Is a patient with worsening COPD and frequent exacerbations a candidate for dupilumab (Dupixent) and what eosinophil count threshold is required?

Dupilumab (Dupixent) for COPD with Frequent Exacerbations

Yes, this patient is a candidate for Dupixent if his blood eosinophil count is ≥300 cells/μL at screening. 1

Specific Eligibility Criteria

Your patient must meet ALL of the following requirements based on the FDA-approved indication 1:

Required Eosinophil Threshold

• Blood eosinophil count ≥300 cells/μL at screening (this is the absolute requirement)
• This threshold identifies patients with type 2 inflammation who will benefit from dupilumab 1, 2

Additional Required Criteria

• Exacerbation history: ≥2 moderate or ≥1 severe COPD exacerbations in the previous year
• Already on triple therapy: Must be on inhaled corticosteroid (ICS) + long-acting β2-agonist (LABA) + long-acting muscarinic antagonist (LAMA) for at least one of those exacerbations
• Chronic bronchitis: Documented chronic productive cough for ≥3 months in the previous year
• Lung function: Post-bronchodilator FEV1 30-70% predicted
• Smoking history: Current or former smoker with ≥10 pack-years
• Age: 40-85 years old

Key Exclusions

• History of asthma (this is critical—dupilumab is NOT indicated for COPD patients with asthma history) 1
• Other pulmonary diseases beyond COPD

Clinical Evidence Supporting Use

The BOREAS and NOTUS trials demonstrated robust efficacy in this specific population 3, 4, 2:

Exacerbation reduction: Dupilumab reduced the annualized moderate/severe exacerbation rate by 30-34% compared to placebo (rate ratio 0.66-0.71) 2, 3, 4. In the pooled analysis, the annualized rate was 0.794 with dupilumab vs 1.156 with placebo 2.

Lung function improvement: Prebronchodilator FEV1 increased by 82-83 mL at week 12 compared to placebo, sustained through 52 weeks 3, 4.

Quality of life: Significant improvements in SGRQ scores (mean difference -3.4 points at week 52) 3.

Eosinophil Count Considerations

The 300 cells/μL Threshold

• This is the FDA-approved screening threshold and should be strictly adhered to 1
• Higher baseline eosinophil counts predict even greater treatment response 5—patients with higher counts showed greater magnitude of exacerbation reduction (p=0.0056)
• The 2023 Canadian Thoracic Society guideline mentions that withdrawing ICS may be particularly harmful in patients with eosinophils ≥300 cells/μL 6, supporting the biological rationale for targeting this population

Important Caveat

• While the 2017 GOLD guidelines mention that exacerbations associated with increased sputum or blood eosinophils may be more responsive to systemic steroids 7, dupilumab represents a more targeted approach specifically validated at the ≥300 cells/μL threshold
• Do NOT use dupilumab in patients with eosinophils <300 cells/μL—there is no evidence supporting efficacy below this threshold

Practical Implementation

Dosing: 300 mg subcutaneously every 2 weeks, added to existing triple therapy (do not discontinue background therapy) 1

Monitoring:

• Recheck eosinophil count if initial screening value is borderline (the trials allowed up to 3 retests to confirm eligibility) 1
• Monitor for conjunctivitis (1.4% incidence) and keratitis (0.1% incidence) 1
• Watch for treatment-emergent eosinophilia ≥500 cells/μL (41.7% in trials, though none were clinically symptomatic) 1

Safety profile: Dupilumab showed favorable safety comparable to placebo, with no increased risk of serious adverse events 2, 3, 4. Importantly, it reduced pneumonia risk (HR 0.65) and showed lower all-cause mortality in real-world data 8.

Alternative Considerations

If your patient does NOT meet the eosinophil threshold or other criteria, the 2023 Canadian guidelines recommend 6:

• Ensuring optimization of triple therapy (LAMA/LABA/ICS)
• Adding macrolide maintenance therapy if continuing to exacerbate despite triple therapy (with appropriate cardiac and infection screening)
• Considering roflumilast or N-acetylcysteine for chronic bronchitic phenotype

The bottom line: Check the eosinophil count. If ≥300 cells/μL and the patient meets other criteria, dupilumab is an evidence-based add-on therapy that significantly reduces exacerbations and improves lung function in this high-risk COPD population.