliximab, 4.3 vs 1.7  g/mL, P  = .0002; for adalimumab, 6.2 vs 3.1  g/mL, P  = .01). Levels of infliximab above 5   g/mL (area under the curve  = 0.75; P < .0001) and levels of adalimumab above 7.1  g/mL (area under the curve  = 0.7; P  = .004) identified @entity1 with @entity33 with 85% specificity. Increasing levels of infliximab beyond 8  g/mL produced only minimal increases in the rate of @entity33 , whereas the association between higher level of adalimumab and increased rate of @entity33 reached a plateau at 12  g/mL. In @entity1 with measurable levels of infliximab >3  g/mL, the presence of antibodies to infliximab was associated with a lower rate of @entity33 compared with @entity1 with similar drug level without antibodies (16% vs 50%, respectively; P  = .003). CONCLUSIONS: In a retrospective study, we found significant association between serum levels of anti- @entity5 @entity39 factor agents and level of @entity33 . We propose that serum levels of 6-10  g/mL for infliximab and 8-12  g/mL for adalimumab are required to achieve @entity33 in 80%-90% of @entity1 with @entity29 , and that this could be considered as a "therapeutic window." Exceeding these levels produces only a negligible gain in proportion of @entity1 with @entity33 .
