Herceptin (chemical name: trastuzumab) is a targeted therapy medicine used to treat HER2-positive breast cancer.
Since 2005, the standard of care has been to give Herceptin for 1 year after surgery and chemotherapy to reduce the risk of recurrence (the cancer coming back) of HER2-positive, early-stage breast cancer.
First results from the PERSEPHONE trial suggest that giving Herceptin for 6 months after surgery and chemotherapy offers the same decrease in recurrence risk as giving it for 1 year.
The research was presented on June 4, 2018 at the American Society of Clinical Oncology 2018 Annual Meeting. Read the abstract of “PERSEPHONE: 6 versus 12 months (m) of adjuvant trastuzumab in patients (pts) with HER2 positive (+) early breast cancer (EBC): Randomised phase 3 non-inferiority trial with definitive 4-year (yr) disease-free survival (DFS) results.”
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 to:
- treat advanced-stage, HER2-positive breast cancers
- lower the risk of recurrence of early-stage, HER2-positive breast cancers with a high risk of recurrence
Treatments given after surgery to reduce the risk of recurrence are called adjuvant treatments.
The PERSEPHONE study included 4,088 women diagnosed with early-stage, HER2-positve breast cancer between October 2007 and July 2015:
- 69% of the cancers also were hormone-receptor-positive
- 85% of the women had chemotherapy after surgery
The women were randomly assigned to receive either 6 months or 12 months of Herceptin after surgery and chemotherapy.
The goal of the study was to see if 6 months of Herceptin after surgery would offer disease-free survival rates after 4 years that were no more than 3% lower than disease-free survival rates in women who were treated with Herceptin for 12 months.
Disease-free survival is how long the women lived without the cancer coming back.
Half the women were followed for more than 5 years and half were followed for shorter periods of time.
The researchers found that:
- 89.4% of the women who received 6 months of Herceptin were alive with no recurrence
- 89.8% of the women who received 12 months of Herceptin were alive with no recurrence
Heart problems, including heart muscle damage and heart failure, are possible serious side effects of Herceptin. Women who received only 6 months of Herceptin were 50% less likely to stop treatment because of heart problems:
- 4% of the women treated with 6 months of Herceptin stopped treatment because of heart problems
- 8% of the women treated with 12 months of Herceptin stopped treatment because of heart problems
"The PERSEPHONE trial first results demonstrate that 6 months of adjuvant trastuzumab is noninferior to 12 months," said Helena Earl of the University of Cambridge at a press briefing about the research. She is the lead author of the study. "Quality of life, patient-reported experience, and health-economic assessments are ongoing. [The study] marks the first steps towards reduction of treatment duration for many women with HER2-positive breast cancer."
While the results suggest a possible new standard of care for HER2-positive, early-stage breast cancer, more research is needed.
"What we're saying at the moment is that we need to have a detailed look at this group of patients," Earl said. "The headline result is that 6 months is as good as 12 months. This is a real-world result, but we need to be very careful and cautious about coming out at this point and saying, 'Yes, 6 months is enough.'"
Stay tuned to Breastcancer.org Research News for the latest information on how long Herceptin is given after surgery for early-stage, HER2-positive disease.