How near-identical versions of biologic insulin are expanding access to life-saving diabetes treatment worldwide
Since its groundbreaking discovery in 1921, insulin has transformed from a life-saving discovery to an expensive necessity for millions with diabetes worldwide. Over a century later, this essential medicine remains out of reach for many of the 150-200 million people who require it to survive and thrive.
Year insulin was discovered
People worldwide requiring insulin
Typical cost savings with biosimilars 6
The arrival of biosimilar insulins represents perhaps the most significant advancement in diabetes treatment since that initial breakthrough, offering equally effective treatment at a fraction of the cost. These near-identical versions of original biologic insulin products are now shaking the foundations of diabetes care, promising to bridge the gap between medical innovation and accessible treatment.
As of 2025, the World Health Organization reports that biosimilars typically cost about 60% less than their originator counterparts, potentially saving healthcare systems billions while expanding treatment access to vulnerable populations 6 .
Like precisely duplicating a house key - exact chemical copies of simple molecules.
Like recreating a detailed handmade sculpture - functionally identical with minor, clinically insignificant variations.
Before approval, biosimilars must undergo rigorous comparison to their reference products through a multi-step process:
Extensive analysis showing highly similar molecular structure to the reference product.
Laboratory and animal studies confirming comparable biological activity.
Human trials demonstrating equivalent efficacy and safety in patients.
This thorough process has earned endorsements from major regulatory bodies worldwide, including the FDA, European Medicines Agency, and World Health Organization, which now recommends that "quality-assured biosimilars of listed biologic medicines should be viewed as interchangeable" 6 .
| Characteristic | Generic Drugs | Biosimilars |
|---|---|---|
| Molecular Size | Small molecules (typically <1000 Da) | Large, complex proteins (>1000 times larger) |
| Structure | Simple, fully defined chemical structure | Complex, three-dimensional protein structures |
| Manufacturing | Chemical synthesis | Living cell systems (biotechnology) |
| Copy Exactness | Identical chemical copy | Highly similar, with allowable minor variations |
| Regulatory Pathway | Abbreviated New Drug Application | Specific biosimilar pathway requiring comparative studies |
| Approval Timeline | Generally faster | Longer development and approval process |
The biosimilar insulin market has gained significant momentum in recent years. As of mid-2025, the United States has approved three insulin biosimilars: two insulin glargine products (Semglee and Rezvoglar) and one insulin aspart (Merilog) 1 . These long-acting and rapid-acting formulations cover the essential basal and bolus insulin needs for both type 1 and type 2 diabetes patients.
Long-acting basal insulin alternatives including Semglee and Rezvoglar.
Rapid-acting mealtime insulin alternative (Merilog) for bolus dosing.
Globally, adoption patterns vary considerably. While the US and Canada have seen relatively stronger uptake driven by policy mandates, European and Asian markets have demonstrated more modest adoption rates. This variability reflects differences in regulatory frameworks, physician preferences, and market access policies across regions 1 .
Despite initial physician and patient hesitation, the clinical evidence supporting biosimilar insulins continues to grow. A comprehensive systematic review protocol registered in 2025 aims to compare real-world effectiveness and safety of insulin biosimilars versus reference products, examining outcomes including HbA1c levels, hypoglycemia rates, and quality of life measures 2 9 .
Shift from human to analog insulin
Increase in combination therapy
Biosimilar adoption rate
Real-world data already shows notable trends in insulin prescribing patterns beyond biosimilars specifically. Over the past two decades, there has been a clear global shift from insulin monotherapy to combination therapy with oral glucose-lowering drugs, and from human insulin to more advanced long-acting and fast-acting insulin analogues, particularly in high-income countries 1 .
One of the most illuminating real-world experiments in biosimilar insulin adoption comes from the United Kingdom, where researchers analyzed prescribing patterns of insulin glargine from 2020 to 2024 across all four UK nations 3 . The study focused on cartridges and pre-filled pens containing insulin glargine 100 units/mL, where prescribers actually had a choice between the reference product (Lantus) and biosimilars (Abasaglar and Semglee).
