This article is part of MPR‘s coverage of the ACAAI 2019 meeting, taking place in Houston, TX. Our staff will report on medical research related to allergies, asthma, and more conducted by experts in the field. Check back regularly for more news from ACAAI 2019.

HOUSTON — Mepolizumab reduced the number of exacerbations in patients with severe asthma, but exacerbations per month remained relatively stable throughout the year without a clear seasonal influence, according to research presented at the 2019 Annual Scientific Meeting of the American College of Allergy, Asthma, & Immunology, held November 7 to 11, in Houston, Texas.

Prior studies have shown a seasonal influence on symptoms, medication use, and hospitalizations in patients with asthma, but there are limited published data on this influence in patients with severe asthma who are being treated with a biologic.

Investigators of this retrospective analysis used real-world data to examine the effect of seasonality on exacerbations pre and posttreatment with mepolizumab. The rates of asthma exacerbations for 12 months before initiating mepolizumab were compared with the rates 12 months after receiving mepolizumab. Exacerbations were defined as an inpatient hospital admission with a primary asthma diagnosis or an outpatient/emergency department visit with an asthma diagnosis and at least 1 dispensing of systemic corticosteroids for approximately 5 days. Exacerbations by month for 12-month baseline and 12-month follow-up were examined in a post hoc analysis.

The 346 patients who met the study criteria experienced minimal monthly variations in asthma exacerbations. However, exacerbations were highest in the fall and winter, particularly in December (n=93). The fewest number of exacerbations was reported in spring and summer, particularly in  August (n=68). This pattern reflects the findings of previous studies.

After treatment with mepolizumab, the number of asthma exacerbations remained relatively constant, with numbers higher from November through March and lower from April through August. Patients experienced a 30% to 50% reduction in the number of asthma exacerbations, with the greatest reductions seen in the winter months.

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Study investigators concluded, “The number of exacerbations per month appeared relatively stable throughout the year. Patients with severe asthma in this cohort did not reflect a clear seasonality of exacerbations.”

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Ortega H, Hahn B, Bogart M, et al. Seasonality of asthma exacerbations in patients treated with mepolizumab. Presented at: American College of Allergy, Asthma, & Immunology Annual Scientific Meeting 2019; November 7-11, 2019; Houston, TX. Abstract P219.

This article originally appeared on Pulmonology Advisor