What’s Trending in Cancer Immunotherapy
June 14, 2013 |
Last week, The Economist ran an article on “checkpoint-inhibitor immunotherapy”—a catchy term referring to a growing class of drugs that enhance the body’s cancer-fighting abilities. They work by eliminating controls that prevent the immune system from attacking the body when it’s in good health.
Ipilimumab —or “ipi,” as the cool kids call it—was the first drug of this kind to receive FDA approval (2011). (Fun fact: It was created by CRI’s Scientific Advisory Council director James P. Allison, Ph.D. Known as a monoclonal antibody, ipi acts like a lock whose chemical key is CTLA-4, a protein on the surface of an immune system cell called a T lymphocyte. When you’re sick, T lymphocytes roam throughout the body, killing infected cells; when you’re well, CTLA-4 helps reign in the activity of this lymphocyte militia. Many cancerous cells, however, are able to evade the immune system’s notice. Therefore, when cancer is present, ipi’s ability to inhibit CTLA-4 helps rally lymphocytes at a time of need.
The success of ipi in treating advanced melanoma has inspired other monoclonal antibody drugs, such as nivolumab and lambrolizumab, which glom onto PD-1, a T cell receptor that also quiets the activity of the immune system’s warrior cells. Nivolumab shrank the tumors and increased the survival rate of approximately one-third of the 107 patients enrolled in a clinical trial at the Yale Cancer Center; lambrolizumab, meanwhile, resulted in positive responses in about one-third of 135 late-stage melanoma patients enrolled in a University of California, Los Angeles trial. On June 10, we blogged about an exciting new drug called MPDL2380A, which prevents a molecule called PD-L1 from binding to PD-1 and suppressing an immune response.
It’s great to see the number of new, exciting immunotherapies that are making a difference in people’s lives. To read more about immunotherapy success stories, click here.