To describe a rapid monitoring plan to assess the impacts of a shift in drug coverage for biosimilar drugs in British Columbia following the introduction of a new policy on 27 May 2019. The Biosimilars Initiative requires users of originator infliximab or etanercept to switch to biosimilar versions of those drugs to maintain coverage. We propose a signal-detection method to provide near-real-time information to policymakers on the impacts of the policy change.
The exposure will be the Biosimilars Initiative, a policy affecting patients using originator infliximab (Remicade) and etanercept (Enbrel) for approved rheumatologic or dermatologic indications. Two policy cohorts and six historical control cohorts of patients using originator infliximab or etanercept will be assembled using linked and de-identified data from the British Columbia Ministry of Health. Patients will be identified during the 6-month period before the policy anniversary. Outcomes will include medication refills and switching, hospital admissions, emergency department visits, and physician visits. Summary outcome measures, such as cumulative incidence or average quantity as applicable, will be examined daily and reported monthly for 1 year. Outcomes in the policy cohorts will be compared with historical controls using likelihood ratios.
The results of this rapid monitoring plan will be based on analyses involving approximately 9000 patients: four infliximab cohorts of approximately 430 patients and four etanercept cohorts of approximately 1800 patients.
Rapid monitoring results will inform ongoing policy decisions related to the Biosimilars Initiative, in terms of impacts on both patient health and health services utilization.