Efficacy of colistimethate sodium and ciprofloxacin for eradicating primary Pseudomonas aeruginosa infection in adults with bronchiectasis

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What is this study about?

Adults with Bronchiectasis often develop a lung infection caused by Pseudomonas aeruginosa, a type of bacteria that can make breathing harder and lead to more flare‑ups. The study examines three ways to treat this infection: an inhaled antibiotic called colistimethate sodium, an oral antibiotic named ciprofloxacin, and a simple saline solution (0.9% Sodium Chloride) used as a control.

The purpose of the trial is to see which of these treatments most effectively clears the bacteria from the lungs, a result known as microbiological eradication. Participants are randomly assigned to receive one of the three options for a short treatment period, then they return for regular check‑ups where sputum samples are collected and health questionnaires are completed to monitor safety, symptom changes, and overall well‑being.

Follow‑up continues for several months after the medication stops, allowing researchers to observe whether the infection stays cleared, how often lung flare‑ups occur, and any side effects that may appear. The information gathered will help determine the best approach to manage this bacterial infection in people with bronchiectasis.

1 baseline assessment and randomization

after you agree to join the study, clinical staff will record your medical history, perform physical measurements, and collect sputum or bronchoscopic samples for culture.

you will be randomly assigned to receive either placebo (0.9% sodium chloride solution for inhalation), colistimethate sodium inhalation, or ciprofloxacin tablets taken by mouth.

2 initiation of study medication

treatment begins on day 1 after randomization.

if you are assigned to the inhalation arm, you will use a nebuliser to receive a solution containing 4 million iu of either sodium chloride (placebo) or colistimethate sodium. the dose is administered once daily by inhalation.

if you are assigned to the oral arm, you will swallow a film‑coated tablet containing 750 mg of ciprofloxacin once daily.

3 continuous medication period

you will continue the assigned medication for a total of three months.

the inhalation solution is prepared each day for nebulisation; the oral tablet is taken with water.

4 first follow‑up visit (month 1)

approximately one month after starting treatment, you will return for a clinic visit.

sputum or bronchoscopic samples will be taken again to check for the presence of p. aeruginosa.

any side effects or safety concerns will be reviewed.

5 second follow‑up visit (month 2)

around two months after treatment initiation, another visit will occur.

repeat cultures will be obtained to assess early microbiological eradication.

clinical status and safety will be evaluated.

6 primary outcome assessment (month 3)

at three months, the main study endpoint is measured.

a sputum or bronchoscopic sample is collected to determine if p. aeruginosa is no longer detectable.

treatment is stopped after this assessment.

7 post‑treatment observation (months 6 and 12)

you will be monitored without study medication at six months and again at twelve months.

samples will be taken to evaluate sustained eradication of the infection.

additional visits will record any exacerbations, quality of life, and safety information.

8 final study completion

after the twelve‑month visit, the study participation ends.

all collected data are compiled for analysis of efficacy and safety of the tested regimens.

Who Can Join the Study?

Age: You must be older than 18 years.
Diagnosis of non‑cystic fibrosis bronchiectasis (NCFB): You need a doctor‑confirmed diagnosis based on symptoms and a special chest scan called high‑resolution CT (HRCT) imaging that was done within the past five years.
Primary infection with Pseudomonas aeruginosa (PA): You must have a recent positive test for this bacteria from a respiratory sample (sputum you cough up or a sample taken during a bronchoscopy). This can be met in one of three ways:
- First isolation: This is the very first time the bacteria has ever been found in any of your respiratory samples.
- Persistence: The bacteria was first found during a flare‑up, you received antibiotics, and the bacteria is still present in a sample taken four weeks after finishing treatment.
- New isolation: You had the bacteria before, but in the last year you had at least three separate tests (at least one month apart) that were negative, and you have not been on long‑term medicines that target PA.
Respiratory sample means a piece of mucus you cough up (sputum) or a small amount of fluid collected from your lungs using a thin tube (bronchoscopy) during routine care.
Clinically stable at enrollment: You must not have had a worsening of symptoms (an exacerbation) in the past month, and you should not need IV (intravenous) antibiotics or a hospital stay.
You must sign a written informed consent form showing that you understand the study and agree to take part.
Both men and women are eligible to join the study.

