The following article is a part of conference coverage from CHEST 2021, being held virtually from October 17 to October 20, 2021. The team at Pulmonology Advisor will be reporting on the latest news and research conducted by leading experts in the field. Check back for more from CHEST 2021.


The use of biologic agents in patients with severe, uncontrolled asthma is effective in a real-world setting, including in patients in subgroups that have not been evaluated in randomized trials. This was among the findings of an analysis of the ongoing, observational CHRONICLE study ( Identifier: NCT03373045) of US adults with severe asthma that were presented at the CHEST 2021 Annual Meeting, held virtually October 17 to 20.

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The analysis comprised US adults with severe asthma being treated with biologics and/or maintenance systemic corticosteroids, plus those who were uncontrolled on high-dose inhaled corticosteroids with additional controllers, between February 27, 2018, and November 1, 2020. For patients starting a biologic or switching between 2 biologics, exacerbation rates were calculated 6 months before and after the start/switch. Patients included in the analysis were required to have data for the full 6 months before and after the start or switch. Results were summarized overall and in specific subgroups of interest.

The analysis drew from 2559 CHRONICLE participants at 122 sites. Of these participants, 409 and 151 individuals either newly started or switched biologic agents, respectively, with 6 months of data on incidence of exacerbation prior to the start/switch. Overall, patients who initiated biologics experienced a 56% decrease in exacerbations—from 1.75 to 0.77 per patient-year. Those participants who started anti-immunoglobulin E (IgE) therapy experienced a 44% reduction (from 1.52 to 0.85 per patient-year), whereas those who initiated anti–interleukin (IL)-5/IL-5R/IL-4R therapies experienced a 60% reduction (from 1.85 to 0.74 per patient-year).

When all biologic therapies were considered, decreases in exacerbations were 52% (from 1.79 to 0.86 patient-years) vs 63% (from 2.40 to 0.89 per patient-year) for the subgroups of individuals with the highest prebiologic blood eosinophilic count (<300 cells/µL vs ≥300 cells/µL, respectively). Further, reductions in exacerbation rates were 55% (from 1.74 to 0.78 per patient-year) vs 62% (from 2.04 to 0.78 per patient-year) in participants with vs without prebiologic forced expiratory volume in 1 second of 80% or more, respectively.

Additionally, exacerbation rate reductions in participants with vs without a reported diagnosis of chronic obstructive pulmonary disease were 44% (from 1.91 to 1.07 per patient-year) vs 57% (from 1.73 to 0.74 per patient-year), respectively. Reductions in exacerbation rates in current smokers vs former smokers were 45% (from 1.99 to 1.09 per patient-year) and 63% (from 1.61 to 0.59 per patient-year), respectively.

Regarding different biologic therapies, participants who switched biologic agents experienced a 43% decrease in exacerbations (from 1.54 to 0.88 per patient-year). Those individuals who switched from an anti-IgE therapy to an anti–IL-5/IL-5R/IL-4R agent experienced a 53% reduction (from 1.38 to 0.65 per patient-year). Moreover, those who switched from one anti–IL-5/IL-5R/IL-4R therapy to another anti–IL-5/   IL-5R/IL-4R agent experienced a 40% exacerbation reduction (from 1.71 to 1.03 per patient-year).

The researchers concluded that the results from the current CHRONICLE study validate and extend the findings of randomized, placebo-controlled trials. Real-world use of biologic therapy is linked to a reduction in exacerbations in multiple patient subgroups who have not been included in prior randomized trials.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures


Panettieri R, Lugogo N, Moore W, et al. Biologic medications for severe asthma are effective in the real-word, including in subgroups not studied in randomized trials. Presented at: CHEST 2021; October 17-20, 2021; Orlando, FL/Virtual. Abstract A20-A25.