Biological Treatments for Eosinophilic Asthma Enter the Airways

Biologics for Severe Asthma: Treatment-Specific Effects Are Important in Choosing a Specific Agent

Patients with uncontrolled severe persistent asthma have greater morbidity, greater use of health care resources, and more impairment in health-related quality of life when compared with their peers with well-controlled disease. Fortunately, since the introduction of biological therapeutics, patients with severe eosinophilic asthma now have beneficial treatment options that they did not have just a few years ago. In addition to anti-IgE therapy for allergic asthma, 3 new biological therapeutics targeting IL-5 and 1 targeting IL-4 and IL-13 signaling have recently been approved by the Food and Drug Administration for the treatment of severe eosinophilic asthma, and approval of more biological therapeutics is on the horizon. These medications decrease the frequency of asthma exacerbations, improve lung function, reduce corticosteroid usage, and improve health-related quality of life. This article reviews the mechanisms of action, specific indications, benefits, and side effects of each of the approved biological therapies for asthma. Furthermore, this article reviews how a clinician could use specific patient characteristics to decide which biologic treatment may be optimal for a given patient.

Biological treatments for severe asthma

PURPOSE OF REVIEW

Asthma is a heterogenous disease associated with different phenotypes and endotypes. The unmet needs with severe asthma have led to the emergence of potential therapeutic targets beyond the existing therapies. Recently, several biologics were examined and some have now been approved to target T2 airway inflammation in patients with severe disease. We provide an overview of recently approved biologic, those which are emerging and highlight unmet needs in this area.

RECENT FINDINGS

Multiple biologics targeting T2 high asthma are now available for clinical use in the appropriate groups of severe asthma. These target overlapping phenotypes, which include allergic and eosinophilic asthma. Available biologics were shown to improve outcomes that include the reduction of exacerbations and improvement of lung function. Some have also demonstrated improvement in patient-reported outcomes. Some of these biologics have also demonstrated beneficial effects on associated asthma comorbidities. Biomarkers help predict response to certain biologics, although only few currently exist. Emerging biologics blocking other pathways of airway inflammation are under development. Several small molecule antagonists and inhibitors are also in development. Biologics and therapies targeting T2 low or non-T2 asthma are needed.

SUMMARY

Recently approved biologic therapies improve asthma outcomes in subset of patients. Future research to uncover better predictors of response can improve the precise approach to therapy of patients with severe disease.

Role of Biologics in Asthma

Patients with severe uncontrolled asthma have disproportionally high morbidity and healthcare utilization as compared with their peers with well-controlled disease. Although treatment options for these patients were previously limited, with unacceptable side effects, the emergence of biologic therapies for the treatment of asthma has provided promising targeted therapy for these patients. Biologic therapies target specific inflammatory pathways involved in the pathogenesis of asthma, particularly in patients with an endotype driven by type 2 (T2) inflammation. In addition to anti-IgE therapy that has improved outcomes in allergic asthma for more than a decade, three anti-IL-5 biologics and one anti-IL-4R biologic have recently emerged as promising treatments for T2 asthma. These targeted therapies have been shown to reduce asthma exacerbations, improve lung function, reduce oral corticosteroid use, and improve quality of life in appropriately selected patients. In addition to the currently approved biologic agents, several biologics targeting upstream inflammatory mediators are in clinical trials, with possible approval on the horizon. This article reviews the mechanism of action, indications, expected benefits, and side effects of each of the currently approved biologics for severe uncontrolled asthma and discusses promising therapeutic targets for the future.

Mouse models of severe asthma for evaluation of therapeutic cytokine targeting

Severe asthma is a heterogeneous inflammatory disease of the airways, which requires treatment with high-dose inhaled corticosteroids or their systemic administration, yet often remains uncontrolled despite this therapy. Over the past decades, research efforts into phenotyping of severe asthma and defining the pathological mechanisms of this disease were successful largely due to the development of appropriate animal models. Recent identification of distinct inflammatory patterns of severe asthma endotypes led to novel treatment approaches, including targeting specific cytokines or their receptors with neutralizing antibodies. Here we discuss how different experimental mouse models contributed to generation of clinically relevant findings concerning pathogenesis of severe asthma and to identification of potential targets for biologic therapy.