The two studies were of similar design and encompass 643 patients from 11 countries. Over the 26 weeks of the two studies, patients treated with Bronchitol had an average 7.3% improvement in lung function (FEV1) compared to baseline (p<0.001) and a highly significant improvement compared to patients in the control group (p<0.001). In the sub group of patients who were also on rhDNase, patients taking Bronchitol showed a 5.3% improvement from baseline (p<0.001), that was again superior to the control group (p=0.020). In the sub group of patients who were not on rhDNase, patients taking Bronchitol showed a 9.44% improvement from baseline (p<0.001), that was also superior to the control group (p=0.009). The overall rate per annum reduction in exacerbations for patients on Bronchitol versus those on control was 25% (NS) and the number of patients experiencing an exacerbation was 29% lower for those taking Bronchitol (NS). This result was achieved in a well treated patient population who overall had a very low rate of exacerbations in the study.