Last week, the Food and Drug Administration approved Yervoy, or ipilumimab, a new treatment for use in patients with advanced malignant melanoma. The decision is a landmark in view of the relative lack of effective, available treatments for this skin cancer once it has spread through the body.

Melanoma, one of the most resistant cancer killers when it is advanced, kills around 9,000 Americans each year. While the skin cancer is often easily cured with surgery, especially when diagnosed early, metastases occasionally spread to the lymph nodes, lungs, liver or even the brain. The more advanced the tumor, the harder it is to treat and cure. Once the tumor has spread, the standard approaches to treatment of metastases, such as chemotherapy with drugs like dacarbazine, temozolomide and cisplatin, will occasionally achieve temporary tumor shrinkage, or remission, but cure is extremely uncommon.

Over the years, many studies have shown that immunotherapy, a technique in which the body’s immunity is stimulated, can help to shrink metastatic melanoma. For several decades, interferon, a protein complex that stimulates immune function, has been used after surgery to try to reduce the chance of melanoma recurrence. Interferon has also been tried to shrink metastases, but benefits have rarely lasted more than a few months. A newer generation of immune stimulation using interleukin-2, which activates immune system cells called T cells that can attack tumor cells, was popularized by the National Cancer Institute and sometimes produced more sustained responses, but the drug was very toxic.

Now comes Yervoy, a novel approach to immune stimulation that has been developed using an antibody that inhibits a protein called cytotoxic T-lymphocyte antigen 4, or CTLA-4. The antibody enhances immune function, allowing the body to defend itself against melanoma cells more effectively and leading to reduction of melanoma.

In the latest trial, of patients who had failed prior melanoma therapy, those who received Yervoy had a median survival — the time point at which half of the patients have succumbed to their disease — of 10 months, an increase of only four months over those who didn’t get the drug. But several patients receiving this agent had prolonged tumor responses lasting many months, a situation infrequently seen in clinical practice. Further trials will be needed to show the best way of using this agent, but the F.D.A. believed that there was sufficient promise and activity to warrant approval.

Another promising area of melanoma research is in the area of oncogenes, a type of gene that appears to give rise to cancer. Some cases of melanoma have been linked to a mutation in an oncogene called B-RAF. Several pharmaceutical companies have developed drugs that inhibit B-RAF oncogene function and can cause substantial shrinkage of metastatic melanoma that can be sustained for lengthy periods. One curious side effect, which has not been fully explained, is the development in patients receiving these drugs of new skin cancers of the non-melanoma type, so-called squamous cell cancers, which must be surgically removed.

These findings represent the first major progress in treatment of advanced melanoma in several decades. Sustained responses have been seen in patients with widespread metastases, and some patients have experienced prolonged survival, with excellent quality of life, as a result of these interventions. This is not yet a home run, but certainly represent an important step in developing a set of useful weapons for one of the most aggressive and dangerous cancers.

Do you have questions about the new melanoma treatment and other promising treatments for advanced disease? Post your questions for Dr. Raghavan in the Comments section, below. He will begin responding to questions beginning later this week.

For more information on melanoma, see The Times Health Guide: Melanoma and our earlier Q&A’s on the Consults blog, “Expert Answers About Melanoma” and “The Many Forms of Melanoma.”

Dr. Derek Raghavan is president of the Levine Cancer Institute, Carolinas HealthCare System in Charlotte, N.C.