Metformin to Reduce Airway Glucose in COPD Patients

Chronic obstructive pulmonary disease (COPD) is the 4th leading cause of death worldwide and affects 1.2 million people in the UK, costing the NHS >£800 million annually. COPD patients are more susceptible to bacterial infections and both chronic and acute infections are common. COPD patients with chronic lung bacterial infection have worse quality of life, faster disease progression, more symptoms and frequent exacerbations. Acute infections are the main cause of COPD exacerbations which cause COPD patients to become acutely unwell and often result in hospitalisation especially in the winter. Antibiotics are frequently used to treat COPD exacerbations and this contributes to the development of antibiotic resistance. Therefore there is a need to develop antibiotic-independent approaches to reducing or preventing bacterial infection in COPD.

The investigators have carried out work in in animal studies and in humans showing that there is a link between high levels of glucose in the lung and bacterial lung infection. Levels of glucose in the lung are higher in COPD patients compared with people without COPD. These higher glucose levels support greater bacterial growth probably because glucose is a nutrient for bacteria. Therefore reducing airway glucose has the potential to inhibit bacterial growth in COPD patients.

In animal studies the investigators have demonstrated that the diabetic drug metformin decreases airway glucose and bacterial growth. The investigators wish to determine if metformin can achieve the same effects in COPD patients. Metformin is safe and cheap, and has been extensively used in COPD patients with diabetes with an excellent safety record. The primary aim of this study will be to determine whether metformin reduces lung glucose in a small group of non-diabetic COPD patients. If it demonstrates that metformin reduces lung glucose concentrations it will justify a larger clinical trial of metformin as a treatment for COPD.

Study Overview

• Status: Completed
• Conditions: Chronic Obstructive Pulmonary Disease
• Intervention / Treatment: Drug: Placebo; Drug: Metformin

Detailed Description

Chronic obstructive pulmonary disease (COPD) is the 4th leading cause of death worldwide and affects 1.2 million people in the UK, costing the NHS >£800 million annually. COPD patients are more susceptible to both chronic and acute bacterial infections. Patients with chronic lung bacterial infection have worse quality of life, faster disease progression, more symptoms and frequent exacerbations. Acute infections are the main cause of acute COPD exacerbations which cause COPD patients to become acutely unwell and often result in hospitalisation especially in the winter. Bacteria are detected in 50-60% of COPD exacerbations. Antibiotics are frequently used to treat COPD exacerbations and this contributes to the development of antibiotic resistance. Therefore any intervention that prevents or reduces bacterial infection in COPD, especially if it is not an antibiotic, will have major benefits for COPD patients, the NHS and for society as a whole.

It is likely that there are many reasons why COPD patients are more susceptible to bacterial infections. From experimental work the investigators have carried out one of the reasons may be high glucose concentrations in the lung.

In healthy lungs glucose levels are kept low and this may be a mechanism that inhibits bacterial growth by depriving them of an essential nutrient. In animal studies the investigators have demonstrated that when levels of glucose in the lung are high, bacterial lung infection is more common. The investigators measured lung glucose concentrations in COPD patients and found that they are higher compared with people without COPD. COPD patients with higher levels of glucose also had more bacteria in their lungs and sputum samples from COPD patients with higher glucose concentrations supported greater bacterial growth in the laboratory.

Therefore this study was the first to link elevated glucose in the lung to bacterial infection in COPD. Therefore reducing airway glucose has the potential to inhibit bacterial growth in COPD patients.

Study Design The proposed study will be a randomised, double-blinded, placebo-controlled, cross-over study of metformin in COPD patients. The primary outcome will be sputum glucose after 3 months' treatment with metformin compared with sputum glucose in those taking placebo. In order to account for potential withdrawals 40 subjects will be recruited.

Study Procedures Potential participants will attend for a screening visit where they will have a full medical history, a physical examination and spirometry carried out to confirm the diagnosis of COPD. A blood test will also be done to measure kidney and liver function and blood glucose to exclude undiagnosed diabetes, kidney disease or liver disease.

If they fulfil the entry criteria and consent to taking part in the study they will have a baseline visit prior to being randomised.

