EGPA, formally known as Churg-Strauss syndrome, is a rare form of asthma that comes from severe inflammation. The inflammation in EGPA is in the walls of small-to-medium sized blood vessels, and can cause adults to develop adult-onset asthma, allergic rhinitis, and sinusitis. EGPA affects roughly 5,000 individuals in the United States, and can result in damage to major organs and bodily structures, including the lungs, heart, gastrointestinal tract, sinuses, nerves, skin, and more. EGPA has symptoms that include weight loss, sinonasal or sinus-related symptoms, breathlessness, muscle or joint pain, and extreme fatigue. Treatment of EGPA involves suppressing the immune response and reducing inflammation.
Nucala is a targeted biologic therapy that helps reduce inflammation caused by a high number of eosinophils in the blood. Eosinophils are an important white blood cell in our bodies that help protect us from infection, however, when too many of them are present, serious inflammation can occur. This inflammation can affect the airways, leading to eosinophilic asthma, as well as in blood vessels, leading to EGPA. Nucala works to reduce this inflammation by targeting interleukin-5 (IL-5), a component involved in our body’s immune response.
The FDA based its approval on the results of a Phase 3 clinical trial called the MIRRA study, The MIRRA study was conducted by the National Institute of Allergy and Infectious Diseases (part of the U.S. National Institutes of Health) and GlaxoSmithKline, and ran for 52 weeks. Over 130 individuals with relapsing and/or refractory EGPA received either a 300 mg injection of Nucala or placebo, in addition to corticosteroids plus or minus immunosuppressants (the current standard of care). This allowed researchers to evaluate the safety and efficacy of Nucala as an add-on treatment for EGPA.
Both primary endpoints of the study were met, which included achieving a significantly longer amount of accrued time in remission from EGPA, as well as a significant proportion of individuals achieving remission at both the 36 and 42-week marks when compared to their placebo-receiving counterparts. Other additional endpoints investigated, such as those targeted toward remission, corticosteroid use, and relapse, were also met. The safety profile of Nucala was comparable to the placebo group, and the most common side effects experienced by those taking Nucala were injection site reactions (which also occurred at a similar rate for those injected with the placebo treatment), headache, fatigue, and back pain. The most serious adverse effect reported was a worsening or exacerbation of asthma and its symptoms.
Nucala is not indicated for use in individuals with status asthmaticus or acute brochiospasms. As is the case with many immune system-affecting medications, individuals taking Nucala must be monitored for signs of serious infection while taking the medication. Individuals taking Nucala should also be monitored for signs of hypersensitivity (allergic) reactions, as well as be tested for tuberculosis infection before starting the medication.1
GSK Achieves Approval for Nucala (mepolizumab) for the Treatment of Eosinophilic Granulomatosis with Polyangiitis (EGPA) for Adults in the US. GlaxoSmithKline. https://www.gsk.com/en-gb/media/press-releases/gsk-achieves-approval-for-nucala-mepolizumab-for-the-treatment-of-eosinophilic-granulomatosis-with-polyangiitis-egpa-for-adults-in-the-us/. Published December 12, 2017. Accessed December 16, 2017.