Trastuzumab

Trastuzumab is a humanised IgG1 monoclonal antibody produced by Chinese hamster ovary cells that binds to the human epidermal growth factor receptor 2 (HER2). 20-30% of primary breast cancers show overexpression of HER2. Trastuzumab inhibits proliferation of tumor cells that overexpress HER2. 

Mechanism of action

Trastuzumab specifically binds with high affinity to sub-domain IV, a juxta-membrane region of HER2’s extracellular domain. Binding inhibits ligand-independent HER2 signalling and prevents the proteolytic cleavage of its extracellular domain, which is normally an activation mechanism of HER2. As a result, trastuzumab inhibits proliferation of human tumor cells that overexpress HER2.

Additionally, trastuzumab is a potent mediator of antibody-dependent cell-mediated cytotoxicity (ADCC).  

Clinical use

Herceptin can only be used when the cancer has been shown to overexpress HER2. In Europe, trastuzumab is indicated for treatment of:

• early breast cancer (without metastases) after surgery, chemotherapy, and radiotherapy  if applicable. It can also be used earlier in treatment, in combination with chemotherapy.
• metastatic breast cancer, used on its own in patients in whom previous treatments have failed.
• When used as an infusion into a vein, Herceptin can also be used for metastatic gastric (stomach) cancer, in combination with cisplatin and either capecitabine or 5‑fluorouracil.

Consult CHMP for details.

What can Sanquin do for you?

We have tests that:

- can measure the levels of free drug in the serum; levels of therapeutic antibodies are assessed using validated ELISAs.

- can measure the immunogenicity of vedoluzimab; human anti-human antibodies are quantified using validated antigen-binding tests (radioimmunoassay or RIA).

As we have hands-on experience in these assays, we can provide you with accurate and reproducible test results. 

Send in samples

If you want to use our drug level or ADA testing services, email us at [email protected].