Herceptin (chemical name: trastuzumab) is a targeted therapy medicine used to treat HER2-positive breast cancer.
Results from an analysis of two large, long-term studies show that adding Herceptin to chemotherapy to treat women diagnosed with early-stage, HER2-positive breast cancer improves overall survival and disease-free survival compared to chemotherapy alone.
The study was published online on Oct. 20, 2014 by the Journal of Clinical Oncology. Read the abstract of “Trastuzumab Plus Adjuvant Chemotherapy for Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: Planned Joint Analysis of Overall Survival From NSABP B-31 and NCCTG N9831.”
Overall survival is how long a woman lives, with or without the cancer growing. Disease-free survival is how long a woman lives without the cancer growing.
HER2-positive breast cancers make too much of the HER2 protein. The HER2 protein sits on the surface of cancer cells and receives signals that tell the cancer to grow and spread. About one out of every four breast cancers is HER2-positive. HER2-positive breast cancers tend to be more aggressive and harder to treat than HER2-negative breast cancers.
Herceptin works by attaching to the HER2 protein and blocking it from receiving growth signals. Herceptin, which is given intravenously, is approved by the U.S. Food and Drug Administration (FDA) to:
- treat advanced-stage, HER2-positive breast cancers
- be given to women with earlier stages of HER2-positive disease as adjuvant treatment (treatment after initial treatment, such as surgery) either alone or as part of a regimen with chemotherapy
A newer form of Herceptin, Herceptin Hylecta (chemical name: trastuzumab and hyaluronidase-oysk), can be given as an injection.
The analysis looked at long-term results from two studies:
- N9831, led by the North Central Cancer Treatment Group Alliance
- NRG B-31, led by the National Surgical Adjuvant Breast and Bowel Project
More than 4,000 women diagnosed with early-stage, HER2-positive breast cancer were in the two studies, both of which looked at whether adding Herceptin to a standard chemotherapy regimen after surgery offered more benefits than the chemotherapy regimen alone. In each study, the women were randomly assigned to receive one of two regimens:
- Adriamycin (chemical name: doxorubicin) plus Cytoxan (chemical name: cyclophosphamide) followed by Taxol (chemical name: paclitaxel)
- Adriamycin (chemical name: doxorubicin) plus Cytoxan (chemical name: cyclophosphamide) followed by Taxol (chemical name: paclitaxel) plus Herceptin
At 10 years after treatment, overall survival was better in women who were treated with Herceptin:
- 84% of the women who received chemotherapy plus Herceptin were alive
- 75.2% of the women who received chemotherapy alone were alive
This means that overall survival was 37% better in women who got Herceptin plus chemotherapy compared to women who got only chemotherapy.
At 10 years after treatment, disease-free survival also was better in women who were treated with Herceptin:
- 73.7% of the women who received chemotherapy plus Herceptin were alive without the cancer growing
- 62.2% of the women who received chemotherapy alone were alive without the cancer growing
This means that disease-free survival was 40% better in women who got Herceptin plus chemotherapy compared to women who got only chemotherapy.
Herceptin may cause side effects, including:
- high blood pressure
- joint and back pain
- hot flashes
Some women getting Herceptin will have decreased heart function during treatment. In rare cases, heart failure can develop. Other studies have shown that heart problems caused by Herceptin are more likely to happen in older women, women with diabetes, and women with preexisting risk factors such as high blood pressure, high cholesterol, and obesity. Heart function can recover when Herceptin treatment stops.
In this study, women who got Herceptin had a very slight increase in the risk of heart problems:
- 0.2% of the women who were treated with Herceptin died from heart problems
- 0.1% of the women who were treated with chemotherapy alone died from heart problems
The findings demonstrate how important Herceptin has been to the treatment of HER2-positive breast cancer, according to Edith Perez, M.D., lead author of the study and deputy director at large of the Mayo Clinic Cancer Center and director of the Breast Cancer Translational Genomics Program at the Mayo Clinic in Florida. Dr. Perez also is a member of the Breastcancer.org Professional Advisory Board.
“This long follow-up of patients shows that we have really altered the natural history of this disease," she said. "Herceptin works -- and it works for a long period of time. The drug has impacted the lives of many women in the U.S. and worldwide."
In the Breastcancer.org Targeted Therapies section, you can learn more about how Herceptin works, when it is used, and what to expect during treatment.
Editor’s Note: This article was updated with information about Herceptin Hylecta, which the FDA approved on Feb. 28, 2019.