title: Delayed onset and protracted progression of anaphylaxis after omalizumab administration in patients with asthma.
abstract: BACKGROUND
  Risk of anaphylaxis is included in the prescribing information for omalizumab, but the nature of these reactions merits further elaboration.
  
  
  OBJECTIVE
  To describe cases of anaphylaxis associated with omalizumab administration in patients with asthma.
  
  
  METHODS
  We reviewed spontaneous postmarketing adverse event reports submitted to the US Food and Drug Administration's Adverse Event Reporting System database and to the manufacturers of omalizumab and cases published in the literature through December 2006. Diagnostic criteria for anaphylaxis outlined by the National Institute of Allergy and Infectious Diseases and the Food Allergy and Anaphylaxis Network were used to screen cases.
  
  
  RESULTS
  One-hundred twenty-four cases of anaphylaxis associated with omalizumab administration in patients with asthma were identified. Many cases had a delayed onset of symptoms beyond 2 hours after dose administration. Many cases were also characterized by a protracted progression, with individual signs and symptoms of anaphylaxis staggered over hours. Review of the case reports did not reveal any predictive risk factors for the delayed onset or protracted progression of anaphylaxis.
  
  
  CONCLUSIONS
  Omalizumab-induced anaphylaxis may be characterized by a delayed onset and a protracted progression of symptoms.
  
  
  CONCLUSIONS
  The unusual timing of anaphylaxis in these cases challenges our understanding of anaphylaxis. A delayed onset of symptoms and protracted progression of anaphylaxis should be taken into account when administering omalizumab.
authors.affiliation: Division of Pulmonary and Allergy Products, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD 20993-0002, USA. susan.limb@fda.hhs.gov
authors.forename: Susan L
authors.initials: SL
authors.lastname: Limb
authors.forename: Peter R
authors.initials: PR
authors.lastname: Starke
authors.forename: Charles E
authors.initials: CE
authors.lastname: Lee
authors.forename: Badrul A
authors.initials: BA
authors.lastname: Chowdhury
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000209:etiology / Q000276:immunology*; D018926:Anti-Allergic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized; D001249:Asthma / Q000150:complications / Q000276:immunology* / Q000628:therapy; D002648:Child; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069444:Omalizumab; D013997:Time Factors
chemical_list: D018926:Anti-Allergic Agents; D018927:Anti-Asthmatic Agents; D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000069444:Omalizumab