Vaccine Stimulates Immune System to Fight
London, UK, 15 November 2006: Onyvax Ltd, the biotechnology
company developing novel cancer therapies, today announces that
the results of a clinical trial of Onyvax-105 in colorectal cancer
patients have been published in the November 15 issue of Clinical
Cancer Research. The American Association for Cancer Research,
publisher of Clinical Cancer Research, has issued a press release
which can be accessed at:
105AD7, the antibody that was the subject of this clinical trial,
was invented by Professor Lindy Durrant at Nottingham University.
In 1999 Onyvax took an exclusive license to the technology.
The target, CD55, is strongly over-expressed in most cancer
types and is prevalent in prostate cancer, Onyvax's principal
area of interest. It is thought to be a key molecule in the development
of cancer with many mechanisms of action that support tumour
growth. Studies to date suggest the most important benefit conferred
on the tumour by CD55 is as a defensive shield, protecting the
tumour from immune attack.
Onyvax believes that by vaccinating the patient with 105AD7
this defensive shield is removed, allowing the immune system
to be more effective in controlling cancer growth. The company
is planning clinical trials in prostate cancer in combination
with Cell Vaccines to investigate synergy between the technologies.
For further information, please contact:
Dr Anthony Walker / Robert Johnson
+44 (0)208 682 9494
+44 (0)20 7831 3113
Notes to editors
Key results of the trial:
In a clinical trial
of 67 patients, researchers at the University of Nottingham
observed that when
Onyvax-105 was administered
before and after surgery to remove cancerous tumors, it helped
stimulated immune cell production in up to 70 percent of patients.
“This is the first vaccine shown to stimulate TNF-alpha – an
immune-system protein that is very effective at killing cancer
cells,” said Lindy Durrant, senior author of the study
and professor of cancer immunotherapy at the university.
The vaccine works by stimulating the patients' immune response
to generate infection-fighting white blood cells called T cells,
which in turn produce immune system proteins called cytokines
that destroy cancer cells. The antibody contained in the vaccine,
called 105AD7, was cloned from a patient who survived seven years
with liver metastases from colorectal cancer, Durrant explained.
“This is very unusual as most patients die within one
year of getting liver metastases,” she said. “I thought
if this antibody had helped this patient, if we could clone it,
it might help others.”
105AD7 is structurally similar to CD55, a protein that attaches
to sugar molecules and is overexpressed in colorectal cancer
cells, protecting them from attack by the body’s immune
system. While low levels of CD55 occur in all cells exposed to
the immune system, increased expression of the protein has been
observed in multiple types of tumors, including up to 80 percent
of colorectal cancers.
During the trial -- the largest to date looking at 105AD7 plus
surgery -- 67 patients with colorectal cancer who were scheduled
for surgery to remove their primary tumor were randomly assigned
to receive either 100 micrograms of 105AD7 with a powder to help
absorb the vaccine, 105AD7 along with BCG (a bacteria used to
stimulate the immune system in cancer patients) during the first
immunization and the powder in subsequent vaccinations, or no
The patients, who had varying degrees of disease, averaged age
66. Twenty-eight patients had colon cancer while in 39 patients
the primary tumor was located in the rectum.
Patients were immunized before surgery on the day they were
recruited for the study, and again two weeks later if surgery
had not yet been performed. The vaccines were continued three,
six and 12 weeks after surgery, and then at three monthly intervals
up to a maximum of 24 months after surgery. Blood samples were
collected from the patients during recruitment, at surgery, and
at the time of the three-, six- and 12-week post-operative immunizations.
Additional blood samples were acquired one month after each subsequent
Laboratory tests of the blood samples indicated that a T-cell
response against the vaccine was recorded in the majority of
patients. The responses tended to have two peaks: one following
the start of the immunization schedule and another several months
later, after additional immunizations. About 70 percent of patients
produced both TNF-alpha and GM-CSF – a protein that stimulates
white blood cell production – in response to both the vaccine
and to CD55.
“The immune responses to both the vaccine and CD55 were
measurable, adding support to the use of CD55 as a target in
cancer treatment,” Durrant said.
Nineteen of the patients died during the follow-up period. Durrant
and colleagues noted that the trial was not designed to study
the effect of the vaccines on survival.
The research was supported by The Research Foundation Stiftelsen
Onkologiska Klinikens i Uppsala Forskningsfond.
Onyvax is committed to the commercialization of new therapies
that significantly prolong survival while maintaining a high
quality of life for cancer patients. The Company is based in
London and has collaborations with leading institutions in Europe
and the US. Further information on Onyvax can be found at www.onyvax.com