Combination of new CFTR correctors and potentiators with antibiotics and anti-inflammatories might be the best strategy to treat CF patients. New antibiotics and effective anti-inflammatories represent an important and largely unmet need. Thanks to the previous pilot project FFC#23/2018, researchers studied the effects of beta-sitosterol (BSS) and L-miglustat in murine models of lung infection. This research extension is aimed at giving deeper insights on anti-inflammatory/anti-infective activities of them both. The effects of BSS on the host inflammatory response will be further investigated by studying its impact on alveolar macrophages, cytokines, chemokines and growth factors involved in lung inflammation in mice infected by Pseudomonas aeruginosa (Pa). The effect of L-miglustat will be experimented in vitro on Pseudomonas biofilm and in vivo in chronically infected mice both before and after established chronic infection. To verify potential interactions with drugs already used in CF patients, combination with VX 809 and VX 770 will be tested. Results from these pre-clinical investigations could provide a proof of concept for planning clinical trials with these new drugs, being BBS already tested in clinical trial for other indications and miglustat could obtain orphan drug designation.