CF START: a randomised registry trial

CF START - The cystic fibrosis (CF) anti-staphylococcal antibiotic prophylaxis trial (CF START); a randomised registry trial to assess the safety and efficacy of flucloxacillin as a longterm prophylaxis agent for infants with CF

The UK CF Registry

We are no longer recruiting babies into the CF START study.

A massive thank you to the families who helped us achieve our target of 480 babies. We will continue to follow all the babies in the study and, with the results on the CF Registry, we are confident that we will answer the trial question in 2027.

For those of you who already have infants taking part in the trial we are continuing to collect your infants data through the CF Registry, even if your appointments are only through the telephone. It's important to us that we still hear about any updates to the medicines your infant is taking. It's also really important that if you are no longer visiting the hospital for clinics that you are taking at home throat swabs, if needed, as directed by your doctor/nurse.

The aim of the CF START trial is determine the safest and most effective way to treat infants diagnosed with Cystic Fibrosis (CF) with antibiotics. At the moment infants in the UK are prescribed an antibiotic, usually flucloxacillin, every day to prevent infection with a bacteria (bug) called Staphylococcus aureus (SA).

Although this approach appears to help prevent SA infection, there is a worry that it may make earlier infection with other bugs, such as Pseudomonas aeruginosa (PsA) more likely.

This trial is designed to test if infants with CF are more likely to get an earlier infection from PsA if they are taking flucloxacillin on a daily basis (“Prevent and Treat”) or Antibiotics in a more targeted manner (“Detect and Treat”).

Parents talk about their experience on the study

The CF START team talk about the Study

Professor Kevin Southern introduces the study and the videos

Professor Alan Smyth describes airway infection in CF

Dr Siobhan Carr discusses the national CF Registry and how it is helping CF START

Dr Paul Aurora describes the multiple breath washout test

Professor Southern reflects on what CF START will mean for you and your baby

Randomised participants

Target participants


Open Sites


Target Sites


CF Start Collaborators


Study funder

This study has been funded by the National Institute for Health Research's Health Technology Assessment (HTA) Programme (ref: 14/22/23).

Study Sponsor

Alder Hey Childrens Hospital Foundation Trust.

Study review and approval

The study has been reviewed by a research ethics committee, who have agreed the study is being conducted in a correct and appropriate manner. The study has also been approved by the Medicines & Healthcare products Regulatory Agency (MHRA).

CF Start Trial Summary and Frequently Asked Questions

Why are we doing this research?

The first infection caused by PsA has proved to be an important moment for those affected by CF, because of the increased treatment requirements.

It is therefore important to find out whether “Prevent and Treat” or “Detect and Treat” leads to earlier PsA airway infection.

This study aims to provide confidence to hospitals and participants that the current way of treating CF infants (“Prevent and Treat”), does not make earlier airway infection by PsA more likely. We will need 480 infants to take part in CF START to make it successful.

What will we have to do if we take part?

A member of your baby's clinical team will talk to you first in more detail and you will be able to ask any questions that you may have. If you have had all of your questions answered and are happy to take part then you will be asked to sign a consent form. You will be given a copy of the consent form and this information sheet to keep.

We will follow up your baby for 4 years and information on your baby's progress will be recorded on the UK CF Registry. You will not be required to attend any extra visits to the hospital aside from those you would normally make.


How will I know which treatment I’m going to have?

In research studies we often split participants up into groups to look at how different treatments work.

participants in one group get a different treatment than participants in another group.

In CF START there are two treatment groups:

  • "Prevent and Treat" (flucloxacillin on a twice daily basis)
  • "Detect and Treat" (Antibiotics in a more targeted manner. For example, if your baby develops a cough)

It is really important that each group in CF START has a similar mix of participants in it. Having a similar mix means that we know that if one group of participants does better than the other, it is very likely to be because of the treatment and not because there are differences in the types of participants in each group.

We use a computer programme that puts participants ‘at random’ into one of the groups – you might hear this described as ‘randomisation’ or ‘random allocation’, but they all mean the same thing. Using randomisation means that participants get mixed into each group, reducing the chance that one group has a different type of patient to another.

In CF START you are equally as likely to be in the “Prevent and Treat” group as you are to be in the “Detect and Treat” group. You and the clinical team will not be able to choose which treatment arm your baby will receive. Your healthcare team will let you know which group you are in as soon as possible.

Will my baby's participation be kept confidential?

Yes, all information collected about you during this study and any future follow up will be confidential, and will be handled, stored and destroyed in accordance with GDPR. We will also let the GP, who your baby will be registered with, know that your baby is participating in CF START. For more information around your data please read our GDPR Leaflet.

Please note that CF Registry data is held outside of the UK, in Amsterdam (part of the European Union (EU)). The EU works to GDPR requirements.

Who has reviewed the study?

Research on licenced drugs, like flucloxacillin, is reviewed by an authority called the Medicines and Healthcare products Regulatory Agency (MHRA). If the MHRA believe it is safe then they will approve the study. This study has been approved by the MHRA.

What are the benefits and risks of taking part?

At present, the normal practice in preventing growth of SA is to take antibiotics in a “Prevent and Treat” manner. However it is not known if this results in earlier infection by PsA. Infants randomised to “Detect and Treat” may receive less antibiotics than they would under standard care. However this may result in earlier infection of SA.

The result of the study will be of benefit to participants with CF, and contribute to a better understanding of the effect of taking flucloxacillin in a “Prevent and Treat” manner, all of which may lead to benefits for your baby and others with CF.

In addition, there will always be a member of the research team that you can phone if you are concerned about anything or for advice.

No additional procedures will be involved over and above normal clinical care unless you choose to be involved in the additional assessment.

How to collect a cough swab sample at home

Here is a short video demonstrating how to collect a cough swab sample at home. Please note that your ward number may differ from the one mentioned in the video.

View Video Here

CF Start Recruiting Centres

Trial Team



Please feel free to contact the CF START study team by any of the means below:


0151 794 9764


Medicines for Children Clinical Trials Unit
University of Liverpool
Institute of Child Health
Alder Hey Children's NHS Foundation Trust
L12 2AP