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Does Fasenra weaken your immune system?

Medically reviewed by Carmen Pope, BPharm. Last updated on Oct 4, 2024.

Does Fasenra suppress the immune system?

Official answer

by Drugs.com

Fasenra does not appear to weaken the immune system, but it does affect how the immune system works. This raises legitimate concerns that it may cause immunosuppression and negatively impact a person's immune response, although no major safety concerns have been identified so far.

Fasenra works by depleting eosinophils, which are a type of white blood cell and part of the immune system that helps fight infection and cancer. Fasenra does this by enhancing the ability of natural killer cells and by depleting basophils. This mechanism of action of Fasenra means it activates certain parts of the immune system but not the entire immune system.

Because of this, researchers are conducting ongoing investigations to determine whether Fasenra weakens the immune system and puts patients at increased risk of infection or cancer.

Fasenra is known to influence a person's response to parasitic infections because eosinophils are involved in the immunological response to these infections. Any existing parasitic infections should be treated before starting Fasenra. If patients become infected with parasites during treatment with Fasenra and do not respond to appropriate treatments, discontinue Fasenra until the infection resolves.

An infection causing a sore throat is also one of the most common side effects of people taking Fasenra, implying that Fasenra increases the risk of contracting a viral infection.

Research has shown Fasenra does not impair the body's immune response to the influenza vaccine and does not lower total antibody (immunoglobulin) concentrations in the blood, which help fight foreign invaders (antigens).

Fasenra is a monoclonal antibody (IgG1, kappa) that binds to the alpha subunit of the interleukin-5 (IL-5) receptor. It activates the immune system to lower the number of eosinophils in the blood in eosinophilic asthma and eosinophilic granulomatosis with polyangiitis (EGPA), both of which are associated with increased numbers of these white blood cells. Fasenra works by blocking IL-5, enhancing the ability of natural killer cells and by depleting basophils.

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References

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What eosinophil count is needed for Fasenra?

Fasenra may be an option for severe asthma if you have an eosinophil count of at least 150-300 cells per microliter (cells/μL), determined from a common blood test, plus you have required an oral corticosteroid treatment (like prednisone) at least twice per year, despite maximum inhalation therapy.

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Can severe asthma lead to COPD?

Severe and poorly controlled asthma can lead to damaged lungs which may increase the risk of developing chronic obstructive pulmonary disease (COPD). Symptoms of asthma and COPD may frequently co-exist in smokers and the elderly. Continue reading

What is considered severe asthma?

Severe asthma is when you require medium to high-dose inhaled corticosteroids combined with other longer-acting medications. Severe asthma can also be defined as having a peak expiratory flow rate (PEF or PEFR) less than 50% of your personal best. This shows severe narrowing of your large airways and is considered a medical emergency and you should get help right away. Your symptoms may include coughing, being very short of breath, wheezing while breathing in and out, or retractions (this is when you can see the muscles between the ribs working hard to keep you breathing). Walking and talking may also be difficult. Continue reading

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