In one of the few published studies exploring the role of ensifentrine in vitro, it was demonstrated that in well-differentiated bronchial epithelial cells that express a CFTR mutation (in vitro model of cystic fibrosis), ensifentrine reduced IL-1β-induced MCP1 and GM-CSF production, while it had no effect on IL-8 [21]. The gene discussed is CFTR; the disease is cystic fibrosis.