Key TakeawaysA new clinical study has shown that a drug combining a monoclonal antibody and a chemotherapy drug works well at treating advancedmetastatic breast cancer.The drug, Enhertu, is already approved as a third-line treatment for HER2-positive metastatic advanced breast cancers.The promising clinical trial results could help Enhertu become approved as a second-line drug for metastatic breast cancer.
Key Takeaways
A new clinical study has shown that a drug combining a monoclonal antibody and a chemotherapy drug works well at treating advancedmetastatic breast cancer.The drug, Enhertu, is already approved as a third-line treatment for HER2-positive metastatic advanced breast cancers.The promising clinical trial results could help Enhertu become approved as a second-line drug for metastatic breast cancer.
In a recent clinical trial, Enhertu performed better than a similar drug that is the current standard treatment for patients with some types of advancedmetastaticbreast cancer.
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The Clinical Trial
In the trial, the researchers wanted to see how Enhertu performed compared to a similar drug called Kadcyla (ado-trastuzumab emtansine), which is the standard treatment for patients with advanced metastatic breast cancer for whom other treatments have failed.
The trial included 524 patients with HER2-positivemetastatic breast cancer. All of the patients had previously been treated with trastuzumab (a chemotherapy drug) and taxane (a drug that stops cells from dividing).
HER2When breast cancer isHER2 positive, it means that the cells contain a lot of protein called human epidermal growth factor (HER2). Having a lot of this protein makes cancer grow and spread faster.
HER2
When breast cancer isHER2 positive, it means that the cells contain a lot of protein called human epidermal growth factor (HER2). Having a lot of this protein makes cancer grow and spread faster.
These findings add to data from the first clinical trial that showed Enhertu benefited patients who had previously been treated with Kadcyla.
Enhertu v. KadcylaEnhertucombines a monoclonal antibody with a chemotherapy drug. It isgiven as intravenous (IV) therapyevery 21 days.Kadcylauses another version of the same monoclonal antibody that’s in Enhertu, but it’s linked to a different chemotherapy agent. Kadcyla is the current standard of care for patients with advanced metastatic breast cancer when other treatments have failed.
Enhertu v. Kadcyla
Enhertucombines a monoclonal antibody with a chemotherapy drug. It isgiven as intravenous (IV) therapyevery 21 days.Kadcylauses another version of the same monoclonal antibody that’s in Enhertu, but it’s linked to a different chemotherapy agent. Kadcyla is the current standard of care for patients with advanced metastatic breast cancer when other treatments have failed.
Enhertucombines a monoclonal antibody with a chemotherapy drug. It isgiven as intravenous (IV) therapyevery 21 days.
Kadcylauses another version of the same monoclonal antibody that’s in Enhertu, but it’s linked to a different chemotherapy agent. Kadcyla is the current standard of care for patients with advanced metastatic breast cancer when other treatments have failed.
AstraZeneca announced the trial’s results on September 18, and the findings were also presented at theEuropean Society for Medical Oncologymeeting.
The Need for New Therapies
Shanu Modi, MD, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York City who was not involved in this study, tells Verywell that the findings are important because the study was “the first randomized trial” of Enhertu and that the drug showed “significant efficacy advantage over the current second-line standard of care therapy.”
Chemotherapy for Metastatic Breast Cancer
Modi says that a difference in a drug’s benefit of this magnitude is not frequently seen, which makes the data “extremely compelling.”
Dorraya El-Ashry, PhD, the chief scientific officer at theBreast Cancer Research Foundation, was also not involved in the trial, but tells Verywell that “people with metastatic disease, no matter the subtype, are in critical need of new therapies.”
El-Ashry says that overall, the results of the trial are “very promising and provide patients with an added tool to treat a life-threatening disease.”
What Is HER2-Low Breast Cancer?
How Does Enhertu Work?
Side Effects & RisksEnhertu’s side effectscan include nausea, fatigue, vomiting, hair loss, constipation, and anemia.A less common but serious risk of Enhertu is an inflammatory lung condition calledinterstitial lung diseasewhich causes difficulty breathing and can lead to heart problems.
Side Effects & Risks
Enhertu’s side effectscan include nausea, fatigue, vomiting, hair loss, constipation, and anemia.A less common but serious risk of Enhertu is an inflammatory lung condition calledinterstitial lung diseasewhich causes difficulty breathing and can lead to heart problems.
Enhertu’s side effectscan include nausea, fatigue, vomiting, hair loss, constipation, and anemia.
A less common but serious risk of Enhertu is an inflammatory lung condition calledinterstitial lung diseasewhich causes difficulty breathing and can lead to heart problems.
“The difference between these two antibody-drug conjugates really lies in the advancements made in the linker-payload technology,” says Modi. A linker-payload is the chemical bond between the antibody and drug.
With Enhertu, Modi says that the payload is a different chemotherapy drug—one that is not commonly used to treat breast cancer.
What Is HER2 Positive Breast Cancer?
Does Enhertu Improve Survival?
Based onprevious data, the researchers already knew that Enhertu can extend the progression-free survival (the length of time before a patient progresses or has a recurrence) for patients with cancer that cannot be surgically removed and for whom other anticancer treatments have failed or stopped working.
El-Ashry says that the results of the recent trial are still only preliminary findings; they only show that the time to progression has increased and do not show if there is an increase in the overall survival of the patients.
