Weight changes after initiating Elexacaftor/Tezacaftor/Ivacaftor in Patients with Cystic Fibrosis

Background: Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators have varying levels of benefit regarding weight gain and growth, ultimately improving lung function and decreasing mortality rates in Cystic Fibrosis (CF) patients. The newly approved triple combination therapy (TCT) has shown weight gain benefits in clinical trials, but its long-term effects have yet to be studied in a site-wide setting. Methods: : This retrospective study of 106 adult and pediatric CF patients on triple combination therapy for a year. We measured Body Mass Index (BMI) and BMI percentile changes and compared changes before and one year after initiation of TCT Results: : TCT use showed weight gain over one year by increasing BMI in adult patients by 1.48 kg/m 2 (p-value < 0.0001). Pediatric patients saw significant benefit in BMI percentile with an average gain of 8.34 percentile (p-value= 0.0047). Discussion: The results of this study suggest that the new triple combination therapy improves BMI and BMI percentile in CF patients. This finding will help future CFF guidelines navigate the era of new modulators and the changes in baseline health that come with it.