Comparing prescribing and spending across originator, follow-on, and interchangeable biosimilar insulin glargine: Opportunities to improve uptake of biosimilar medications

BACKGROUND: Administrative barriers (eg, prior authorizations, slow reimbursement, and poor communication between providers and payers) and inconsistency regarding cost savings are potentially slowing the acceptance of biosimilar medications by providers and patients. In this study, we used the example of interchangeable biosimilar insulin glargine, the first-ever interchangeable biosimilar approved by the US Food and Drug Administration in 2021, as a case study to discuss the potential challenges and benefits of biosimilars. OBJECTIVE: To describe trends in market share and spending for originator, follow-on, and biosimilar insulin glargine products and to discuss the potential benefits and challenges of biosimilars for providers and patients and whether the introduction of these products lowers insulin glargine costs for payers and members in Minnesota. METHODS: This retrospective descriptive study evaluated prescribing and cost data for insulin glargine, using pharmacy claims data from the Minnesota All Payer Claims Database for 2015-2023, including claims from commercial and public payers (ie, Medicare and Minnesota Health Care Programs). Yearly totals of filled prescriptions and average payer and member per-prescription costs were used to construct trends. RESULTS: Prescription volume for originator insulin glargine steadily decreased by 58.9% across all payers from 2015 to 2018, whereas prescriptions for the follow-on product increased from 32 to 167,052 total prescriptions between 2016 and 2018. Biosimilar prescribing grew from 0.3% of all insulin glargine prescribed in 2021 to 8.3% in 2023. When compared with the originator medication, follow-on and biosimilar insulin glargine provided consistent reduced claims payments to all payers and inconsistent cost savings to members. CONCLUSIONS: Although payers experience consistently reduced claims-based spending from biosimilar and follow-on insulin glargine compared with originator insulin glargine, inconsistent patient cost savings are a missed opportunity to improve affordability for cost-burdened patients. Additionally, until administrative barriers are resolved, providers may be less inclined to consistently prescribe biosimilars. Both issues may contribute to the slow, uneven uptake of biosimilars, and policymakers should incentivize both commercial and public payers to favor biosimilar prescribing, reduce barriers to prescribing, and ensure that cost savings are passed on to patients.