“These are interim results and so the overall survival (OS) rate—while trending towards being increased—did not reach significance,” says El-Ashry.
Approving Enhertu for Earlier Use
Currently, Enhertu is only approved as a third-line treatment (which means that it’s not used until other drugs have been tried and have failed) for some patients with HER2-positive breast cancer.Modi says that not every type of breast cancer is HER2 positive—about 15% to 20% are. According to El-Ashry, there are currently “168,000 women and men living with metastatic breast cancer.”
Dorraya El-Ashry, PhDPeople with metastatic disease, no matter the subtype, are in critical need of new therapies.
Dorraya El-Ashry, PhD
People with metastatic disease, no matter the subtype, are in critical need of new therapies.
The monoclonal antibody component of Enhertu, trastuzumab, has been approved for treating breast and gastrointestinal cancers for years. One brand name of the drug isHerceptin.
Before Herceptin, HER2-positive breast cancers had anincreased risk of metastasizingand patients had a poor overall chance of survival. El-Ashry says that targeted HER2 therapies have significantly changed the outcomes for these patients.
The results of the recent clinical trial may help Enhertu get approved for use earlier in treatment as second-line therapy for HER2-positive breast cancer.
“The is significant in that it adds Enhertu to the armamentarium of new, more effective HER2 directed therapies for metastatic HER2 positive breast cancer,” says El-Ashry. “The next step will be to study the drug’s overall survival benefit to gauge its effectiveness.”
What This Means For YouAn antibody-drug conjugate called Enhertu is showing promise in clinical trials as a treatment for some patients with advanced metastatic breast cancer. The drug is already approved in the United States as a third-line treatment for HER2-positive breast cancer and may eventually be approved for earlier use in some HER2-positive breast cancer patients.
What This Means For You
An antibody-drug conjugate called Enhertu is showing promise in clinical trials as a treatment for some patients with advanced metastatic breast cancer. The drug is already approved in the United States as a third-line treatment for HER2-positive breast cancer and may eventually be approved for earlier use in some HER2-positive breast cancer patients.
How Is HER2-Positive Breast Cancer Treated?
5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Daiichi Sankyo.Enhertu highlights of prescribing information.Cortés J, Kim SB, Chung WP, et al.Trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in patients (Pts) with HER2+ metastatic breast cancer (mBC): Results of the randomized phase III DESTINY-Breast03 study.Ann Oncol. 2021;32(suppl 5):S1287-S1288. doi:10.1016/j.annonc.2021.08.2087Modi S, Saura C, Yamashita T, et al.Trastuzumab deruxtecan in previously treated HER2-positive breast cancer.N Engl J Med. 2020;382(7):610-621. doi:10.1056/NEJMoa1914510Daiichi Sankyo, AstraZeneca.Understanding HER2+ mBC and Enhertu.Daiichi Sankyo, AstraZeneca.Results with Enhertu.
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Daiichi Sankyo.Enhertu highlights of prescribing information.Cortés J, Kim SB, Chung WP, et al.Trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in patients (Pts) with HER2+ metastatic breast cancer (mBC): Results of the randomized phase III DESTINY-Breast03 study.Ann Oncol. 2021;32(suppl 5):S1287-S1288. doi:10.1016/j.annonc.2021.08.2087Modi S, Saura C, Yamashita T, et al.Trastuzumab deruxtecan in previously treated HER2-positive breast cancer.N Engl J Med. 2020;382(7):610-621. doi:10.1056/NEJMoa1914510Daiichi Sankyo, AstraZeneca.Understanding HER2+ mBC and Enhertu.Daiichi Sankyo, AstraZeneca.Results with Enhertu.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Daiichi Sankyo.Enhertu highlights of prescribing information.Cortés J, Kim SB, Chung WP, et al.Trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in patients (Pts) with HER2+ metastatic breast cancer (mBC): Results of the randomized phase III DESTINY-Breast03 study.Ann Oncol. 2021;32(suppl 5):S1287-S1288. doi:10.1016/j.annonc.2021.08.2087Modi S, Saura C, Yamashita T, et al.Trastuzumab deruxtecan in previously treated HER2-positive breast cancer.N Engl J Med. 2020;382(7):610-621. doi:10.1056/NEJMoa1914510Daiichi Sankyo, AstraZeneca.Understanding HER2+ mBC and Enhertu.Daiichi Sankyo, AstraZeneca.Results with Enhertu.
Daiichi Sankyo.Enhertu highlights of prescribing information.
Cortés J, Kim SB, Chung WP, et al.Trastuzumab deruxtecan (T-DXd) vs trastuzumab emtansine (T-DM1) in patients (Pts) with HER2+ metastatic breast cancer (mBC): Results of the randomized phase III DESTINY-Breast03 study.Ann Oncol. 2021;32(suppl 5):S1287-S1288. doi:10.1016/j.annonc.2021.08.2087
Modi S, Saura C, Yamashita T, et al.Trastuzumab deruxtecan in previously treated HER2-positive breast cancer.N Engl J Med. 2020;382(7):610-621. doi:10.1056/NEJMoa1914510
Daiichi Sankyo, AstraZeneca.Understanding HER2+ mBC and Enhertu.
Daiichi Sankyo, AstraZeneca.Results with Enhertu.
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