Kaftrio use not tied to activity gains in youths with cystic fibrosis
Quality-of-life scores improved in some areas in small observational study
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Kaftrio (elexacaftor/tezacaftor/ivacaftor) use was not associated with additional improvements in physical activity among children and adolescents with cystic fibrosis (CF) in a small observational study.
Even so, those who started Kaftrio during the study or were already receiving it showed improvements in some health-related quality-of-life domains, including treatment burden and respiratory symptoms.
Researchers recommended further research with larger patient groups to explore the underlying mechanisms related to physical activity and quality of life in the modulator era.
Study tracks activity in youths with CF
The study, “One year follow-up of physical activity and health-related quality of life in youth with Cystic Fibrosis in the modulator era,” was published in Scientific Reports.
Kaftrio, sold as Trikafta in the U.S., is a combination CFTR modulator therapy that helps defective CFTR proteins work more effectively, addressing the underlying cause of CF.
Although Kaftrio has been shown to improve lung function and nutritional status, with studies projecting longer survival for some people with CF, its effects on physical activity and health-related quality of life (HRQoL) in children and adolescents with CF remain poorly understood.
This study, conducted at the CF center of Ghent University Hospital in Belgium, included 34 youths with CF, ages 6-17, 38% of whom were male. Participants were assessed at the study’s start and again at follow-up, with follow-up timing varying by treatment group.
Of the patients, 13 were Kaftrio-naïve, meaning they did not receive Kaftrio at either visit; 14 initiated Kaftrio between the two visits; and seven were receiving Kaftrio throughout. A healthy reference cohort of 264 children and adolescents was used for comparison.
Activity measured with wearable device
To measure physical activity, participants wore a small wearable accelerometer on the right hip during waking hours for seven consecutive days. This calculated total physical activity, as well as the time spent in moderate-to-vigorous physical activity (MVPA), meaning activity intense enough to raise the heart rate, such as brisk walking or sports. Researchers then converted the activity data into scores adjusted for age and sex.
At the start of the study, youths with CF had significantly lower average MVPA scores than the healthy reference cohort, although total physical activity scores were similar between the groups. Over the follow-up period, changes in both MVPA and total physical activity scores did not differ significantly across the three Kaftrio groups.
Numerically, MVPA scores increased across all three groups, while total physical activity scores remained stable. By the time of follow-up, the CF group’s physical activity levels were comparable to those of the healthy reference cohort.
Yet, the Kaftrio-naïve group had lower MVPA and total physical activity scores than those receiving Kaftrio. Still, this difference was not statistically significant, meaning it could have occurred by chance.
HRQoL was assessed using the Cystic Fibrosis Questionnaire-Revised (CFQ-R), a validated questionnaire designed specifically for people with CF. It examines seven domains: physical functioning, emotional state, body image, eating disturbances, treatment burden, respiratory symptoms, and digestion symptoms.
This analysis showed that changes in treatment burden, which reflect how burdensome the daily treatment routine feels, varied across the three groups. The Kaftrio-naïve group showed mixed patterns, with treatment burden tending to worsen during adolescence.
Most youths with CF in the Kaftrio-initiated group showed improved scores, suggesting reduced treatment burden after starting Kaftrio. The Kaftrio-throughout group showed generally stable scores, with individual improvements observed mainly at younger ages.
Quality-of-life changes varied by group
Physical functioning scores were generally high across all groups and remained largely stable. Still, five patients showed steep declines in physical functioning scores, and four of those cases coincided with the transition from the parent-reported to the self-reported version of the questionnaire, which can produce different results for the same child.
Respiratory symptoms eased in both the Kaftrio-initiated and Kaftrio-throughout groups, while the Kaftrio-naïve group showed mixed changes, including some declines.
The scientists noted that the study included a small number of patients, which may have made it harder to detect true differences between groups.
“This longitudinal study suggests that [Kaftrio] does not lead to additional improvements in [physical activity] of [youths with CF],” the team concluded. “[Youths with CF] initiating or already receiving [Kaftrio] did show improvements in some HRQoL domains.”
“Future longitudinal research is warranted with larger cohorts to explore the underlying mechanisms related to [physical activity] and HRQoL in the modulator era,” the team added.
