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 will determine whether or not these treatments become a part of the standard of care for metastatic breast cancer. Some may even go on to be part of early stage breast cancer care.
Learn about clinical trials for people with metastatic breast cancer.
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.
Today, 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 class of drugs designed to interrupt the growth of cancer cells.
Palbociclib (Ibrance) is the only CDK4/6 inhibitor FDA-approved for breast cancer treatment. It’s used in combination with hormone therapy to treat hormone receptor-positive, HER2-negative metastatic breast cancers.
Other CDK4/6 inhibitors are under study for use in metastatic breast cancer treatment.
Some findings show the CDK4/6 inhibitor ribociclib in combination with the aromatase inhibitor letrozole may give people more time before the cancer spreads compared to letrozole alone for hormone receptor-positive, HER2-negative metastatic breast cancers .
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 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 benefited 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.
Some drugs contain biological products such as antibodies. A biosimilar drug is very similar to a brand name drug that contains biological products.
To be approved by the U.S. Food and Drug Administration (FDA), the biosimilar drug must work the same way as the brand name drug and it must have the same :
Biosimilar drugs cost less than brand name drugs.
Some biosimilar drugs for breast cancer are under study. However, today, none are FDA-approved.
A large study found a biosimilar form of trastuzumab is as safe and effective as trastuzumab in the treatment of HER2-positive metastatic breast cancer .
However, this biosimilar form of trastuzumab is not yet FDA-approved.
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. For this reason, they are sometimes called “checkpoint inhibitors.”
Many types of immunotherapy drugs are under study. Clinical trials are studying whether they may play 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 tests should not be used to guide treatment because they have not been shown to offer benefit [43-45].
However, these topics are under 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 does.
BreastCancerTrials.org in collaboration with Susan G. Komen offers a custom matching service to help you find a metastatic breast cancer clinical trial.
Learn more about clinical trials for people with metastatic breast cancer and find a list of resources to help you find a clinical trial.
Our commitment to research
At Susan G. Komen©, we are committed to saving lives by meeting the most critical needs in our communities and investing in breakthrough research to prevent and cure breast cancer. Our Research Program is an essential driving force for achieving this mission. Since our inception in 1982, Komen has provided funding to support research grants that have greatly expanded our knowledge of breast cancer and helped us understand that breast cancer is not just a single disease but many diseases, unique to each individual. Going forward, our commitment to research will contribute significantly to our ability to achieve our bold goal of reducing the current number of breast cancer deaths in the U.S. by 50 percent by 2026.
To date, Komen has provided more than $920M to researchers in 48 states and 21 countries to support research that has resulted in a better understanding of breast cancer; earlier detection; personalized, less invasive treatments for what was once a “one-treatment-fits-all” disease; and improvements in both quality of life and survival rates.
Learn more about our continuing investment in research and the exciting research that we are funding, because nothing would make us happier than ending breast cancer forever.
*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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