Low Prices Fail to Boost Insulin Biosimilar Uptake in the UK

Despite early price advantages and long-standing regulatory approval, biosimilar insulin glargine has yet to gain significant traction in the UK market.1 A comprehensive analysis of primary care prescribing data from 2020 to 2024 across all 4 nations of the UK revealed that originator insulin products, particularly Lantus (insulin glargine), continue to dominate prescriptions, raising questions about the effectiveness of market-based strategies alone in promoting biosimilar adoption.2

The findings from the study, published in Pharmacy, point to persistent barriers to biosimilar uptake and underscore the complexity of achieving cost savings in biologic prescribing through competition alone.

Since biosimilar insulin glargine first entered the UK market in 2014, there have been high hopes that these agents would drive down the cost of long-acting insulin therapy for patients with diabetes.2 Today, several biosimilar insulin glargine products are approved by the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA), including Abasaglar (biosimilar to Lantus), Semglee, and most recently, Insulin Glargine Medac.2-4 These biosimilars offer clinically comparable efficacy and safety to the originator product, Lantus, yet they continue to face resistance in widespread clinical adoption, only obtaining 24% market share in England, 5% in Northern Ireland, 24% in Scotland, and 11% in Wales in 2024, even after the MHRA declared all biosimilars as interchangeable with their reference products in 2022.1,2

The present study, which reviewed prescribing patterns and pricing across England, Northern Ireland, Scotland, and Wales, found that Lantus consistently remained the most prescribed insulin glargine product throughout the study period.2 In fact, by 2024, Lantus was not only the market leader but also the least expensive option in all 4 nations—a reversal of expectations that further eroded incentives for biosimilar use. In England, for example, Lantus accounted for 66% of all insulin glargine prescriptions in 2020 and 65% in 2024, while biosimilars increased only slightly from 15% to 24% over the same period. Abasaglar was prescribed 6 times more often than Semglee, while use of generic descriptions declined by 63%.

Northern Ireland saw even less movement toward biosimilars. Lantus made up 90% of prescriptions across the 5-year span, and biosimilar usage barely nudged upward from 4% to 5%. In Scotland, total insulin glargine prescriptions declined by 13% from their 2020 peak, but Lantus maintained a 62% to 63% share. Although Semglee became available in mid-2023, biosimilar use only modestly increased from 20% to 24%. Wales showed a similar pattern, with Lantus holding 80% of the market by 2024 and biosimilar uptake climbing gradually from 7% to 11%.

A key factor dampening biosimilar growth was pricing. In mid-2021, Lantus underwent a series of price reductions that made it the least expensive insulin glargine product in every nation.5 By 2024, the actual price per pre-filled device in England had dropped to £6.83 for Lantus compared with £6.93 for Abasaglar.1 These price dynamics were similar in Scotland and Wales, even though only gross ingredient costs were available for those regions. Rather than allowing biosimilars to undercut the originator, Lantus’ manufacturer appears to have adjusted its pricing strategy to neutralize competitive threats and retain market share.

Despite support from the MHRA for biosimilar interchangeability, national prescribing guidelines from the British National Formulary do not permit automatic substitution, meaning that brand switching must be initiated by prescribers. This regulatory friction, combined with prescriber familiarity with Lantus and potentially limited awareness of the cost implications, may help explain why biosimilar adoption remains modest a decade after market entry.

These findings echo earlier concerns that the potential cost savings from biosimilars will remain unrealized without active measures to support their uptake. Although the UK continues to lead globally in biosimilar regulation and access, the case of insulin glargine demonstrates that achieving meaningful shifts in prescribing requires more than regulatory approval and competitive pricing. Addressing inertia in prescriber behavior, clarifying policy around switching, and better aligning economic incentives may be necessary steps to fully unlock the value of biosimilars in the UK health care system.

References

1. Agirrezabal I, Sánchez-Iriso E, Mandar K, Cabasés JM. Real-world budget impact of the adoption of insulin glargine biosimilars in primary care in England (2015–2018). Diabetes Care. 2020.43(8):1767-1773. doi:10.2337/dc19-2395

2. Alsaif M, Blumer Z. Insulin glargine biosimilar prescribing and cost trends in the United Kingdom’s primary care from 2020 to 2024. Pharmacy. 2025;13(3):85. doi:10.3390/pharmacy13030085

3. Semglee summary of product characteristics. European Medicines Agency. Accessed July 5, 2025. https://www.ema.europa.eu/en/documents/product-information/semglee-epar-product-information_en.pdf

4. Abasaglar summary of product characteristics. European Medicines Agency. Accessed July 5, 2025. https://www.ema.europa.eu/en/documents/product-information/abasaglar-epar-product-information_en.pdf

5. Guidance on the licensing of biosimilar products. MHRA. February 27, 2025. Accessed July 5, 2025. https://www.gov.uk/government/publications/guidance-on-the-licensing-of-biosimilar-products/guidance-on-the-licensing-of-biosimilar-products

6. Press release: Sanofi cuts U.S. list price of Lantus, its most-prescribed insulin, by 78% and caps out-of-pocket Lantus costs at $35 for all patients with commercial insurance. News release. Sanofi. March 16, 2023. Accessed July 5, 2025. http://sanofi.com/en/media-room/press-releases/2023/2023-03-16-20-06-43-2629188