Herceptin (chemical name: trastuzumab) is a targeted therapy medicine used to treat HER2-positive breast cancer.
Results from two studies confirm that 1 year of Herceptin, rather than 2 years or 6 months, after surgery seems to be best for reducing the risk of recurrence (the cancer coming back) in women diagnosed with HER2-positive early-stage breast cancer.
The research was presented at the 2012 Congress of the European Society for Medical Oncology (ESMO) in Vienna on Oct. 1, 2012.
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
- lower the risk of recurrence of early-stage HER2-positive breast cancers with a high risk of recurrence
A newer form of Herceptin, Herceptin Hylecta (chemical name: trastuzumab and hyaluronidase-oysk), can be given as an injection.
Treatments given after surgery to reduce the risk of recurrence are called adjuvant treatments.
The first analysis offered long-term results from the HERA (Herceptin Adjuvant) trial. More than 5,000 women diagnosed with early-stage HER2-positive breast cancer participated in the HERA trial, which started in 2001.
Besides surgery (followed by radiation therapy in many cases), all of the women got chemotherapy, either before surgery, after surgery, or both before and after surgery. After chemotherapy was done, the women were randomly chosen to get either Herceptin or placebo (a sugar water infusion) for 1 year or 2 years. After 1 year of follow-up, an early analysis showed the women who got Herceptin had a 46% lower risk of recurrence compared to those who didn't get Herceptin. Because these early results were so promising, HERA ended early in 2005 and the women who didn't get Herceptin could start Herceptin if they wanted to (called crossing over); many of them chose to start Herceptin.
The latest HERA analysis includes 8 years of follow-up, comparing the results of women who got Herceptin for 1 year to women who got Herceptin for 2 years.
The researchers found that 2 years of Herceptin doesn’t offer any more benefits than 1 year of Herceptin:
- 367 women who got Herceptin for 1 year had a recurrence
- 367 women who got Herceptin for 2 years had a recurrence
The researchers also reported that women who got Herceptin were about 24% less likely to die from breast cancer than women who got the placebo.
Women treated with Herceptin sometimes have serious side effects, including:
- heart failure
- high blood pressure
- joint pain
- back pain
- hot flashes
Still, serious side effects were seen in only about 1% of the women who got Herceptin in the HERA trial.
The second analysis offered results from the PHARE (Protocol for Herceptin as adjuvant therapy with Reduced Exposure) trial. More than 3,380 French women diagnosed with early-stage HER2-positive breast cancer are participating in PHARE. After surgery and other treatments, the women were randomly assigned to get Herceptin for either 6 months or 1 year. The researchers wanted to see if getting Herceptin for only 6 months would offer the same benefits as getting it for an entire year.
After about 4 years of follow-up, the researchers found that:
- 219 women who got Herceptin for 6 months had a recurrence
- 176 women who got Herceptin for 1 year had a recurrence
While the results aren’t conclusive, they suggest that 1 year of Herceptin is better at reducing the risk of recurrence than only 6 months of Herceptin.
The results of these two studies reinforce the current treatment standard: getting Herceptin for 1 year after surgery and other treatments is best for reducing recurrence risk in women diagnosed with early-stage HER2-positive breast cancer.
If you’ve been diagnosed with early-stage HER2-positive breast cancer, your doctor will likely recommend Herceptin for 1 year (and possibly other treatments) after surgery to reduce the risk of the cancer coming back. If your doctor recommends Herceptin for a length of time other than a year, it’s a good idea to ask why and talk about these studies. Together, you and your doctor can decide on a treatment plan that makes the most sense for you and your unique situation.
Editor’s Note: This article was updated with information about Herceptin Hylecta, which the FDA approved on Feb. 28, 2019.