Experts at the University of Dundee have announced promising results from a clinical trial of a potential new antibody treatment tackling antibiotic-resistant Pseudomonas bacteria in people with bronchiectasis.
Data from the GREAT-2 trial, led by researchers from the University’s School of Medicine, has shown promise in helping patients who are living with the chronic lung disease bronchiectasis and are infected with Pseudomonas aeruginosa, a hard-to-treat and commonly antibiotic-resistant bacteria. The initial study findings have been presented this week at the 2025 American Thoracic Society (ATS) conference - one of the world’s largest gatherings of lung health experts.
Bronchiectasis is the third most common airway disease, after asthma and COPD, and results in a persistent cough, chest pains, and increased mucus production. People with bronchiectasis are especially vulnerable to frequent and serious lung infections.
“Pseudomonas is one of the World Health Organization’s priority pathogens due to its resistance to many antibiotics,” explained Professor James Chalmers, the trial’s chief investigator and Professor and Consultant Respiratory Physician at Dundee’s School of Medicine.
“Patients with this particular infection have triple the risk of death, hospital visits, and very poor quality of life compared to patients without this infection. Pseudomonas is extremely difficult to treat and often does not respond to treatment with conventional antibiotics. We urgently need new options.”
The GREAT-2 proof-of concept trial tested a bispecific antibody called gremubamab, developed by AstraZeneca. This antibody is designed to enhance the body’s natural immune response by targeting two specific features of Pseudomonas aeruginosa that help the bacteria cause damage. By targeting these features, the antibody helps reduce infection and inflammation.
Bacterial infections are typically treated with broad spectrum antibiotics which can kill “bad bacteria” but also kill “good bacteria” and over time infections become resistant to antibiotics. Antibody treatments are more targeted and aim to only affect the target bacteria and may be less likely to induce resistance compared with antibiotics.
“This research represents a new approach to treating Pseudomonas infections and shows real promise for developing highly targeted, non-antibiotic therapies to treat bacterial infections,” said Dr Merete Long, Lead Scientist on the study from Dundee’s School of Medicine. “That’s especially important as we face the growing global challenge of antibiotic resistance.”
The trial was the first to be run through the EMBARC network – a Europe-wide clinical research collaboration supported by the European Respiratory Society (ERS), focused on improving care and finding new treatments for bronchiectasis.
After encouraging results in the laboratory, researchers conducted a clinical trial, giving monthly injections of the antibody to people with persistent Pseudomonas infection. Trial data showed a significant reduction of Pseudomonas in the lungs, fewer disease flare-ups, known as exacerbations, and large improvements in symptoms and quality of life in bronchiectasis patients receiving the antibody compared to a placebo injection.
Gremubamab was well-tolerated in the study, with AE and SAE incidence similar overall between gremubamab and placebo treatment.
“When you see this kind of improvement in quality of life and reduced chest infections it is very encouraging” said Professor Chalmers. “The symptom improvements we have seen in patients in the trial are greater than anything we’ve seen before with antibiotic treatments. If this can be replicated in larger trials, this could be a major step forward in developing treatments for antibiotic resistant Pseudomonas infections and bronchiectasis.”
There are currently no approved therapies that specifically target either bronchiectasis or Pseudomonas aeruginosa, with current treatment involving nebulised (inhaled) broad-spectrum antibiotics, which must be used several times a day. Repeated use of antibiotics can contribute to antibiotic resistance - where bacteria become harder, or even impossible, to treat with existing drugs.
“Serious bacterial infections are significant and growing threats to global health and, therefore, it is exciting to see the scientific promise of a monoclonal antibody approach against one of these bacterial pathogens,” said Tonya Villafana, Vice President, Franchise and Medical & Scientific Affairs, Vaccines & Immune Therapies, AstraZeneca.
“AstraZeneca now has several antibodies in the clinic targeting high-priority pathogens, including a half-life extended version of gremubamab called AZD0292 targeting Pseudomonas aeruginosa in patients with bronchiectasis.”
The study was funded by the European Respiratory Society (ERS) and AstraZeneca. The European Multi-Centre Bronchiectasis Audit and Research Collaboration (EMBARC) ran the study alongside input from the European Lung Foundation’s (ELF) patient-led advisory group.