Lapatinib is a new drug that targets epidermal growth factor receptors on tumour cells. Its brand name is Tykerb.

Epidermal growth factor receptors (EGFR) are part of the system that controls the growth of cells in our bodies. When an EGFR is stimulated it sends signals to the cell which encourages new cells to be made.

Many types of cancer produce large amounts of EGFR. So drugs are being developed to target these receptors, in the hope that this might slow their growth.

The two most important types of EGFR to be discovered so far are ErbB1 and ErbB2 (also known as HER1 and HER2). Lapatinib attacks both the ErbB1 and ErbB2 receptors.

There has been a lot of publicity lately about a drug called Herceptin (trastuzumab). This targets the HER2 receptor. About 1 in 5 breast cancers carry an excess of HER2 receptors, and are called HER2 positive tumours. Studies have shown that Herceptin is an effective treatment for HER2 positive breast cancer.

Early trial results suggest that Lapatinib may be effective in treating EGFR receptor-positive breast cancer. It is still at an early stage of testing but has several possible advantages over Herceptin, these include:

• It is active against both ErbB1 and ErbB2, not just ErbB2 receptors
• It can be taken as a tablet
• It appears to have few side effects
• There is no evidence of the possible heart damage which can occur with Herceptin.

As Lapatinib is still at an early stage of development, it's not generally available. However, there are ongoing clinical trials into its effectiveness and safety. You can find more about current trials on our website. Depending on the results of these studies Lapatinib may become more widely available in the future.

Reference

• Gomez HL et al. A phase II, randomized trial using the small molecule tyrosine kinase inhibitor lapatinib as a first-line treatment in patients with FISH positive advanced or metastatic breast cancer. Proc Am Soc Clin Oncol 2005;23(suppl):203s. Abstract 3046