The Food and Drug Administration (FDA) has approved Nucala (mepolizumab; GlaxoSmithKline) for adults and children aged 12 years and older with hypereosinophilic syndrome (HES) for six months or longer without another identifiable non-blood related cause of the disease.

HES is a heterogeneous group of rare disorders associated with persistent eosinophilia (higher than normal levels of a type of disease-fighting white blood cell) with evidence of organ damage. Symptoms include skin rashes, itching, asthma, difficulty breathing, abdominal pain, vomiting, diarrhea, arthritis, muscle inflammation, congestive heart failure, deep venous thrombosis, and anemia.

Nucala is an interleukin-5 (IL-5) antagonist monoclonal antibody (IgG1kappa) that is also indicated for the treatment of patients aged 6 years and older with severe asthma with an eosinophilic phenotype and for adult patients with eosinophilic granulomatosis with polyangiitis, a rare autoimmune condition that causes blood vessel inflammation. The new indication for Nucala is the first approval for HES patients in nearly 14 years. For the treatment of HES, Nucala has received orphan drug designation, which provides incentives to assist and encourage drug development for rare diseases.

Food and Drug Administration (FDA). FDA Approves First Drug to Treat Group of Rare Blood Disorders in Nearly 14 Years [news release]. September 25, 2020. Available at: click here. Accessed September 28, 2020.