Pilot and feasibility study of dietary composition with elexacaftor-tezacaftor-ivacaftor concentrations in people with cystic fibrosis.

BACKGROUND

Nutritional support for people with cystic fibrosis (PwCF) after the implementation of novel drug therapies is shifting from managing malnutrition through a high-fat, high-calorie diet to managing emerging incidences of obesity in this population. Additionally, dietary recommendations prescribed with elexacaftor/tezacaftor/ivacaftor (ETI) recommend taking this drug with a fat-containing meal, which is variably interpreted by patients. This pilot and feasibility study was conducted to assess dietary fat intake and body composition on ETI plasma concentrations.

METHODS

Ten participants were enrolled in a 1:1 crossover design by dietary recommendations. To mimic recommendations made during routine clinical care, participants were instructed to consume either a general healthful diet (no more than 30% calories from fat) or a high-fat diet (>40% calories from fat) for a week before crossing over to the alternative diet.

RESULTS

This pilot study was acceptable to and feasible for study participants. Most participants increased fat intake calories when following a high-fat diet. Body composition measurements showed a trending correlation between lean mass and fat-free mass with ETI plasma concentrations. ETI compounds were quantified in plasma at 0 h (prior to the ETI morning dose) and 6 h after ingestion, and consuming a high-fat diet did not significantly impact ETI concentrations.

CONCLUSIONS

Consuming a higher-fat diet did not significantly impact ETI plasma concentrations, and all participants were in range for clinical effectiveness of ETI regardless of fat intake. This work provides vital pilot data to design larger studies to clarify dietary composition for optimal ETI exposure for PwCF on this therapy.