Trends in Omalizumab Utilization for Asthma: Evidence of Suboptimal Patient Selection

Background Utilization trends of omalizumab, a first-in-its-class asthma biologic approved in 2003 for individuals not controlled by inhaled corticosteroids (ICSs), may reveal lessons in patient selection. Objective To describe utilization patterns for omalizumab since its introduction in 2003, with a focus on patient-level characteristics of patients for whom omalizumab was initiated. Methods Using a large US database of administrative claims, we identified privately insured and Medicare Advantage beneficiaries with asthma between 2003 and 2015. Characteristics of incident (no omalizumab use in the previous 12 months) and prevalent users of omalizumab for asthma were described and omalizumab use trends graphed. A comparison cohort (1:5 matching proportion) of nonomalizumab users was compared with incident omalizumab users on demographic characteristics, medication adherence (medication possession ratio [MPR]) for ICSs and/or ICS/long-acting β-agonist (ICS-LABA), exacerbation frequency, and asthma control in the 6 months before omalizumab initiation. Results We identified 7,658 prevalent and 3,399 incident omalizumab users. Omalizumab incidence peaked in the second quarter of 2004 at 0.65 per 1,000 individuals with asthma, whereas prevalence peaked in the fourth quarter of 2006 at 3.22; as of fourth quarter 2015, rates were 0.14 and 1.96, respectively. In the 12 months before omalizumab initiation, 72.5% had low adherence (MPR ≤ 0.75) and 48.6% had very low adherence (MPR ≤ 0.5) to ICSs and/or ICS-LABA. In the period 2003 to 2015, the mean number of exacerbations in the 12 months before incident use ranged from 1.50 to 2.11 and the proportion that had poor asthma control (≥3 rescue inhalers dispensed) ranged from 54% to 67%. Incident omalizumab users were less likely to have good asthma control than the matched cohort of nonusers (adjusted odds ratio, 0.53 [0.48-0.59]). Conclusions Omalizumab use for asthma has been gradually decreasing following a peak shortly after its market availability. Many omalizumab users have low or very low adherence rates for ICSs and/or ICS-LABA in the 12 months before omalizumab initiation.