Significant Progress in Understanding How Immunotherapy Works And How the Immune System Recognizes Cancer
A new study published in the New England Journal of Medicine has identified a mechanism that may explain why ipilimumab controls melanoma in only some people. The study also provides new important insights on the identity of molecules, on the surface of cancer cells, which allow the body’s immune system to identify and destroy them.
Ipilimumab (YervoyTM), a drug that boosts the body’s natural immune defense against tumors has shown promising results in some patients with melanoma.
In this study, Alexandra Snyder and colleagues from the Memorial Sloan Kettering Cancer Centre in New York found that drug-responsive tumors share a certain type of mutation that makes cancer cells express new antigens — substances that T cells can detect and recognize as foreign to the body.
“We identified a specific subset of tumor antigens found only in patients who respond well to CTLA-4 blockade therapy,” says Dr. Chan, the senior author of this study. The researchers believe these mutations make tumors express the new antigens that the immune system then reacts to — and ipilimumab works by enhancing that reactivity.
As reported by Cancer Research UK, Dr. Sergio Quezada, from the UCL, London believes that this is a “a huge breakthrough” and the researchers have “actually discovered molecular motifs that will inform the development of the next generation of therapies”.
Source: N Engl J Med, 2014 Nov 19. [Epub ahead of print]