Rationale: There is no consensus on criteria to include in an asthma remission definition in real life. Factors associated with achieving remission after biologic initiation remain poorly understood. Objectives: To quantify the proportion of adults with severe asthma achieving multidomain-defined remission after biologic initiation and identify prebiologic characteristics associated with achieving remission that may be used to predict it. Methods: This was a longitudinal cohort study using data from 23 countries from the International Severe Asthma Registry. Four asthma outcome domains were assessed in the 1 year before and after biologic initiation. A priori–defined remission cutoffs were: 0 exacerbations/yr, no long-term oral corticosteroid (LTOCS), partly/well-controlled asthma, and percent predicted FEV1 ⩾ 80%. Remission was defined using two (exacerbations + LTOCS), three (+control or +lung function), and four of these domains. The association between prebiologic characteristics and postbiologic remission was assessed by multivariable analysis. Measurements and Main Results: A total of 50.2%, 33.5%, 25.8%, and 20.3% of patients met criteria for two-, three- (+control), three- (+lung function), and four-domain remission, respectively. The odds of achieving four-domain remission decreased by 15% for every additional 10 years of asthma duration (odds ratio, 0.85; 95% confidence interval, 0.73–1.00). The odds of remission increased in those with fewer exacerbations per year, lower LTOCS daily dose, better control, and better lung function before biologic initiation. Conclusions: One in five patients achieved four-domain remission within 1 year of biologic initiation. Patients with less severe impairment and shorter asthma duration at initiation had a greater chance of achieving remission after biologic treatment, indicating that biologic treatment should not be delayed if remission is the goal.

Introduction: International registries provide opportunities to describe use of biologics for treating severe asthma in current clinical practice. Our aims were to describe real-life global patterns of biologic use (continuation, switches, and discontinuations) for severe asthma, elucidate reasons underlying these patterns, and examine associated patient-level factors. Methods: This was a historical cohort study including adults with severe asthma enrolled into the International Severe Asthma Registry (ISAR; http://isaregistries.org, 2015– 2020) or the CHRONICLE Study (2018– 2020) and treated with a biologic. Eleven countries were included (Bulgaria, Canada, Denmark, Greece, Italy, Japan, Kuwait, South Korea, Spain, UK, and USA). Biologic utilization patterns were defined: 1) continuing initial biologic; 2) stopping biologic treatment; or 3) switching to another biologic. Reasons for discontinuation/switching were recorded and comparisons drawn between groups. Results: A total of 3531 patients were included. Omalizumab was the most common initial biologic in 2015 (88.2%) and benralizumab in 2019 (29.6%). Most patients (79%; 2791/3531) continued their first biologic; 10.2% (356/3531) stopped; 10.8% (384/3531) switched. The most frequent first switch was from omalizumab to an anti–IL-5/5R (49.6%; 187/377). The most common subsequent switch was from one anti–IL-5/5R to another (44.4%; 20/45). Insufficient efficacy and/or adverse effects were the most frequent reasons for stopping/switching. Patients who stopped/switched were more likely to have a higher baseline blood eosinophil count and exacerbation rate, lower lung function, and greater health care resource utilization. Conclusion: The description of real-life patterns of continuing, stopping, or switching biologics enhances our understanding of global biologic use. Prospective studies involving structured switching criteria could ascertain optimal strategies to identify patients who may benefit from switching.