Skip to main content

How does Nucala (mepolizumab) work? What is the MOA?

Medically reviewed by Kristianne Hannemann, PharmD. Last updated on March 31, 2025.

Official answer

by Drugs.com

Nucala (mepolizumab) is a monoclonal antibody that reduces inflammation by targeting eosinophils, a type of white blood cell. Excess eosinophils can contribute to inflammation, leading to conditions such as severe eosinophilic asthma and hypereosinophilic syndrome.

Mechanism of Action (MOA)

Nucala works by blocking interleukin-5 (IL-5), a cytokine responsible for the growth, activation, and survival of eosinophils. By inhibiting IL-5, Nucala lowers eosinophil levels in the body, helping to reduce inflammation and manage symptoms of eosinophil-related diseases.

How Is Nucala Administered?

Nucala is given as a subcutaneous (under-the-skin) injection once every four weeks. It is approved for the treatment of:

  • Severe eosinophilic asthma
  • Chronic rhinosinusitis with nasal polyps
  • Eosinophilic granulomatosis with polyangiitis (EGPA)
  • Hypereosinophilic syndrome (HES)

Always follow your healthcare provider’s instructions for safe and effective use. For complete prescribing information, consult your doctor or review the official medication guide.

References

Nucala [package insert]. Revised March 2023. GlaxoSmithKline LLC. Accessed 05/29/2024 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=fefb887c-e4ac-431e-8893-e9d1a5a63fea

Read next

How does the Nucala copay card work and do I qualify?

With a Nucala copay card, you may pay as little as $0 for out-of-pocket costs if you have commercial insurance. The maximum benefit per year is up to $15,000 for most patients. Continue reading

How long does it take for Nucala to work?

Nucala starts working within 48 hours; however, it may take up to 4 weeks before the maximum effect of Nucala is seen for both asthma and eosinophilic granulomatosis with polyangiitis (EGPA). In asthma, the greatest reductions in eosinophils were seen with higher dosages, for example, a 64% reduction in eosinophils was seen with a 12.5mg SC dose and a 90% reduction was seen with a 250mg SC dose after 48 hours. Continue reading

Can Nucala cause weight gain?

Weight gain has not been reported as a side effect of Nucala during clinical trials. Medications such as corticosteroids that may be used to treat eosinophilic asthma are more likely to cause weight gain. Continue reading

Related medical questions

Drug information

Related support groups