Cellulitis of LegPhase 3COATNCT05584007
Cellulitis Optimal Antibiotic Treatment
A Phase 3 study testing Flucloxacillin Only Product in Oral Dose Form in people with Cellulitis of Leg, run by University of Southampton at 1 site in United Kingdom.
Trial summary
To determine whether a short course of oral flucloxacillin (5 days) is non-inferior to a standard course (7 days) in terms of pain over days 6-14 (indicative of persistence or recurrence associated with the symptoms of most importance to patients) in adults with cellulitis of the leg presenting in primary care. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cellulitis of Leg
- What is being tested?
- Flucloxacillin Only Product in Oral Dose Form
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 334 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 29 Aug 2023to Jul 2027
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Must be aged 18 years or older
- Currently showing symptoms of cellulitis (such as pain, tenderness, redness, other change in skin color, warmth to touch) in one leg for 10 days or less
- Pain rated as 3/10 or higher on a numerical rating scale (0-10) at baseline assessment
- Be willing to be randomized to either trial arm (5-day or 7-day treatment)
- Able to complete trial procedures in the English language.
Who cannot join
- Have penicillin allergy
- Have bilateral cellulitis
- Have had antibiotics for cellulitis within the past month
- Have post-operative cellulitis (within 30 days of operative procedures on the same leg)
- Have cellulitis resulting from human/animal bite injury
- Have Cellulitis associated with chronic (>6 weeks) leg ulceration
- Require immediate hospital admission or out-patient intravenous antibiotic therapy
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site, 1 recruiting
- Recruiting
Royal South Hants Hospital
Southampton
Ian Ward
Ian Ward
About this study
Official title: A Blinded, Non-inferiority Phase III Trial of 5 Versus 7 Days of Oral Flucloxacillin in Primary Care Patients With Lower Limb Cellulitis
To determine whether a short course of oral flucloxacillin (5 days) is non-inferior to a standard course (7 days) in terms of pain over days 6-14 (indicative of persistence or recurrence associated with the symptoms of most importance to patients) in adults with cellulitis of the leg presenting in primary care.
Read the detailed description
Cellulitis is a deep infection of the skin and subcutaneous tissues and most often occurs in the legs. It is a painful condition that is associated with inflammation and swelling of the site, and often systemic symptoms such as fever, headache, muscle aches, malaise, and fatigue. Patients report feeling unwell and that it has a significant impact on their mobility and ability to carry out their usual activities. NICE guidelines recommend oral flucloxacillin 500-1000 mg four times daily for 5-7 days as first-line treatment for most patients with cellulitis in the community, but most prescriptions are dispensed for a 7-day course. We will be assessing the effectiveness and safety of a 5-day treatment vs. the standard 7-day treatment. We also aim to evaluate the cost-consequences of a shorter course from an NHS and personal perspective. Participants will be randomly allocated to one of two groups. In addition to usual care, participants will either be assigned to a 5-day oral flucloxacillin course or a standard 7-day flucloxacillin course. Participants will be prescribed a 5-day course of oral flucloxacillin, and two additional tablets will be posted to the participants which will either be the antibiotic or a placebo tablet. Participants will be asked to fill out daily questionnaires and express their experiences with the shortened course and taking part in the trial.
- Conditions
- Cellulitis of Leg
- Being tested
- Flucloxacillin Only Product in Oral Dose Form, Placebo Only Product in Oral Dose Form
- Keywords
- Primary care, Antibiotic treatment, Antibiotic resistance, Pain, Cost consequences
- Medical subject headings
- Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Flucloxacillin Only Product in Oral Dose FormDrug
Patients will be prescribed flucloxacillin 500mg QDS for 5 days followed by blinded flucloxacillin 500mg for 2 days, reaching a total of 7 days of antibiotic treatment
Placebo Only Product in Oral Dose FormDrug
Patients will be prescribed flucloxacillin 500mg QDS for 5 days followed by a blinded placebo for 2 days, reaching a total of 5 days of antibiotic treatment
| Study group | Role | What they receive |
|---|---|---|
| Intervention | Placebo comparator | Flucloxacillin 500mg four times a day (QDS) for 5 days (unblinded NHS prescription) followed by blinded placebo QDS for 2 days (5 days of antibiotic) Receives: Drug: Flucloxacillin Only Product in Oral Dose Form; Drug: Placebo Only Product in Oral Dose Form |
| Control | Active comparator | Flucloxacillin 500mg QDS for 5 days (unblinded NHS prescription) followed by flucloxacillin 500mg QDS (blinded) for 2 days (7 days of antibiotic) Receives: Drug: Flucloxacillin Only Product in Oral Dose Form |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pain assessment
Self-reported pain (measured using the Pain Numeric Rating Scale (0-10))
Measured: Days 7-16
Secondary outcomes (10)
Use of additional antibiotics
Any reported use of antibiotics other than the initial 5 days of flucloxacillin and 2 days of IMP)
Measured: Up to day 28
Patient-reported assessment of how well they are feeling
Numeric rating scale NRS (0-10) and assessed as repeated measures
Measured: Days 6-14
Health related quality of life
EQ-5D-5L - values, and individual dimension (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) level scores using repeated measures.
