Biosimilar switch letter (Bevacizumab)

December 2025

Dear Patient,

Change from originator medicine to biosimilar medicine

We are writing to inform you of an upcoming change to your treatment. Your current medicine, Bevacizumab Avastin® will be replaced with a biosimilar medicine called Bevacizumab Abevmy®. This change is part of our commitment to providing safe, effective, and sustainable care.

What is a biosimilar?

A biosimilar is a medicine that is very similar to an existing biological medicine (known as the originator). It has been rigorously tested to ensure it works in the same way and provides the same clinical benefits as the originator.

You may have heard of some medicines you take described as generics, for example supermarket own brand ibuprofen is the generic version of Nurofen®. Generics are exact copies of the original medicine and are relatively simple to copy and manufacture. The same idea applies to biosimilars, but it is not possible to make an exact copy of an originator medicine due to the complex way they are made. Biosimilars are very similar to the originator medicine but not identical.

Why are we making this change?

Clinical Equivalence: You can expect to have the same results from your biosimilar medicine Bevacizumab Abevmy® as if you’d had the originator medicine. Bevacizumab Avastin®. Biosimilars undergo strict regulatory assessment to confirm they are as safe and effective as the originator. Your treatment schedule and monitoring will remain the same.

Cost-Effectiveness: Using biosimilars helps the NHS save money, allowing resources to be reinvested into patient care.

Access and Sustainability: This change supports wider access to treatments and ensures long-term availability.

How can I be confident that it will work the same?

The companies that make biosimilars have to show the licensing authority for medicines very strict evidence of their effectiveness, safety and quality. Clinical studies have to be conducted in a large group of people to show that the medicine works just as well and is just as safe as the originator product.

Biosimilars take several years to develop and prove that they work in the same way to the originator medicine. This is another way biosimilars are different to generics. Generics do not need studies in people who are ill and take much less time and money to develop.

Other important information

If you have any questions, concerns, or would prefer to discuss this change further, please speak to your clinical team.

With best wishes,

Pharmacy Department, Velindre Cancer Services

Acknowledgement:

Produced including content from Cancer Vanguard Patient Information Leaflet
UK/MKT/SDZ/17-0027i June 2017.