The Who, What, Where, When and Sometimes, Why.


What is a biologic?

Some drugs are made from biologics (biological products) such as antibodies or proteins. Biologics come from living things, including animal cells, plant cells and bacteria.

Trastuzumab (Herceptin) and pertuzumab (Perjeta) are breast cancer treatment drugs made from biologics (they are antibodies). Other drugs, such as vaccines and insulin, are also biologics.

What is a biosimilar?

A biosimilar is a “generic-like” version of a drug that contains biologics.

A generic drug has the exact same active chemical ingredients as the original drug. However, it’s not possible to make an exact copy of a biologic because it’s a living thing.

A biosimilar is highly similar to the original biologic drug and works the same way in the body. So, it’s a “generic-like” version of a biologic drug.

Biosimilar names

The name of a biosimilar includes the name of the original biologic drug. For example, trastuzumab-dkst is a biosimilar to the drug trastuzumab. Biosimilars also have brand names.

FDA approval of biosimilars

To be approved by the U.S. Food and Drug Administration (FDA), a biosimilar must work the same way as the original drug and it must [166]:

  • Be as safe when used alone or in combination with other treatments
  • Be as effective when used alone or in combination with other treatments
  • Have similar side effects (they can’t be different from those of the original drug)
  • Be the same form as the original drug (for example, if the original drug is given by an injection under the skin, the biosimilar must also be given by an injection under the skin)

Once a biosimilar is approved by the FDA, it’s safe to use.

Biosimilars for breast cancer treatment

At this time, the FDA-approved biosimilars for breast cancer treatment are all biosimilars to trastuzumab (Herceptin). 

Other biosimilars to trastuzumab as well as biosimilars to other drugs used to treat breast cancer are under study.

Biosimilars to trastuzumab

Trastuzumab (Herceptin) is a HER2-targeted therapy drug. It’s used to treat early and metastatic HER2-positive breast cancers. Biosimilars to trastuzumab can also be used to treat early and metastatic HER2-positive breast cancers.

Biosimilars to trastuzumab include (in alphabetical order):

  • Trastuzumab-anns (Kanjinti)
  • Trastuzumab-dkst (Ogivri)
  • Trastuzumab-dttb (Ontruzant)
  • Trastuzumab-pkrb (Herzuma)
  • Trastuzumab-qyyp (Trazimera)

These biosimilars are FDA-approved, so they are all as safe and as effective as trastuzumab (and each other).

Biosimilars used to treat side effects of breast cancer treatment

Some drugs used to treat side effects of chemotherapy and other breast cancer treatments are made from biologics. Some of these drugs have biosimilars.

For example, some people get filgrastim (Neupogen) or pegfilgrastim (Neulasta) to help maintain their blood counts during chemotherapy. Tbo-filgrastim (Granix) and pegfilgrastim-jmdb (Fulphila) are biosimilars to these drugs. Some insurance companies ask that these biosimilars be used instead of the original drugs, just as they ask for generic drugs to be used instead of the brand name drugs.

Biosimilar costs

Due to the complex manufacturing process, biosimilars are costly to produce. As more biosimilars become available, costs may go down over time.

It’s not known how the cost of biosimilars will affect patient costs.

Talk with your health care provider

Your health care provider can tell you whether a biosimilar may be part of your breast cancer treatment plan.

If you have questions about biosimilars, talk with your health care provider.

Updated 04/08/24



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