Choosing and switching biologics for patients with severe asthma: Real-world data from the German Asthma Net (GAN)

With six biologics available to treat severe asthma in 2025, choosing the optimal initial therapy and deciding to which other biologic to switch in case of insufficient benefit is challenging. To better understand patients' characteristics depending on the chosen biologic and patterns of switch, we evaluated adult patients with severe asthma from the GAN registry who were biologic-naïve at baseline. Between 2011 and 2024, 2,649 patients with severe asthma newly received a biologic, 26% anti-interleukin-5 receptor (IL5R), 25% anti-IL5, 16% anti-IL4R, 24% anti-immunoglobulin E (IgE), and 9% anti-thymic stromal lymphopoietin (TSLP). Distribution of biologics varied between time periods, reflecting their availability over time. Patients treated with anti-IgE were youngest at asthma diagnosis (mean 26 years) and had the highest rates of allergic comorbidities (80%). Blood eosinophils were highest in patients receiving anti-IL5R (median 433/µL) and lowest in those receiving anti-TSLP (median 159/µL), while FeNO was highest in patients treated with anti-IL5, anti-IL5R, or anti-IL4R (median 39, 38, and 35 ppb, respectively). 14.3% (n = 378) of patients were switched from the first biologic to a different one. The most frequent switch constellations were anti-IL5 to anti-IL5R, anti-IL5R to anti-IL4R, and anti-IL5 to anti-IL4R. After a switch, depending on the constellation up to 46% of patients reached remission. Phenotyping patients with severe asthma determines the choice of biologic therapy in real-world practice. Choice and switch of biologic have evolved over time influenced by availability of different drugs. Our analysis supports the practice of switching to a different biologic in case of insufficient initial response.