Purpose: Ustekinumab indicated for moderate-to-severe plaque psoriasis patients has recommended weight-dependent dosing of 45mg or 90mg with administration at weeks 0, 4, and every 12 weeks thereafter. An understanding of real-world ustekinumab utilization may offer additional information for the interpretation of existing clinical trial-based comparative cost-effectiveness data. This study evaluated the observed distribution of 45mg ustekinumab dosing in biologic-experienced and biologic-naïve psoriasis patients.
Method: Health insurance claims from the Thomson Reuters MarketScan® Commercial and Medicare Supplemental databases were analyzed. Inclusion criteria: 1 ustekinumab index medical/pharmacy claim (09/25/2009-10/31/2010); age ≥18 years at index; ≥ 6 months pre-index continuous enrollment; and ≥1 psoriasis diagnosis code (696.1) on or pre-index. Biologic experience was defined as evidence of another biologic pre-index. Dose strength was evaluated based on an assessment of time between doses (index to 3rd dose) and cost, to account for multiple vials/syringes in a single claim. Utilization outcomes included the proportion of patients receiving 45mg of ustekinumab at each dose, mean strength at each dose (based on all dose strengths), and dose changes (i.e., increase or decrease from prior dose). Intervals were defined as days between doses.
Result: 1,000 psoriasis patients receiving ustekinumab were evaluated (n=599 biologic-experienced). The overall proportion of 45mg ustekinumab use was 63.3%, 71.0%, and 69.0% for the first 3 doses, respectively. Mean strength across the first 3 doses was 63.5mg, 58.8mg, and 59.2mg, respectively. Dose distribution and mean strength results were similar for biologic-experienced and biologic-naïve patients. Dose changes occurred in 9.0% and 15.8% of all patients at doses 2 and 3, respectively. The majority of changes were dose decreases (79.7% at dose 2 and 57.6% at dose 3). Overall median (mean± SD) dose intervals were 28 (31.1±24.9) and 84 (80.7±34.9) days for 1st to 2nd and 2nd to 3rd doses, respectively.
Conclusion: This study suggests that most psoriasis patients prescribed ustekinumab, regardless of biologic experience, were initiated at a 45mg dose and had median dose intervals consistent with prescribing information. These data may offer a reference for evaluating dosing components of comparative psoriasis biologic cost-effectiveness analyses.
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