FDA accepts GSK’s filing of Nucala (mepolizumab) for use in chronic rhinosinusitis with nasal polyps

If approved, Nucala would be the only treatment approved in the US for use in four eosinophil-driven diseases.

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Issued: London, UK

GlaxoSmithKline plc (GSK) today announced that the US Food and Drug Administration (FDA) has accepted a regulatory submission seeking approval for the use of its anti-IL5 biologic Nucala (mepolizumab) as a treatment for patients with chronic rhinosinusitis with nasal polyps (CRSwNP).

CRSwNP is an inflammatory condition, characterised by raised eosinophil levels, in which soft tissue growth known as nasal polyps develop in the upper nasal cavity. Nasal polyps can cause chronic symptoms such as nasal obstruction and discharge. Patients with severe disease may require surgical intervention, however polyps can recur meaning patients go through repeated surgeries that become progressively less effective and more risky.

The submission is based on data from the pivotal SYNAPSE study which explored the effect of Nucala in over 400 patients with CRSwNP. All patients in the study had a history of previous surgery (approximately one in three had ≥3 surgeries) and needed further surgery due to severe symptoms and increased size of their polyps.

If the submission is approved, Nucala would become the first anti-IL5 biologic to be approved for CRSwNP in the US and the only treatment approved for use in four eosinophil-driven diseases.

Nucala is currently approved in the US for patients with severe eosinophilic asthma aged six years and older and for adults with eosinophilic granulomatosis with polyangiitis (EGPA). It also recently became the first biologic to be approved for patients aged 12 years and older with hypereosinophilic syndrome (HES). Nucala is not approved as a treatment for CRSwNP anywhere in the world.

About chronic rhinosinusitis with nasal polyps (CRSwNP)

CRSwNP is a chronic inflammatory disease of the nasal passage linings or sinuses leading to soft tissue growth known as nasal polyps in the upper nasal cavity and is characterised by elevated levels of eosinophils. The resultant swellings can grow in both nostrils (bilateral) resulting in chronic rhinosinusitis, greatly impacting a patient’s quality of life due to nasal obstruction, loss of smell, facial pain, facial pressure and nasal discharge. Surgery to remove the polyp tissue may be indicated for severe cases. However, polyps have a strong tendency to reoccur often leading to repeat surgery. 

About mepolizumab

First approved in 2015 for severe eosinophilic asthma (SEA), mepolizumab is the first-in-class monoclonal antibody that targets IL-5. It is believed to work by preventing IL-5 from binding to its receptor on the surface of eosinophils, restoring blood eosinophils to more normal levels. The mechanism of action for mepolizumab has not been definitively established.

Mepolizumab has been developed for the treatment of diseases that are driven by inflammation caused by eosinophils. It has been studied in over 3,000 patients in 26 clinical trials across a number of eosinophilic indications and has been approved under the brand name Nucala in the US, Europe and in over 20 other markets, as an add-on maintenance treatment for patients with SEA. It is approved for paediatric use in SEA from ages six to 17 in Europe, the US and several other markets. In the US, Japan, Canada and a number of other markets, it is approved for use in adult patients with EGPA. It was approved for use in HES in the US in September 2020. Mepolizumab is currently being investigated in CRSwNP and COPD. It is not currently approved for use in CRSwNP or COPD anywhere in the world.  

Important safety information

The following information is based on the US Prescribing Information for Nucala in licensed indications only. Please consult the full Prescribing Information for all the labelled safety information for Nucala.

Nucala is indicated in the US for the:

  • Add-on maintenance treatment of patients six years and older with severe asthma with an eosinophilic phenotype. Nucala is not indicated for the relief of acute bronchospasm or status asthmaticus.
  • Treatment of adult patients with eosinophilic granulomatosis with polyangiitis (EGPA).
  • Treatment of adult and paediatric patients aged 12 years and older with hypereosinophilic syndrome (HES) for ≥6 months without an identifiable non-hematologic secondary cause.


Nucala should not be administered to patients with a history of hypersensitivity to mepolizumab or excipients in the formulation.


  • Hypersensitivity reactions (e.g., anaphylaxis, angioedema, bronchospasm, hypotension, urticaria, rash) have occurred after administration of Nucala. Discontinue Nucala in the event of a hypersensitivity reaction.
  • Do not use to treat acute bronchospasm or status asthmaticus.
  • Herpes zoster infections have occurred in patients receiving Nucala. Consider vaccination if medically appropriate.
  • Do not discontinue systemic or inhaled corticosteroids abruptly upon initiation of therapy with Nucala. Decrease corticosteroids gradually, if appropriate.
  • Treat patients with pre-existing helminth infections before therapy with Nucala. If patients become infected while receiving treatment with Nucala and do not respond to anti-helminth treatment, discontinue Nucala until parasitic infection resolves.


Most common adverse reactions (incidence ≥5%) in severe asthma clinical trials included headache, injection site reaction, back pain, and fatigue. Injection site reactions (e.g. pain, erythema, swelling, itching, burning sensation) occurred in 8% of subjects treated with 100 mg of Nucala versus 3% treated with placebo.

In a clinical trial in patients with EGPA receiving 300 mg of Nucala, no additional adverse reactions were identified to those reported in severe asthma clinical trials. Injection site reactions (e.g. pain, erythema, swelling) occurred in 15% of subjects treated with 300 mg of Nucala versus 13% treated with placebo. 

In a clinical trial in patients with hypereosinophilic syndrome, no additional adverse reactions were identified to those reported in the severe asthma trials. Injection site reactions (e.g. burning, itching) occurred in 7% of subjects treated with 300 mg of Nucala versus 4% treated with placebo.

GSK’s commitment to respiratory disease

For over 50 years, GSK has led the way in developing medicines that advance the management of asthma and COPD. From introducing the world’s first selective short-acting beta agonist in 1969, to launching six treatments in five years to create today’s industry-leading respiratory portfolio, we continue to innovate so we can reach the right patients, with the right treatment. Working together with the healthcare community, we apply world-class science to discover and understand the molecules that become the medicines of tomorrow. We won’t stand still until the simple act of breathing is made easier for everyone.  

About GSK

GSK is a science-led global healthcare company with a special purpose: to help people do more, feel better, live longer. For further information please visit www.gsk.com/about-us.

Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described under Item 3.D "Risk Factors" in the company's Annual Report on Form 20-F for 2019 and as set out in GSK’s “Principal risks and uncertainties” section of the Q3 Results and any impacts of the COVID-19 pandemic.