HELSINKI — The benefit of omalizumab is greater in patients who have early-onset allergic asthma or severe asthma with frequent exacerbations than in those who have other asthma phenotypes, according to a multicenter, retrospective study.
The phenotypes of patients with asthma "could help us choose the optimal treatment to improve disease control," said investigator Paloma Campo, MD, PhD, from the Regional University Hospital of Malaga in Spain. "This is quite important because the prevalence of uncontrolled severe asthma is increasing."
Currently, asthma is uncontrolled and severe in about 4% of patients, she reported here at the European Academy of Allergy and Clinical Immunology Congress 2017.
In their study, Dr Campo and her colleagues assessed patients 18 years and older with uncontrolled, persistent, severe asthma who responded well to omalizumab. The average duration of treatment was 44.5 months.
Two-thirds of the 345 patients were women, mean age was 48 years, 79.4% were nonsmokers, and 16.2% were exsmokers who had not smoked in more than a year. The mean time since asthma diagnosis was 7 years.
At baseline, before starting omalizumab, 50.1% of the patients experienced daily asthma symptoms. After 1 year of therapy, however, 55.4% had no symptoms and 44.6% experienced symptoms on fewer than 2 days a week.
Mean forced expiratory volume in 1 second (FEV₁) increased from 71.4% at baseline to 85.9% at 1 year, which was a significant 14.7% improvement (P < .0001).
Furthermore, 36.4% of the patients were able to reduce their use of oral corticosteroids after starting omalizumab, and 49.9% were able to reduce their use of inhaled corticosteroids — from a high to a medium dose or from a medium to a low dose.
The proportion of patients needing only a low dose of inhaled steroids increased from 2.0% at baseline to 17.2% at 1 year. And the proportion needing a high dose of inhaled steroids decreased from 78.5% at baseline to 43.5% at 1 year.
In addition, after 1 year of omalizumab therapy, the mean number of nonsevere asthma exacerbations dropped from 9.8 to 1.3 (P < .0001), the mean number of missed work days dropped from 12.4 to 0.6 (P < .0001), the mean number of unscheduled primary care visits dropped from 4.7 to 0.7, and the mean number of unscheduled specialist visits dropped from 1.7 to 0.3.
Dr Campo and her colleagues assigned each patient to one of six phenotypes, developed using European Respiratory Society and American Thoracic Society guidelines (Eur Respir J. 2014;43:343-373) and Spanish Society of Allergology and Immunology criteria.
Of the 345 patients, 29.9% had severe asthma with frequent exacerbations, 23.8% had early-onset allergic asthma, 18.0% had severe steroid-dependent asthma, 13.6% had early- or late-onset hypereosinophilic severe asthma, 9.3% had asthma with persistent airway obstruction, and 5.5% were obese women with severe asthma.
Early-Onset Allergic and Severe Asthma
More than half the cohort — 53.7% — had either severe asthma with frequent exacerbations or early-onset allergic asthma.
Because a good response to omalizumab was one of the inclusion criteria for the study, the investigators did not collect data on adverse events, Dr Campo explained in response to a question from the audience.
Another member of the audience pointed out that by limiting the study population to good responders, without any analysis of various biologic markers or more detail, it makes it difficult to tease out who will have a better initial response to omalizumab.
Dr Campo explained that the team was unable to compare in early and late responders when they did their analysis. However, they have collected data on asthma biomarkers, which they are in the process of analyzing.
"We're searching for biomarkers that can define who is the best responder to omalizumab," she said.
"If the phenotypes correspond well to the biomarkers, that's something we would like to know," said Len Horovitz, MD, an internist and pulmonologist at Lenox Hill Hospital in New York City. But they aren't necessarily essential, he explained.
"A biomarker may be interesting and give you a clue to the problem, but it doesn't necessarily identify a problem patient," said Dr Horovitz, who did not attend the presentation but is familiar with the research. "There are biomarkers that are useful, but they may not end up having clinical importance."
It makes sense to examine phenotypes in responders to biologic therapies for several reasons, he told Medscape Medical News. "First, these drugs could be double-edged swords. While they may give you success in suppressing symptoms and in response to the drug, there are also side effects."
Studies like these, Dr Horovitz pointed out, help physicians select patients who might respond well to therapy and limit adverse events. It also helps ensure that the high cost of treatment is justified.
For patients with a disease phenotype that is unlikely to respond well to omalizumab, Dr Horovitz said physicians can consider it only as a last resort after trying everything else.
"I think the takeaway is that a drug — and certainly an expensive injectable treatment with a lot of adverse side effects — has to be used in the appropriate asthmatic subset, and not just in anyone," he said. "There has to be convincing evidence before you treat the patient that this might be a particularly good choice."
Dr Campo reports that she works for Novartis. Dr Horovitz has disclosed no relevant financial relationships.
European Academy of Allergy and Clinical Immunology (EAACI) Congress 2017: Abstract 072. Presented June 18, 2017.
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Cite this: Omalizumab Response Varies by Asthma Type - Medscape - Jun 27, 2017.