What are the indications for injectable Omalizumab (anti-IgE antibody)?

Indications for Injectable Omalizumab

Omalizumab is indicated for patients aged 12 years and older with moderate-to-severe persistent allergic asthma whose symptoms are inadequately controlled with high-dose inhaled corticosteroids plus long-acting beta-agonists (Step 5-6 therapy) and who have IgE-mediated allergic asthma with positive skin test or in vitro reactivity to a perennial aeroallergen. 1, 2, 3

Primary Indications

1. Allergic Asthma

• Patient criteria:
  • Age ≥6 years (FDA approved for ages 6 and older) 2, 3
  • Moderate-to-severe persistent allergic asthma
  • Inadequate control despite medium-to-high dose inhaled corticosteroids (ICS) plus long-acting beta-agonists (LABAs)
  • Positive skin test or in vitro reactivity to a perennial aeroallergen
  • Evidence of elevated IgE levels
  • Typically used at treatment steps 5-6 in asthma management 1, 2

2. Chronic Spontaneous Urticaria (CSU)

• Patient criteria:
  • Age ≥12 years 3
  • Remains symptomatic despite H1-antihistamine treatment 1, 4
  • Does not require allergen sensitivity or elevated IgE levels for this indication

3. Chronic Rhinosinusitis with Nasal Polyps (CRSwNP)

• Patient criteria:
  • Age ≥18 years 3
  • Inadequate response to intranasal corticosteroids

4. IgE-Mediated Food Allergy

• Patient criteria:
  • Age ≥1 year 3
  • For reduction of allergic reactions including anaphylaxis with accidental food exposure

Mechanism of Action

Omalizumab is a recombinant DNA-derived humanized monoclonal antibody that:

• Binds to free IgE in the blood
• Prevents IgE from attaching to high-affinity IgE receptors (FcεRI) on mast cells and basophils 3
• Reduces FcεRI expression on inflammatory cells
• Blocks the subsequent inflammatory cascade triggered by IgE 1, 3
• Reduces blood and tissue eosinophils and inflammatory mediators (IL-4, IL-5, IL-13) 3

Dosing Considerations

• Dosage is determined by patient's body weight and baseline serum total IgE level 2, 5
• For allergic asthma, standard dosing tables apply for IgE levels up to 700 IU/mL (US) or 1500 IU/mL (EU) 6
• Administered subcutaneously every 2-4 weeks depending on dose calculation 2, 5

Clinical Benefits

In allergic asthma, omalizumab has demonstrated:

• Reduction in clinically significant exacerbations 7
• Decreased need for rescue medications 2
• Improved asthma control and quality of life 2, 7
• Reduced need for oral corticosteroids 1, 2
• Potential benefits for allergic comorbidities (allergic rhinitis, atopic dermatitis, food allergy) 8

Important Considerations and Precautions

• Risk of anaphylaxis: Approximately 0.09-0.2% of patients may experience anaphylaxis 1, 2

  • Patients should be observed for 30 minutes after each injection
  • For the first three injections, observation should be extended to 2 hours 2
  • Patients should be educated about signs of anaphylaxis and prescribed an epinephrine autoinjector

• Treatment assessment: Response should be evaluated after 16 weeks of therapy 2

  • If no meaningful improvement is seen after 16 weeks, treatment should be reconsidered

• Contraindications: Severe hypersensitivity to omalizumab or its components

Clinical Pearls

• For patients with IgE levels >1500 IU/mL (outside standard dosing tables), emerging evidence suggests omalizumab may still be effective, though this use would be off-label 6
• Omalizumab may have benefits for multiple allergic comorbidities beyond its primary indications 8
• Adherence rates with omalizumab are typically higher than with other controller medications, possibly due to administration by healthcare professionals 1

While omalizumab is expensive compared to other asthma therapies, its ability to reduce exacerbations and improve quality of life in appropriate patients with severe disease makes it a valuable treatment option for those who remain symptomatic despite maximal conventional therapy.