Real-World Dosing and Utilization of Ustekinumab Among Patients With Psoriasis
Published Online: June 20, 2014
Qian Cai, MS, MSPH; Chureen Carter, PharmD, MS; Azza AbuDagga, PhD, MHA; Brad Schenkel, MS; Megan Jones, PharmD, MPA; and Hiangkiat Tan, BPharm, MS
Psoriasis—a chronic, inflammatory skin disease affecting approximately 2.2% of the US population—is considered the most prevalent immune-mediated inflammatory disease.1,2 Approximately 80% of patients with psoriasis have mild to moderate disease, whereas the remaining 20% have moderate to severe disease.3 Mild psoriasis involves itching and burning on affected parts of the body, while severe psoriasis is also frequently associated with joint pain or arthritis.3-6 As a multisystemic disorder, psoriasis is frequently associated with a number of comorbid conditions, including psoriatic arthritis, cardiovascular disorders, hypertension, dyslipidemia, metabolic syndrome, obesity, and diabetes. 7-11 Notably, due to skin lesions, patients with psoriasis also often experience significant psychological comorbidities, such as anxiety and depression.12,13
There is no available cure for psoriasis; therefore, various lines of therapies are used to alleviate disease symptoms, reduce or clear plaques, and induce remission.14 Conventional therapies, including topical agents, phototherapy (such as psoralen plus ultraviolet A or ultraviolet B), and systemic medications (such as methotrexate, retinoids, or cyclosporine) have been used as the mainstay treatments of psoriasis. However, previous studies have shown that, for some patients, these therapies may be limited in the long term due to adverse events (AEs).3,15,16 With the increased understanding of the immunology of psoriasis, biologics have emerged as an alternative option with significant impact on providing long-term continuous psoriasis control by interfering with T cell function, by inhibiting tumor necrosis factor-α, or by selectively targeting interleukin-12 (IL-12) and IL-23.3,16,17 The American Academy of Dermatology (AAD) guidelines recommend biologics in the management of psoriasis when 1 or more conventional systemic medications are not tolerated due to AEs, are unsuitable due to comorbidities, or fail to produce an adequate response.3,16 Furthermore, the most recent AAD guidelines emphasize that biologics have no relevant drug interactions and have fewer significant safety issues compared with conventional systemic agents; they also highlight the benefits of biologic treatments for patients with complex medical and dermatologic histories on various medications.16
Ustekinumab, as the first agent to inhibit IL-12/23, is a novel biologic. It was approved by the FDA in September 2009 for the treatment of moderate to severe psoriasis,18 and has also been recently recommended as a first-line systemic treatment specifically for patients with chronic plaque psoriasis.16,19 The dose of ustekinumab is determined on the basis of patient weight. For patients weighing 100 kg (220 lb) or less, the recommended dose is 1 initial 45-mg dose followed by another dose 4 weeks later, then another 45-mg dose every 12 weeks thereafter. For patients weighing more than 100 kg (220 lb), the recommended dose is 1 initial 90-mg dose followed by another dose 4 weeks later, then a 90-mg dose every 12 weeks thereafter. It is worth noting that 45-mg ustekinumab was also shown to be efficacious in patients weighing more than 100 kg; however, 90-mg ustekinumab resulted in greater efficacy in these patients.18 Clinical trials have demonstrated the safety and efficacy of ustekinumab in improving the symptoms of psoriasis.20-23 Recently published 5-year efficacy and safety results demonstrate the long-term response associated with ustekinumab as well as the lack of any dose-related or cumulative toxicity with increasing duration of ustekinumab exposure for up to 5 years.24,25 Additionally, results from a phase 3, doubleblind trial have shown that the efficacy of ustekinumab was superior to that of etanercept in patients with psoriasis. 26,27 Despite these positive findings on the efficacy and safety of ustekinumab in clinical trials, limited studies are available to quantify the real-world utilization and dosage patterns of ustekinumab. The main objective of this study was to assess the characteristics and dosing patterns of patients with psoriasis initiated on ustekinumab therapy using a large retrospective administrative claims database.
This retrospective analysis used patient-level data from the HealthCore Integrated Research Database (HIRD, HealthCore Inc, Wilmington, DE). HIRD includes longitudinal claims data from 14 geographically dispersed health plans in the United States, covering approximately 44 million insured lives at the time this study was conducted. HIRD consists of integrated medical claims, pharmacy claims, and eligibility files. All study data were de-identified and developed in compliance with the Health Insurance Portability and Accountability Act. It was determined that a waiver of informed consent from an institutional review board was not required to conduct this study.
The study population consisted of patients 18 years or older who received ustekinumab and had at least 1 medical claim for psoriasis (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9- CM] code of 696.1x) during the study period of September 1, 2009, through November 30, 2010. Ustekinumab was identified from medical claims using the Healthcare Common Procedure Coding System code C9261, or any of the following National Drug Codes ([NDCs]: 57894006002, 57894006003, 57894006103) from pharmacy claims. The date of the first medical or pharmacy claim for ustekinumab was designated as the index date.
All patients included in the analysis were required to have at least 12 months of continuous health plan enrollment prior to the index date. Due to the recent availability of ustekinumab and its early uptake at the time of the study, limited follow-up data were available for the study patients. Therefore, no minimum follow-up period was required and variable follow-up was allowed; however, patients were followed through the latest date of their continuous eligibility after the index date. Patients were excluded from the study if they had a claim for another biologic (ie, adalimumab, alefacept, etanercept, or infliximab) on the index date (Appendix).
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