Immune-boosting Vaccines Show Guarantee In Two Cancer Types
An experimental treatment, from Accentia Biopharmaceuticals Inc. of Tampa, Florida, seemed to delay the return of lymphoma, a cancer of immune cells, by more than a year among patients who achieved remission after chemotherapy. In a second study, twice as many patients with severe, late-stage melanoma, a skin cancer, saw their tumors shrink after treatment with a vaccine developed at the National Cancer Institute.
The findings were released today at the American Society of Clinical Oncology meeting in Orlando, Florida. After three decades of failed efforts to develop cancer vaccines, success is starting to emerge, said Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, based in Atlanta.
“After 30-plus years of trying to find something that works with cancer vaccines, here we find the first glimmer of hope,” Lichtenfeld said. The two studies, along with an April 29 report that Dendreon Inc.s treatment, called Provenge, extended lives of men with prostate cancer, “suggest that perhaps were finally getting through the barriers to effective vaccine therapy in cancer treatment,” he said.
Accentias lymphoma vaccine is an individualized treatment made from a protein on the surface of cancer cells taken from people with a form of non-Hodgkins lymphoma.
Infection Fighters
When the protein is introduced back into patients through the vaccine, it ramps up the infection-fighting cells in their immune system so they eliminate cancer cells left after chemotherapy, said Stephen Schuster, an associate professor of medicine at the University of Pennsylvania in Philadelphia and the lead author of the lymphoma study.
Biovest International, the Accentia unit that plans to market the vaccine under the name Biovaxid, also developed a system for quickly growing the cells used in the product in bioreactors, small, sterile units the size of a microwave oven, said Douglas Calder, a Biovest spokesman, in a May 29 phone interview.
Biovest plans to submit the results of the study to the U.S. Food and Drug Administration and to European regulators in 60 to 90 days and will seek conditional approval to market the vaccine, Calder said. The company expects it will need to provide additional confirmatory data in a study that could be conducted after the vaccine is cleared for marketing, he said.
The patients treated with the vaccine had follicular lymphoma, a form of non-Hodgkins lymphoma, a cancer of the immune system that affects about 65,000 people in the U.S., according to Schuster.
Cancer Return Slowed
Seventy-six patients were treated with the lymphoma vaccine and 41 received a placebo. The two groups were followed for an average of almost five years. It took 44 months for cancer to return in the patients treated with the vaccine, compared with 31 months in patients who didnt get the experimental treatment.
The melanoma vaccine, which is easily made and has no commercial sponsor, is created from a synthetic peptide that matches the proteins found in melanoma cells, said Douglas Schwartzentruber, medical director of the Center for Cancer Care in Goshen, Indiana, the lead author of the study.
Serious Skin Cancer
Melanoma, the most serious type of skin cancer, is diagnosed in 53,000 people in the U.S. each year, according to the American Cancer Society. One hundred eighty-five patients whose tumors had spread to other organs were treated with the vaccine, known as gp100.
The vaccine prods infection-fighting cells known as lymphocytes to seek out and kill cancer cells. The vaccine is used along with a drug called interleukin-2, marketed by Swiss drugmaker Novartis AG as Proleukin, which multiplies the number of lymphocytes.
“You supercharge the lymphocytes to recognize and destroy melanoma cancer cells,” said Schwartzentruber, in a May 29 phone interview. “Now you have an army of these lymphocytes that can go and attack the melanoma cancer cell.”
Among the patients treated with the vaccine and interleukin-2, 22 percent had their tumors shrink. In the second group, treated with interleukin-2 alone, the tumors shrank in 9.7 percent of the patients. The vaccine also modestly extended the lives of these seriously ill patients, Schwartzentruber said. After following the patients for an average of 28 months, 30 percent of the patients treated with the vaccine were still alive, compared with 23 percent of those in a control group.
Raising Hopes