Researchers studied 112 people with cystic fibrosis (CF) who took a new three-part medication called elexacaftor/tezacaftor/ivacaftor (ETI) for up to 30 months. The drug significantly improved lung function, helping people gain weight and reducing dangerous lung infections by 85%. While the medication worked remarkably well overall, doctors noticed some patients gained too much weight and a few had minor liver changes. The study shows this drug is a major breakthrough for CF patients, but people taking it need regular check-ups to watch for weight gain and liver health.

The Quick Take

  • What they studied: How well a new three-part CF medication (ETI) works over 2.5 years, looking at lung health, weight, nutrition, and blood chemistry in people with the most common type of CF
  • Who participated: 112 people with cystic fibrosis, average age 31 years old, all carrying the same genetic mutation (F508del), treated between July 2021 and December 2024
  • Key finding: The medication improved lung function by about 15 points (on a standard scale) and stayed improved for 24 months. Serious lung infections dropped by 85%, and dangerous inflammation markers fell by 80% within 6 months. However, more people became overweight, and a small number had temporary liver enzyme changes.
  • What it means for you: If you have this type of CF, this drug appears to be life-changing for lung health. However, you’ll need regular monitoring for weight gain and liver function. This is not a cure, but it significantly improves how well your lungs work and reduces infections.

The Research Details

This was a real-world cohort study, meaning researchers followed actual CF patients taking the medication in regular clinical settings (not a controlled lab experiment). They looked back at medical records from 112 people who started the drug between July 2021 and December 2024. Researchers collected information about lung function, weight, blood tests, and other health markers at the start of treatment and then again at 6 months, 12 months, 24 months, and 30 months.

The researchers measured several important things: how well lungs work (using a test called FEV₁), body weight and nutrition status, blood cholesterol and sugar levels, inflammation markers, and liver health. They tracked whether patients had serious lung infections and looked for any new cases of CF-related diabetes.

This type of study is valuable because it shows how the medication works in real patients in regular hospitals and clinics, not just in perfect research conditions. However, because researchers were looking back at existing records rather than carefully controlling every detail, there’s always some uncertainty about the results.

Real-world studies like this are important because they show whether medications actually help patients in everyday life, not just in controlled research settings. CF is a serious genetic disease affecting the lungs and digestive system, so understanding how new treatments work over years—not just weeks or months—helps doctors make better decisions about patient care.

This study has several strengths: it followed patients for a long time (up to 30 months), it measured many different health markers, and it looked at real patients in actual medical settings. However, there are some limitations: it’s a smaller group (112 people), it only included people with one specific genetic type of CF, and researchers couldn’t compare it to a control group not taking the medication. The study was also done in one country, so results might differ in other populations.

What the Results Show

The medication produced impressive and lasting improvements in lung function. At 24 months, lung function improved by about 15 points on the standard measurement scale and stayed at that level. This is a big deal because CF typically causes lung function to get worse over time, so maintaining improvement is remarkable.

Serious lung infections (called exacerbations) dropped dramatically—by 85%. This means people spent less time in the hospital and had fewer dangerous infections. Inflammation markers in the blood fell by 80% within just 6 months, suggesting the medication quickly reduces the body’s harmful inflammatory response.

Nutrition improved significantly. Many CF patients struggle to maintain healthy weight because their digestive systems don’t work properly. With this medication, the number of underweight patients dropped from 12.5% to just 1.8%. Teenagers showed particularly good weight gain. However, this success came with a trade-off: the percentage of overweight patients rose from 15.2% to 27.7%, suggesting some people gained too much weight.

Blood cholesterol levels increased slightly but stayed within normal, healthy ranges. Blood sugar control remained stable, and no new cases of CF-related diabetes developed during the study. Vitamin D levels improved, while vitamin B12 fluctuated depending on whether people took supplements. Most importantly, liver function remained stable in almost all patients. Only 4.5% of people had mild, temporary increases in liver enzymes, and no one developed liver scarring or fibrosis.

This medication represents a major advance in CF treatment. Previous CF medications helped some patients, but this three-part combination (ETI) works much better for people with the F508del mutation, which is the most common CF genetic type. Earlier studies showed the medication improved lung function in the short term (6-12 months), but this study confirms those benefits last at least 2.5 years. The dramatic reduction in infections and inflammation is consistent with what researchers expected based on earlier research.

This study followed only 112 people, which is a relatively small group. All participants had the same genetic type of CF, so results might not apply to people with other CF mutations. The study didn’t include a comparison group of CF patients not taking the medication, so we can’t be 100% certain the improvements came from the drug rather than other factors. The research was done in one country, so results might differ in other regions with different healthcare systems. Finally, 30 months is still relatively short-term; we don’t yet know what happens after 5 or 10 years of treatment.

The Bottom Line

If you have CF with the F508del mutation, this medication appears to be highly beneficial and should be strongly considered in consultation with your CF care team (confidence level: high). The evidence for improved lung function and reduced infections is strong. However, you should commit to regular monitoring including: lung function tests every 3-6 months, weight and nutrition checks regularly, blood tests for cholesterol and liver function every 6-12 months, and blood sugar screening annually. Work with your care team to manage weight gain through proper nutrition counseling (confidence level: high).

This research is most relevant for people with CF who have the F508del genetic mutation (about 90% of CF patients). It’s also important for CF doctors and care teams deciding on treatment strategies. Parents of children with this type of CF should discuss this medication with their medical team. People with other CF mutations should ask their doctors whether similar medications might help them. This research is less relevant for people without CF.

Lung function improvements appear within the first 6 months and continue improving through 12 months, then stabilize. Infection rates drop quickly—the 85% reduction was measured over the study period. Weight gain happens gradually over months. You shouldn’t expect to feel dramatically different overnight, but most patients notice improvements in energy and fewer infections within 3-6 months. Long-term benefits (beyond 2.5 years) are still being studied.

Want to Apply This Research?

  • Track weekly weight and monthly lung function measurements (FEV₁ if you have a home spirometer). Log any respiratory infections or hospital visits. Record energy levels and exercise tolerance on a 1-10 scale weekly.
  • Set up reminders for monthly weight check-ins and quarterly blood test appointments. Create a nutrition plan with your dietitian to manage healthy weight gain. Log daily food intake to monitor calories and nutrients. Track exercise minutes weekly to support cardiovascular health alongside medication benefits.
  • Use the app to create a 6-month dashboard showing: weight trend (target: stable in healthy range), lung function trend (target: maintained or improving), infection frequency (target: zero or minimal), and appointment completion rate (target: 100% of scheduled tests). Share monthly summaries with your CF care team to catch any concerning trends early.

This research summary is for educational purposes only and should not replace professional medical advice. The findings apply specifically to people with cystic fibrosis carrying the F508del mutation. If you have CF or suspect you might, consult with your CF care team or pulmonologist before making any treatment decisions. While this medication shows promising results, it requires careful medical supervision and regular monitoring. Do not start, stop, or change any CF medications without explicit guidance from your healthcare provider. Individual results may vary, and this study does not represent a cure for cystic fibrosis.