Measured: Days 6-14
Health related quality of life used to estimate Quality Adjusted- Life Years (QALYs)
EQ-5D-5L - values, and individual dimension (mobility, self-care, usual activities, pain/discomfort, anxiety/depression) level scores using repeated measures.
Measured: Days 6-14
Leg swelling and warmth
Participant reported questionnaire
Measured: Day 7, 14, 21, 28
Time until self-reported recovery
Participant reported questionnaire
Measured: Day 7, 14, 21, 28
Time until self-assessed extent of cellulitis starts to reduce (with no subsequent increase)
Participant reported questionnaire
Measured: Day 7, 14, 21, 28
Hospital admissions
Number of hosptial admissions since randomisation, collected from primary care notes review
Measured: 12 months
Recurrent cellulitis episodes over 12 months (number of episodes)
Recurrent cellulitis episodes over 12 months (number of episodes) since randomisation, collected from primary care notes review
Measured: 12 months
Complications over 12 months
Number of reported complications since randomisation, collected from primary care notes review
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Oct 2022
- Study start29 Aug 2023
- Primary completionMay 2026 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cellulitis of LegStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A phase III blinded, multi-center, non-inferiority trial assessing the effectiveness and safety of 5 days vs 7 days of oral flucloxacillin 500mg QDS for lower leg cellulitis, and to evaluate the cost-consequences of a shorter course from an NHS and personal perspective. Participants will be recruited in NHS primary care settings in England and Wales. We will primarily recruit through general practices but will explore the possibility of recruiting through out-of-the-hours and urgent care settings.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 334 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Southampton
- Sponsor type
- University, hospital or other
- Collaborators
- University of East Anglia, University of Nottingham, Norfolk and Norwich University Hospitals NHS Foundation Trust, University Hospital Southampton NHS Foundation Trust
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05584007
- Sponsor's protocol ID
- ERGO 67073
- Acronym
- COAT
- Status last verified
- Mar 2026
- First submitted
- 7 Sep 2022
- Last updated
- 15 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data from all centers will be analyzed together and published as soon as possible. Planned publication of the results in a high-impact peer-reviewed journal. Planned publication of protocol in a peer-review journal. The datasets generated and/or analyzed during the current study will be published as a supplement to the publication of the results. Individual investigators may not publish data concerning their patients that are directly relevant to questions posed by the trial until the Trial Management Group (TMG) has published its report. The TMG will form the basis of the Writing Committee and advise on the nature of publications.
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Blinded, Non-inferiority Phase III Trial of 5 Versus 7 Days of Oral Flucloxacillin in Primary Care Patients With Lower Limb Cellulitis
- ClinicalTrials.gov ID
- NCT05584007
- Acronym / sponsor ID
- COAT / ERGO 67073
- Conditions
- Cellulitis of Leg
- Keywords
- Primary care, Antibiotic treatment, Antibiotic resistance, Pain, Cost consequences
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 334 participants (estimated)
- Lead sponsor
- University of SouthamptonUniversity, hospital or other
- Collaborators
- University of East Anglia, University of Nottingham, Norfolk and Norwich University Hospitals NHS Foundation Trust, University Hospital Southampton NHS Foundation Trust
- Study start
- 29 Aug 2023 (actual)
- Primary completion
- May 2026 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 18 Oct 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To determine whether a short course of oral flucloxacillin (5 days) is non-inferior to a standard course (7 days) in terms of pain over days 6-14 (indicative of persistence or recurrence associated with the symptoms of most importance to patients) in adults with cellulitis of the leg presenting in primary care.
