New Cancer Vaccines Show Promising Results for Melanoma and Lymphoma

After more than three decades of failed attempts at developing cancer vaccines, researchers say they have their first “glimmer of hope.” In findings announced Sunday at the American Society of Clinical Oncology meeting in Orlando, Florida, a vaccine helped shrink the tumors of patients with severe, late-stage melanoma and delayed worsening of the disease. In a second study, an experimental treatment appeared to delay the return of lymphoma by more than a year among patients in remission after chemotherapy.

Vaccines work by stimulating the body’s immune system to react as if there were a real infection—recognizing it, destroying it and “remembering” it, so that it can fight it quickly should it enter the body later. Researchers theorize that once the body can distinguish cancer cells, it can kill them before the cancer has an opportunity to recur.

The melanoma vaccine, developed by the National Cancer Institute (NCI) and called gp 100:209-217, or gp 100, is created from a synthetic peptide that matches the proteins found in melanoma cells, explained Dr. Douglas Schwartzentruber, medical director of the Center for Cancer Care in Goshen, Indiana, and the lead author of the study. The vaccine had little effect in early trials, but the researchers found that by adding a drug called interleukin-2, the infection-fighting cells known as lymphocytes were multiplied, leaving “an army of these lymphocytes that can go and attack the melanoma cancer cell.”

The vaccine was tested in 185 patients whose tumors had spread to other organs. Half were treated with interleukin-2 alone and half were given the vaccine as well. Among those treated with the vaccine and interleukin-2, 22 percent had their tumors shrink, compared to 9.7 percent of those given interleukin-2 alone. The vaccine also modestly extended the lives of the patients, adding about a month and a half to the period before the cancer began to spread again. “These results will give patients and the oncology community hope that we are making some progress against this disease,” Schwartzentruber said, and added that this vaccine combination is only a first step. He says other combinations of drugs that stimulate the immune system and target cancer cells need to be developed and tested in order to improve the results.

Melanoma is the most serious type of skin cancer. When it spreads from its original site, melanoma is difficult to treat and resistant to most therapies. The five-year survival rates for localized and metastatic melanoma are 65 percent and 16 percent respectively. According to the American Cancer Society, approximately 69,000 people in the U.S. will be diagnosed melanoma in 2009, and about 8,600 will die of the disease.

The lymphoma vaccine, from Accentia Biopharmaceuticals Inc. of Tampa, Florida, is an individualized treatment also made from a protein on the surface of cancer cells. When the protein is introduced back into the person through the vaccine, it increases the infection-fighting cells in their body’s immune system so they eliminate any cancer cells remaining after chemotherapy, explained Stephen Schuster, an associate professor of medicine at the University of Pennsylvania in Philadelphia and the lead author of the lymphoma study.

Seventy-six patients who had follicular lymphoma, a form of non-Hodgkin’s lymphoma that affects about 65,000 people in the U.S., were treated with the vaccine, while 41 received a placebo. The two groups were followed for an average of nearly five years. In patients treated with the vaccine, it took 44 months for the cancer to return, compared with 31 months in those receiving the placebo. “We’re on the verge of having therapeutic vaccination for cancer become a reality in the next five years,” Schuster said in a phone interview with Bloomberg.  

According to company spokesman Douglas Calder, Biovest International, a unit of Accentia, plans to submit the study results to the U.S. Food and Drug Administration (FDA) and to European regulators in 60 to 90 days and will seek conditional approval to market the vaccine under the name Biovaxid. He says the company has also developed a system for quickly growing the cells used in the vaccine in bioreactors—small, sterile units the size of a microwave oven.

Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, based in Atlanta, says that while the result of the two studies raise hopes, more work needs to be done to demonstrate that the therapies are truly beneficial. “Our hopes have been dashed many times before so we have to be cautious in our optimism going forward,” he said.