The baseline visit will include:

1. Physical examination and measurement of vital signs
2. Completion of quality of life (St George's Respiratory Questionnaire (SGRQ)) and symptom questionnaires (COPD Assessment Test (CAT))
3. Collection of samples. The samples collected will include blood samples, nose samples collected using nasal synthetic absorption matrix (SAM) strips and induced sputum.

After baseline assessment, subjects will either be commenced on metformin (500mg twice a day after meals) or placebo for 3 months during which time the participants will have monthly visits. At these visits the same assessments and sampling as the baseline will be carried out, together with collection of data regarding exacerbations and adverse events. Following a 2 week washout period the subjects will crossover to the other study arm for another 3 months and follow the same study protocol.

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Phase 2

Contacts and Locations

Study Locations

• United Kingdom
  • Greater London
    • London, Greater London, United Kingdom, W2 1NY
      • Imperial College Respiratory Research Unit, St Mary's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 40 and 75 years
• Clinical diagnosis of COPD confirmed with spirometry (Post-bronchodilator FEV1/FVC <70%).
• Smoking history >15 pack years
• Absence of infection >8 weeks prior to study entry
• No use of antibiotics and/or oral corticosteroids >8 weeks prior to study entry
• Able to understand and consent to the study procedures

Exclusion criteria:

• Diabetes including diabetes diagnosed at screening
• History of hepatic or renal impairment or diagnosed on screening bloods
• Patients already taking metformin irrespective of indication
• Known allergy or hypersensitivity to metformin
• Pregnancy or breastfeeding
• Any other significant medical condition likely to interfere with the study
• Unable to provide informed consent
• Excessive alcohol intake (>21 units/week)
• BMI < 18.5kg/m2

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo Group; Placebo	Drug: Placebo; Placebo
Active Comparator: Treatment Group; Metformin 500mg/1g bd	Drug: Metformin; The Drug was administered 500 mg twice daily for one week and increased to 1g twice daily for the reminder of the 3 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sputum Glucose Concentration	The median concentration of glucose in sputum following 3 months treatment with metformin or placebo.	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nasal Glucose Concentrations	The median concentration of glucose in nasal samples following 3 months treatment with metformin or placebo.	3 months
Sputum Bacterial Load	The bacterial load in sputum using qPCR was not measured. Therefore, data were not collected	3 months
Sputum Inflammatory Markers	The median concentration of inflammatory cells and cytokines in sputum was not measured. Therefore, data were not collected.	3 months
Quality of Life Score (COPD Assessment Test)	The COPD Assessment Test (CAT): the CAT features 8 questions ranked from 0-5 with a minimum score of 0 and maximum possible score of 40. Higher scores indicate a greater impact on patient health due to their COPD, a difference of ≥2 is considered meaningful. The questionnaire's were completed by every participant at every visit up to 8 times: V1 is at the baseline, then V2-4 are at monthly intervals. V5 is at the baseline after crossing arms -1 month washout, V6-8 are monthly after that.	1 month
Quality of Life Score (St George's Respiratory Questionnaire)	St George's Respiratory Questionnaire (SGRQ): the SGRQ contains 50 items with a minimum score of 0 and a maximum score of 100. Higher scores indicate a greater impact on quality of life due to COPD and a difference of ≥4 is meaningful The questionnaire's were completed by every participant at every visit up to 8 times: V1 is at the baseline, then V2-4 are at monthly intervals. V5 is at the baseline after crossing arms -1 month washout, V6-8 are monthly after that.	1 month
Lung Function	FEV1(Forced Expiratory Volume Test) was performed up to 8 times: V1 is at the baseline, then V2-4 are at monthly intervals. V5 is at the baseline after crossing arms -1 month washout, V6-8 are monthly after that.	1 month

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Principal Investigator: Sebastian Johnston, Imperial College London

Study record dates

Study Major Dates

• Study Start (Actual): May 17, 2022
• Primary Completion (Actual): May 31, 2023
• Study Completion (Actual): June 1, 2023

Study Registration Dates

• First Submitted: August 2, 2018
• First Submitted That Met QC Criteria: August 28, 2018
• First Posted (Actual): August 29, 2018

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 17, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: Chronic Obstructive Pulmonary Disease
• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive; Physiological Effects of Drugs; Hypoglycemic Agents; Metformin
• Other Study ID Numbers: 18SM4819; 2018-001755-12 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No