ORLANDO – The goal of treatment is the same for all asthma cases, regardless of severity: “to enable a patient to achieve and maintain control over their asthma,” according to Stanley J. Szefler, MD, a professor of pediatrics at the University of Colorado at Denver, Aurora.
That goal includes “reducing the risk of exacerbations, emergency department visits, hospitalizations, and progression as well as reducing impairments, including symptoms, functional limitations, poor quality of life, and other manifestations of asthma,” Dr. Szefler, also director of the Children’s Hospital of Colorado pediatric asthma research program, told colleagues at the annual meeting of the American Academy of Pediatrics.
Severe asthma challenges
These aims are more difficult with severe asthma, defined by the World Health Organization as “the current level of clinical control and risks which can result in frequent severe exacerbations and/or adverse reactions to medications and/or chronic morbidity,” Dr. Szefler explained. Severe asthma includes untreated severe asthma, difficult-to-treat asthma, and treatment-resistant severe asthma, whether controlled on high-dose medication or not.
Allergen sensitization, viral respiratory infections, and respiratory irritants (such as air pollution and smoking) are common features of severe asthma in children. Also common are challenges specific to management: poor medication adherence, poor technique for inhaled medications, and undertreatment. Poor management can lead to repeated exacerbations, adverse effects from drugs, disease progression, possible development of chronic obstructive pulmonary disease (COPD), and early mortality.
The National Heart, Lung, and Blood Institutefor treatment of pediatric asthma recommend a stepwise approach to therapy, starting with short-acting beta2-agonists as needed (SABA p.r.n.). The clinician then assesses the patient’s symptoms, exacerbations, side effects, quality of life, and lung function to determine whether the asthma is well managed or requires inhaled corticosteroids, or another therapy in moving through the steps. Each step also involves patient education, environmental control, and management of the child’s comorbidities.
It is not until steps 5 and 6 that the guidelines advise considering the biologic omalizumab for patients who have allergies. But other biologic options exist as well. Four biologics currently approved for treating asthma include omalizumab, mepolizumab, benralizumab, and reslizumab, but reslizumab is approved only for patients at least 18 years old.
Biologics for pediatric asthma
Omalizumab, which targets IgE, is appropriate for patients at least 6 years old in whom inhaled corticosteroids could not adequately control the symptoms of moderate to-severe persistent asthma. Dosing of omalizumab is a subcutaneous injection every 2-4 weeks based on pretreatment serum IgE and body weight using a dosing table that starts at 0.016 mg/kg/IgE (IU/mL). Maximum dose is 375 mg every 2 weeks in the United States and 600 mg every 2 weeks in the European Union.
The advantages of an anti-IgE drug are its use only once a month and its substantial effect on reducing exacerbations in a clearly identified population. However, these drugs are costly and require supervised administration, Dr. Szefler noted. They also carry a risk of anaphylaxis in less than 0.2% of patients, requiring the patient to be monitored after first administration and to carry an injectable epinephrine after omalizumab administration as a precaution for late-occurring anaphylaxis.
Mepolizumab is an anti–interleukin (IL)–5 drug used in patients at least 12 years old with severe persistent asthma that’s inadequately controlled with inhaled corticosteroids. Peripheral blood counts of eosinophilia determine if a patient has an eosinophilic phenotype, which has the best response to mepolizumab. People with at least 150 cells per microliter at baseline or at least 300 cells per microliter within the past year have shown a good response to mepolizumab. Dosing is 100 mg subcutaneously every 4 weeks.
For patients with atopic asthma, mepolizumab is effective in reducing the daily oral corticosteroid dose and the number of both annual exacerbations and exacerbations requiring hospitalization or an emergency visit. Other benefits of mepolizumab include increasing the time to a first exacerbation, the pre- and postbronchodilator forced expiratory volume in one second (FEV1) and overall quality of life.
Patient reductions in exacerbations while taking mepolizumab were associated with eosinophil count but not IgE, atopic status, FEV1 or bronchodilator response in the DREAM study (Lancet. 2012 Aug 18;380:651-9.).
Two safety considerations with mepolizumab include an increased risk of shingles and the risk of a preexisting helminth infection getting worse. Providers should screen for helminth infection and might consider a herpes zoster vaccination prior to starting therapy, Dr. Szefler said.
Benralizumab is an anti-IL5Ra for use in people at least 12 years old with severe persistent asthma and an eosinophilic phenotype (at least 300 cells per microliter). Dosing begins with three subcutaneous injections of 30 mg every 4 weeks, followed by administration every 8 weeks thereafter.
Benralizumab’s clinical effects include reduced exacerbations and oral corticosteroid use, and improved asthma symptom scores and prebronchodilator FEV1. Higher serum eosinophils and a history of more frequent exacerbations are both biomarkers for reduced exacerbations with benralizumab treatment.