Is lapatinib a targeted drug?

Lapatinibis a HER2 inhibitor targeted therapy. Lapatinib fights HER2-positive breast cancer by blocking certain proteins that may cause cells to grow uncontrollably.
Cancer cells grow in an uncontrolled manner. Lapatinib works within cancer cells by interfering with certain proteins called kinases that stimulate this uncontrolled growth.

Some cancer cells produce too many copies of a specific gene called HER2 (human epidermal receptor 2). The HER2 gene produces a protein called the HER2 receptor. HER2 receptors are like ears or antennae on the surface of all cells. Cancerous breast cells with too many HER2 genes produce too much of the HER2 receptor protein and are considered HER2-positive.

The HER2 receptor uses protein signals called kinases to control the energy cells need to grow and reproduce. Cancerous breast cells with too much HER2 may have too much kinase activity, so the cancer cells grow too much, too quickly.

Lapatinib is a HER2 inhibitor that interferes with HER2-related kinases in cells and limits the energy required for the growth and reproduction of breast cancer cells. By limiting energy, lapatinib can slow or stop cancer growth.

Lapatinib is a targeted therapy, but unlike Herceptin and bevacizumab, it is not an immune-targeted therapy. Immune-targeted therapies are variations of natural antibodies that work similarly to the antibodies produced by our immune system. Lapatinib is a compound, not an antibody.

Lapatinib works differently than Herceptin and pertuzumab, which are also HER2 inhibitors. Herceptin and pertuzumab block the HER2 protein on the surface of breast cancer cells. Pertuzumab targets a different region of the HER2 receptor than Herceptin, so its mode of action is thought to be complementary to Herceptin. Lapatinib blocks HER2 protein in cells. Because of this different mechanism, lapatinib may be effective in HER2-positive cancers that have stopped responding to Herceptin.

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Reference materials:https://www.breastcancer.org/treatment/targeted-therapy/tykerb