The appropriate location for biopsy sampling is a common question in gastrointestinal diseases such as Crohn’s disease (CD) and ulcerative colitis (UC). Standardization of biopsy procurement is essential during drug development to define response to therapy.

The assessment of mucosal healing and histological remission is becoming an important endpoint in CD and UC clinical trials. To determine the value of histology and biomarkers to response to therapy, it is important to collect biopsy samples in a consistent and reproducible manner.  The presence of inflamed and normal appearing mucosa poses challenges in determining the optimal location to sample pre- and post-treatment.  While it is generally believed that biopsies should be collected from the edge of ulcers if present, there is a lack of empirical data to support this strategy. To address this, our team conducted a prospective study in patients with CD-related ileocolonic ulcers to determine the optimal location of biopsy procurement for assessing histological disease activity, gene expression and immune cell markers.

Biopsies were collected from defined locations in relation to the edge of the largest ulcer and blindly assessed using common histology scoring indices and evaluated for targeted pro-inflammatory biomarkers by qPCR and immunohistochemistry methods.  This study concluded that biopsies collected from the ulcer edge produced the highest histological disease activity scores and gene expression levels compared to biopsy collected further away (Novak et al., 2019). While more research is needed to relate these findings to other disease indications, we believe this will enable standardization of biopsy procurement in both clinical trials and in clinical practice.