FDA approves GSK’s Nucala to Treat HES

Rare Daily Staff

The U.S. Food and Drug Administration approved GlaxoSmithKline’s Nucala to treat pediatric patients aged 12 years and older with hypereosinophilic syndrome, the first and only targeted biologic treatment to be approved in the United States for patients with this condition.

Hypereosinophilic syndrome (HES) is a rare and under-diagnosed disorder, making it difficult to estimate its overall prevalence. Patients with HES have a persistent and marked overproduction of eosinophils, a type of white blood cell. People with HES may have eosinophil levels three times greater than normal. When eosinophils infiltrate certain tissues, they can cause inflammation and organ damage that, over time, can impact patients’ day-to-day ability to function. Complications can range from fever and malaise to respiratory and cardiac problems. If left untreated, the symptoms of HES become progressively worse and the disease can be life-threatening.

Nucala was first approved in 2015 for severe eosinophilic asthma. It is a 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 to normal levels. At normal levels eosinophils may play a role in maintaining health.

The FDA approval follows a priority review of data from a clinical development program that included positive results from a pivotal phase 3 study. The study showed 50 percent fewer patients experienced a HES flare (worsening of symptoms or eosinophil threshold requiring an escalation in therapy) when treated with Nucala, compared to placebo, when added to standard of care treatment over the 32-week study period.

Most common adverse reactions (incidence ≥5%) in severe asthma clinical trials included headache, injection site reaction, back pain, and fatigue. Injection site reactions occurred in 8 percent of subjects treated with 100 mg of Nucala versus 3 percent treated with placebo.

Nucala is currently used as an add-on maintenance therapy for severe eosinophilic asthma and for the treatment of eosinophilic granulomatosis with polyangiitis and is being investigated in several other eosinophil-driven diseases.

Photo: Hal Barron, chief scientific officer and president of R&D for GSK