Who Cannot Join the Study?

Having an infection with PA (a type of bacteria) that is resistant to the study medicines, or having an infection with other kinds of bacteria.
Taking part in another clinical trial at the same time.
Choosing not to take part in the study.
Having a medical reason (called a contraindication) that makes it unsafe to use the study drugs ciprofloxacin or colistin.
Having had a problem or allergic reaction to breathing medicine in a nebulizer (a device that turns liquid medicine into a mist you inhale).
Having any of the following conditions: cystic fibrosis (a genetic lung disease), uncontrolled asthma (wheezing and breathing difficulty), tuberculosis (a serious lung infection), or a weakened immune system (immunosuppression).
Having a serious disease that affects the whole body (systemic disease) that has not been under control in the past three months.
Being on long‑term (chronic) antibiotic treatment.
Having poor kidney function measured as a glomerular filtration rate (a test of kidney health) less than 30 ml/min/1.73 m².
Being a woman who could become pregnant and not using a highly effective method of birth control (contraception).
Being a woman who is currently pregnant or is breastfeeding (breastfeeding).

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Bellvitge University Hospital	L'hospitalet De Llobregat	Spain
Fundacio Hospital Sant Joan De Deu De Martorell	Martorell	Spain

Other Sites

Site Name	City	Country
Hospital Clinic De Barcelona	Barcelona	Spain
Hospital Universitari Arnau De Vilanova De La Gerencia Territorial De Lleida	Lleida	Spain
Hospital General Universitario Gregorio Maranon	Madrid	Spain
Hospital Universitario 12 De Octubre	Madrid	Spain
Hospital Universitario De Getafe	Getafe	Spain
Althaia Xarxa Assistencial Universitaria De Manresa Fundacio Privada	Manresa	Spain
Hyfabiyy Vsnh dsbmisxq	Barcelona	Spain
Huezzysk Dy Ll Sctzh Clai I Snhm Pet	Barcelona	Spain
Ftcbvgvrp Pcxh Lb Iqvhxlnwcotdg Bpqywcezc Dwb Hxlnvpjs Urrxabefycolp Lq Psb	Madrid	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	01.04.2026

Trial locations

Investigated drugs:

Colistimethate sodium is an antibiotic that is given as an inhaled solution through a nebulizer. The medication is breathed in so it goes directly into the lungs, where it works to kill the bacteria *Pseudomonas aeruginosa* that cause infection in people with bronchiectasis. In this trial the inhaled form is being tested to see if it can clear the infection and keep it from coming back.

Ciprofloxacin is an oral antibiotic taken as a tablet. After swallowing, the drug is absorbed into the bloodstream and then reaches the lungs and other parts of the body. It fights *Pseudomonas aeruginosa* by stopping the bacteria from growing. In the study, the tablet form is being evaluated to determine whether it can successfully eliminate the infection when taken by patients with bronchiectasis.

Investigated diseases:

Bronchiectasis

Bronchiectasis – A long‑lasting lung condition where the airways become abnormally widened and lose their normal shape. The widened airways collect mucus, making it harder to clear and often causing a persistent cough. Over time, the buildup of mucus can lead to repeated infections that worsen the airway damage. Each infection may increase the amount of mucus and the frequency of coughing. As the condition progresses, breathing may become more difficult and the symptoms may become more noticeable.

Trial ID:

2025-524454-34-00

Protocol code:

IIBSP-PAB-2025-212

Trial Phase:

Human Pharmacology (Phase I) – Other

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Efficacy of colistimethate sodium and ciprofloxacin for eradicating primary Pseudomonas aeruginosa infection in adults with bronchiectasis

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?