Effectiveness of biosimilar adoption within a UK tertiary hospital: 6‐year follow‐up

Abstract Health systems encourage switching from originators to biosimilars as biosimilars are more cost‐effective. The speed and completeness of biosimilar adoption is a measure of efficiency. We describe the approach to biosimilar adoption at a single hospital Trust and compare its efficiency against the English average. We additionally follow up patients who reverted to a previously used biologic, having switched to a biosimilar, to establish whether they benefitted from re‐establishing prior treatment. The approach we describe resulted in a faster and more complete switch to biosimilars, which saved an additional £380 000 on drug costs in 2021/2022. Of patients who reverted to their original biologic, 87% improved short‐term, and a time on treatment analysis showed the benefit was retained long term. Our approach to biosimilar adoption outperformed the English average and permits patients to revert to their original biosimilar post‐switch if appropriate.