Eosinophilic granulomatosis with polyangiitis
Eosinophilic granulomatosis with polyangiitis (EGPA) is a vasculitis characterized by disseminated necrotizing eosinophilic granulomas. EGPA is driven by a response similar to that seen in Th2-high asthma. Adult-onset asthma with sinusitis and allergic rhinitis is the most common EGPA presentation. Of all the biologics, mepolizumab has been best studied as treatment for those with EGPA and asthma symptoms. One small study demonstrated disease remission in 8 of 10 cases (Moosig F, et al. Ann Intern Med. 2011 Sep 6;155[5]:341-3). However, many of these patients relapsed after discontinuing therapy.
Eosinophilic esophagitis
Recent reports demonstrated a large portion of adults with a
diagnosis of eosinophilic
esophagitis (EoE) also have a history of asthma. Currently, standard treatment is proton pump
inhibitors and diet modifications. The prevalence of EoE has increased with growing awareness of the disease. Unrecognized and untreated EoE can lead to devastating complications such as esophageal fibrosis, strictures, and food impaction. Similar to some of the above-mentioned syndromes,
EoE is also driven by a Th2 response and eosinophilic inflammation. A recent study in 2022 showed that 31% to 38% of
people with EoE had concomitant asthma (Dellon ES, et al. N Engl J Med. 2022 Dec 22;387 [25]:2317-30). In this population, a weekly dose of dupilumab, 300 mg, led
to a significant improvement in dysphagia symptoms and
histology when compared with placebo.
Allergic bronchopulmonary aspergillosis
Despite its low prevalence worldwide, allergic bronchopulmonary aspergillosis (ABPA) is frequently encountered when managing severe asthma. Current treatment is long-term, relatively high dose systemic corticosteroids. In light of their unfavorable side effect profile, steroid-sparing approaches are being sought. Dupilumab, omalizumab, mepolizumab, and benralizumab have all been tested for their effects on ABPA. Thus far, mepolizumab has the most convincing evidence to support its use for asthma with concomitant ABPA, mainly because it has the most rapid onset of action. Up to 90% of patients with ABPA were able to stop systemic steroids between 2 and 14 months after starting mepolizumab (Schleich F, et al. J Allergy Clin Immunol. 2020 Jul-Aug;8[7]:2412-3.e2).
Bronchiectasis
Asthma and bronchiectasis can coexist in up to 77% of patients. Typically, the pathophysiology behind bronchiectasis is focused around neutrophilic inflammation. New evidence suggests some patients with bronchiectasis, usually in the setting of comorbid adult-onset asthma, demonstrate an eosinophilic Th-2 response. The association is seen more commonly in female patients, the elderly, and nonsmokers. A small prospective study with four patients with severe asthma and bronchiectasis showed significant improvement with less exacerbations, increased pre-bronchodilator FEV1, and a reduction of serum and sputum eosinophils after starting mepolizumab treatment (Carpagnano GE, et al. J Asthma Allergy. 2019 Mar 5;12:83-90). Clinical trials designed to clarify the role for biologics for asthma with co-morbid bronchiectasis are currently underway.