Most adult patients using biologics for severe asthma do not switch biologics, and only a relatively small proportion of patients either switch biologics or discontinue their use. These were among study results published recently in the Journal of Asthma and Allergy.

Investigators sought to characterize the real-world use of biologics and switching patterns among patients with severe asthma globally. The study sample was a historical cohort of adults with severe asthma who were treated with a biologic, including 3531 patients from 11 countries (Bulgaria, Canada, Denmark, Greece, Italy, Japan, Kuwait, South Korea, Spain,

United Kingdom, and US) enrolled in either the International Severe Asthma Registry from 2015 to 2020 or the CHRONICLE Study Identifier: NCT03373045) from 2018 to 2020. Participants were also required to have a minimum follow-up of 6 months after biologic initiation.

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Biologics used were omalizumab, mepolizumab, reslizumab, benralizumab, or dupilumab.

Biologic utilization patterns were defined as: 1) continuing with the initial biologic; 2) discontinuing biologic treatment; or 3) switching to another biologic. Switch patterns were established for biologic use by total population and by country and analyzed by age, age of asthma onset, long-term oral corticosteroid use, and presence of nasal polyps.

The most common initial biologic in 2015 was omalizumab (88.2%) and in 2019 it was benralizumab (29.6%). For patients in this study, 79% (2791) continued their first biologic; 10.2% (356) stopped; 10.8% (384) switched. The most common first switch was from omalizumab to an anti–IL-5/5R (49.6%) and the most common subsequent switch was from one anti–IL-5/5R to another (44.4%). Researchers found patients who stopped/switched were more likely to have a higher exacerbation rate and baseline blood eosinophil count, lower lung function, and greater health care resource utilization. The most frequent reasons for stopping/switching were insufficient efficacy and/or adverse effects. International patterns with respect to stopping and switching biologics were also observed, with more “switchers” in South Korea, Japan, and Denmark, fewer “switchers” in Spain and Bulgaria, and the highest proportion of “stoppers” in Japan and the US.

According to researchers, further research is necessary to determine reasons for biologic stopping/switching to predict more accurately those most likely to benefit from continuation, stopping, or switching.  Researchers noted that most switches occurred within 12 months of the initial prescription, an action most likely related to payer recommendation instead of medical recommendation. Furthermore, it is still unknown whether the first biologic prescribed to a patient is usually the best one for that individual, or whether clinicians do not switch as often as would be optimal. “Prospective studies involving structured switching criteria could ascertain optimal strategies to identify patients who may benefit from switching,” the investigators noted.

Disclosure: This research was supported by Optimum Patient Care Global and AstraZeneca Ltd. Additionally, some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Menzies-Gow AN, McBrien C, Unni B, et al. Real world biologic use and switch patterns in severe asthma: data from the International Severe Asthma Registry and the US CHRONICLE Study. J Asthma Allergy. Published online January 13, 2022. doi:10.2147/JAA.S328653