Twice-yearly biologic maintenance therapy for severe asthma/chronic rhinosinusitis

GlaxoSmithKline plans to introduce Exdensur (depemokimab 100 mg/mL solution for subcutaneous [SC] injection) by the end of July 2026. The new biologic is indicated as an add-on maintenance treatment in adults and adolescents (≥ 12 years of age) with severe asthma characterized by an eosinophilic phenotype and who are inadequately controlled by medium- to high-dose inhaled corticosteroids plus another asthma controller. The product is not indicated for the relief of acute bronchospasm or status asthmaticus. Exdensur is also approved as an add-on maintenance treatment with intranasal corticosteroids in adults with severe chronic rhinosinusitis with nasal polyps who are inadequately controlled by systemic corticosteroids and/or surgery.1Depemokimab is a long-acting monoclonal antibody that targets human interleukin-5 (IL-5), a key cytokine involved in eosinophilic inflammation. It may exert its therapeutic effect in asthma and chronic rhinosinusitis with nasal polyps by blocking IL-5 signaling to reduce the production and survival of eosinophils.The recommended dosage of depemokimab in severe eosinophilic asthma (adults and adolescents ≥12 years of age) is 100 mg SC every six months. For chronic rhinosinusitis with nasal polyps in adults, the recommended dosage is 100 mg SC every six months.Depemokimab should be administered SC into the upper arm, thigh or abdomen. It may be self-administered or given by a caregiver after appropriate training.1The most common adverse effects of depemokimab (all ≤ 2%) are pruritus, administration-related systemic reactions (e.g., headache, fatigue, rash) and injection site reactions (e.g., pain, erythema, swelling, itching). In terms of more serious adverse effects, cases of elevated liver enzymes have occurred, some with features of autoimmune hepatitis, although a causal relationship has not been established. Hypersensitivity reactions, such as anaphylaxis, have been reported with other monoclonal antibodies that target IL-5.1No drug interactions have been established. Depemokimab is expected to have a low potential for drug–drug interactions.1Exdensur will be supplied in a 1 mL prefilled pen (autoinjector) and 1 mL prefilled syringe. These devices should be stored under refrigeration (2°C–8°C) and protected from light. They may be removed from the refrigerator and kept in the unopened carton for up to seven days at room temperature (up to 30°C), when protected from light. However, they should be discarded if left out of the refrigerator for more than seven days. Once the carton is opened, Exdensur must be administered within eight hours.1Exdensur is the only long-acting biologic for severe eosinophilic asthma/chronic rhinosinusitis with twice-yearly dosing.2 Three other IL-5 directed treatments are approved for severe eosinophilic asthma in Canada: mepolizumab (Nucala), reslizumab (Cinqair) and benralizumab (Fasenra). These agents are dosed more frequently (every 2–8 weeks).3,4 Other biologics approved for severe eosinophilic asthma in Canada include dupilumab (Dupixent), omalizumab (Xolair, Omlyclo) and tezepelumab (Tezspire); all are dosed every two to four weeks.4 Medical Letter consultants note that in patients with severe asthma and elevated eosinophil levels, addition of twice-yearly injections of depemokimab to background therapy reduced asthma exacerbation frequency, but did not significantly improve lung function or quality of life. Depemokimab has the advantage of less frequent administration compared to other drugs approved for this indication, but there are no trials directly comparing the efficacy and safety of these agents. All of these drugs are expensive.3References:GlaxoSmithKline Inc. Exdensur (depemokimab injection) product monograph. Mississauga, ON; June 15, 2026. (accessed July 16, 2026).GlaxoSmithKline. Exdensur (depemokimab injection) approved in Canada for the treatment of severe asthma and chronic rhinosinusitis with nasal polyps. June 16, 2026. (accessed July 16, 2026).Anon. Depemokimab (Exdensur) for severe eosinophilic asthma. Med Lett Drugs Ther 2026;68:44-6.TRC Healthcare. Biologics for asthma. Modified January 2026. Pharmacist’s Letter/Pharmacy Technician’s Letter/Prescriber Insights. November 2025. [411164]

Twice-yearly biologic maintenance therapy for severe asthma/chronic rhinosinusitis

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