How NUCALA works to target eosinophils

NUCALA targets interleukin-5 (IL-5)

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

How NUCALA works

NUCALA mechanism of action diagram


NUCALA mechanism of action diagram

The MOA of mepolizumab in asthma has not been definitively established.


This video illustrates the MOA for mepolizumab in asthma.

Role of eosinophils in health and in severe asthma

Eosinophils cell diagram
Eosinophils cell diagram

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
NUCALA reduced blood eosinophil levels and maintained within normal levels

4.5-year open-label study4,5

Reduction in blood eosinophils over 4.5 yr chart
Reduction in blood eosinophils over 4.5 yr chart

Mean blood eosinophil levels5: 240 cells/µL at baseline; ~40-50 cells/µL on treatment.

Results are descriptive. The clinical significance of these pharmacodynamics data is unknown. 

Note: Mean normal blood eosinophil levels in a general population of subjects without confounding factors have been reported as 100 cells/µL (range: 34-257) and 107 cells/µL (5th, 95th percentile: 30, 395); levels vary based on age, sex, environmental exposures, and comorbid conditions.6,7