Exploring Definitions and Predictors of Severe Asthma Clinical Remission after Biologic Treatment in Adults

<b>Rationale:</b> 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. <b>Objectives:</b> 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. <b>Methods:</b> 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. <i>A priori-</i>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. <b>Measurements and Main Results:</b> 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. <b>Conclusions:</b> 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.