[Pancreatic enzyme replacement in mucoviscidosis (CF): clinical evaluation of a gastric acid-resistant pancreatin preparation in encapsulated microtablet form]

Pancreatic enzyme replacement therapy for people with cystic fibrosis

BACKGROUND

Most people with cystic fibrosis (CF) (80% to 90%) need pancreatic enzyme replacement therapy (PERT) to prevent malnutrition. Enzyme preparations need to be taken whenever food is taken, and the dose needs to be adjusted according to the food consumed. A systematic review on the efficacy and safety of PERT is needed to guide clinical practice, as there is variability between centres with respect to assessment of pancreatic function, time of commencing treatment, dose and choice of supplements. This is an updated version of a published review.

OBJECTIVES

To evaluate the efficacy and safety of PERT in children and adults with CF and to compare the efficacy and safety of different formulations of PERT and their appropriateness in different age groups. Also, to compare the effects of PERT in CF according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 07 November 2019. We also searched an ongoing trials website and the websites of the pharmaceutical companies who manufacture pancreatic enzyme replacements for any additional trials. Most recent search: 26 December 2019.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in people of any age, with CF and receiving PERT, at any dosage and in any formulation, for a period of not less than four weeks, compared to placebo or other PERT preparations.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials and extracted outcome data. They also assessed the risk of bias and quality of the evidence (GRADE) of the trials included in the review.

MAIN RESULTS

14 trials were included in the review (641 children and adults with CF), two of these were parallel trials and 12 were cross-over trials. Interventions included different enteric and non-enteric-coated preparations of varying formulations in comparison to each other. The number of participants in each trial varied between 14 and 129. 13 trials were for a duration of four weeks and one trial lasted seven weeks. The majority of the trials had an unclear risk of bias from the randomisation process as the details of this were not given; they also had a high risk of attrition bias and reporting bias. The quality of the evidence ranged from moderate to very low. We mostly could not combine data from the trials as they compared different formulations and the findings from individual trials provided insufficient evidence to determine the size and precision of the effects of different formulations.

AUTHORS' CONCLUSIONS

There is limited evidence of benefit from enteric-coated microspheres when compared to non-enteric coated pancreatic enzyme preparations up to one month. In the only comparison where we could combine any data, the fact that these were cross-over trials is likely to underestimate the level of inconsistency between the results of the trials due to over-inflation of CIs from the individual trials.There is no evidence on the long-term effectiveness and risks associated with PERT. There is also no evidence on the relative dosages of enzymes needed for people with different levels of severity of pancreatic insufficiency, optimum time to start treatment and variations based on differences in meals and meal sizes. There is a need for a properly designed trial that can answer these questions.

Indirect parameters of pancreatic function in cystic fibrosis (CF) during a controlled double-blind trial of pancreatic supplementation

During two treatment periods (4 weeks each), serum immunoreactive trypsin (IRT), immunoreactive human lipase in stool (IRL), and chymotrypsin (CT) activity in stool were determined in 16 cystic fibrosis patients and compared with fecal fat excretion (72-h sampling). Fecal fat estimation revealed mild to severe steatorrhea in all 16 patients (X = 13.7 +/- 9.0 g/24 h) in at least one study period. Stool fat excretion was highest in underweight adolescents and adults. Comparison of IRT and IRL with stool fat values showed no significant statistical correlation. IRT values revealed an inverse exponential correlation with age, with a steep decline at the age of 5 years. CT levels were very high in 14 of our 16 patients during supplementation therapy, whereas 2 patients showed subnormal CT values. We conclude that since indirect parameters of pancreatic function do not correlate with stool fat excretion, stool fat remains the best indirect parameter for the assessment of pancreatic insufficiency in cystic fibrosis. Leaving pancreatic enzyme supplementation in cystic fibrosis patients on the basis of normal serum trypsin or fecal lipase values does not appear to be adequate.

Enzyme-replacement therapy: problems and prospects

Several diseases can, at least in theory, be treated by the administration of an enzyme, the deficiency of which is the cause of the disease. Various attempts have been made to correct enzymatic deficiencies responsible for the clinical manifestation of diseases for which prevention cannot be achieved by modification of the diet or by supportive therapy with drugs. Except for treating certain digestive disorders, enzyme-replacement therapy has not yet found a broad application. In this review article a compilation is given of the problems and prospects of enzyme-replacement therapy in diseases caused by the deficiency of an enzyme.