OBSERVE-5: Comparison of Etanercept-Treated Psoriasis Patients From Canada and the United States

Background: OBSERVE-5 surveillance registry results evaluating etanercept safety and effectiveness in patients with moderate to severe psoriasis from Canada and the United States have been reported from data collected between May 2006 and December 2012. Although both countries have an identical indicated starting dose, the maintenance dose can differ and thus affect management strategies and outcomes. Objective: To compare the long-term safety and effectiveness outcomes of etanercept in the Canadian and US cohorts. Methods: Primary end points included exposure-adjusted event incidence rates of serious adverse events and serious infectious events. Secondary end points included exposure-adjusted event incidence rates of events of medical interest and efficacy outcomes. Results: Over 5 years, Canadian patients received a higher maintenance dose of etanercept (50 mg twice/week) more frequently than those from the United States. Safety outcome comparisons revealed that Canadian patients had a significantly lower occurrence of serious adverse events than patients from the United States, with an overall exposure-adjusted event incidence rate per 100 patient-years of 4.46 (95% confidence interval [CI], 3.05-6.29) vs 7.76 (95% CI 7.04-8.54), respectively. Serious infectious event rates were not significantly different between the 2 countries. Secondary outcomes of events of medical interest and effectiveness also did not reveal significant differences between the 2 cohorts. Conclusion: After 5 years of etanercept use, safety and effectiveness outcomes were similar between patients from Canada and the United States, with the exception of a significantly lower rate of serious adverse events in the Canadian population.