Clinical Trials for HER2 Mutant-Positive Tumors are research studies intended to develop new therapies and treatment options for cancer patients who are positive for the human epidermal growth factor receptor-2 (HER2) mutation. The HER2 protein is present in everyone and is located on the surface of cells and its main function is to regulate cell growth. However, if extra copies of the gene create the HER2 protein, it can cause the cancer cells to be more aggressive.
While the prognosis of HER2-positive tumors tends to be somewhat poorer than for HER2-negative tumors, the widespread adoption of HER2 therapies is making a difference in survival rates, as well as reducing the risk for recurrence.
According to the National Cancer Institute (NCI), HER2-positive tumors are most often found in breast cancer patients, but can also be found in the following cancer types:
- Stomach (gastric)
Testing for HER2 Positive Tumors
To qualify for clinical trials for HER2 mutant-positive tumors, patients need to get tested for their present gene mutations. There are two established ways to test HER2 status in a tumor. The Immunohistochemistry (IHC) measures the amount of HER2 protein present. The Fluorescent in situ hybridization (FISH) looks at the genetic level for the number of copies of the gene present, an increased number of gene copies is known as amplification.
Cancer cells that are HER2 positive are more likely to spread throughout the body and grow at an increased rate. Testing positive for the HER2 mutation gives your doctor an insight on which treatments are more likely to be effective. There are also new treatments in clinical trials that target HER2-positive cells.
What is HER2 Positive Breast Cancer?
HER2-positive breast cancer is not inherited. Instead, it’s considered a somatic genetic mutation. This type of mutation occurs during one’s lifetime. Having a close relative with HER2-positive breast cancer does not increase your risk for breast cancer or HER2-positive cancer.
About 25% of breast cancers are HER2-positive and those with metastatic breast cancer are the most likely to be positive for the HER2 mutation. The most common treatments for these patients include one or a combination of the following:
- Hormone therapy
- Targeted therapies
Targeted therapies can be more effective than standard treatments because they target the mutations within cells that cause the overproduction and spread of cancer cells. The drugs aim to either trigger the immune system to attack the cell, alter proteins within the cell, block blood vessels feeding the cancer cells, or blocking any signals supporting the growth of the cancer cells. They also aim to avoid healthy cells, which can lead to less side effects than other treatments.
Targeted therapy drugs being used for research and to treat patients in clinical trials for HER2-positive breast cancer are:
- Trastuzumab (Herceptin)
- Tucatinib (FDA approved in April of 2020)