Many new treatments for metastatic breast cancer are under study. Most of these are drug therapies. Some focus on treating the whole body, while others focus on the breast, chest wall and nearby lymph nodes.
Findings from clinical trials of these treatments will determine whether or not they become a part of standard care for metastatic breast cancer. Sometimes, these treatments go on to be part of early stage breast cancer care.
Learn about clinical trials.
Tyrosine kinase inhibitors are targeted therapies for cancer. Although some tyrosine kinase inhibitors are used to treat other types of cancer, lapatinib (Tykerb) is the only one FDA-approved for the treatment of breast cancer. Lapatinib is only used to treat HER2-positive metastatic breast cancer.
Other tyrosine kinase inhibitors are under study for use in metastatic breast cancer treatment.
Learn more about lapatinib in the treatment of metastatic breast cancer.
Poly(ADP-ribose) polymerase (PARP) inhibitors are a class of drugs under study for many types of cancer, including breast cancer. PARP is an enzyme involved in DNA repair.
At this time, PARP inhibitors are only offered in clinical trials for people with metastatic breast cancer. Early findings suggest PARP inhibitors hold the most promise for people with metastatic breast cancer who have a BRCA1 or BRCA2 gene mutation .
CDK4 and CDK6 are enzymes important in cell division. CDK4/6 inhibitors are a new class of drugs designed to interrupt the growth of cancer cells. The CDK4/6 inhibitor palbociclib (Ibrance) in combination with hormone therapy is FDA-approved for the treatment of hormone receptor-positive, HER2-negative metastatic breast cancers (learn more).
Other CDK4/6 inhibitors are under study for use in metastatic breast cancer treatment.
PI3 kinase is an enzyme important in cell growth. The PIK3CA gene helps control PI3 kinase enzyme activity. Some breast cancers have a mutation in the PIK3CA gene (this gene mutation is in the genes of breast cancer, not the person). This mutation can affect PI3 kinase and cause the tumor to grow.
PI3 kinase inhibitors are a new class of drugs designed to interrupt PI3 kinase signals and stop the growth of cancer cells. PI3 kinase inhibitors are under study for the treatment of metastatic breast cancer.
Anti-angiogenesis drugs, such as bevacizumab (Avastin), block the growth of new blood vessels (angiogenesis). Without a blood supply, the cancer cannot grow.
Although early data showed bevacizumab offered benefit to some women with metastatic breast cancer, longer-term follow-up data did not confirm these findings. In 2011, the FDA withdrew its approval for the use of bevacizumab in the treatment of metastatic breast cancer .
However, bevacizumab and other anti-angiogenesis are still under study for the treatment of metastatic breast cancer. Bevacizumab is still FDA-approved for use in other cancers.
Drugs that help the body’s immune system attack cancer cells are now used to treat many cancers (including melanoma and lung cancer). These drugs “take the brakes off” the natural factors that limit how the immune system can control tumor cells.
Clinical trials are studying whether immunotherapy drugs have a role in metastatic breast cancer treatment.
Tumors often develop resistance (stop responding) to drugs used to treat metastatic breast cancer. New ways to monitor response to treatment are under study.
Many studies have shown circulating tumor cell levels can help predict survival for people with metastatic breast cancer [40-41]. The more circulating tumor cells in the blood, the more advanced the metastatic breast cancer is likely to be. Having more of these cells may also predict a lack of response to treatment. Similarly, circulating tumor DNA is under study for use in monitoring metastatic breast cancer and predicting treatment response in metastatic cancers .
At this time, circulating tumor cell and circulating tumor DNA testing are not routinely done in clinical practice. It is still not known how much more information these tests provide over standard tests and tumor to help guide treatment (and thus, improve survival). Recent findings show no benefit of using circulating tumor cells to guide treatment . However, this topic is under active study.
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After talking with your health care provider, we encourage you to consider joining a clinical trial of new treatments for metastatic breast cancer. If your medical center does not offer clinical trials, you may want to get a referral to a cancer center that offers clinical trials of new metastatic breast cancer treatments.
BreastCancerTrials.org in collaboration with Susan G. Komen offers a custom matching service that can help you find a clinical trial for people with metastatic breast cancer.
Learn more about clinical trials and find a list of resources to help you find a clinical trial.
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*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date at this time.
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