# The impact of biosimilar use on healthcare utilization among new users of etanercept for inflammatory arthritis: a population-based regression discontinuity analysis

## TL;DR

A study in Canada found that using biosimilars instead of original drugs for arthritis treatment had no significant impact on healthcare use or safety.

## Contribution

This study provides real-world evidence on biosimilar effectiveness and safety using a policy change as a natural experiment.

## Key findings

- Biosimilar policy implementation did not significantly affect physician visits or hospitalizations.
- Biosimilar use showed no unintended consequences on healthcare utilization or safety.
- Results suggest biosimilars are as effective and safe as originator drugs in real-world settings.

## Abstract

Epidemiological evidence on biosimilars’ real-world performance is limited. On July 18th, 2017, a biosimilar health policy was implemented in British Columbia (BC), Canada, mandating all patients initiating a new biologic medication to be prescribed a biosimilar (if/when available). Exploiting a policy change as a natural experiment, we assessed the real-world impact of biosimilar use for inflammatory arthritis (IA) on health resource utilization as a surrogate marker of real-world effectiveness and safety.

Using administrative health data, we identified all incident etanercept users for IA in BC with initiation dates between 2014 and 2020 (n = 3004) [63·6% female; mean (S.D.) age at IA disease diagnosis 52·5 (16·6) years]. Healthcare utilization over three years after initiation was assessed using outcomes including — physician visits (PV), all-cause hospitalizations (ACH), infection-related hospitalizations (IRH), length of hospital stays (LOS), and emergency room visits (ERV). Using regression discontinuity design, we compared healthcare utilization risk in patients initiating etanercept immediately before/after policy-change date, representing the intention-to-treat effect. Additionally, we estimated the complier average causal effect of biosimilar use with instrumental variable (IV) control function method.

Intention-to-treat analyses showed no significant impact of biosimilar policy implementation on PV, HOSP, IRH, LOS, or ERV, with respective adjusted RRs of 0·96 (95% CI: 0·82–1·12), 0·84 (95% CI: 0·49–1·44), 0·91 (95% CI: 0·21–3·86), 0·94 (95% CI: 0·41–2·15), and 0·91 (95% CI: 0·44–1·88). IV analyses indicated biosimilar use in routine settings did not significantly change healthcare utilization, compared to originator etanercept.

No significant impact of biosimilar policy or actual biosimilar use on healthcare utilization was observed, suggesting equivalent real-world effectiveness and safety of biosimilars to originators and no unintended consequences of the policy change.

CHIR and 10.13039/501100000038NSERC.