C33-11 Clinical Remission Rates After Biologic Therapy Initiation in Severe Asthma

Abstract Rationale Biologic therapies have transformed severe asthma management and disease remission is increasingly observed as an achievable treatment goal. However, few real-world US-based asthma remission studies after biologic initiation exist. Here we evaluate clinical remission rates at 12 months after biologic initiation in a large electronic health record (EHR)-based cohort in a major US city. Methods We conducted a retrospective cohort study of patients with asthma who initiated a biologic (Benralizumab, Mepolizumab, Tezepelumab, Dupilumab or Omalizumab) between 01/01/2017 and 05/01/2025 at Penn Medicine. We identified patients with asthma as having a primary asthma diagnosis code and no COPD diagnosis. Biologic initiation date was defined as the first date of biologic prescription recorded in the EHR among patients with adequate follow-up, defined as ≥ 9 months of documented clinical encounters within the 12-month assessment post biologic initiation. Clinical remission was defined using a 3-component definition adapted from registry studies: 1) no asthma exacerbations, 2) no oral corticosteroid (OCS) use, and 3) minimal rescue medication use (≤2 short-acting beta-agonist SABA prescriptions) as a proxy for symptom control. In a subset of patients with available spirometry data, we assessed 4-component remission by adding stable lung function (FEV180% predicted OR ≥ 100 mL increase from baseline) as a fourth component as reported in registry studies. Results Among 1,465 patients who initiated their first biologic therapy, 465 (31.7%) had adequate follow-up and were included in the primary analysis. Included patients were mostly female(71%), white (56%) and privately insured (51%). At 12 months, 157 of 465 patients(33.8%; 95% CI: 29.5-38.3%) achieved 3-component clinical remission. Individual component rates were: no exacerbations (45.8%), no OCS prescription (45.8%), and minimal SABA prescription (61.1%). In the subset with available spirometry data (n = 48, 10.3% of primary cohort), mean baseline predicted FEV1 was 61.6% (SD 20.7%), with no significant change at 12-month follow-up (61.1%, SD 23.2%). FEV1 improvement (80% predicted or ≥ 100 mL increase from baseline) was achieved by 19 of 40 patients (47.5%). In this spirometry subset, 14 of 48 patients (29.2%) achieved 3-component remission, and 6 of 48 (12.5%; 95% CI:4.7-25.2%) achieved 4-component remission including lung function improvement. Conclusion One-third of patients prescribed biologics achieved clinical remission 12 months after biologic initiation. The addition of lung function criteria in a small subset indicated substantially reduced remission rates, highlighting the challenge of achieving complete multi-domain remission, particularly in patients with significant baseline airflow obstruction. This abstract is funded by: NHLBI