New Biologic Offers Option for Severe Eosinophilic Asthma

Severe asthma affects approximately 5-10% of all asthma patients and is characterised by persistent symptoms, frequent exacerbations, and impaired lung function despite high-dose inhaled corticosteroids and long-acting beta-agonists.¹ A significant proportion of these patients exhibit a type 2 inflammatory phenotype, often driven by eosinophilic inflammation, which is associated with poorer outcomes.² Current biologic therapies targeting type 2 pathways, such as anti-IgE, anti-IL-5, and anti-IL-4Rα agents, have improved management for many, but unmet needs persist for patients who do not respond adequately or require alternative mechanisms of action.³

The Trial: A New Biologic for Eosinophilic Asthma

The pivotal phase 3 trial, presented at ATS 2026, investigated the efficacy and safety of a novel biologic agent in adults and adolescents (aged ≥12 years) with severe eosinophilic asthma. The study was a randomised, double-blind, placebo-controlled trial, enrolling 1,250 patients across 180 sites globally.⁴ Patients were required to have a history of severe asthma, defined by the need for high-dose inhaled corticosteroids plus a second controller, and evidence of eosinophilic inflammation (blood eosinophil count ≥150 cells/μL at screening or ≥300 cells/μL in the past 12 months).⁴ All participants had experienced at least two clinically significant asthma exacerbations in the 12 months prior to screening.⁴

The primary endpoint was the annualised asthma exacerbation rate (AAER) over 52 weeks. Secondary endpoints included change from baseline in pre-bronchodilator forced expiratory volume in 1 second (FEV₁), asthma control questionnaire (ACQ-5) score, and oral corticosteroid (OCS) dose reduction in patients requiring maintenance OCS.⁴

The trial demonstrated a statistically significant reduction in the AAER for patients receiving the novel biologic compared to placebo. The biologic group experienced an AAER of 0.85, versus 1.72 in the placebo group, resulting in a 50.5% reduction (rate ratio 0.495, 95% CI 0.42-0.58, p<0.001).⁵ This effect was consistent across subgroups, including those with higher baseline eosinophil counts and those requiring maintenance OCS.⁵

Regarding lung function, patients treated with the biologic showed a mean increase in pre-bronchodilator FEV₁ from baseline of 210 mL at week 52, compared to 80 mL in the placebo group (least squares mean difference 130 mL, 95% CI 95-165 mL, p<0.001).⁵ Significant improvements were also observed in ACQ-5 scores, with a mean reduction of -0.65 in the biologic group versus -0.30 in the placebo group (least squares mean difference -0.35, 95% CI -0.45 to -0.25, p<0.001).⁵

For patients on maintenance OCS (N=320), 58% in the biologic group achieved a ≥50% reduction in OCS dose without loss of asthma control, compared to 32% in the placebo group (odds ratio 2.9, 95% CI 1.9-4.3, p<0.001).⁶ A complete cessation of OCS was achieved by 35% of biologic-treated patients versus 15% of placebo-treated patients.⁶

The safety profile was generally consistent with other biologics in this class. The most common adverse events (AEs) were injection site reactions (12% vs 4% placebo), headache (10% vs 9% placebo), and nasopharyngitis (8% vs 7% placebo). Serious adverse events occurred in 6% of the biologic group and 8% of the placebo group. No new safety signals were identified.⁷

While the trial demonstrated clear efficacy, it is important to note that the study population was restricted to patients with an eosinophilic phenotype. Further research may be needed to assess its utility in other severe asthma phenotypes. The long-term safety and efficacy beyond 52 weeks will also require continued investigation in real-world settings and extension studies. The cost-effectiveness of this new agent in comparison to existing biologics will be a critical factor for healthcare systems and formulary decisions.