Everything You Need To Know About Trastuzumab

Trastuzumab is the first therapy directed against an oncogene for patients with HER-2 positive breast cancer. An oncogene is a gene that has a great capacity for mutation or transformation that induces the formation of cancer in a tissue.

On the other hand, that a breast cancer is HER-2 positive refers to a type of neoplasm that has overexpressed receptors for this protein. The HER-2 proteins are receptors on the breast cells produced by the HER-2 gene that are required under normal conditions. These proteins allow breast cells to divide and repair themselves.

HER-2 positive breast cancers account for 20-30% of breast tumors in humans. This type of cancer was correlated with a poor prognosis, such as reduced recurrence-free survival and overall survival.

Mechanism of action: how does trastuzumab work in the body?

This medicine consists of a humanized monoclonal antibody. That is, it is a drug formed by an antibody produced by a single type of cell of the immune system: B lymphocytes.

We say that it is humanized because it is a combination of a human antibody with a small proportion of a monoclonal antibody from a mouse or rat. The animal portion of the antibody binds to the target antigen and the human portion makes it less likely that the body’s immune system will destroy it.

In this sense, trastuzumab acts on the HER-2 receptor of mammary cells, preventing the cell proliferation of cells that have this receptor overexpressed. It causes, finally, the death of these. It also triggers an antibody-controlled immune response against cells that overexpress the HER-2 receptor.

Therapeutic indications of trastuzumab

Trastuzumab, as we already know, is indicated for the treatment of metastatic breast cancer in which tumors have overexpressed HER-2 receptors. It can be administered in two different ways.

First, monotherapy alone can be given. This regimen is chosen for those patients who have already received at least two chemotherapy regimens for metastatic disease.

Previous chemotherapy must have included at least one anthracycline and one taxane. These are other anticancer drugs. To administer trastuzumab as monotherapy, patients who also have positive hormone receptors must have failed hormonal treatment, unless this is not indicated by any medical condition of the patient.

Second, trastuzumab can be given together with a taxane, such as paclitaxel. Doctors choose this option when patients have not received prior chemotherapy.

Adverse reactions of trastuzumab

Like other drugs on the market, trastuzumab is not without a number of adverse effects. We understand adverse effects as all those undesirable and unintended events that occur in an expected way with treatment with a drug.

In this sense, l as most reported adverse reactions during clinical trials were infusion – related symptoms, such as fever and chills after the first dose. On the other hand, approximately 10% of the patients presented:

• Abdominal and chest pain.
• Diarrhea, nausea, and vomiting
• Joint and muscle pain.
• Skin rashes

There are another series of adverse reactions that have been described in between 1% and 10% of patients. Some of them are:

• Flu syndrome.
• Back pain.
• Vasodilation
• Tachycardia.
• Lack of appetite.
• Dry mouth
• Anxiety.
• Taste alteration
• Leukopenia

Trastuzumab: an important contribution to treatment

Trastuzumab has made a very important contribution to the therapeutic options available for metastatic breast cancer. This drug provides a significant advantage in metastatic disease, especially in HER-2 positive patients receiving concomitant treatment with paclitaxel.

Despite these advances, it is essential to continue active research. Studies suggest that chemotherapy drug combinations should be evaluated, as well as improved detection of HER-2 proteins. A more specific detection would bring the benefit of proposing a more efficient treatment for the patients who really need it.