'Vaccine' spurs immune attack on melanoma.

'Vaccine' spurs immune attack on melanoma

Researchers this week reported some "dramatic" improvements among patients with widespread melanoma who received vaccination-like injections to spur the immune system to attack this particularly lethal form of skin cancer.

Malcolm S. Mitchell and his colleagues at the University of Southern California at Los Angeles formulated the experimental treatment using cultured, fragmented human melanoma cells. While it cannot prevent cancer, they say the vaccine seems to prod the immune system's killer T-cells to destroy existing tumors. Preliminary tests in 12 people had suggested the vaccine slowed melanoma progression (SN: 10/24/87, p.267).

Now Mitchell reports some striking results among a group of 79 people whose melanoma had spread beyond the initial skin site to distant body parts, although the primary skin tumors had been surgically removed. Each participant received weekly injections for four weeks, followed by another injection in the sixth week and monthly booster shots for those showing a treatment response.

The researchers found that 18 of the 79 patients (23 percent) had tumors that shrank to half their original size or completely vanished for at least a month. Five of the 18 survived two years or more, with one patient still living nearly four years after treatment.

Mitchell, who described the new results at an American Cancer Society science writers' seminar in Daytona Beach, Fla., says this is a significant survival advantage; most people with widely disseminated melanoma who receive conventional treatment die within a year after doctors detect tumor spread. Only 30 to 40 percent of melanoma patients benefit from standard chemotherapy, and among these the reprieve is often brief, adds John Laszlo of the American Cancer Society. In all, melanoma kills about 6,300 people in the United States each year.

Mitchell says the experimental vaccine caused swelling at the injection site but no other adverse reactions. In contrast, he notes, standard chemotherapy often causes severe side effects.

One unexpected result of Mitchell's trial: An 83-year-old man with melanoma in the skin lining the back of the eye showed "remarkable" tumor shrinkage and vision improvement. Such tumors usually grow inexorably and resist chemotherapy, leaving surgical removal of the eye as the only remedy, Mitchell says. He and his colleagues now plan to give the vaccine to 30 people with melanoma of the eye to see whether it can halt tumor growth and preserve eyesight.