Longitudinal Effects of Elexacaftor/Tezacaftor/Ivacaftor: Multidimensional Assessment of Neuropsychological Side Effects and Physical and Mental Health Outcomes in Adolescents and Adults

Abstract

Background: Italy initiated elexacaftor/tezacaftor/ivacaftor (ETI) for people with cystic fibrosis (pwCF) in July 2021. It has led to dramatic improvements in lung function, BMI, sweat chloride, and respiratory symptoms. However, few data are available on side effects or effects on a broad range of outcomes.

Research question: How does ETI affect mental health, cognitive processing, neuropsychological side effects, GI symptoms, and health-related quality of life over time?

Study design and methods: This was a prospective, "real-world" longitudinal study. Participants were recruited consecutively and evaluated at initiation (T0) and after 1 month, 3 months, and 6 months of starting treatment. Assessments included depression (nine-item Patient Health Questionnaire), anxiety (seven-item Generalized Anxiety Disorder), cognition (Symbol Digit Modalities Test), GI Symptom Tracker, and health-related quality of life (Cystic Fibrosis Questionnaire-Revised). Based on literature, an ad hoc questionnaire was developed to assess side effects: insomnia, headache, memory problems, "brain fog," and concentration problems. Following descriptive analyses, longitudinal data were analyzed by using mixed models for repeated measures, controlling for age and sex when appropriate.

Results: Ninety-two consecutive pwCF (female/male, 46/46; mean age, 25.4 years) participated. FEV₁ increased initially and then remained stable. BMI also increased significantly from T0 to 6 months (P < .01). Depression improved from T0 to 1 month (P < .001); however, no changes in anxiety were found. Cognitive processing improved from T0 to subsequent assessments. Positive changes were reported on the GI Symptom Tracker for stools and adherence challenges, although no changes were found for abdominal pain and digestion. Side effects occurred in 10% to 29%, with no reduction over time; insomnia increased significantly across time. Female participants reported more side effects than male participants (ie, insomnia, headache, concentration problems, brain fog).

Interpretation: This prospective study evaluated the effects of ETI using multiple measures. Significant improvements were found in many domains; however, side effects were reported by a substantial proportion of pwCF, with no improvements over time. Female participants reported more side effects than male participants. pwCF should be followed up systematically to assess the frequency of side effects after starting this new modulator.

Keywords: GI symptoms; cystic fibrosis; elexacaftor/tezacaftor/ivacaftor; mental health; modulators; neuropsychological; physical health; side effects.