Standard Medication for HER-2 Breast Cancer Remained Top Rx

HER2 positive breast cancer patients taking trastuzumab had fewer disease events than those taking lapatinib

(RxWiki News) The approval of a new medication represents new options for patients. But the new option isn't always the best option. When it comes to treating HER-2 positive breast cancer, the standard medication still appears to beat the newer option.

A recent study found that, compared with a newer medication called lapatinib (brand name Tykerb), the older trastuzumab (brand name Herceptin) led to fewer disease events in those with HER-2 positive breast cancer when used in addition to standard chemotherapy.

Disease events are cases of breast cancer recurrence anywhere in the body, a new cancer, or death from any cause.

HER-2 positive breast cancer is when the cancer makes a protein called human epidermal growth factor receptor 2. This protein is known to promote growth of cancer cells. About one in five people with breast cancer has this type.

Patients are usually treated for HER-2 positive breast cancer with chemotherapy and a medication that interferes with the HER protein receptor, such as lapatinib or trastuzumab.

Edith Perez, MD, from the Mayo Clinic in Jacksonville, Florida, conducted this study with colleagues.

The study, which lasted from 2007 to 2011, included 8,381 people with HER-2 positive breast cancer. These patients received either a combination of lapatinib and trastuzumab or one of the medications alone.

When both medications were given together, the participants did not live longer disease-free than when taking either medication alone. The combination only led to more harmful effects because of the increased toxicity to their bodies.

After four and a half years of follow-up, 14 percent of people who were given only trastuzumab had at least one disease event, and 18 percent of those who only took lapatinib had at least one disease event.

In 2011, early results showed that lapatinib was inferior to trastuzumab. At that point, patients on lapatinib were offered trastuzumab. About 52 percent of people taking lapatinib took at least one dose of trastuzumab.

In a press release, Dr. Perez said that her team showed that lapatinib was less effective than trastuzumab in stopping the cancer from spreading.

"There was a trend for additional benefit if those patients were switched to trastuzumab, that cardiac safety was better than predicted, and that the number of brain metastases appeared similar for the patients who received either lapatinib or trastuzumab,” she said.

The study results were presented at the European Society for Medical Oncology Congress in Madrid at the end of September.

The study was funded by The Breast Cancer Intergroup of North America , the Breast International Group, the National Cancer Institute and Glaxo SmithKline; the company that makes lapatinib.

Review Date: 
October 3, 2014