Dr. Tripathy on Immunotherapy Potential in HER2-Positive Breast Cancer

Debu Tripathy, MD, chair of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, discusses the potential role of immunotherapy in the treatment of patients with HER2-positive breast cancer.

According to Tripathy, it is highly likely that HER2-positive breast cancers are, in fact, immunogenic enough to support a rationale for exploring more immune-based therapies in the future. Past evidence has shown that a small subset of patients had immune infiltrates and a lot of lymphocytes in the tumor, indicating that they were immunogenic. Moreover, those patients seemed to do better even without trastuzumab (Herceptin), which potentially suggests a natural immunity that chemotherapy alone can help with, says Tripathy.

It is also possible, he says, that antibodies such as trastuzumab and pertuzumab (Perjeta) are actually activating the immune system in addition to blocking HER2 signaling. These antibodies do have the ability to recruit T cells and activate antibody-dependent cellular cytotoxicities. This could explain the profound impact on survival that agents such as trastuzumab and pertuzumab have had for patients with this disease.

Immune effects are very persistent, says Tripathy, and they may explain some of the very long responses that have been observed in some patients with HER2-positive breast cancer.