Budesonide is a glucocorticoid used in the management of asthma, the treatment of various skin disorders, allergic rhinitis and ulcerative colitis. The precise mechanism of corticosteroid actions on inflammation in asthma is not well known. Inflammation is an important component in the pathogenesis of asthma. Corticosteroids have been shown to have a wide range of inhibitory activities against multiple cell types (e.g., mast cells, eosinophils, neutrophils, macrophages, and lymphocytes) and mediators (e.g., histamine, eicosanoids, leukotrienes, and cytokines) involved in allergic- and non-allergic-mediated inflammation. The anti-inflammatory actions of corticosteroids may contribute to their efficacy in asthma. Commonly reported side effects of budesonide include: acne vulgaris, moon face, and bruise. Other side effects include: ankle edema, hirsutism, weakness, arthralgia, nausea, and rhinitis. Ketoconazole, a potent inhibitor of cytochrome P450 (CYP) isoenzyme 3A4 (CYP3A4), the main metabolic enzyme for corticosteroids, increased plasma levels of orally ingested budesonide.

CHF6001 is a phosphodiesterase 4 (PDE4) inhibitor optimised for inhaled delivery and tolerability, for the treatment of Asthma and Chronic Obstructive Pulmonary Disease. CHF6001 was 7- and 923-fold more potent than roflumilast and cilomilast, respectively, in inhibiting PDE4 enzymatic activity. CHF6001 inhibited PDE4 isoforms A-D with equal potency, showed an elevated ratio of high-affinity rolipram binding site versus low-affinity rolipram binding site and displayed >20,000-fold selectivity versus PDE4 compared with a panel of phosphodiesterases. CHF6001 effectively inhibited the release of tumor necrosis factor-α from human peripheral blood mononuclear cells, human acute monocytic leukemia cell line macrophages (THP-1), and rodent macrophages (RAW264.7 and NR8383). CHF6001 has the potential to be an effective topical treatment of conditions associated with pulmonary inflammation, including asthma and chronic obstructive pulmonary disease.