Clinical validation of an evidence-based method to adjust pancreatic enzyme replacement therapy through a prospective interventional study in paediatric patients with cystic fibrosis

Background A method to adjust Pancreatic Enzyme Replacement Therapy in Cystic Fibrosis is not currently available. Objectives To assess the in vivo efficacy of a method to adjust the dose of enzymatic supplement in CF extrapolated from previous in vitro digestion studies (theoretical optimal dose, TOD). Secondly, to assess how individual patient characteristics influence the expected coefficient of fat absorption (CFA) and thus to identify an individual correction factor to improve TOD. Methods A prospective interventional study in 43 paediatric patients with CF from 5 European centres. They followed a 24h fixed diet with the theoretical optimal dose for each meal. Faecal collection was carried out between colorimetric markers in order to include all the faeces corresponding to the fixed diet. Beta regression models were applied to assess the associations of individual patient characteristics with the CFA. Results Median CFA was 90% (84, 94% 1 ^st , 3 ^rd Q.) with no significant differences among centres. Intestinal transit time was positively associated with CFA (p = 0.007), but no statistical associations were found with and age, gender, phenotype or BMI. Regression model showed no improvement of the in vitro predicted theoretical optimal dose when taking individual patient characteristics into account. Conclusion Strict adherence to the theoretical optimal dose of enzymatic supplement for a prescribed meal, led to median CFA levels at the clinical target of 90% with a low variability between patients. The proposed method can be considered as a first approach for an evidence-based method in PERT dosing based on food characteristics. Results have to be confirmed in free dietary settings.