New Canadian Severe-Asthma Guideline Puts Individualized Biologic Care in Focus
A new Canadian Thoracic Society guideline updates treatment recommendations for children, adolescents and adults with severe asthma. The 2026 document puts greater emphasis on matching add-on therapy to disease features, biomarkers, age and prior response, while adding practical direction on home biologic administration.
In this article & details
The Canadian Thoracic Society (CTS) has published an updated national guideline for managing severe asthma in children, adolescents and adults. The September 2026 document replaces the Society’s 2017 severe-asthma position statement and reflects a decade of expanding biologic options, growing evidence about treatment harms and a more detailed understanding of airway inflammation.
Severe asthma is not simply asthma that feels difficult to control. Before treatment is escalated, clinicians need to confirm the diagnosis and review factors that can mimic poor control or undermine therapy, including inhaler technique, adherence, environmental exposures and co-existing conditions. The guideline is aimed at people whose disease remains severe despite appropriate foundational care—not as a general medication algorithm for every person with asthma.
Age and disease pattern matter
The guideline separates recommendations for children aged 6–11, adolescents aged 12–17 and adults. It also distinguishes severe asthma with ongoing exacerbations from severe asthma that is currently controlled. Those differences matter because trial evidence, Health Canada indications and the potential benefit of a biologic are not identical across ages or clinical patterns. The authors did not identify relevant evidence to support recommendations for children aged 1–5.
For eligible patients, the guideline updates advice on anti-IgE treatment and IL-5 pathway therapies, and adds recommendations addressing IL-4/IL-13 and TSLP pathways. The options include omalizumab, mepolizumab, benralizumab, reslizumab, dupilumab and tezepelumab, with recommendations depending on age, exacerbations and evidence of relevant inflammatory features. The guideline also discusses depemokimab based on the evidence available to the panel; that discussion should not be read as a statement that every option has the same Canadian authorization or coverage status.
Biomarkers inform—but do not make—the decision
Blood eosinophil counts, fractional exhaled nitric oxide (FeNO), allergic features, exacerbation history and co-existing conditions can help identify which pathway is most likely to be relevant. These tests do not operate as stand-alone “yes/no” gates. The document notes differences in the strength of evidence between medicines and patient groups, and emphasizes clinical context and shared decision-making rather than choosing a biologic from one lab result.
Another notable addition is guidance on home administration of biologics. Moving injections out of a clinic is not simply a convenience decision: the guideline describes preparation, training for patients or caregivers, informed consent and a structured check of whether treatment is being taken as planned. The choice should remain individualized, including consideration of the patient’s confidence and ability to manage the medicine safely.
What pharmacy teams can take from the update
The guideline reinforces the value of a careful medication review before or alongside specialist escalation. Pharmacy teams can help identify missed doses, device-use problems, duplicate or confusing inhaler regimens and questions about adverse effects. They can also encourage patients with persistent exacerbations to raise the pattern with their prescriber, rather than treating repeated oral corticosteroid bursts as an inevitable part of their routine.
This is not a direction for pharmacists to select or initiate a biologic outside their scope or local authority. Biologic choice, eligibility, monitoring and access remain clinical decisions that require the prescriber and patient to consider the guideline, product monographs, coverage criteria and individual circumstances. The practical contribution in the pharmacy is often to make sure the treatment plan can be followed and that barriers are surfaced early.
CTS says the guideline was developed using GRADE methods and is intended to support evidence-informed care across Canadian practice settings. As with any guideline, recommendations should be interpreted alongside current product information and the patient’s clinical picture.
Primary sources
References
- CTS severe-asthma guideline (2026) — Canadian Thoracic Society / Taylor & Francis, Primary clinical guideline; GRADE-based recommendations for children, adolescents and adults.
- CTS guideline library and publication update — Canadian Thoracic Society, Confirms September 2026 publication and current status.
- CTS announcement: severe-asthma guideline published — Canadian Thoracic Society, Official announcement dated September 14, 2026.
