A rapid monitoring plan following a shift in coverage from brand name to biosimilar drugs for rheumatoid arthritis in British Columbia

Abstract

Purpose: 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. Methods: 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. Results: 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. Conclusions: 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.

Rapid monitoring of health services utilization following a shift in coverage from brand name to biosimilar drugs in British Columbia—An interim report

“…9 Likelihood ratios were used instead of P values or confidence intervals because the interpretation of a likelihood ratio remains the same regardless of how many times the analysis is updated. 4 We expected the CID to fluctuate substantially during early follow-up given that, initially, the number of events is often small and erratic between groups. For this reason, we proposed that statistical significance be determined when the likelihood ratios were sustained above 7.1.…”

“…A cumulative incidence difference (CID) was determined to be statistically significant if a likelihood ratio for the difference was greater than 7.1 9 . Likelihood ratios were used instead of P values or confidence intervals because the interpretation of a likelihood ratio remains the same regardless of how many times the analysis is updated 4 . We expected the CID to fluctuate substantially during early follow‐up given that, initially, the number of events is often small and erratic between groups.…”

“…The British Columbia Ministry of Health requested a real‐time assessment of the Biosimilars Initiative to monitor unintended adverse impacts on patient health or health services utilization 3 . In response, a rapid monitoring plan was developed to assess these impacts, while more comprehensive studies are planned 4 . In the absence of direct measurements of patient health outcomes, health services utilization was considered a proxy for measuring intended and unintended drug effects.…”

“…3 In response, a rapid monitoring plan was developed to assess these impacts, while more comprehensive studies are planned. 4 In the absence of direct measurements of patient health outcomes, health services utilization was considered a proxy for measuring intended and unintended drug effects. For example, an increase in switching to a different bDMARD could indicate an adverse effect or decreased effectiveness of a drug.…”

Rapid monitoring of health services use following a policy to switch patients from originator to biosimilar etanercept—a cohort study in British Columbia

“…These methodologies require significant resources and are limited to a single analysis, which is often delayed. The aim of this rapid monitoring analysis was to detect signals of intended and unintended impacts on health services utilization over a one-year period following the launch of the Biosimilars Initiative for patients treated with originator etanercept [ 25 , 26 ]. Our study was designed to detect potential signals of unintended negative impacts in an entire population, and not to accept or reject a hypothesis of harm in the presence of a sampling error.…”