The results revealed a surprising paradox: despite significant cost advantages at launch, biosimilars failed to achieve dominant market position in any UK nation. By 2024, biosimilars captured only 24% of the market in England and Scotland, 11% in Wales, and a mere 5% in Northern Ireland 3 .
| Country | 2020 Biosimilar Share | 2024 Biosimilar Share | Growth | Dominant Product in 2024 |
|---|---|---|---|---|
| England | 15% | 24% | +9% | Lantus (65% share) |
| Scotland | 15% | 24% | +9% | Lantus (65% share) |
| Wales | 7% | 11% | +4% | Lantus (77% share) |
| Northern Ireland | 2% | 5% | +3% | Lantus (87% share) |
Even more surprisingly, the reference product Lantus eventually lowered its price to become the least expensive option by 2024, explaining some of the prescribing persistence.
The research methodology provides an excellent example of how real-world evidence is generated in pharmaceutical policy:
Researchers obtained community prescribing data published monthly at the GP practice level for all four UK nations 3 .
Using the Dictionary of Medicines and Devices (dm+d), researchers identified all insulin glargine products and their specific British National Formulary codes.
Data was aggregated at national levels and analyzed over the 5-year period to identify prescribing and cost patterns.
Researchers tracked net ingredient costs and actual prices paid, accounting for discounts and dispenser payments.
"The introduction of biosimilars does not automatically result in altered prescribing practices," emphasizing the need for "active switching policies and prescriber engagement" 3 .
Understanding biosimilars requires specific methodological approaches and assessment tools. The systematic review protocol by researchers from the University of Toronto provides insight into the "scientist's toolkit" for evaluating biosimilar insulin in real-world settings 2 9 .
| Assessment Category | Specific Metrics | Research Significance |
|---|---|---|
| Effectiveness Outcomes | HbA1c (primary), fasting plasma glucose, time in range, microvascular complications | Documents comparable glycemic control |
| Safety Outcomes | Hypoglycemia events (primary), diabetic ketoacidosis, weight gain, injection site reactions | Establishes similar safety profile |
| Healthcare Utilization | Physician visits, emergency department visits, hospital admissions for hypo-/hyperglycemia | Measures impact on healthcare system |
| Patient-Reported Outcomes | Health-related quality of life, treatment satisfaction | Captures patient experience and acceptance |
| Long-Term Safety | Immunogenicity, incident cancers, sustained glycemic control | Addresses concerns about long-term use |
This methodological framework emphasizes that comprehensive biosimilar assessment extends beyond simple laboratory measures to include real-world functional outcomes, patient experiences, and system-wide impacts – all crucial for establishing biosimilars as truly equivalent alternatives in clinical practice.
The slow uptake of biosimilar insulins despite their proven efficacy and initial cost advantages stems from multiple complex barriers:
Healthcare providers often hesitate to switch stable patients, while patients themselves may fear disrupting effective regimens 1 .
In some regions, contradictory guidelines create confusion, such as in the UK where the Medicines and Healthcare products Regulatory Agency declares biosimilars interchangeable, but the British National Formulary advises prescribing by brand name to avoid "inadvertent switching" 3 .
Pharmaceutical benefit management practices sometimes favor reference products due to rebate structures, while limited awareness and trust among providers and patients persists 7 .
Successful biosimilar adoption requires coordinated approaches:
Implementation of supported transition clinics with patient education, as demonstrated in Irish hospitals where a switch to a biosimilar maintained stable disease control while generating substantial cost savings 5 .
Formulary management that prioritizes biosimilars, such as CVS's decision to exclude Humira from most formularies in 2024, which rapidly shifted prescribing patterns 7 .
Targeted information campaigns for healthcare professionals addressing safety and efficacy concerns while emphasizing potential system-wide savings that could improve overall access to care.
Additional US patients who could access biologic medicines with broader biosimilar availability by 2025 4
Emphasizes biosimilars are key to expanding global access to essential biological medicines, particularly in low- and middle-income countries 6
Biosimilar insulins represent far more than just "cheaper alternatives" – they embody the convergence of biotechnological innovation, regulatory science, and health equity advocacy. As the evidence base continues to grow through real-world studies and systematic reviews, the case for biosimilars as equivalent therapeutic options becomes increasingly compelling.
The journey from the discovery of insulin a century ago to the development of biosimilar versions today reflects an ongoing evolution in how we balance medical innovation with accessible healthcare.
While challenges remain in achieving widespread adoption, the potential for biosimilar insulins to expand global access to essential diabetes treatment while generating substantial healthcare savings suggests they will play an increasingly crucial role in diabetes management for the coming decade.
As research continues to address knowledge gaps and implementation strategies improve, biosimilar insulins may finally fulfill the promise made when insulin was first discovered: that this life-sustaining treatment would be accessible to all who need it, regardless of their economic circumstances.