The metastatic setting is where most of the immuno-oncology drugs are being studied in breast cancer. Patients with TNBC appear to have higher objective response rates than the patients with ER-positive disease, at least with single-agent therapy and with a combination of endocrine therapy.
What are the biggest challenges in neoadjuvant therapy for patients with HER2-positive disease?
One of the biggest challenges is understanding who needs which treatment with pertuzumab, trastuzumab, and chemotherapy. There are other patients who could achieve a good response with fewer treatments. We need to determine whether to start with fewer treatments. Additionally, those who do not accomplish a pCR could be salvaged with additional treatment after surgery. The KATHERINE study addresses this, but we will have to wait for the results.
Is there anything else you would like to add?
I would like to convey that it is a smarter option to start with chemotherapy for TNBC and HER2-positive breast cancer. If a patient has residual disease, this provides them with a backup option to receive additional treatment after surgery. That additional treatment is usually capecitabine for TNBC, since it is shown by a randomized trial to improve OS by 70% to 79% at 3 years. For the patients with HER2-positive disease, this provides the option to receive one of the more aggressive treatments, including pertuzumab or neratinib.