Melanoma vaccine demonstrates
promising results in large multi-site study
CHICAGO, May 31 Results from the largest multi-site study to date
evaluating a peptide-derived therapeutic vaccine for melanoma, have demonstrated
a correlation between tumor growth (progression free survival) and immune
response for patients with advanced disease who received the vaccination. The
findings provide promising evidence that researchers can activate a patient's
own immune system to fight advanced melanoma, according to investigators from
the Eastern Cooperative Oncology Group (ECOG), who are presenting their findings
at the 38th annual meeting of the American Society of Clinical Oncology (ASCO)
in Chicago.
"This is the first time we have evaluated peptide-derived melanoma vaccine
results from a multicenter cooperative group trial," said John Kirkwood, M.D.,
principal investigator of the study, and professor of medicine at the University
of Pittsburgh and director of the Melanoma Center at the University of
Pittsburgh Cancer Institute (UPCI). "While these results are preliminary, we
have found evidence that the vaccine stimulates an immune response and that
there is a resultant benefit for patients who receive the vaccine."
The phase II study evaluated a multiepitope CD8 T-cell vaccine comprised of
three peptides derived from tumor-associated antigens of melanoma. The vaccine
was evaluated alone, in combination with granulocyte macrophage-colony
stimulating factor (GM-CSF), in combination with interferon and in combination
with both GM-CSF and interferon.
The study included 120 patients with metastatic melanoma. Immune response
data was evaluated for the first 60 patients. Final analysis of the data will
take several more months to be evaluated.
Patients received the vaccine by injection once every two weeks for 12 weeks.
Immune response was induced in 32 percent of the patients and response to
vaccination correlated significantly with non-progression of disease and longer
survival.
The study found that disease progressed in only 37 percent of those patients
who had an immune response to the vaccine, compared to disease progression in 60
percent of those patients who did not have any evidence of immune response to
the vaccination. Disease remained stable in 56 percent of the patients who had
an immune response to the vaccine, compared to 28 percent who did not have
evidence of an immune response. There were objective responses in several
patients treated with the triple peptide vaccine, including one complete and two
partial responses, but these did not appear to correlate with ELISPOT assays for
immune response.
According to Dr. Kirkwood, the vaccine was fairly well tolerated by most
patients with typical side effects that included vaccine site discomfort and
expected toxicity to interferon and GM-CSF.
Malignant melanoma is one of the deadliest forms of skin cancer. An estimated
54,200 new cases of melanoma are expected in 2003 and 7,600 deaths are expected
to occur.
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The study includes more than 30 institutions across the country and is funded
by a grant from the National Institutes of Health and awards to ECOG from the
Schering Plough and Immunex Corporations.
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