Trastuzumab Extends Survival Years Down the Line
Analysis of two studies that were important in getting trastuzumab approved for early-stage, HER2-positive breast cancer found that years after treatment, there are significant survival benefits for those who took trastuzumab.
Background and Goals
Between 15 and 30 percent of breast cancers are HER2-positive. This means that the cancer grows because of too many human epidermal growth factor receptor 2 proteins on the breast cells. Today, the standard treatment for early-stage and metastatic HER2-postive breast cancer is trastuzumab (Herceptin) plus chemotherapy. Before trastuzumab, people with HER2-positive breast cancer tended to have worse outcomes than people with other types of breast cancer. But trastuzumab has greatly improved this.
Trastuzumab was first approved for metastatic breast cancer. In the early 2000s, studies were done to test how well it worked in people with early-stage disease. Those studies led to FDA-approval of trastuzumab for early-stage treatment in 2006.
Researchers have continued to do follow-up with the people involved in those trials. They recently presented updated information about how these people were doing years after their treatment finished.
This research looked at a North Central Cancer Treatment Group study (NCCTG N9831) and a National Surgical Adjuvant Breast and Bowel Project study (NSABP B-31). Between the two studies, 4,046 people with early-stage, HER2-positive breast cancer received
- Two chemotherapy medicines, doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan)
- The chemotherapy medicine paclitaxel (Taxol)
Some participants also received trastuzumab while taking paclitaxel, and afterward.
Researchers looked at overall survival, OS, the time from joining the study until death from any cause. The OS results could not be considered statistically significant, or not likely due to chance, until a certain number of deaths happened. That number, 710, was reached in September 2012. Disease-free survival, DFS, the time from joining the study until breast cancer recurrence, new breast cancer or death from any cause, was also measured.
As of Sept. 15, 2012, after a median follow-up of more than 8 years
- OS was 37 percent higher for those who took trastuzumab than those who did not
- DFS was 40 percent higher for those who took trastuzumab than for those did not
Of the 2,028 study participants who took trastuzumab,
- 76.7 percent were alive with no evidence of disease, versus 66.3 percent of the participants who didn't take trastuzumab
- 10.4 percent died from breast cancer, versus 16.9 percent of those who didn't receive trastuzumab
- 1.6 percent died from other known causes, versus 2.5 percent of those who didn't receive trastuzumab
In this study, trastuzumab was associated with a higher number of deaths from heart problems and from unknown causes. However, research shows trastuzumab-related heart problems are rare and not long-term issues. The benefits of this medicine outweigh these risks. Of the participants in this analysis who took trastuzumab,
- .4 percent died from heart problems, versus 0.1 percent of those who didn't receive trastuzumab
- 1.7 percent died from unknown causes, versus 1.1 percent of those who didn't receive trastuzumab.
What This Means for You
Trastuzumab is one of the biggest achievements in breast cancer history. It has helped millions of people with HER2-positive breast cancer, which was once very hard to treat. This study shows that even 8 or more years past treatment, many people continue to do well after taking trastuzumab. If you’re one of those millions of people who have taken this medicine, or you’re planning to take it, you may find the results of this analysis comforting.
Trastuzumab wouldn’t exist if people hadn’t agreed to take part in clinical trials, such as the ones mentioned in this article. There are many trials happening now looking at ways to make HER2-positive treatment better. Talk to your doctor and visit ClinicalTrials.gov to learn more about new trials and whether you qualify for them.
For past LBBC coverage of NSABP B-31, one of the studies used in this analysis, click here.
Perez, Edith A.; Romond, Edward H.; Suman, Vera J. et al. 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. Journal of Clinical Oncology. Volume 32, Issue 33, November 20, 2014; 10.1200/JCO.2014.55.5730.