GLP-1 drugs improve weight, lung function, and insulin needs in adults with cystic fibrosis
In the largest published case series, 11 adults with cystic fibrosis treated with GLP-1 agonists experienced weight loss (median 7.2 kg), improved lung function in most, and a 31.5% reduction in daily insulin dose for those with CF-related diabetes.
Quick Facts
What This Study Found
All 11 CF patients lost weight (median -7.2 kg). 8/11 improved FEV1 (up to +18%), 9/11 improved FVC (up to +26%). All 7 with CFRD reduced insulin (mean -31.5% total daily dose). Glucose time in range improved (mean +11%).
Key Numbers
11 patients (3 male, 7 female, ages 24-47, BMI 25.7-43.7). 9 on semaglutide, 2 on tirzepatide. Duration 1-50 months. Median weight loss 7.2 kg. BMI change -0.9 to -8.1. FEV1 improved in 8 of 11 (change -5 to +18). FVC improved in 9 of 11 (change +1 to +26). Mean insulin reduction 31.5%. 4 discontinued.
How They Did This
Retrospective case series of 11 adults with CF (3 male, 7 female, age 24-47, BMI 25.7-43.7) treated with GLP-1 agonists (semaglutide or tirzepatide) for 1-50 months at a single CF center.
Why This Research Matters
As CF life expectancy increases, more patients face obesity and CF-related diabetes. This first substantial report shows GLP-1 drugs may address both while unexpectedly improving lung function—a critical finding for a disease where lung decline is the primary driver of mortality.
The Bigger Picture
CF treatment has been revolutionized by CFTR modulators like elexacaftor/tezacaftor/ivacaftor, but weight gain and metabolic complications are emerging side effects. GLP-1 drugs could become an important complementary therapy, addressing obesity and diabetes while potentially supporting lung health.
What This Study Doesn't Tell Us
Very small case series (n=11) without controls. Retrospective design. Single center. Variable treatment duration (1-50 months). Lung function improvements could be confounded by other treatments. 4/11 (36%) discontinued, raising tolerability concerns.
Questions This Raises
- ?Why did lung function improve—is it due to weight loss reducing chest wall restriction, or a direct anti-inflammatory effect?
- ?Are GLP-1 drugs safe for CF patients with lower BMIs who may lose too much weight?
- ?Would a controlled trial confirm these lung function benefits in CF?
Trust & Context
- Key Stat:
- 31.5% less insulin needed All CF patients with diabetes reduced daily insulin while on GLP-1 therapy, with most also showing improved lung function
- Evidence Grade:
- Case series (lowest level of clinical evidence) but the largest published on this topic. Provides important hypothesis-generating data that warrants controlled trials.
- Study Age:
- Published in 2025; addresses the emerging intersection of CF metabolic complications and GLP-1 therapy.
- Original Title:
- Glucagon-like-peptide-1 agonist therapy in adults with cystic fibrosis.
- Published In:
- Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society, 24(1), 40-46 (2025)
- Authors:
- Park, Sanghoon, Jain, Raksha(2), Mirfakhraee, Sasan(2)
- Database ID:
- RPEP-12962
Evidence Hierarchy
Frequently Asked Questions
Can people with cystic fibrosis take GLP-1 drugs like semaglutide?
This case series suggests GLP-1 drugs can be used in CF patients with obesity or diabetes, with most experiencing weight loss, improved blood sugar control, and even better lung function. However, tolerability was an issue—2 of 11 stopped due to severe nausea. More research is needed before routine use.
Why might GLP-1 drugs improve lung function in CF?
The improvement is not fully explained yet. It could be that weight loss reduces the mechanical burden on the lungs, or GLP-1 drugs may have direct anti-inflammatory effects that benefit CF airways. This unexpected finding is one of the most intriguing aspects of the study and needs further investigation.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-12962APA
Park, Sanghoon; Jain, Raksha; Mirfakhraee, Sasan. (2025). Glucagon-like-peptide-1 agonist therapy in adults with cystic fibrosis.. Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society, 24(1), 40-46. https://doi.org/10.1016/j.jcf.2024.08.005
MLA
Park, Sanghoon, et al. "Glucagon-like-peptide-1 agonist therapy in adults with cystic fibrosis.." Journal of cystic fibrosis : official journal of the European Cystic Fibrosis Society, 2025. https://doi.org/10.1016/j.jcf.2024.08.005
RethinkPeptides
RethinkPeptides Research Database. "Glucagon-like-peptide-1 agonist therapy in adults with cysti..." RPEP-12962. Retrieved from https://rethinkpeptides.com/research/park-2025-glucagonlikepeptide1-agonist-therapy-in
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.