Detailed description
Cellulitis is a deep infection of the skin and subcutaneous tissues and most often occurs in the legs. It is a painful condition that is associated with inflammation and swelling of the site, and often systemic symptoms such as fever, headache, muscle aches, malaise, and fatigue. Patients report feeling unwell and that it has a significant impact on their mobility and ability to carry out their usual activities. NICE guidelines recommend oral flucloxacillin 500-1000 mg four times daily for 5-7 days as first-line treatment for most patients with cellulitis in the community, but most prescriptions are dispensed for a 7-day course. We will be assessing the effectiveness and safety of a 5-day treatment vs. the standard 7-day treatment. We also aim to evaluate the cost-consequences of a shorter course from an NHS and personal perspective. Participants will be randomly allocated to one of two groups. In addition to usual care, participants will either be assigned to a 5-day oral flucloxacillin course or a standard 7-day flucloxacillin course. Participants will be prescribed a 5-day course of oral flucloxacillin, and two additional tablets will be posted to the participants which will either be the antibiotic or a placebo tablet. Participants will be asked to fill out daily questionnaires and express their experiences with the shortened course and taking part in the trial.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- A phase III blinded, multi-center, non-inferiority trial assessing the effectiveness and safety of 5 days vs 7 days of oral flucloxacillin 500mg QDS for lower leg cellulitis, and to evaluate the cost-consequences of a shorter course from an NHS and personal perspective. Participants will be recruited in NHS primary care settings in England and Wales. We will primarily recruit through general practices but will explore the possibility of recruiting through out-of-the-hours and urgent care settings.
| Arm | Type | Receives |
|---|---|---|
| Intervention | Placebo comparator | Drug: Flucloxacillin Only Product in Oral Dose Form, Drug: Placebo Only Product in Oral Dose FormFlucloxacillin 500mg four times a day (QDS) for 5 days (unblinded NHS prescription) followed by blinded placebo QDS for 2 days (5 days of antibiotic) |
| Control | Active comparator | Drug: Flucloxacillin Only Product in Oral Dose FormFlucloxacillin 500mg QDS for 5 days (unblinded NHS prescription) followed by flucloxacillin 500mg QDS (blinded) for 2 days (7 days of antibiotic) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Must be aged 18 years or older
- Currently showing symptoms of cellulitis (such as pain, tenderness, redness, other change in skin color, warmth to touch) in one leg for 10 days or less
- Pain rated as 3/10 or higher on a numerical rating scale (0-10) at baseline assessment
- Be willing to be randomized to either trial arm (5-day or 7-day treatment)
- Able to complete trial procedures in the English language.
Key exclusion criteria (7 listed)
- Have penicillin allergy
- Have bilateral cellulitis
- Have had antibiotics for cellulitis within the past month
- Have post-operative cellulitis (within 30 days of operative procedures on the same leg)
- Have cellulitis resulting from human/animal bite injury
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Flucloxacillin Only Product in Oral Dose FormPatients will be prescribed flucloxacillin 500mg QDS for 5 days followed by blinded flucloxacillin 500mg for 2 days, reaching a total of 7 days of antibiotic treatment | Drug | Control, Intervention |
| Placebo Only Product in Oral Dose FormPatients will be prescribed flucloxacillin 500mg QDS for 5 days followed by a blinded placebo for 2 days, reaching a total of 5 days of antibiotic treatment | Drug | Intervention |
Primary outcome
Pain assessment
Time frame: Days 7-16
Self-reported pain (measured using the Pain Numeric Rating Scale (0-10))
10 secondary outcomes
Use of additional antibiotics
Time frame: Up to day 28
Patient-reported assessment of how well they are feeling
Time frame: Days 6-14
Health related quality of life
Time frame: Days 6-14
Health related quality of life used to estimate Quality Adjusted- Life Years (QALYs)
Time frame: Days 6-14
Leg swelling and warmth
Time frame: Day 7, 14, 21, 28
Time until self-reported recovery
Time frame: Day 7, 14, 21, 28
Time until self-assessed extent of cellulitis starts to reduce (with no subsequent increase)
Time frame: Day 7, 14, 21, 28
Hospital admissions
Time frame: 12 months
Recurrent cellulitis episodes over 12 months (number of episodes)
Time frame: 12 months
Complications over 12 months
Time frame: 12 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2026.
- Individual participant dataSharing planned: No. Data from all centers will be analyzed together and published as soon as possible. Planned publication of the results in a high-impact peer-reviewed journal. Planned publication of protocol in a peer-review journal. The datasets generated and/or analyzed during the current study will be published as a supplement to the publication of the results. Individual investigators may not publish data concerning their patients that are directly relevant to questions posed by the trial until the Trial Management Group (TMG) has published its report. The TMG will form the basis of the Writing Committee and advise on the nature of publications.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Flucloxacillin Only Product in Oral Dose Form in people with Cellulitis of Leg, run by University of Southampton at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sophie Varkonyi-Clifford (0 23 8059 1532, coat@soton.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pain assessment (time frame: Days 7-16). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2026.