Nucala vs. Xolair for Asthma: 5 Differences Between These Biologics

For many health conditions, biologics — medications that come from living sources — have opened the door for new and effective treatment options for chronic conditions. In 2003, Xolair (omalizumab) became the first FDA-approved targeted biologic for asthma. 

Over a decade later, the FDA approved Nucala (mepolizumab) — another targeted biologic for asthma that works in a different way. Since then, several other biologics have been approved to help reduce asthma flare-ups and improve quality of life.

If you’re living with severe asthma, you may be wondering if a biologic like Xolair or Nucala is right for you. The answer usually depends on the type of asthma you have. That’s because the two medications work differently in the body to target specific causes of asthma symptoms. We cover five key differences between Nucala and Xolair below.

1. Nucala and Xolair are approved for different types of asthma

Both Nucala and Xolair are under-the-skin (subcutaneous) injections approved to treat asthma — though they each treat a different type. Your healthcare provider will review your health history, symptoms, and test results to determine which type of asthma you have.

Nucala is approved to treat severe eosinophilic asthma. This type of asthma is associated with high levels of eosinophils, a type of white blood cell. Eosinophils normally help fight off infections, but they can also contribute to asthma symptoms by causing inflammation in the respiratory tract.

Xolair is approved to treat moderate-to-severe allergic asthma. This type of asthma is usually triggered or worsened by allergens, such as pollen and pet dander. When your immune system reacts to these allergens, it makes antibodies called immunoglobulin E (IgE). This is the main culprit behind allergic asthma symptoms. Eosinophils are also involved, but to a different degree.

Nucala and Xolair are typically added on to your asthma treatment plan if your symptoms aren’t being managed with other asthma medications, such as steroid inhalers. After proper training, both medications have the option for you or a caregiver to administer the injections at home.

2. Nucala and Xolair work differently in the body

Nucala and Xolair are both monoclonal antibodies — lab-made antibodies that target specific substances in the body. But Nucala targets interleukin-5 (IL-5) and Xolair targets IgE.

IL-5 is an immune system protein that helps eosinophils grow, turn on, and survive in the body. Nucala works by blocking IL-5 from binding to eosinophils, preventing these effects. This helps lessen lung inflammation by reducing the amount of eosinophils in your blood.

As mentioned above, IgE antibodies are formed when your immune system reacts to an allergen. These IgE antibodies bind to certain immune cells, which triggers allergic inflammation when you encounter the allergen again. Xolair prevents this from happening by blocking IgE from binding to these immune cells. It has also been shown to lower eosinophil levels in the blood.

3. Your Xolair dosage is determined by a blood test, your age, and your body weight

Nucala and Xolair are both given as subcutaneous injections into the abdomen, thigh, or upper arm. But how your dose is determined and how often you receive it is different between the medications.

Nucala is given every 4 weeks (1 month). Your specific dose is determined by your age. For severe asthma, people ages 12 and older inject 100 mg per dose, and children ages 6 to 11 years old receive 40 mg per dose. Nucala isn’t approved to treat younger kids with severe asthma.

Before starting Xolair for allergic asthma, your healthcare provider will perform a blood test to measure the amount of IgE in your blood. This will determine your Xolair dose and how often you should inject it. They’ll also factor in your age and body weight.

• Adults and adolescents ages 12 and older: Doses range from 150 mg to 375 mg, given every 2 or 4 weeks. Higher IgE levels and body weights typically require a higher Xolair dose and more frequent injections.

• Children ages 6 through 11 years old: Doses range from 75 mg to 375 mg, given every 2 or 4 weeks. Similar to the older age group, higher IgE levels and body weights typically require a higher Xolair dose and more frequent injections.

• Children ages 5 and younger: Xolair isn’t approved for this age group.

4. Xolair has a boxed warning for severe allergic reactions, while Nucala does not

While rare, both Nucala and Xolair can cause severe allergic reactions (anaphylaxis) after receiving them. But Xolair has a boxed warning (the FDA’s strictest medication warning) for its anaphylaxis risk. This is because anaphylaxis is possible at any time, even after 1 year or more of routine treatment.

You’ll receive your first three (or more) Xolair injections in a healthcare setting and monitored for a period of time afterwards, likely a couple hours. This allows your care team to monitor you for anaphylaxis and to provide treatment quickly if it occurs. Most anaphylaxis cases have happened within the first three Xolair doses.

While Xolair can be administered at home, this may not be an option for everyone. For example, people with a history of anaphylaxis to other substances may not be good candidates. That’s because studies suggest they may be at higher risk of anaphylaxis with Xolair.

Your healthcare provider will consider your health history, ability to administer injections, and other factors when determining if you or a caregiver can administer Xolair injections at home.

5. Nucala and Xolair have other approved uses

In addition to severe asthma, both Nucala and Xolair are also approved to treat chronic rhinosinusitis with nasal polyps (CRSwNP) in adults. This condition is common in people with severe asthma. Eosinophils and IgE both play a role in CRSwNP.

Since Nucala helps to reduce eosinophil levels, it can be useful in other conditions associated with high levels of eosinophils. Nucala is currently the first and only approved treatment for eosinophilic granulomatosis with polyangiitis. It’s also the first and only biologic approved for hypereosinophilic syndrome.

Xolair can also help treat chronic hives, another allergic condition, in people ages 12 and older. You may be prescribed Xolair if your symptoms aren’t being managed by antihistamines, such as desloratadine (Clarinex).

Ways to save on Nucala and Xolair

There are ways to save on Nucala and Xolair, which are available as reference (“brand-name”) medications. Currently, several Xolair biosimilars are in the last phase of clinical trials and may be available in a few years. Biosimilars would be highly similar to brand-name Xolair, but likely at a lower cost.

Until then, you may be able to pay as little as $0 for Nucala or as little as $0 for Xolair by using a manufacturer copay card. Patient assistance programs are also available to make your prescription more affordable, if you qualify.

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Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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