Biologic Therapy Utilization in Patients With Moderate to Severe Psoriasis and Psoriatic Arthritis: An Observational Summary of Biologic Therapy Use in a Clinical Setting

Plaque psoriasis affects approximately 2% to 3% of the global population, with psoriatic arthritis observed in approximately 20% to 30% of these individuals. Upon advances in research pathophysiology and treatment over the past decade, biologic therapies have been used more to treat moderate to severe psoriasis. In Canada, reimbursement bodies have defined prior authorization criteria to determine patient eligibility for funding of biologic treatments in moderate to severe plaque psoriasis. Generally, patients will have been treated with conventional therapies such as topical steroids, phototherapy, or systemic treatments such as methotrexate and cyclosporine before starting a biologic therapy. In difficult cases or severe flares in otherwise controlled disease, practitioners may augment the regimen with one or more conventional treatments. The objective of this observational report was to identify treatment pathways for psoriasis and psoriatic arthritis patients in Canada by examining initial biologic treatment and subsequent treatment optimization patterns for informed reimbursement discussions and decisions. A retrospective chart review was conducted at Newlab Clinical Research using medical records of patients who received at least 1 of 4 biologic agents approved at that time of the survey in Canada for the treatment of plaque psoriasis (adalimumab, etanercept, infliximab, ustekinumab). The study population consisted of patients who had moderate to severe plaque psoriasis, diagnosed by a dermatologist, for at least 6 months before the study index date and who attended Newlab Clinical Research between 2008 and 2013. All current and previous agents prescribed for the treatment of psoriasis were captured. A total of 248 patients with psoriasis treated with biologics were identified, of whom 27 (10.9%) were also diagnosed with psoriatic arthritis. Prior to initiating treatment with a biologic, most patients (72.1%) were treated with (or contraindicated to) methotrexate/cyclosporine. Treatment was supplemented with topical agents (70.6%) and/or followed by a course of ultraviolet light phototherapy (51.6%). Only 2.4% of patients were treated with a biologic first. Of 248 patients treated with biologics, almost half (47.6%) needed add-on therapy, whereas 16.5% of patients had an increase in dose or dosing interval. Furthermore, 14.1% of patients added a topical agent, 10.5% a topical steroid, or 6.5% a course of phototherapy while continuing biologic therapies. Finally, 30.4% of patients switched to another biologic treatment. Adalimumab was the most common agent used as a second-line agent (37.2%), and patients who started on adalimumab mainly switched to ustekinumab as a second-line agent (73.9%). Infliximab was the agent least often used as second-line therapy.