Nutritional Impact of Orkambi Treatment in 2 to 5 Year Old Children Homozygous for F508del Mutations

Orkambi is a novel FDA approved (August, 2018) therapy for use in patients with cystic fibrosis (CF) who are 2 to 5 years of age and homozygous for F508del mutations in the CFTR gene. It is a combination of lumacaftor and ivacaftor that addresses both the processing and gating defects of the F508del mutation. This investigator-initiated study is designed to evaluate the nutritional, growth and GI impact of Orkambi treatment for this unique younger (2 to 5 years) patient cohort. This proposal extends previous highly informative nutrition and weight gain investigation of ivacaftor treatment in people with CF gating mutations to another CFTR modulator treatment (Orkambi) in people homozygous for F508del mutations. The primary aims of the study are to evaluate the impact of 24 weeks of Orkambi treatment in 2 to 5 year old subjects with CF homozygous for F508del mutations on sleeping or resting energy expenditure, growth status and gut health and function in n=32 children ages 2.0 to 5.9 years of age. Protocol evaluations will occur at baseline (pre-treatment) and 12 and 24 weeks after clinically prescribed Orkambi treatment has begun. Other outcomes of significant clinical interest in young subjects with CF will be explored. All subjects will be evaluated as outpatient at The Children's Hospital of Philadelphia, and will be recruited both regionally and nationally to ensure timely enrollment.