PERT Dose Affects Weight Gain in Infants with Cystic Fibrosis, Study Finds

Stacy Grieve, PhD avatar

by Stacy Grieve, PhD |

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Infants with CF, birth weight

Cystic fibrosis is (CF) patients receiving higher doses of pancreatic enzyme replacement therapy (PERT) gain more weight, a recent report shows.

PERT is a tablet that contains pancreatic enzymes. When taken with food, this therapy can improve the absorption of necessary nutrients.

Many CF patients struggle with weight gain. This is because the majority of them have exocrine pancreatic insufficiency (EPI), in which the pancreas does not make enough of the enzymes needed to break down food.

This is particularly problematic for CF patients because many studies show that early growth of children can predict lung function and survival. Consequently, CF patients often are prescribed high-fat, high-protein diets in addition to PERT so they can achieve optimal weight gain and growth.

Although it is known that PERT can improve weight gain, the best dose to reach optimal weight gain is still not clearly defined.

Now, in the study, “Relationship of Initial Pancreatic Enzyme Replacement Therapy Dose with Weight Gain in Infants with Cystic Fibrosis,” published in the Journal of Pediatric Gastroenterology and Nutrition, a research team assessed the association between dosing of PERT and weight gain in children with CF.

The researchers accessed information from the CF Foundation Patient Registry. A total of 502 children, all born in 2010, met the criteria to be included in the study.

The team looked at two different measures of weight changes: weight-for-age z score (WAZ) and weight-for-length percentile (W/L%). WAZ is a way of measuring how close a child’s weight is to the age-matched normal population. W/L% compares children of similar height or length.

Researchers observed that the initial PERT dose correlated with positive changes in WAZ and W/L% at age two. Children who received higher doses of PERT were more likely to gain more weight.

According to the results, an initial dose of less than 1500 lipase units/kg/largest meal (lipase is an enzyme included in PERT) resulted in a higher likelihood of attaining better WAZ and W/L% scores.

This also holds true when only children who started receiving PERT in the first three months of life — a group considered the early dosing group — were included in the analysis.

“In conclusion, higher initial PERT dosing ([greater than or equal to] 1500 LU/kg/largest meal) in infants with CF appears to be associated with an increased likelihood of favorable weight-related outcomes at 2 years,” the researchers wrote.

However, the team acknowledged this dose is higher than the current guidelines.

Such “dosing regimen is associated with a total daily dose of PERT that is likely to exceed the current guideline recommendations,” they wrote.

They added that “while our findings cannot be used in isolation to prove causation or to identify or recommend a specific initial PERT dose for patients with CF, they suggest that current recommendations for initial PERT dosing should be re-evaluated and tested in a prospective clinical trial to evaluate both efficacy and safety.”