Melanoma Vaccine Shows Promise in Trial06/01/11
WEDNESDAY, June 1 (HealthDay News) -- For patients with advanced
melanoma, the most dangerous type of skin cancer, a vaccine
combined with an immune-boosting drug is showing promise in a large
Therapeutic cancer vaccines, unlike typical vaccines that
prevent infections, are meant to jump-start the immune system to
help it battle existing tumors.
In this Phase 3 clinical trial, conducted at 21 care centers,
researchers randomly assigned 185 patients with metastatic
melanoma, meaning the cancer had spread, to either the vaccine
followed by interleukin-2, a drug that activates the immune system,
or interleukin-2 alone.
Those given the vaccine-drug combo showed more improvement than
those given the drug alone, according to the study, which was
published in the June 2 issue of the
New England Journal of Medicine.
About 16 percent of those given the vaccine/interleukin-2
combination saw their tumors shrink by 50 percent or more, compared
to 6 percent given interleukin-2 alone.
Those in the vaccine/drug group also had slightly longer
"progression-free" survival -- 2.2 months compared to 1.6 months --
meaning they had more time in which the tumor didn't grow.
Patients given the combo also lived an average of nearly 7
months longer than those only give interleukin-2 -- nearly 18
months compared to about 11 months. While a "strong trend," those
results were not statistically significant, said lead study author
Dr. Douglas Schwartzentruber, medical director of the Goshen Center
for Cancer Care at Indiana University Health.
"This is the first time that a vaccine has shown benefit in the treatment of patients with metastatic melanoma, and it's an early example of success with a cancer vaccine," Schwartzentruber said.
He and the other researchers reported that although the
treatment-related toxic effects were similar in both groups, the
vaccine "added some toxic effects" in the combination therapy
group, including transient heart problems such as an abnormally
rapid heart beat (tachycardia) and arrhythmias (15 percent vs. 2
In addition, the researchers reported one treatment-related
death in the interleukin-2-only group and two such deaths in the
combination therapy group.
Therapeutic vaccines are being studied for several types of
cancers, with varying degrees of success, said William Chambers,
director of clinical cancer research and immunology for the
American Cancer Society.
In the melanoma trial, "they had a response. It wasn't a huge
response, but clearly there was a fairly significant number that
had a response," Chambers said. "And with this disease, there has
not been a lot of success in treating these patients. The prognosis
has been poor. They learned some significant lessons in this
In order for this vaccine to work, patients had to have a
particular tissue type, called HLA-A2, which is present in about
half of whites.
Last year, the U.S. Food and Drug Administration approved a
vaccine to treat prostate cancer. Researchers at University of
California, Los Angeles are also working on a vaccine to treat
glioblastoma, the most aggressive type of malignant brain
The melanoma vaccine is based on a peptide, or a small portion
of a protein, that's present on the surface of the melanoma cancer
cells. Known as the gp100 peptide vaccine, the injection primes the
immune system to recognize the protein, so that it then seeks out
cells that produce the protein and destroys them.
The immune-boosting drug, interleukin-2, enhances the vaccine's
effectiveness by stimulating the production of lymphocytes, a type
of white blood cell that circulates throughout the body. More
circulating lymphocytes means there are more cells available to do
the job the vaccine has "educated" them to do, Schwartzentruber
The five-year survival rate for melanoma patients is less than
10 percent, experts said. Interleukin-2 is already FDA-approved to
treat metastatic melanoma and kidney cancer.
The researchers said their next step is to improve the vaccine's
efficacy. They hope by combining the vaccine with other agents
(called adjuvants) or immune-boosting drugs, they might get a
"We have now a strong proof of principal that with an immunological treatment we can see benefit, but at this point the benefits are small," Schwartzentruber said. "What we've decided to do is to try to develop a more potent vaccine before we do another trial."
The vaccine, if eventually approved by the FDA, would be
relatively inexpensive because it is based on a protein that's
present in most melanoma cancers, whereas other vaccines have had
to be created for each individual patient, the researchers
The vaccine was developed at the U.S. National Cancer Institute,
which also funded the study.
American Academy of Family Physicians has more on
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