ASCO Annual Meeting
June 1, 2014
Results from a large study show that the combination of lapatinib (Tykerb) and trastuzumab (Herceptin) plus chemotherapy after surgery is not more effective than only trastuzumab plus chemotherapy for women with early-stage, human epidermal receptor 2 (HER2)-positive breast cancer. HER2 is a specialized protein found on the surface of breast cells that can contribute to cancer growth. Both lapatinib and trastuzumab are targeted therapies, which are treatments that target the cancer’s specific genes, proteins, or the tissue environment that contributes to cancer growth and survival. In this case, both drugs target HER2, but in different ways.
Treatment with trastuzumab and chemotherapy after surgery lowers the risk of the cancer returning for women with HER2-positive, early-stage breast cancer. However, about 20% of patients have the cancer come back within 10 years, often having spread to other parts of the body. Previous research suggested that adding lapatinib to trastuzumab might provide an additional benefit over trastuzumab by itself.
For this study, 8,381 women with newly diagnosed, early-stage, HER2-positive breast cancer who already had surgery received one of the following treatment options: lapatinib plus trastuzumab given at the same time, trastuzumab followed by lapatinib, or trastuzumab by itself. The majority received these treatments after chemotherapy, although many received chemotherapy that overlapped with the HER2-targeted therapy.
After four years, the percentage of women alive with no signs of cancer was similar regardless of the treatment received. For women who received lapatinib and trastuzumab together, 88% were alive and had no signs of recurrent cancer after four years. For those who received trastuzumab followed by lapatinib, 87% were alive and had no signs of recurrent cancer after four years. And, 86% of women who received only trastuzumab were alive and had no signs of recurrent cancer after four years. Researchers also found that the combination of lapatinib and trastuzumab was linked with more side effects, especially diarrhea, rash, and liver problems.
What this means for patients
“We were encouraged to see that patients with HER2-positive, early-stage breast cancer are doing rather well with standard trastuzumab therapy,” said senior study author Edith Perez, MD, Deputy Director at Large at the Mayo Clinic Cancer Center in Jacksonville, FL. “But we were surprised that adding lapatinib did not provide further benefit, since the combination of these drugs was promising when given prior to surgery in a smaller study.”
Questions to ask your doctor
- What type and stage of breast cancer do I have?
- Is it HER2-positive? What does this mean?
- What are my treatment options?
- Will HER-2 targeted therapy be a part of my treatment?
- What are the side effects of each treatment, and how can they be managed?