This site requires JavaScript to be enabled to work properly. Please modify your settings or use a different browser to continue


Leaving GSK Pro

You are leaving GSK Pro to visit a separate website not associated with GSK Pro, a portal for US Healthcare Professionals.There are website links to third-party sites on GSK Pro. GSK is not responsible for content on third-party websites.





Interleukin 5 (IL-5) is the major cytokine responsible for the growth and differentiation, recruitment, activation, and survival of eosinophils

Target IL-5 in severe asthma with NUCALA

The mechanism of action of mepolizumab in asthma has not been definitely established.
This video illustrates the mechanism of action (MOA) for NUCALA.

The mechanism of action (MOA) of mepolizumab in asthma has not been definitely established.
This video illustrates the MOA for NUCALA.

Two sides to the eosinophil story

Role of eosinophils in maintaining health includes1:

  • Regulating the immune system
  • Tissue regeneration and repair
  • Host protection (eg, defending against parasitic infection)

Too many airway tissue eosinophils in patients with severe asthma* is associated with2,3:

  • Increased symptoms
  • Greater likelihood for exacerbations
  • Airway inflammation
  1. *According to the American Thoracic Society (ATS) and European Respiratory Society (ERS), severe asthma is a type of asthma that requires treatment with high-dose inhaled corticosteroids (ICS), plus a second controller and/or systemic corticosteroid to prevent it from becoming uncontrolled, or asthma that remains uncontrolled despite this therapy.4



  1. Weller PF, Spencer LA. Functions of tissue-resident eosinophils. Nat Rev Immunol. 2017;17:746-757.
  2. Wenzel S. Severe asthma in adults. Am J Respir Crit Care Med. 2005;172(2):149-160.
  3. Malinovschi A, Fonseca JA, Jacinto T, Alving K, Janson C. Exhaled nitric oxide levels and blood eosinophil counts independently associate with wheeze and asthma events in National Health and Nutrition Examination Survey subjects. J Allergy Clin Immunol. 2013;132(4):821-827 e5.
  4. Chung KF, Wenzel SE, Brozek JL, et al. International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma. Eur Respir J. 2014;43:343-373.
  5. Data on file, GSK.
  6. Khatri S, Moore W, Gibson PG, et al. Assessment of the long-term safety of mepolizumab and durability of clinical response in patients with severe eosinophilic asthma. J Allergy Clin Immunol. 2019;143(5):1742-1751.
  7. Pouliquen IJ, Kornmann O, Barton SV, et al. Characterization of the relationship between dose and blood eosinophil response following subcutaneous administration of mepolizumab. Int J Clin Pharmacol Ther. 2015;53(12):1015-1027.
  8. Pavord ID, Korn S, Howarth P, et al. Mepolizumab for severe eosinophilic asthma (DREAM): a multicenter, double-blind, placebo-controlled trial. Lancet. 2012;380:651-659.