Single-arm, open-labelled, safety and tolerability of intrabronchial and nebulised bacteriophage treatment in children with cystic fibrosis and Pseudomonas aeruginosa .

INTRODUCTION: Cystic fibrosis (CF) is a multisystem condition that is complicated by recurrent pulmonary infections requiring aggressive antibiotic treatment. This predisposes the patient to complications such as sensorineural hearing loss, renal impairment, hypersensitivity and the development of antibiotic resistance. Pseudomonas aeruginosa is one of the more common organisms which cause recurrent infections and result in greater morbidity and mortality in people living with CF. Bacteriophages have been identified as a potential alternative or adjunct to antibiotics. We hypothesise that bacteriophage therapy is a safe and well-tolerated treatment in children with CF infected with P. aeruginosa infection in their airways.

METHODS: This single-arm, open-labelled, non-randomised trial will run for a maximum period of 36 months with up to 10 participants. Adolescents (≥12 years and <18 years of age) who continue to shed P.aeruginosa (within 3 months of enrolment) despite undergoing eradication therapy previously, will be considered for this trial. Non-genetically modified bacteriophages that have demonstrated obligate lytic activity against each of the study participants' P. aeruginosa strains will be selected and prepared according to a combination of established protocols (isolation, purification, sterility testing and packaging) to achieve close to good manufacturing practice recommendations. The selected bacteriophage will be administered endo-bronchially first under direct vision, followed by two times a day nebulisation for 7 days in addition to standard CF treatment (intravenous antibiotics, physiotherapy to be completed as inpatient for 10-14 days). Safety and tolerability will be defined as the absence of (1) fever above 38.5°C occurring within 1 hour of the administration of the nebulised bacteriophage, (2) a 10% decline in spirometry (forced expiratory volume in 1 s %) measured preadministration and postadministration of the first dose of nebulised bacteriophage. Clinical reviews including repeat sputum cultures and spirometry will be performed at 3, 6, 9 and 12 months following bacteriophage treatment.

ETHICS AND DISSEMINATION: Our clinical trial is conducted in accordance with (1) good clinical practice, (2) Australian legislation, (3) National Health and Medical Research Council guidelines for the ethical conduct of research.

TRIAL REGISTRATION NUMBER: Australia and New Zealand Clinical Trial Registry (ACTRN12622000767707).