On September 8, Erasmus MC Pedro Miranda Afonso published a paper in the Annals of the American Thoracic Society titled “Evaluating Long-Term Effectiveness of Cystic Fibrosis Modulator Therapies After Rapid Adoption: A Dual-Approach Study“, providing new important insights into the long-term effects of cystic fibrosis (CF) modulator therapies. This study focuses on the drug ivacaftor, aiming to assess its effectiveness in protecting patients’ long-term lung function in the real world.
The study points out that while modulator therapies like ivacaftor show significant short-term benefits in clinical trials, the results differ in long-term observational studies. As new drugs become the standard treatment for most CF patients in the United States, the lack of a contemporaneous control group makes it increasingly difficult to evaluate their long-term effectiveness. To address this, the research team employed two analytical approaches: first, a self-controlled comparison of lung function before and after the use of ivacaftor in the same patients; second, a between-group comparison of treated patients with untreated, similarly affected patients.
The results indicate that both children and adult patients using ivacaftor experienced initial improvements in lung function. Through self-comparison, the percentage of one-second forced expiratory volume (ppFEV1) improved on average by 4.54% to 6.53%. Furthermore, compared to the untreated F508del homozygous patient control group, treated patients exhibited a slower decline in lung function, with inter-group differences ranging from 0.36% to 0.64%. The study shows that the rate of lung function decline in adults is slower than in children. The effectiveness conclusions drawn from both analytical methods are similar, although slight differences were observed in younger individuals.
The conclusion of this study is that ivacaftor is associated with improvements in ppFEV1 across all age groups, but the magnitude of improvement is approximately only half of what was observed in clinical trials. The findings emphasize the need to consider the impact of treatment initiation bias in future studies of CFTR modulator effectiveness and support the use of self-controlled analyses. However, for younger individuals, caution is warranted in interpreting results due to developmental changes that may affect comparability before and after treatment.