HES is a rare disorder

HES is a condition in which high levels of eosinophils—a type of white blood cell—can lead to inflammation, tissue damage, and eventually, organ damage.

Eosinophil levels for patients with HES are often around 10 times normal level.

Illustration Of Three Eosinophil Cells Associated with Hypereosinophilic Syndrome (HES) Illustration Of Three Eosinophil Cells Associated with Hypereosinophilic Syndrome (HES)
Icon Representing a Doctor Discussion about Hypereosinophilic Syndrome (HES)

Learn more about HES and talk to your doctor about treatment options.
You may feel better about your treatment plan and managing the condition.

What are eosinophils, and how are they related to HES?

Eosinophils are white blood cells, a normal part of our immune system. When you have HES, a blood disorder, your body has too many eosinophils.

Having a high number of eosinophils in the blood can eventually lead to tissue and multiple organ damage, as these eosinophils can enter tissues and cause inflammation. HES can affect any organ in the body, including skin, lungs, stomach, GI tract, heart, nerves, joints, blood vessels, and other organs.

The mechanism of action of FASENRA in HES is not fully understood. FASENRA is a biologic treatment approved to treat people 12 years and older with HES.

Icon Representing Discussing Hypereosinophilic Syndrome (HES) Icon Representing Discussing Hypereosinophilic Syndrome (HES)

FASENRA is approved to treat HES.

Find Out More About FASENRAarrow


frequently asked questions

HES is a condition in which high levels of eosinophils—a type of white blood cell—can lead to inflammation, tissue damage, and eventually, organ damage.

Eosinophil levels for patients with HES are often around 10 times normal level.

HES can affect different organs, including skin, lungs, stomach, GI tract, heart, nerves, joints, blood vessels, and other organs. Multiple organs can be affected at the same time, and symptoms will vary depending on which organs are affected.

Each person’s symptoms are unique, however common symptoms can include tiredness, fever, cough, rash, stomach pain, or shortness of breath, and they can change over time and worsen without treatment.