A trial to determine the efficacy of dry powder mannitol in improving lung function in subjects with Cystic Fibrosis aged six to seventeen years

1. Personally provide, or have a legal guardian provide written informed consent to participate in the trial, according to local regulations;
2. rhDNase and maintenance antibiotic use is allowed but treatment must have been established at least 3 months prior to screening. The subject must remain on rhDNase and / or maintenance antibiotics for the duration of the trial. The subject must not commence treatment with rhDNase or maintenance antibiotics during the trial;
3. Have a confirmed diagnosis of cystic fibrosis (sweat test result ¡Ý 60 mEq/L chloride and/or genotyping showing two identifiable mutations consistent with a diagnosis of cystic fibrosis);
4. Be aged ¡Ý 6 years and < 18 years;
5. Have a percentage of predicted FEV1 of ¡Ý 30% and ¡Ü 90% at Screening (Visit 0). Percentage of predicted FEV1 will be calculated using Wang for children aged < 8 years, and using NHanes III for those ¡Ý 8 years; and
6. Be able to perform all the techniques necessary to measure lung function.

1. Be using maintenance nebulised hypertonic saline;
2. Be considered ¡°terminally ill¡±; eligible for lung transplantation, or have received a lung transplant previously;
3. Require home oxygen or assisted ventilation;
4. Have had an episode of massive haemoptysis defined as acute bleeding ¡Ý 240 ml in a 24-hour period and/or recurrent bleeding ¡Ý100 ml/day over several days in the three-months prior to Screening (Visit 0);
5. Have a known intolerance to mannitol;
6. Be taking non-selective ¦Â blockers;
7. In the three months prior to Screening (Visit 0) have had a myocardial infarction; a cerebral vascular accident; major ocular, abdominal, chest or brain surgery;
8. Have a known cerebral, aortic or abdominal aneurysm;
9. Be currently participating in, or have participated in another investigative drug trial within four weeks of Screening (Visit 0);
10. Be pregnant or breastfeeding, or plan to become pregnant whilst in the trial;
11. For females of childbearing potential, be using an unreliable form of contraception (at the discretion of the investigator);
12. Have any concomitant medical, psychiatric, or social condition that, in the Investigator¡¯s opinion, would put the subject at significant risk, may confound the results or may significantly interfere with the subject¡¯s participation in the trial; or
13. Have a ¡°failed¡± or ¡°incomplete¡± mannitol tolerance test.