Asthma is a chronic inflammatory disorder of the airways leading to recurring episodes of wheezing, breathlessness, chest tightness, and coughing, with episodes characterized by airflow obstruction within the lung that is reversible, either spontaneously or with treatment. Disease severity is classified based on frequency and severity of symptoms—i.e., intermittent, mild persistent, moderate persistent, or severe persistent. Patients with severe persistent disease—comprising about 20% of the total U.S. asthma population—have more-frequent and more-severe exacerbations, often despite treatment, and are the targets for several emerging agents that may better serve this costly asthma subpopulation.
Physicians typically treat asthma patients in a stepwise manner, according to Global Initiative for Asthma Management and Prevention (GINA) guidelines, with the goal of maintaining patients on minimal drug therapy to achieve disease control. However, the limits of existing treatments and physicians’ frequent need to go through several lines of maintenance therapy create significant market potential for treatments that better serve the patients with more severe, persistent disease.
Inhaled corticosteroid (ICS) therapy, commonly GlaxoSmithKline’s Flovent (fluticasone propionate), is the mainstay of treatment for persistent asthma. Physicians may add a long-acting beta2 agonist (LABA), either in a separate inhaler or as a LABA/ICS fixed-dose combination inhaler such as GlaxoSmithKline’s Advair (salmeterol/fluticasone propionate) to boost efficacy. Severe asthma uncontrolled by LABA/ICS therapy and/or a leukotriene inhibitor (Merck’s Singulair [montelukast, generics]) or theophylline may receive oral corticosteroids or Genentech/Novartis’s anti-immunoglobulin E (IgE) biologic, Xolair (omalizumab), the latter if the patient has severe and/or refractory symptoms, elevated IgE levels, and perennial allergen sensitization. Xolair is the only treatment option beyond oral corticosteroids for severe, refractory asthma. However, it is relatively expensive, requires closely monitored SC injection, and carries a black box warning regarding anaphylaxis risk.
The pipeline for asthma includes several key therapies, including emerging interleukin (IL)-5 antagonists for severe, refractory patients with eosinophilic asthma. Employing the results from our survey of 103 clinicians (51 allergists, 52 pulmonologists) and 30 managed care organization (MCO) pharmacy/medical directors, we analyze the dynamics that will limit or promote market access for new market entrants, including Boehringer Ingelheim/Pfizer’s long-acting antimuscarinic antagonist (LAMA) Spiriva, GlaxoSmithKline’s once-daily LABA/ICS FDC Breo, and three IL-5 antagonists—Cephalon’s Cinquil (reslizumab), GlaxoSmithKline’s Bosatria (mepolizumab), and MedImmune/BioWa’s benralizumab. These therapies may offer incremental gains in safety, efficacy, and/or convenience. We also expect the launch of biosimilar omalizumab and branded-generic and generic forms of leading therapies (e.g., Advair), which will launch at a discount to their existing branded formulations.