The Science of Biosimilars
Biosimilars are biologic medicines that have been proven to be highly similar to another biologic medicine that is already available in the Canadian marketplace and is no longer protected by a patent. They are proven to be safe and have the same therapeutic effect as their reference biologic.
In order for biosimilars to be approved in Canada, Health Canada evaluates whether the information provided by the manufacturer “shows that the biosimilar and the reference biologic drug are highly similar” and that “there are no clinically meaningful differences in efficacy and safety between the biosimilar and the reference biologic drug” (Health Canada Fact Sheet: Biosimilars). As Health Canada states, “you can have the same confidence in the quality, efficacy and safety of a biosimilar as in any other biologic drug.”
Biosimilar medicines are not new. They have been used for over a decade in Europe, and have led to over 700 million patient days of clinical experience.
Building From a Strong Foundation: Biologic Medicines
Biologics are medicines that are produced by living organisms, in living cells. A piece of DNA is added to a cell. The cell then either copies or translates the DNA into a protein, sugar, or nucleic acid that becomes the biologic medicine. These cells become ‘factories’ that endlessly produce the substances needed to target a particular illness.
Biologic medicines are used in the treatment, diagnosis or prevention of disease and include therapeutic proteins, DNA vaccines, monoclonal antibodies and fusion proteins. One of the reasons biological medicines are so effective is that they are tailor-made to interact with specific targets in the body. This targeting increases the potential that the medication will have the desired effect against the disease it is designed to treat.
This way of producing a drug is different than most medicines available today which are created through chemical synthesis. These synthesized medicines are sometimes known as “small molecule” drugs, while biologic medicines are sometimes referred to as “large molecule” drugs, because these molecules are literally larger than drugs based on simpler compounds.
The molecules in biologic medicines are often 200 to 1,000 times the size of a small-molecule drug and are far more structurally complex. Due to both their large size and sensitivity, biologic medicines are almost always injected or infused into the patient’s body.
Insulin for human use is one of the most well known biologics, often produced by modifying insulin generated by the pancreases of pigs. Over the past 30 years, biologic medicines have provided treatment options for people who suffer from some of the most serious medical conditions, including multiple sclerosis, diabetes, cancer, and rheumatoid arthritis.
What Are Biosimilars?
A biosimilar medicine is a biologic that has been approved by Health Canada after a rigorous and evidence-based review process. Health Canada requires every biosimilar to demonstrate its similarity to an already-approved biologic drug known as the “reference biologic.”
Biosimilars have essentially the same active substance, are produced to the same standards and deliver comparable safety and efficacy effects as the reference biologics. This is proven in clinical studies comparing the biosimilar to the original reference biologic before the biosimilar can be approved.
Given the structural and molecular complexity of biologics, biosimilars are not expected to be identical to the reference products. The features of the biosimilar known as “critical quality attributes” need to match the reference biologic so that the two products work in the same way and have the same biological function for each patient.
Health Canada’s approval of a biosimilar is based on evidence such as studies to compare the characteristics of the proposed biosimilar and the reference biologic drug. These studies include:
Purity and impurity profiles
Health Canada will only approve a biosimilar product once it has demonstrated equivalent efficacy, safety, tolerability and immunogenicity to its reference product.
As biosimilars continue to be adopted as treatment options by health care professionals and patients across Canada and around the world, experience with these products continues to grow.