Personalized Inhaled Bacteriophage Therapy Shows Promise for Cystic Fibrosis: Study

Nine adult CF patients (eight female, one male; median age 32 years, range 22–46 years) with MDR or PDR Pseudomonas infection were enrolled in a compassionate-use treatment protocol. The infections had failed multiple previous antibiotic regimens. Either a nebulized phage cocktail or a single-phage therapy was administered to each patient, chosen on the basis of anticipated evolutionary trade-offs that would compel the bacteria into becoming either less virulent or more antibiotic-sensitive.

Notably, both patients tolerated the phage therapy with no occurrence of adverse effects. The phages were administered via inhalation, which is where the infection was present.

Results

• Patients enrolled: 9 (8 women, 1 man)

• Median age: 32 years (range 22–46)

Type of infection: MDR or PDR Pseudomonas aeruginosa resistant to conventional antibiotics

• Method of delivery: Nebulized cocktail or single phage therapy

• Safety: No adverse effects reported

Reduction of bacteria:

• Median: Reduction in Pseudomonas of 10⁴ CFU/ml

• Mean: Reduction of 10² CFU/ml (P = 0.006)

Improvement of lung function:

• Median FEV1: +6%

• Mean FEV1: +8% (P = 0.004)

• Sputum microbiome: Remains unchanged

• Trade-offs: Compromise loss of antibiotic resistance or virulence of bacteria

Personalized nebulized phage therapy is shown to be a safe and effective method of decreasing bacterial load and enhancing lung function in cystic fibrosis patients with drug-resistant Pseudomonas aeruginosa infection. The novel therapy not only reduces bacterial numbers but also imposes genetic trade-offs on bacteria that can decrease their resistance and virulence.

Reference:

Chan, B.K., Stanley, G.L., Kortright, K.E. et al. Personalized inhaled bacteriophage therapy for treatment of multidrug-resistant Pseudomonas aeruginosa in cystic fibrosis. Nat Med (2025). https://doi.org/10.1038/s41591-025-03678-8