The triple combination therapy consisting of elexacaftor/tezacaftor/ivacaftor (ETI) has made a tremendous impact for the health of persons with one of the most serious and most common genetic forms of cystic fibrosis. This medication dramatically improves lung health and helps persons with CF live a longer and healthier life. These medications also help persons with CF regain weight, which is important for health because being underweight in those with CF is associated with a higher risk of worsening lung disease and mortality. However, what is not yet known is whether the weight gain with ETI therapy is healthy weight gain such as muscle mass or less health gain such as excess adipose tissue. To address this knowledge gap, Dr. Katie Larson Ode from our division teamed with a group of investigators at several other hospitals across the country to study this in persons on ETI therapy. They found, perhaps concerningly, that the weight gain occurred mainly as increased fat mass and that the changes were associated with reduced insulin sensitivity. These results indicate a need to closely monitor and further study the metabolic impact of ETI therapy. Their study has been published in the journal Pediatric Pulmonology and is titled “The Impact of elexacaftor/tezacaftor/ivacaftor on Body Composition in a Small Cohort of Youth with Cystic Fibrosis”. It can be found at this pubmed link.