A 2x2 factorial, randomised, open-label trial to determine the clinical and cost- effectiveness of hypertonic saline (HTS 6%) and carbocisteine for airway clearance versus usual care over 52 weeks in adults with bronchiectasis: A protocol for the CLEAR clinical trial

Abstract Background Current guidelines for the management of bronchiectasis (BE) highlight the lack of evidence to recommend mucoactive agents, such as hypertonic saline (HTS) and carbocisteine, to aid sputum-removal as part of standard care. We hypothesise that mucoactive agents (HTS or cabocisteine, or a combination) are effective in reducing exacerbations over a 52-week period, compared to usual care. Methods A 52-week, 2x2 factorial randomised open label trial to determine the clinical and cost-effectiveness of HTS 6% and carbocisteine for airway clearance versus usual care: CLEAR (clinical and cost-effectiveness of hypertonic saline (HTS 6%) and carbocisteine for airway clearance versus usual care). Patients will be randomised to either (i) Standard care and twice daily nebulised HTS (6%), (ii) Standard care and carbocisteine (750mg three times per day until visit 3 reducing to 750mg twice per day), (iii) Standard care and combination of twice-daily nebulised HTS and carbocisteine, or (iv) Standard care. The primary outcome is the mean number of exacerbations over 52 weeks. Key inclusion criteria: adults with a diagnosis of BE on computed tomography scans, BE as the primary respiratory diagnosis, two or more pulmonary exacerbations in the last year requiring antibiotics and production of daily sputum. Discussion This trial’s pragmatic research design avoids the significant costs associated with double-blind trials whilst optimising rigor in other areas of trial-delivery. CLEAR will provide evidence as to whether HTS, carbocisteine or both are effective and cost-effective for BE patients.