GlaxoSmithKline (GSK) announced that the US Food and Drug Administration (FDA) have approved Nucala (mepolizumab), a monoclonal antibody that targets interleukin-5 (IL-5), as a treatment for patients with chronic rhinosinusitis with nasal polyps (CRSwNP). This new indication for mepolizumab is for the add-on maintenance treatment of CRSwNP in adult patients 18 years of age and older with inadequate response to nasal corticosteroids.
CRSwNP accounts for 2-4% of the US population, affecting more than 5 million people. CRSwNP is one of a variety of diseases arising from inflammation in different tissues associated with elevated levels of a type of white blood cell called eosinophils. It is often characterised by raised eosinophil levels, in which soft tissue growth, known as nasal polyps, develop in the sinuses and nasal cavity. CRSwNP can cause chronic symptoms such as nasal obstruction, loss of smell, facial pressure and nasal discharge.
Mepolizumab is the first anti-IL-5 biologic to be approved for adult patients with CRSwNP in the US.
Clinical basis of approval:
The approval of mepolizumab as a treatment for CRSwNP is based on data from the pivotal SYNAPSE study which explored the effect of mepolizumab vs. placebo in over 400 patients with CRSwNP. Mepolizumab achieved significant improvement in reducing the size of nasal polyps and nasal obstruction. All patients in the study received standard care, had a history of previous surgery (approximately one in three had =3 surgeries) and were in need of further surgery due to severe symptoms and increased size of their polyps. SYNAPSE showed that there was a 57% reduction in the proportion of patients who had surgery in the group treated with mepolizumab vs. placebo, HR=0.43 (95% CI 0.25, 0.76). In addition, the proportion of patients requiring systemic corticosteroid use during the 52-week treatment period was lower in patients who received mepolizumab.
Mepolizumab is also approved for use in three other eosinophilic driven diseases, the first indication being for patients with severe eosinophilic asthma aged six years and older. Additionally, mepolizumab was the first biologic therapy indicated for adults with eosinophilic granulomatosis with polyangiitis (EGPA) and also the first biologic to be approved for patients aged 12 years and older with hypereosinophilic syndrome (HES).
CRSwNP is a chronic inflammatory disease of the nasal passage linings or sinuses which can lead to soft tissue growths known as nasal polyps and is often characterised by elevated levels of eosinophils. The resultant swellings can grow in both nostrils (bilateral) greatly impacting a patient due to various symptoms including nasal obstruction, loss of smell, facial pressure and nasal discharge. Surgery may be indicated for severe cases. However, polyps have a strong tendency to reoccur often leading to repeat surgery.
First approved in 2015 for severe eosinophilic asthma (SEA), mepolizumab is the first-in-class monoclonal antibody that targets IL-5. It is believed to work by preventing IL-5 from binding to its receptor on the surface of eosinophils, reducing blood eosinophils and maintaining them within normal levels. A normal level of blood eosinophils being less than 500 eosinophils/microliter.