Hormone Headlines Blog

Biosimilar Insulin Treatment: What the Science Says

September 28, 2022

About 7 million Americans rely on insulin to manage their diabetes, but the cost of insulin is a barrier for many. This is especially true for people with lower incomes or high-deductible health plans. According to the Journal of the American Medical Association (JAMA): 

  • Among people with employer-based health insurance, 55% of insulin users spend more than $50 per month on insulin. For some, the out-of-pocket cost is as high as $400 per month or more.
  • As many as one in four insulin users limit how much insulin they take to save money. This could lead to serious health problems or even death.

The high price of insulin is a complex problem with no simple solution. Biosimilar insulins are a big leap forward. Some benefits include a safe option as effective as other insulins at a lower price.

What exactly is Biosimilar Insulin?

To understand biosimilar insulin, it helps to know some key terms. 

Reference product. A reference product is the original version of a product that already has FDA approval. 

Biosimilar product. For a product to be biosimilar, it must be highly similar in structure to a biological medication, such as an insulin, and have no clinically meaningful differences from the original product. Additionally, a biosimilar product can also be interchangeable.  

Interchangeable product is a biosimilar product that has met additional requirements. Research must show that switching back and forth between this biosimilar and its reference product does not affect safety or effectiveness. 

A pharmacist can switch interchangeable insulin for its reference product if state law allows it, and this is an option for some biosimilar insulins. This happens routinely with generic drugs, and it has led to big savings.  

Expanding Access to Insulin

Both generic and biosimilar insulins are versions of existing drugs. However, there is a key difference. While generic medications have chemical structures that are well-defined and easily reproducible, the process for manufacturing biosimilar medications is more complex. Therefore, the FDA developed an approval pathway that takes into account the uniqueness of these products. 

The FDA approved two insulins in 2021 via this pathway: 

  • Semglee (insulin glargine-yfgn), the first interchangeable biosimilar insulin 
    Reference product: Lantus (insulin glargine, a long-acting insulin) 
  • Rezvoglar (insulin glargine-aglr), which is biosimilar but not interchangeable 
    Reference product: Lantus (insulin glargine) 

There is also another insulin glargine product on the market called Basaglar. It was developed through an earlier FDA pathway, and it is not interchangeable with Lantus. 

If a biosimilar insulin has achieved the interchangeability designation, it can easily be substituted for as a less expensive option at the pharmacy. Since Semglee received interchangeable status in 2021, the savings are already apparent. For someone with no insurance coverage but a discount card, the cash price of Semglee is about 63% lower than that of regular insulin glargine.

Other biosimilar products are in development. For example, studies are underway on a potential biosimilar for NovoLog (insulin aspart), a rapid-acting insulin.  

Ensuring Safety and Effectiveness

A biosimilar insulin may cost less than its brand-name counterpart. The rigorous FDA approval process has evaluated the safety and efficacy of biosimilar products. A drug company testing a new biosimilar does not have to repeat the lengthy clinical trials that were required for the original product, but additional studies are needed. 

Analytical studies. These studies are the bedrock of biosimilar research. They compare the structure and function of a would-be biosimilar to its reference product. The two products should be highly similar. But because insulin is made using living sources, some slight variations may occur. Any minor differences should not affect how the insulin performs in clinical use. 

Clinical pharmacology studies. These studies are often part of the research process, too. The proposed biosimilar is given to volunteers. Compared to the reference product, it should: 

  • Move through the body in the same way 
  • Provide the same treatment effects 
  • Not trigger an unwanted immune response 

Switching studies. Additional studies are conducted to show that a biosimilar insulin can be interchanged with its reference product. Volunteers alternate between using the two products several times over a set period of time. Switching back and forth should not lead to increased safety risks or decreased effectiveness. 

For example, one 36-week switching study looked at the biosimilar now known as Semglee. The results showed that volunteers who switched between this biosimilar and Lantus got the same treatment benefits as those who stayed on Lantus the whole time. The two groups also had similar safety profiles. 

Facts for Patients and Providers

Whether you are a person with diabetes who takes insulin or a health care provider who prescribes it, here are some important things to know about biosimilar insulins: 

Indications for use. Semglee and Rezvoglar are indicated to improve blood sugar control in: 

  • Adults and children with type 1 diabetes 
  • Adults with type 2 diabetes who use insulin 

Route of administration. Both Semglee and Rezvoglar are available in autoinjector pen form. Semglee is also sold in a vial for use with a syringe. 

Pharmacy-level substitution. Some states allow pharmacists to substitute an interchangeable insulin for its reference product. They don’t need to consult the provider who wrote the prescription first. The FDA’s high standards for approval mean that you can expect the same clinical results from the interchangeable insulin. 

The FDA’s Purple Book database is the go-to source for facts on all approved insulins, including biosimilar ones.

Volunteering for a Clinical Trial

Clinical trials are research studies that are conducted in people to assess a treatment. Participation is always voluntary. Clinical trials play a crucial role in bringing new treatment options, such as biosimilar insulins, to market. Volunteers who take part are helping to advance diabetes care for themselves and others. 

People of different races and ethnicities may respond in a slightly different manner to medications. This has been a concern because past trials did not always include representatives from certain ethnic groups and races. Today, researchers are committed to including diverse participants, and this is crucial for improving health equity. 

Learn more about taking part in clinical trials and find ongoing studies at clinicaltrials.gov. 

The development of this resource was made from an unrestricted education grant and the generous support of our sponsor, Viatris Pharmaceuticals. Viatris had no influence on the content of this material or its development.  

Last Updated:

  1. Health Care Cost Institute. Capping out-of-pocket spending on insulin would lower costs for a substantial proportion of commercially insured individuals. https://healthcostinstitute.org/hcci-research/capping-out-of-pocket-spending-on-insulin-would-lower-costs-for-a-substantial-proportion-of-commercially-insured-individuals-1. Accessed August 5, 2022.
  2. Herkert D, Vijayakumar P, Luo J, et al. Cost-related insulin underuse among patients with diabetes. JAMA Internal Medicine. 2019;179(1):112-114. 
  3. Rosenthal E. When high prices mean needless death. JAMA Internal Medicine. 2019;179(1):114-115. 
  4. Kuehn BM. First interchangeable biosimilar insulin drug is approved. JAMA. 2021;326(9):801. 
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