Effect of omalizumab in Japanese patients with severe allergic asthma and rhinitis

Background :
There is evidence that humanized monoclonal antibody against IgE (Omalizumab) is effective in mainly North American and or European population of severe allergic asthma. In this study, we examined the effectiveness of omalizumab on clinical symptoms, pulmonary function, and airway inflammation in Japanese patients with severe allergic asthma.

Method :
We conducted a prospective open-label study that enrolled patients with severe allergic asthma in adult who visited Allergy Center, Saitama Medical University in Japan.  All patients were uncontrolled despite medication including high-dose inhalational corticosteroids, long-acting beta agonist, leukotriene receptor antagonist, theophylline, and oral predonisolone.  Omalizumab was added on their treatments and we evaluated symptoms using Asthma Contol Test(ACT), peak expiratory flow rate(PEFR), exhaled nitric oxide (eNO), sputum eosinophils, and nasal symptoms before and 12-16 weeks after administering omalizumab.

Results :
Seven  patients were enrolled, and administered with omalizumab for 12-16 weeks. The mean age was 52 years and four patients (57%) were female. All patients had allergic comorbidities (7 had rhinitis, 3 had dermatitis, 2 had conjunctivitis). The five patients (71%) were taking the oral corticosteroid as controller.  Omalizumab significantly improved ACT scores especially dose of rescue use of short-acting beta2-agonist (p<0.05) and PEFR (p<0.05).  Furthermore, omalizumab significantly decreased exhaled both eNO (p<0.05) and the percentage of eosinophils in induced sputum. On the other hand, nasal symptoms were not change following induction of omalizumab.

Conclusion :Clinical effectiveness of omalizumab was confirmed in Japanese population of severe allergic asthma, but not rhinitis. The therapeutic potency of omalizumab on asthma likely involves anti-inflammatory properties such as decreasing eNO or airway eosinophilia.