Biosimilar medicines are very similar versions of a biological medicine
A medicine made from living organisms, such as protein, bacteria or yeast, is known as a biological medicine.
Since the 1980s, hundreds of biological medicines have been approved for the treatment of diseases such as cancers, diabetes, heart attacks, rheumatoid arthritis, Crohn's disease and many more.
Around 300 new biological medicines are currently under development for the treatment of cancer and related conditions.
A biosimilar medicine is a very similar version of an already-approved biological medicine, in terms of its characteristics, quality, safety and efficacy.
A biosimilar medicine is not considered a generic medicine, as it is virtually impossible to make an exact copy of a living organism. However, much like generics, biosimilar medicines are also based on original medicines that have reached the end of their patents.
Biosimilar medicines are developed to increase treatment options, and can usually be produced at a lower cost than the original biological medicine.
How biological and biosimilar medicines work
Unlike traditional chemical medicines which are made by combining chemical ingredients, biological and biosimilar medicines are made from living organisms.
Biological medicines usually have more complex and larger structures than their traditional counterparts. For example, Aspirin, a chemical medicine, contains 21 atoms, while a biological medicine may contain more than 20,000 atoms.
As a result, biological medicines are more sensitive and are more likely to cause an immune reaction in the body than chemical medicines.
Once administered, a biological medicine can mimic the natural protein in a patient, thereby helping to reduce symptoms and slow the progression of a disease. Biological medicines, such as vaccines, can also prevent disease.
Biological, and biosimilar, medicines are often administered by injection or infusion, whereas chemical medicines are usually taken as a tablet or capsule. Many traditional medicines can be self-administered, but biological medicines are often administered in hospital as an injection or with the assistance of medical staff.
Why aren't biosimilar medicines considered the same as generic medicines?
Once a product patent expires, manufacturers are legally allowed to develop a generic version of a chemical product, or a biosimilar version of a biological product.
While it's relatively easy to manufacture an exact generic copy of a simple chemical structure, it's almost impossible to make an exact copy of a living organism.
Therefore, if someone is talking about a generic medicine, they are referring to the exact copy of a traditional chemical medicine that is no longer under patent.
A biosimilar, on the other hand, refers to a highly similar but not identical version of a biological medicine
Why can't different manufacturers make an exact copy of a biological medicine?
There are three main reasons why it is virtually impossible for different manufacturers to replicate a biological medicine:
- As living organisms, there will always be some differences between medicines even if this does not affect how the medicine works
- The structures are large and complex, making it difficult to create an exact copy
- The final medicine is highly dependent on the manufacturing process, and once the original patent for a medicine expires each manufacturer has to make their own decisions around the cell lines, conditions to grow the cells, stabilising compounds to use, as well as how the medicine is packaged and stored.
Biosimilar medicines - latest developments
In January 2017, the US Food and Drug Administration (FDA) released draft guidance detailing the agency’s expectations for demonstrating biosimilar interchangeability.
The guidance recommends that sponsors looking to have a biosimilar approved as interchangeable with its reference biological medicine, conduct one or more switching studies to show that patients can alternate between the two products safely and without diminished efficacy.
The FDA is currently seeking input from interested persons on this topic, and will be accepting submissions until March 2017.
Biosimilar medicines and bowel cancer
There are a handful of biosimilar medicines currently available in Australia, and some of these are relevant to cancer patients receiving chemotherapy (see Table 1).
For example, the active substance known as epoetin lambda is used to treat anaemia in patients receiving chemotherapy for certain types of cancer. The active substance known as filgrastim is used to help the body make new white blood cells following treatment with some types of chemotherapy.
Table 1: TGA approved biological and biosimilar medicines relevant to cancer patients (as at 1 January 2017)
*TGA registered but not currently available.
Over the next few years, we expect to see a wave of biosimilar medicines available in Australia as patents for the original biological medicines start to expire. Recent reports indicate this may include biosimilars for the targeted therapy, Avastin (bevacizumab).
Bowel Cancer Australia will continue to monitor developments on the availability of biosimilar medicines and any new evidence of how they may impact bowel cancer patients.
Talk to your doctor or oncologist to learn more about biological and biosimilar medicines, if they are suitable for you, and any potential side effects.