First new drug for advanced melanoma in a decade

31 March 2011

Ipilimumab has become the first new drug to be FDA approved for the treatment of previously treated metastatic melanoma for more than a decade.

Ipilimumab, developed by Bristol-Myers Squibb and Medarex, is a monoclonal antibody that consists of millions of copies of a human antibody that binds to CTLA-4 protein molecule on T cells — white blood cells that patrol the body for signs of illness. CTLA-4 serves as a control switch for the immune system’s response to disease. With no antibody attached, CTLA-4 suppresses the immune response. Ipilimumab reverses that condition, unleashing the immune attack on abnormal cells, including cancer cells.

“Ipilimumab is the first in a new class of drugs that has been shown to offer a survival benefit for metastatic melanoma, which is often a fatal disease, and hopefully, this will lead to the development of related treatments for other cancers,” said F Stephen Hodi, MD, director of the melanoma treatment center at Dana-Farber Cancer Institute and a lead investigator of the national clinical study of ipilimumab.

“While ipilimumab, on average, extended the lives of patients by four months, there is also a group of patients who experienced a greater benefit and lived many months while being treated with this drug,” said Hodi. “This is a big step in the right direction because it demonstrates that this class of drugs can benefit cancer patients.”

In the clinical trial of the drug, about 60 percent of the patients treated with ipilimumab experienced adverse side effects to the therapy, as did 32 percent of the patients treated with gp100 vaccine (one of the treatment regimens in the trial). The complications were generally immune system-related and most often affected the skin and gastrointestinal tract. The most common included diarrhea, nausea, constipation, fatigue, decreased appetite, and rash. While the adverse effects could be severe and long-lasting, most of them were reversible with appropriate treatment.