science

Mepolizumab

Mepolizumab is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Mepolizumab rather than just read about it. In short: Mepolizumab, sold under the brand name Nucala, is a humanized monoclonal antibody used for the treatment of severe eosinophilic asthma, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic syndrome. The most common side effects include headache, injection site reactions, and back pain.

Key takeaways

Mepolizumab belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Mepolizumab to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Mepolizumab from memory before moving on to harder problems.

Reference excerpt

Mepolizumab, sold under the brand name Nucala, is a humanized monoclonal antibody used for the treatment of severe eosinophilic asthma, eosinophilic granulomatosis with polyangiitis, and hypereosinophilic syndrome. The most common side effects include headache, injection site reactions, and back pain.

Medical uses Mepolizumab is approved by the US Food and Drug Administration (FDA) for the maintenance treatment of severe asthma in patients aged six years or older and with an eosinophilic phenotype in combination with other medicines used to treat asthma. In the European Union it is approved as an add-on treatment for severe refractory eosinophilic asthma in adults. In studies, mepolizumab cut the necessity for hospitalisation due to asthma exacerbations in half, as compared to placebo. In December 2017, the FDA expanded mepolizumab's indication to treat adults with eosinophilic granulomatosis with polyangiitis, which is a rare autoimmune condition that can cause vasculitis. In September 2020, the FDA expanded mepolizumab's indication to treat adults and children aged twelve years and older with hypereosinophilic syndrome for six months or longer without another identifiable non-blood related cause of the disease. In May 2025, the FDA approved mepolizumab as an add-on therapy for people with chronic obstructive pulmonary disease who exhibit an eosinophilic phenotype.

Side effects Common side effects in clinical trials included headache (19% of patients under mepolizumab treatment versus 18% under placebo), injection site reactions (8% versus 3%), infections of the urinary tract (3% versus 2%) and the lower respiratory tract, eczema and muscle spasms (both 3% versus <1%). The most common side effects in people with hypereosinophilic syndrome include: upper respiratory tract infection and pain in extremities (such as the hands, legs and feet).

Overdose Single doses of 15 times the usual therapeutic dose have been tolerated in studies without significant side effects.

Interactions No interaction studies have been conducted. The interaction potential is considered to be low.

Pharmacology

Mechanism of action Mepolizumab binds to IL-5 and prevents it from binding to its receptor, more specifically the interleukin 5 receptor alpha subunit, on the surface of eosinophil white blood cells. While eosinophils play a role in inflammation associated with asthma, the exact mechanism of mepolizumab is unknown.

Pharmacokinetics After subcutaneous injection, mepolizumab has an estimated bioavailability of 80% and reaches highest blood plasma concentrations after four to eight days. Like other antibodies, it is degraded by proteolytic enzymes. Its biological half-life is 20 days on average, ranging from 16 to 22 days in different individuals.

Chemistry The substance is an IgG1 kappa monoclonal antibody, the two heavy chains consisting of 449 amino acids each, and the two light chains consisting of 220 amino acids each. The protein part has a molar mass of about 146 kDa, and the sugar part of 3 kDa.

History Phase III clinical trials in severe eosinophilic asthma were completed in 2014. Mepolizumab was evaluated in a randomized, double-blind, multicenter, placebo-controlled trial in 108 participants with hypereosinophilic syndrome. In the study, participants were randomly assigned to receive mepolizumab or placebo by injection every four weeks. The trial compared the proportion of subjects who experienced a hypereosinophilic syndrome flare during the 32-week treatment period. A hypereosinophilic syndrome flare was defined as worsening of clinical signs and symptoms of hypereosinophilic syndrome or increasing eosinophils (disease-fighting white blood cells) on at least two occasions. The trial compared the proportions of participants with at least one flare over a 32-week treatment period, as well as the time to the first flare. Fewer participants in the mepolizumab treatment group (28%) had hypereosinophilic syndrome flares compared to participants in the placebo group (56%), with a 50% relative reduction. In addition, the time to the first hypereosinophilic syndrome flare was later, on average, for participants treated with mepolizumab versus placebo.

Society and culture

Legal status In November 2015, the US Food and Drug Administration (FDA) approved mepolizumab for severe asthma, and in December 2015 mepolizumab was authorized for medical use in the European Union. In September 2020, mepolizumab was approved in the United States to treat adults and children aged twelve years of age and older with hypereosinophilic syndrome for six months or longer without another identifiable non-blood related cause of the disease. In January 2024, mepolizumab was approved in China for use in severe asthma with an eosinophilic phenotype. In May 2025, the FDA approved mepolizumab as an add-on therapy for people with chronic obstructive pulmonary disease who exhibit an eosinophilic phenotype.

References

Worked examples

Example 1 — a first encounter with Mepolizumab

Start with the simplest possible case. Write down what Mepolizumab claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Mepolizumab before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Mepolizumab ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Mepolizumab

In research: Mepolizumab appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Mepolizumab in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Mepolizumab is common in secondary-school and first-year university syllabi. It links to neighbouring topics Anti-asthmatic agents, Anti-interleukin monoclonal antibodies, Drugs developed by GSK plc, so understanding it makes those chapters shorter.
In everyday life: Look for Mepolizumab outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Mepolizumab in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mepolizumab means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Mepolizumab out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mepolizumab in simple terms?

Why does Mepolizumab matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Mepolizumab?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Mepolizumab.