Clinical Remission and Its Determinants in Adult Severe Asthma Patients Receiving Biologic Therapy: A Retrospective Analysis

<b>Background/Objectives:</b> In recent years, the concept of clinical remission under treatment in asthma has gained increasing attention. It is defined as the absence of exacerbations, asthma symptoms, and oral corticosteroid use for at least 12 months, together with improved or stable lung function. This study aimed to evaluate the clinical remission rates and associated factors in patients with severe asthma receiving biologic therapy with either omalizumab (anti-IgE) or mepolizumab (anti-IL-5). <b>Methods</b>: Adult patients with severe asthma and type 2 inflammation who started omalizumab or mepolizumab between January 2009 and December 2023 in our allergy clinic were retrospectively analyzed. Sociodemographic and clinical characteristics were reviewed. Clinical remission rates were assessed at the first and most recent years of maintenance therapy. Independent markers were identified using multivariable analyses. <b>Results</b>: A total of 160 patients were included (mean age 53.8 ± 14.6 years; 81.9% female). Of these, 85.6% received omalizumab and 14.4% mepolizumab. Remission rates at one year and at the latest follow-up were 60.0% and 43.7%, respectively. Patients achieving remission had higher total IgE levels. Psychiatric comorbidity negatively affected remission. The one-year remission rates were 91.3% in the mepolizumab group and 54.7% in the omalizumab group. Higher baseline blood eosinophil counts and Asthma Control Test (ACT) scores were positive markers, while psychiatric disease was inversely associated. <b>Conclusions</b>: Omalizumab and mepolizumab achieved meaningful clinical remission rates in severe asthma. Elevated ACT scores and eosinophil counts and absence of psychiatric comorbidities were independent markers, underscoring the need for individualized biologic therapy to achieve sustained remission.