When people look for lower-cost cancer medicines, they meet two words: generic and biosimilar. Both are versions of an original medicine, and both can cost less. But they are not the same thing. This guide explains the difference, with trastuzumab (Herceptin) as the main example, and answers the question most people ask: is a biosimilar as good as the original?
Generics: copies of chemical medicines
Most tablets, such as imatinib or letrozole, are made by chemistry. Their active ingredient is a small molecule that can be copied exactly. A generic medicine contains the same active ingredient as the original brand1. For more on generic cancer tablets, see our guide to generic imatinib.
Biosimilars: versions of biological medicines
Biological medicines (biologics) are made from living sources, such as cells, yeast or bacteria. They are usually large, complex proteins, such as antibodies, and are harder to purify and manufacture than chemical medicines1. In cancer care, one example is the antibody trastuzumab, which is given as an injection or drip4.
Because they come from living cells, all biological medicines have some natural variability2. So another company cannot make an exact copy. Instead, it makes a biosimilar: a biological medicine that is highly similar to the original (the “reference” medicine), with no clinically meaningful differences in safety, quality or effectiveness12. The European Medicines Agency says a biosimilar is not regarded as a generic for exactly this reason2.
| Generic | Biosimilar | |
|---|---|---|
| Made from | Chemical ingredients1 | Living sources, such as cells1 |
| Compared with | The original brand1 | The original (reference) biologic1 |
| Identical to the original? | Same active ingredient1 | Highly similar, not identical12 |
| Typical form in cancer care | Tablets and capsules | Injections and drips |
Are biosimilars as safe and effective?
Regulators in the US and Europe say yes, for approved biosimilars. The FDA says you can expect the same safety and effectiveness from a biosimilar as from the original over the course of treatment, and that biosimilars are given at the same strength and dose, in the same way, with the same potential side effects1. The European Medicines Agency applies the same standards of quality, safety and effectiveness as for all biological medicines, and monitors their safety after approval in the same way2.
The lower price comes from manufacturers not needing to repeat every trial already done with the original. The FDA stresses that the lower cost is not a reflection of a biosimilar’s safety or effectiveness1.
Switching and interchangeability
- Starting or switching. The FDA says biosimilars can generally be used whether or not you were first treated with the original1.
- In the EU, regulators consider approved biosimilars interchangeable from a scientific point of view: a biosimilar can be used instead of its reference medicine, or another biosimilar of the same medicine, after careful consideration of the product information2.
- In the US, a biosimilar with “interchangeable” status can be swapped at the pharmacy without asking the prescriber, depending on state law1.
Any switch should be agreed with your cancer team, who will record exactly which product you receive.
Trastuzumab: what to check
Trastuzumab is a targeted antibody for cancers with large amounts of a protein called HER24. In the US, the original (Herceptin) is licensed for HER2-positive breast cancer and HER2-positive stomach cancer, and HER2 status must be confirmed by testing first3. Some practical points apply whether you have the original or a biosimilar:
- Heart checks. Trastuzumab can weaken the heart, especially when given with anthracycline chemotherapy, so heart function is checked before and during treatment3.
- Infusion reactions and lung problems can happen, and it can harm an unborn baby3.
- Do not mix up similar names. Trastuzumab must not be swapped for, or with, the related medicines trastuzumab emtansine (Kadcyla) or trastuzumab deruxtecan (Enhertu). They are different medicines3.
Always check the name, strength and form on the pack, and ask your team to record which product you were given.
Where to find biologic cancer medicines
Our Herceptin alternatives page explains the options. We stock Hertraz 150 mg and Hertraz 440 mg injections. Hertraz is a trastuzumab biosimilar made by Biocon in India, where the regulator approved it as a “similar biologic” in 20135. The same Biocon-made trastuzumab is sold in the US and Europe under a different name, Ogivri, and is approved there as a biosimilar: by the FDA in 2017 and in the EU678. The Hertraz packs we supply are the Indian product, not the US or EU one, so check with your treatment team whether it suits you where you live. See our trastuzumab and rituximab pages and our breast cancer medicines. These are hospital-administered medicines and need a prescription. For how they differ from chemotherapy, see is it chemotherapy?
Frequently asked questions
Is a biosimilar the same as a generic?
No. A generic is an exact copy of a chemical medicine. A biosimilar is a highly similar version of a biological medicine, which cannot be copied exactly because it is made in living cells.
Are trastuzumab biosimilars as effective as Herceptin?
Approved biosimilars have no clinically meaningful differences from the original in safety or effectiveness, according to the FDA and the European Medicines Agency. They are given at the same dose and in the same way.
Can I switch from Herceptin to a biosimilar during treatment?
Regulators say biosimilars can generally be used whether or not you started on the original. Any switch should be agreed with your cancer team.
Why are biosimilars cheaper?
Manufacturers do not have to repeat all the trials already done with the original medicine. The lower price is not a sign of lower quality.
Is Kadcyla a biosimilar of Herceptin?
No. Trastuzumab emtansine (Kadcyla) is a different medicine, not a biosimilar, and it must not be swapped with trastuzumab.
Sources & references
- US Food and Drug Administration. Biosimilars Basics for Patients. Content current as of 1 August 2024.
- European Medicines Agency. Biosimilar medicines: Overview.
- US National Library of Medicine, DailyMed. Herceptin (trastuzumab) prescribing information.
- Cancer Research UK. Trastuzumab (Herceptin). Last reviewed 18 March 2024.
- GaBI Online. Mylan launches trastuzumab ‘similar biologic’ in India. February 2014.
- GaBI Online. FDA approves trastuzumab biosimilar Ogivri. January 2018.
- European Medicines Agency. Ogivri (trastuzumab): EPAR, biosimilar medicine.
- Health Policy Watch. As biosimilar of key cancer drug spreads, where is the price reduction? 11 December 2017. (Biocon’s trastuzumab is sold as CANMAb and Hertraz in India and as Ogivri in the US.)
Related reading
This content is for informational purposes only and is not medical advice. Do not switch any cancer medicine without your cancer team’s agreement. Used as prescribed by a licensed medical professional.
A. Srinivasan is a licensed clinical pharmacist with 24 years of experience. He holds a B.Pharm and M.Pharm from University of Madras. At OnlineMeds, he reviews medicine and health content to help ensure it is accurate, evidence-based, and easy to understand.