Real-world healthcare utilization and effectiveness of omalizumab for the treatment of severe asthma

Background — Omalizumab is indicated for the treatment of moderate to severe asthma. There is limited observational evidence on the costs and effectiveness of omalizumab.

Objective — To examine the costs and effectiveness of omalizumab for treatment of severe asthma relative to nonusers.

Methods — We conducted a within-person repeated-measures matched cohort study in Ontario, Canada from April 1, 2012 to March 31, 2014. Continuous users of omalizumab were matched with up to 4 nonusers according to age, sex, recent specialist visits, oral corticosteroid use, asthma severity, and Charlson comorbidity score. The primary outcome was direct healthcare costs. Secondary outcomes were asthma-related hospitalizations or emergency department visits and oral corticosteroid use. The association between omalizumab use and each outcome was assessed using mixed-effects models adjusting for confounders.

Results — Ninety-five omalizumab users and 352 nonusers were matched. Among users, there was a significant increase in healthcare costs of $1,796 per person owing to the cost of the medication at treatment initiation (P < .0001). Costs did not change significantly among nonusers ($85 increase in average monthly costs per person; P = .59). We found no significant changes in the rates of asthma-related hospitalizations or emergency department visits among omalizumab users (P = .44) or nonusers (P = .99) between pre- and postintervention periods.

Conclusion — The use of omalizumab was associated with increased costs but no evidence of lower rates of clinically important outcomes. These results suggest omalizumab had limited effectiveness in our study population. Future studies should further explore subsets of patients most likely to benefit from omalizumab therapy.