Mucosal healing with methotrexate versus azathioprine treatment in pediatric Crohn's disease as reflected by fecal calprotectin.

Background/objectives: The current treatment goal for inflammatory bowel disease (IBD) is achievement of mucosal healing (MH). While established with biologic or azathioprine (AZA) therapies, the data on MH with methotrexate (MTX( treatment is scarce. We aimed to compare MH rate as reflected by FC in children with Crohn's disease (CD) treated with either MTX or thiopurines monotherapy.

Methods: A cross-sectional multicenter study including children with CD (<18 years), with documented mucosal ulcerations/erosions on their first endoscopy, who were in clinical and biochemical remission for at least 6 months on MTX or AZA/6-MP monotherapy and had fecal calprotectin (FC) measurements during remission. Clinical remission was defined as PCDAI<10 and normal C-reactive-protein (CRP) level. FC < 100 μg/gr was used as a marker of MH. Demographic, clinical and laboratory data were retrieved from the medical charts.

Results: 64 patients (41 males, age 16.6±4.2 years) were included; 36 with MTX, 26 with AZA and 2 with 6-MP treatment. The mean treatment dose was 14.0±1.8 mg/m2 for MTX, and 1.8±0.66 mg/kg for AZA, and mean therapy duration was 22 ±17.1 months. MH (FC < 100 μg/gr) was demonstrated in 14/36 (39%) and 18/28 (64%) of patients on MTX and AZA/6-MP therapy, respectively (p=0.04). Rates of FC < 300 μg/gr were comparable [27/36 (75%) MTX, 24/28 (86%) AZA/6-MP, p=0.29]. MH was associated with longer treatment duration (p=0.03).

Conclusions: MH as reflected by FC < 100 μg/gr, was higher with AZA/6-MP compared to MTX treatment in pediatric CD.