Evaluating Long-Term Effectiveness of Cystic Fibrosis Modulator Therapies after Rapid Adoption: A Dual-Approach Study
Bibliographic record
Abstract
RATIONALE: Modulator therapies like ivacaftor have revolutionized clinical management of cystic fibrosis, showing marked short-term benefits in trials but heterogeneous findings in long-term observational studies. Since newer modulators have become the standard of care for the majority living with cystic fibrosis in the United States, characterizing long-term effectiveness with real-world data is increasingly difficult because of the lack of contemporary comparator groups for performing between-subjects analyses. OBJECTIVES: To determine the extent to which ivacaftor preserves long-term lung function and compare the results of within- and between-subjects analyses for evaluating its real-world effectiveness. METHODS: This retrospective cohort study used data from the U.S. Cystic Fibrosis Foundation Patient Registry (2003-2016). We used two approaches to evaluate ivacaftor effectiveness on percent predicted forced expiratory volume in 1 second (ppFEV1): 1) within-subject comparisons of ppFEV1 before and after ivacaftor initiation; and 2) comparisons between ivacaftor-treated and untreated individuals with similar disease pathology. We modeled data from 560 ivacaftor-treated individuals with the G551D variant. For between-subjects comparisons, we used propensity scores to match the treated group with 2,800 untreated F508del homozygous individuals. Modulator initiation bias was assessed and accounted for in each model. RESULTS: Our results showed an initial average improvement in ppFEV1 in ivacaftor-treated children and adults (ranging from 4.54% to 6.53% predicted based on within-subject comparison of before vs. after ivacaftor initiation). There was a slower decline in adults, compared with children. These ivacaftor-treated cohorts experienced less decline relative to their F508del homozygous counterparts (between-group differences in treated vs. control ranged from 0.36% to 0.64% predicted). Both the within- and between-subjects comparisons demonstrated similar degrees of ivacaftor effectiveness. However, small differences between the two approaches were observed in younger individuals. CONCLUSIONS: Ivacaftor was associated with improved ppFEV1 across all age groups, with the magnitude of improvement roughly 50% of that observed in clinical trials. The results support the need to account for modulator initiation bias and the use of within-subject analysis in future CFTR (cystic fibrosis transmembrane conductance regulator) modulator effectiveness studies, but caution is advised in younger individuals because of developmental changes that may affect pre- and post-treatment comparability.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.041 | 0.041 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.005 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".