Related Experiment Video
Updated: Apr 26, 2026
Defining Substrate Specificities for Lipase and Phospholipase Candidates
Published on: November 23, 2016
Dependence of PERT endpoint on endogenous lipase activity
1From the Division of Gastroenterology and Inborn Errors Products, Office of New Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD.
Objective:
To clarify and to understand the potential for misinterpretation of change in fecal fat quantitation during pancreatic enzyme replacement therapy (PERT) trials for treatment of exocrine pancreatic insufficiency.
Methods:
Analysis of clinical trials submitted to the U.S. Food and Drug Administration (FDA) for approval of PERT that enrolled 123 cystic fibrosis adult and pediatric patients treated with Creon, Pertzye, Ultresa, and Zenpep.
Results Conclusions:
The CFA% defines lipase activity as a percentage of converting substrate of "Total Daily Dietary Fat Intake." PERT trials performed to date have modified the definition to converting the "Shared Daily Fat Intake," generating "Partial CFA" for the exogenous lipase: the higher the activity of coexisting endogenous lipase, the lower the "Partial CFA" of exogenous measured. This review shows that "Partial CFA" is not CFA. Enrollment of patients with low HPLA during treatment may improve the interpretability of "Partial CFA" measured by PERT trials.
