IL5 and chronic rhinosinusitis with nasal polyps: Similarly, mepolizumab, a humanized monoclonal antibody that selectively inactivates IL-5, in the phase 3 study SYNAPSE, showed a significant improvement in nasal polyp size, nasal obstruction, and sinonasal symptoms, including sense of smell and quality of life in patients with CRSwNP under continuous medical treatment and previous nasal surgery [161].