A Study to Investigate Lung Deposition of Radiolabelled OligoG

Aged at least 18 years at screening. Understands and is willing, able and likely to comply with all study procedures and restrictions.

Demonstrates understanding of the study and willingness to participate as evidenced by voluntary written informed consent (signed and dated) obtained before any trial-related activities.

Male or female with a confirmed diagnosis of cystic fibrosis defined by:

i.Clinical features consistent with the diagnosis of cystic fibrosis (Rosenstein et al., 1998); AND ii.Sweat chloride ≥ 60 mmol/L by pilocarpine iontophoresis; OR iii.Genotypic confirmation of 2 CF-causing mutations

Positive microbiological finding of Pseudomonas aeruginosa (mucoid or nonmucoid) in expectorated sputum (and/or swab) documented within the last 24 months prior to screening. Negative finding is acceptable provided the proportion of patients enrolled with positive findings is at least 80%.

At screening, FEV1 must be between 35 and 80% of the predicted normal value following adjustment for age, gender and height according to the Knudson equation (Knudson et al., 1983)

Clinically stable in the opinion of the referring physician at CF unit.

Female subjects of child-bearing potential and male subjects participating in the study who are sexually active must use acceptable contraception. For the purpose of this study, acceptable contraception is defined as:

i.Oral, injected or implanted hormonal methods or contraception; OR ii.Placement of an intrauterine device (IUD) or intrauterine system (IUS); OR iii.Barrier methods of contraception: condom or occlusive cap with spermicidal foam/gel/film/cream/suppository

Exclusion Criteria:

On-going acute illness. Patients must not have needed an outpatient visit, hospitalisation or required any change in therapy for other pulmonary disease between screening and AV1.

History of, or planned organ transplantation.

Requirement for continuous (24 hour/day) oxygen supplementation.

Concomitant administration of inhaled mannitol or hypertonic saline within 48 hours of Period 1, Day 1.

Clinically significant abnormal findings on haematology or clinical chemistry. In addition, any value ≥ 3 x the upper limit of normal will exclude the patient from participating in the study.

Unable to perform pulmonary function tests according to ATS criteria.

Pregnant or breast-feeding women.

Participated in any interventional clinical trial within the 28 days prior to AV1.

Documented or suspected, clinically significant, alcohol or drug abuse.

Known allergies or intolerances to alginates.

Any active malignant disease (with the exception of basal cell carcinoma; BCC).

Any serious or active medical or psychiatric illness, which in the opinion of the investigator, would interfere with patient treatment, assessment or compliance with the protocol.

Haemoptysis more than 60 mL at any time within 30 days before study drug administration.

Participation in this study will exceed the limits of total radiation exposure allowed in any 12 month period (5 mSv), or will exceed 10 mSv over any three year period.

Males who intend to father a child in 3 months following study or are unwilling to abstain from sexual intercourse with pregnant or lactating women. Females who are intending to become pregnant in 3 months following study.

Any non-removable metal objects such as metal plates, screws etc in their head, neck, chest or abdominal area.

As a result of a physical examination or screening investigations, the physician responsible considers the patient unfit for the study.