September 25, 1998

Melanoma vaccine spurs body’s own immune response

Melanoma vaccine spurs body's own immune response

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Dr. Mark Kelley is testing a new vaccine to treat melanoma. (Photo by Donna Jones Bailey)

Vanderbilt's is among a group of leading cancer centers around the world testing a new vaccine designed to enlist the body's immune system as an ally in the fight against the deadly skin cancer melanoma.

The vaccine, produced and developed at the John Wayne Cancer Institute, is made from three types of cultured melanoma cells that have been killed with radiation so they cannot grow. These cells have a wide range of protein markers called antigens, some of which are likely also to be found on the vaccine recipient's melanoma cells.

Like a shirt waved under a bloodhound's nose, these antigens are hoped to send the immune cells on a hunt for melanoma cells lurking in the patient's body.

"The goal is to stimulate a strong immune system response to the antigens on the melanoma cells in the vaccine," said Dr. Mark C. Kelley, assistant professor of Surgery and clinical director of the Vanderbilt Breast Center.

"Then those immune system cells would seek out and attack any residual melanoma cells, which would delay or prevent recurrence of the disease."

Melanoma is the most deadly form of skin cancer. The disease is expected to strike about 40,000 Americans this year, and the number of cases has been steadily on the rise since the early 1970s.

Funded by the National Cancer Institute, the Phase III trial is the final stage of testing to determine the vaccine's effectiveness before it could become widely available.

The Vanderbilt Cancer Center is one of 32 sites around the world testing the vaccine in patients with melanoma that has spread to other parts of the body (Stage IV) and in patients whose disease has spread to the lymph nodes (Stage III).

In both groups of patients, the vaccine is given after surgical removal of the melanoma. The vaccine is given over a period of five years: every two weeks for two months, once a month for 10 months, once every two months during the second year, every three months during the third year, and every six months during the fourth and fifth year. The first two injections are accompanied by an adjuvant to "prime" the immune system for a stronger response.

Patients in the Stage IV group are randomly assigned to receive either the vaccine or a placebo. Stage III patients are randomly assigned to receive the vaccine or a year-long regimen of interferon, an immune system-stimulator. Interferon is given by high-dose, intravenous infusion five days a week for one month, then three times a week through subcutaneous injection thereafter.

Interferon is the only documented effective treatment for Stage III melanoma, but it is also very toxic ‹ so much so that at least one-fourth of patients who start it never complete the regimen. By contrast, the vaccine seems very well-tolerated, only causing small sores at the injection site and mild flu-like symptoms.

"Interferon is a very difficult drug to tolerate, and the improvement in survival, while statistically significant, is modest at best," Kelley said. "We hope that this vaccine will lengthen the time of survival and give patients an improved quality of life."

The study represents a new concept in cancer therapy that has never been demonstrated as effective in a widespread way before, Kelley said. It also represents an increased effort in melanoma treatment at the Vanderbilt Cancer Center. The VCC's multi-disciplinary melanoma team, including physicians, nurses and others from surgery, medical oncology, radiation oncology and dermatology, is working together to bring the latest in treatment approaches to more patients and to help develop improvements in therapy.