Cure4CF Update

Don’t Fear the GLP-1RA: Follow the Science

What a new cystic fibrosis study tells us

Professor Jodie Simpson

You can’t scroll through the news or social media without seeing something about GLP-1RA medicines.

They’re miracle drugs. They’re dangerous. They’re being overused. They’re transforming obesity care. They’re creating new problems.
There is a lot of noise.

And somewhere between the hype and the fear, I think we’re in danger of missing the most important part of the conversation: What does the science actually tell us?

For millions of people around the world, glucagon-like peptide-1 receptor agonists (GLP-1RAs) are already proving life-changing. Their impact extends beyond weight loss, with important effects on blood glucose and metabolic health, and growing interest in their potential role in preventing or delaying type 2 diabetes.

But what caught my attention recently was a new Australian study that asked whether GLP-1RA medicines might actually have an impact on the lungs of people with cystic fibrosis-related diabetes.

Cystic fibrosis-related diabetes (CFRD) has traditionally been treated with insulin. But CF is changing. CFTR modulator therapies have transformed life for many people with CF. They have also changed the metabolic picture of the disease. As people live longer and some gain weight, obesity and insulin resistance are becoming more common — meaning that some of the assumptions that shaped CF diabetes care in the past may need to be reconsidered.

That is why studies like this matter.

The study, published in September in the Diabetes, Obesity and Metabolism Journal, was conducted by researchers from South Australia. It was a small, retrospective exploratory study involving adults with CF-related diabetes who were receiving care through the South Australian Adult Cystic Fibrosis Service. A retrospective exploratory study means the team looked back at data they had collected between 2021 and 2024 and studied the changes that occurred between those who were using standard care insulin and those who had commenced GLP-1RA alongside insulin. To be included in the analysis, people had to have had stable lung function for 2 years. The primary outcome explored was lung function (FEV₁ specifically).

Ten people with CFRD were treated with a GLP-1 receptor agonist alongside insulin. They were compared with 15 people receiving standard insulin therapy. The researchers looked at lung function, blood glucose control, insulin requirements, time in glucose range, hypoglycaemia and body weight.

After 12 months of GLP-1RA treatment in conjunction with usual insulin therapy, lung function significantly improved and the increase was more than those people who experienced that were using insulin alone.  Interestingly, glucose control improved (measured by HbA1c) in those using GLP-RA therapy. This means that both lung function and glucose control improved. Not only that, but time spent in the target glucose range improved, daily insulin requirements fell by a and body weight decreased by around 4.1 kg which was different from those who used insulin alone, where an overall increase in weight was recorded. The team have hypothesised that the improvements in lung function may not be due to weight changes alone because both FEV1 and FVC were positively impacted, where as only FVC might be expected to be improved due to weight loss alone. They are curious if changes in inflammation may also be providing some of the gains.

But this is where following science really matters. This study does not prove that GLP-1RA medicines improve lung function in CF. It is expected that people who take GLP-1RA alongside insulin therapy would have a reduction in weight, but the significant change in FEV1 warrants more research.

It was small. It was retrospective. The treatment group was selected in routine clinical practice rather than randomly assigned, and the people receiving GLP-1RA treatment had a substantially higher BMI at the beginning of the study than the comparison group. The authors are very clear about this. They describe their findings as hypothesis-generating and they need to be confirmed in prospective randomised trials.

So why am I excited about it?

Because sometimes the most valuable research doesn’t give us an answer. It gives us a better question.

The researchers suggest several possible explanations for the improvement in lung function. It could partly relate to weight loss or better glucose control. But they also raise the possibility of direct effects of GLP-1 receptor agonists on the lung or changes in inflammation. And that is the part I find particularly interesting.
Could GLP-1 receptor biology have a role in CF beyond diabetes and weight management?
Could there be effects on inflammation in the airway and in the body more generally?
Could metabolic health and lung health be more closely connected than we have appreciated?
And, in a post-modulator world, are we going to need to rethink some of the assumptions that have shaped CF care for decades?

We don’t know yet. And I think that is exactly the point. There is a tendency in public conversations about GLP-1RA medicines to swing between two extremes: extraordinary promises on one side and fear on the other. Neither is particularly helpful.

People deserve treatments that are safe, effective and supported by good evidence. They also deserve research that asks what else these medicines might be able to do — particularly when the biology gives us a reason to look more closely. This study doesn’t give us permission to declare that GLP-1RA medicines are a new treatment for CF lung disease. But it does give us a reason to investigate further.

At Cure4CF, this is exactly why we fund research.

Because progress doesn’t always come from knowing the answer. Sometimes it comes from having the courage to investigate the unexpected.

Research is the answer — but first, research has to ask the right question.

And I think this paper has given us a very interesting one.

The original publication

Ephraums LA, Mignone ER, Lange K, Routley A, Morton J, Hopkins E, Chapman S, Gagliardi L, Horowitz M, Umapathysivam MM. Glucagon-Like Peptide-1 Receptor Agonist Use Is Associated With Improved Lung Function in Cystic Fibrosis-Related Diabetes. Diabetes, Obesity and Metabolism. 2026. doi:10.1111/dom.71312.

Read the original open-access publication: https://doi.org/10.1111/dom.71312

Note: This blog is a plain-language commentary on the published research letter. It is not medical advice and should not be interpreted as a recommendation to use GLP-1 receptor agonists for cystic fibrosis.