Immunotherapy and breast cancer

You are likely aware of the growing buzz about immunotherapy, cancer treatment that either activates the body’s immune system. The basic science is this: cancer cells often have tumor antigens, or specific molecules, on their surface. These antigens could be targets for the body’s immune system and can be attacked. Unfortunately, cancer cells paralyze or neutralize this response. Scientists have learned how to recognize the regulators that do this and attack them with immunotherapy. Simply put, immunotherapy drugs "take the brakes off" the natural responses that may limit the control of cancer cells. With that change, the hope is that more cancer cells can be killed. Often given in tandem with chemotherapy, the theory is that immunotherapies may better find and help destroy cancer cells.

For some time, immunotherapies have been studied and used to treat other kinds of cancer. There have been some spectacular successes, so research has expanded to include other kinds of cancer. Clinical trials are underway to study the use of immunotherapies in the treatment of women with metastatic breast cancer. As you likely know, this is the usual pattern of clinical trials: they explore the value of a treatment in advanced cancer, and, sometimes, the drug ends up being part of the treatment of early cancer. That is, the research begins with advanced disease and, if that works well, extends to care of early cancer in the hope of eradicating them.

In early March, the FDA approved the first immunotherapy drug for the treatment of advanced or metastatic breast cancer. Receiving accelerated approval (something that happens when a study is powerfully positive) for the treatment of locally advanced or metastatic triple negative breast cancer, it is a combination of immunotherapy and chemotherapy: Tecentriq and Abraxane.

The approval came after a study, published in October, found that these drugs extended the progression-free survival from 4.8 to 7.4 months. Please note that this is certainly an improvement, but it is also certainly not as much as we need. Progression-free survival means the time before the cancer begins to grow; it is not necessarily related to how long the person will live.

I have written before about headlines that are wildly promising and the truth that may be somewhat less robust. Most certainly this is a big step forwards and, hopefully, will lead to more research and more time. However, it is far from a cure for cancer, and the women I know with metastatic breast cancer are hoping for a whole lot more than three more months. We need to continue to provide support for cancer research and to enable scientists to discover treatments that can eventually truly extend life in a meaningful way—or, even better, stop cancer before it begins.