Key takeaways:

• Dupilumab was the most commonly prescribed first biologic.
• Reslizumab was the most commonly discontinued biologic.
• Mepolizumab was the most common biologic prompting a switch.

PHOENIX — More than half of patients with severe asthma changed biologics or discontinued treatment as they and their clinicians explored solutions, according to an abstract presented at the CHEST Annual Meeting.

However, trial-and-error approaches may lead to delays in disease control, higher costs and adverse effects, Isabella Novoa Caicedo, MD, postdoctoral research fellow, division of pulmonary, allergy and critical care medicine, Mayo Clinic, and colleagues wrote.

Data derived from Novoa Caicedo I, et al. Real-world biologic treatment outcomes: Continuation, discontinuation, and switching pathways in asthma patients at an academic center. Presented at: CHEST Annual Meeting; Oct. 18-21, 2026; Phoenix.

“There are now several biologics available for severe asthma, but we still do not have a clear roadmap for choosing among them,” Novoa Caicedo told Healio.

With a lack of trials directly comparing these biologics, she continued, clinicians use biomarkers, comorbidities and clinical judgment to guide their primary selection.

“We wanted to understand what happens in real-world practice after that first choice, including how often patients continue, switch or stop their first biologic and what drives these different treatment trajectories,” Novoa Caicedo said.

The retrospective, observational study comprised 4,296 patients with severe asthma who received at least one biologic approved by the FDA at a large academic center based in the United States between Jan. 1, 2003, and Nov. 26, 2025. The cohort included 38.7% who continued treatment with a single biologic via ongoing renewals or refills, 17.2% who switched biologics at least once and 44% who discontinued treatment without renewing or switching. Patients most often began treatment with dupilumab (Dupixent; Sanofi, Regeneron; 40%), omalizumab (Xolair; Genentech, Novartis; 23%) or mepolizumab (Nucala, GSK; 20.8%).

The most common discontinued biologics included reslizumab (Cinqair, Teva; 78%), omalizumab (64%), mepolizumab (44%) and benralizumab (Fasenra, AstraZeneca; 44%). The biologics that were discontinued the least often were tezepelumab (Tezspire; AstraZeneca, Amgen; 27%) and dupilumab (34%).

Patients who switched most commonly switched from mepolizumab (34%), omalizumab (23%) and dupilumab (23%), and the most common biologic taken following the switch was dupilumab.

“The groups were generally similar in age and sex, but we observed some differences in baseline clinical characteristics,” Novoa Caicedo said.

Systemic corticosteroid use and higher markers for type 2 inflammation were more common among patients who eventually switched, she said. Also, lower eosinophil levels and greater obstructions in airflow were more common among those who stopped.

“However, there was substantial overlap across the groups,” Novoa Caicedo said. “These baseline characteristics may help inform biologic selection but appear to have limited ability to predict a patient’s future biologic treatment trajectory.”

Also, she said, patients often switched because the first choice was not effective, leaving them with symptoms that persisted in addition to dependence on corticosteroids, along with responses that faded after initial improvement. But poor efficacy did not explain all the switches.

“One-third of evaluable switches occurred while the patient’s asthma was improving,” she said. “This was particularly striking for insurance-related switches, where 96% occurred while the patient was improving.”

Other factors driving switches included insurance coverage, cost, and adverse events, she said. Also, access had an impact on whether patients could initiate treatment, Novoa Caicedo noted.

“Nearly one-third of patients in our chart-reviewed switching cohort had at least one biologic that was ordered but never started, most often because of insurance denial or cost,” she said.

“This highlights that real-world biologic trajectories are influenced not only by clinical response, but also by whether patients can access and remain on the therapy selected for them,” she said. The researchers noted that standard clinical assessments may have underlying differences that drive these switches and discontinuations and that selecting a biologic is a complicated process that often depends on trial and error.

Also, the researchers warned that these approaches may delay asthma control while adding to healthcare costs and subjecting patients to unnecessary adverse effects.

“Baseline clinical characteristics can help inform the initial biologic choice, but there is substantial overlap between patients who ultimately continue, switch or stop treatment,” Novoa Caicedo said. “This limits our ability to predict a patient’s future biologic trajectory using currently established clinical characteristics and biomarkers alone.”

Emerging biomarkers and other factors may enable clinicians to identify asthma phenotypes that current tools cannot capture as well as which patients may have the best responses to particular therapies, she continued.

“In the meantime, continued reassessment remains important, since response can change over time and treatment changes may reflect not only effectiveness, but also access, adverse events and other factors,” she said.

The researchers also plan on continuing their study.

“Our detailed chart review focused primarily on reasons for switching, and we are currently expanding this work to better characterize the factors associated with biologic discontinuation,” Novoa Caicedo said.

By expanding these findings prospectively, she and her colleagues also hope to better understand the evolution of responses to biologics and trajectories of treatment over time.

“We are also interested in emerging biomarkers that may identify phenotypes not captured by current clinical tools and improve our ability to predict future biologic trajectories,” Novoa Caicedo said.

“Ultimately, we hope this work can help inform future research and move biologic selection toward a more individualized approach, both when choosing the initial therapy and when deciding whether and when to switch,” she said.

For more information:

Isabella Novoa Caicedo, MD, can be reached at NovoaCaicedo.LauraIsabella@mayo.edu.