New treatment regimens for metastatic HER2-positive breast cancer
There is a new emerging treatment option for metastatic HER2-positive breast cancer. Following very encouraging & positive results from two clinical trials, these options have emerged. The tests looked at tucatinib and trastuzumab deruxtecan (Enhertu) in women who had already been treated for HER2-positive breast cancer. This is a type of metastatic breast cancer that makes too much of the HER2 protein.
In one of the trials, women treated with tucatinib in addition to trastuzumab and capecitabine lived longer than women who received only trastuzumab & capecitabine. The treatment also benefited women in the trial whose cancer had spread to the brain, a particularly challenging group to treat.
Trastuzumab deruxtecan was tested in a smaller trial, called DESTINY-Breast01, and wasn’t compared directly with another treatment. But many women in the study who received the drug saw their tumors shrink and lived for an extended period without their cancer getting worse.
In Dec 2019, the results of both clinical trials were presented at the San Antonio Breast Cancer Symposium (SABCS) and also published in the New England Journal of Medicine.
Although there have been several severe side effects reported,. Especially with trastuzumab deruxtecan, many patients have lung infections, which also lead to deaths. Hence, more studies and care are required before these regimens become part of the universal protocol.
The FDA’s approval of trastuzumab deruxtecan comes with a warning of lung-related infections called interstitial lung disease (ILD).
Her 2 positive breast cancer patients, whose cancer has also spread to the brain, were also included in both of these trials. Usually, in trials of breast cancer, patients whose cancer has spread to the brain are excluded. These two trials were exceptions.
Based on the results of HER2CLIMB, using tucatinib with trastuzumab and capecitabine together should be a great way to treat women with HER-2-positive breast cancer.
