There are few successful treatments for melanoma, a deadly form of skin cancer, when in its advanced stages. Every year more than 8,000 Americans die from melanoma, according to the American Cancer Society. This year, more than 68,000 will be diagnosed with the disease.

Standard treatments, including chemotherapy and the drug interleukin-2, have had limited success.  Now a new therapy has emerged that improves patient survival. It’s called ipilimumab, and it’s a monoclonal antibody treatment. Findings from a study of the drug’s effectiveness were recently released at the American Society of Clinical Oncology meeting earlier this month in Chicago.

Caroline Bevona, MD, head of the Melanoma Clinic at Lahey Clinic, provides insight into this new therapy.

What is a monoclonal antibody treatment, and how does it work?

Monoclonal antibodies, like ipilimumab, are made from the cells of animals or humans, and are grown in the lab. The body’s immune system work to fight infection, and it can also destroy cancer cells. One of the cell types involved in this process is called the ‘T cell.’ The new drug works by blocking a molecule called CTLA-4, which is found on the surface of T cells. They free T cells, so that they attack cancer cells.

How effective is ipilimumab?

I would consider it a major breakthrough for treating metastatic melanoma. Up until now, the therapies have not been very effective. Although this drug is effective in only a subset of patients, those who respond to it have their lives extended by years. In a multicenter phase III trial, the one and  two-year survival rates on the drug were 45 percent and 23 percent, double the survival of those not on the drug. Median survival was 10 months.

Are there side effects?

Some of the side effects include tiredness, diarrhea, and inflammation of the colon, nausea, hepatitis, skin rashes and damage to the endocrine system. Most of the time, these are treatable and reversible, but there have also been some deaths associated with ipilimumab’s use.

When might it be available?

Ipilimumab is currently in phase III trials, which is the final phase of drug testing before it can be approved by the FDA for general use. Currently if someone qualifies, they can receive this medication through a clinical trial. It is also available “on a compassionate basis” at many medical centers nationwide.

Are there long-term considerations for this therapy?

The success of this therapy gives hope that other treatments that work in a similar way will be developed, which may be effective for an even greater number of people with metastatic melanoma.