In an unselected cohort of consecutive patients with adult-onset asthma, 5.9% had severe asthma and 2% were eligible for anti-interleukin (IL)-5 therapy, according to the results of the Seinäjoki Adult Asthma Study (SAAS; ClinicalTrials.gov Identifier: NCT02733016) published in The Journal of Allergy and Clinical Immunology: In Practice.

Recent research has identified a number of different asthma phenotypes that benefit from particular treatment approaches. Age is a critical factor in determining phenotype. Adult-onset asthma is often characterized by less responsiveness to inhaled corticosteroids (ICS), is often nonatopic, and has a poorer prognosis. Several subtypes of adult-onset asthma have been proposed, including obesity-related, smoking, severe obstructive, mild to moderate/well-controlled, atopic asthma, and late-onset eosinophilic asthma, which is often severe. Antibodies against the IL-5 pathway were developed to treat late-onset eosinophilic steroid-resistant asthma. However, the prevalence of severe asthma and the number of adults with asthma who may derive benefit from anti-IL-5 therapy are not known.

Pinja Ilmarinen, PhD, of the Department of Respiratory Medicine at the Seinäjoki Central Hospital in Finland, and colleagues, evaluated the prevalence and characteristics of patients with severe asthma and patients eligible for anti-IL-5 therapy in 203 participants from the SAAS, a 12-year follow-up study of new-onset adult asthma.

The investigators noted that 4 of the 203 patients, or 2% of the total cohort, would be eligible for anti-IL-5 therapy. Patients with nonsevere asthma, severe asthma, and patients eligible for anti-IL-5 therapy did not differ significantly with regard to sex, age at asthma onset, and lung function parameters at diagnosis and at the 12-year follow-up visit. However, patients with severe asthma were more often current smokers at diagnosis and had higher body mass index at the 12-year follow-up visit compared with patients with nonsevere asthma and anti-IL-5 therapy-eligible asthma.

Patients with severe asthma were also more likely to have systemic rheumatic disease, thyroid disorder, or treated dyspepsia as a comorbidity at the 12-year follow-up. Fractional exhaled nitric oxide and total immunoglobulin E levels were highest in patients eligible for anti-IL-5 therapy and lowest in patients with severe asthma, while neutrophils were highest in patients with severe asthma and lowest in patients who were eligible for anti-IL-5 therapy.

Healthcare usage also differed in the groups: patients with severe asthma and patients who were anti-IL-5 therapy eligible had a higher number of asthma-related visits. However, there was no statistically significant difference between individuals with severe asthma and individuals who were anti-IL-5 therapy-eligible regarding the number of planned or unplanned healthcare visits. While all anti-IL-5-eligible patients had ≥3 sick leaves in the 2 years before the 12-year follow-up visit, this was the case in only 16.7% of patients with severe asthma. In contrast, patients with severe asthma had the most hospitalizations over the entire 12-year follow-up period, accounting for 31% of all hospitalizations, 5 times what might be expected given the prevalence of disease.

The researchers concluded that both patients with severe asthma and patients eligible for anti-IL-5 therapy constituted a high burden to the healthcare system. They argued that identifying these phenotypes as early as possible is important as targeted treatment in patients may lead to lower long-term healthcare use.

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Disclosures: The analysis and write-up of this study was funded by AstraZeneca; however, AstraZeneca was not involved in the study’s planning or execution. Several authors report financial relationships with AstraZeneca, Mundipharma, and Orion Pharma, among other pharmaceutical companies.

Reference

Ilmarinen P, Tuomisto LE, Niemelä O, Kankaanranta H. Prevalence of patients eligible for anti-IL-5 treatment in a cohort of adult-onset asthma [published online June 9, 2018]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2018.05.032