Eligibility of monoclonal antibody-based therapy for patients with severe asthma: a Canadian cross-sectional perspective.

Background: Based on immunologic phenotypes underlying asthma, use of monoclonal antibody based therapies is becoming the new standard of care for severe, corticosteroid refractory clinical symptoms. Patients may qualify for one or more of these targeted treatments, based on clinical characteristics and approved indications. However, the statistics are not well characterized, particularly in the Canadian population.

Methods: The objective of this observational study was to identify and describe the proportion of patients with severe asthma who were eligible for targeting IgE, IL-5, or both pathways of immunomodulation. We reviewed a cross-sectional cohort of patients in a Canadian Allergy and Immunology referral practice. We also compared demographic and clinical characteristics of each group.

Results: Of the 128 patients with severe asthma, 84 (66%) were eligible for omalizumab, 100 (78%) for mepolizumab, 52 (41%) for reslizumab, and 68 (53%) for benralizumab. Overlap in treatment eligibility varied; 68 (53%) patients were eligible for both omalizumab and mepolizumab, 47 (37%) were eligible for omalizumab and benralizumab, and 37 (29%) were eligible for all four medications. Patient demographics and clinical characteristics were similar, and levels of serum biomarkers varied based on locally approved prescribing criteria.

Conclusion: In this severe asthma population from a Canadian Allergist's practice, one-third of individuals qualified for all currently available biologics. 41-78% were eligible for at least one mAb. Patients were most likely to be eligible for mepolizumab. Objective assessments to determine asthma phenotype, along with further characterization of safety profiles will lead to further advances in asthma management.