Randomized clinical trial: Effective gluten degradation by Aspergillus niger-derived enzyme in a complex meal setting

The Aspergillus niger-derived prolyl endoprotease (AN-PEP) has previously been shown to degrade gluten in healthy subjects when added to an intragastrically infused meal. The current study investigated the efficacy of AN-PEP in a physiological meal setting. In this randomized placebo-controlled crossover study, 18 gluten-sensitive subjects consumed a porridge containing 0.5 g gluten together with two tablets either containing a high or low dose of AN-PEP, or placebo. Gastric and duodenal content was sampled over 180 minutes, and areas under the curve of gluten concentrations were calculated. The primary outcome, i.e. success rate of high dose AN-PEP defined as at least 50% gluten degradation compared to placebo in the duodenum, was achieved in 10 of 13 comparisons. In the stomach, gluten levels were reduced from 176.9 (median, interquartile range 73.5–357.8) to 22.0 (10.6–50.8, p = 0.001) in the high dose and to 25.4 μg × min/ml (16.4–43.7, p = 0.001) in the low dose. In the duodenum, gluten levels were reduced from 14.1 (8.3–124.7) in the placebo to 6.3 (3.5–19.8, p = 0.019) in the high dose and to 7.4 μg × min/ml in the low dose (3.8–12.0, p = 0.015). Thus even in a physiological meal setting, AN-PEP significantly degraded most gluten in the stomach before it entered the duodenum.