OBJECTIVES:  To develop an economic model to explore the relative contribution of potential mechanisms driving the value of a new technology to manage Pseudomonas aeruginosainfections in Cystic Fibrosis (CF). METHODS: Following a literature review to identify published models in CF, a previously published model (Tappenden et al, 2013) was replicated and adapted to explore a variety of clinically plausible mechanisms by which a new technology could impact upon health-related quality of life, resource use and cost. These included: drug acquisition costs, reduction in inhaled aminoglycoside use, exacerbation risk, exacerbation level (major/minor), exacerbation costs, exacerbation disutility, mortality risk, CF progression and HRQL. The model estimated costs from the perspective of the NHS and health outcomes using quality-adjusted life-years (QALYS) in line with UK guidelines for economic evaluation and was developed probabilistically to account for parameter uncertainty. The new technology was defined as an adjunct to standard of care treatment (in this case inhaled aminoglycosides). RESULTS: Model results indicated that the cost-effectiveness of the new technology in CF was highly sensitive to its price with large shifts in incremental cost-effectiveness observed across relatively small changes in the daily acquisition cost. The potential reduction in adjunctive inhaled aminoglycoside therapy was the next most important driver of cost-effectiveness. The third most important driver of cost effectiveness was reduction in risk of exacerbations. CONCLUSIONS:  The development of an early model allows for a detailed understanding of the mechanisms which drive the potential value of a new technology. This can be used to focus not only technology development but also the design of studies for evidence collection to best capture the value. The wider benefits of reduced inhaled aminoglycoside use, e.g. reductions in resistance and treatment-related side-effects, are an area of uncertainty and warrant further research.