BioSante Pharmaceuticals, Inc. (NASDAQ: BPAX) today announced positive
results of a human clinical study that show that its GVAX Leukemia
vaccine may be able to reduce or eliminate the last remaining cancer
cells in some chronic myeloid leukemia (CML) patients taking the drug
Gleevec (imatinib mesylate). All patients enrolled in the trial used
Gleevec for at least one year and still had cancer cells present. The
study was conducted by researchers at the Johns Hopkins Kimmel Cancer
Center in Baltimore, Maryland, led by Hyam Levitsky, M.D., professor of
oncology, medicine and urology at the Cancer Center. The research was
funded by the National Institutes of Health.
“We are very excited by these GVAX Leukemia vaccine data”
In a study published in Clinical Cancer Research, Johns Hopkins Sidney
Kimmel Comprehensive Cancer Center investigators used a vaccine made
from CML cells irradiated to halt their cancerous potential and
genetically altered to produce an immune system stimulator called
GM-CSF. The treated cells also carry molecules, called antigens,
specific to CML cells, which prime the immune system to recognize and
kill circulating CML cells.
“We want to get rid of every last cancer cell in the body, and using
cancer vaccines may be a good way to mop up residual disease,” said Dr.
Levitsky. “More research to confirm and expand the results is needed,”
Levitsky said.
The GVAX Leukemia vaccine was given to 19 CML patients with measurable
cancer cells, despite taking Gleevec for at least one year (range 13-53
months). Each patient was given a series of four vaccines administered
in three-week intervals while remaining on a stable dose of Gleevec.
After a median of 72 months of follow-up, the number of remaining cancer
cells declined in 13 patients, eight of whom had increasing disease
burden before vaccination. Twelve patients reached their lowest levels
of residual cancer cells to date following vaccination. In seven
patients, CML became completely undetectable.
Patients receiving the GVAX Leukemia vaccine experienced relatively few
side effects that included injection site pain and swelling, occasional
muscle aches and mild fevers.
“We are very excited by these GVAX Leukemia vaccine data,” said Stephen
M. Simes, BioSante’s president & CEO. “Johns Hopkins Kimmel Cancer
Center work in leukemia using BioSante’s GVAX is one of many different
forms of cancer being investigated, including pancreatic cancer, breast
cancer and multiple myeloma. We look forward to working with Johns
Hopkins’s investigators to bring better cancer therapies to patients in
need. BioSante owns the commercial rights to all GVAX vaccines as a
result of our acquisition in 2009 of Cell Genesys.”
According to the investigators, most patients with CML will need to
remain on Gleevec therapy for the rest of their lives. More than 90
percent of them will achieve remission, but about 10 to 15 percent of
patients cannot tolerate the drug long term. Gleevec, one of the first
targeted cancer therapies with wide success in CML patients, destroys
most leukemic cells in the body, but in most patients, some cancerous
cells remain and are measurable with sensitive molecular tests. These
remaining cells are a source of relapse, according to the investigators,
especially if Gleevec therapy is stopped.
In 2010, approximately 5,050 new cases will be diagnosed with CML and
approximately 470 people will die. The average person's lifetime risk of
getting CML is about 1 in 645. The average age at diagnosis of CML is
around 66 years. Over half of cases are diagnosed in people 65 and
older. This type of leukemia mainly affects adults, and is rarely seen
in children.
%2c_analyze_by_microscope-Jarun_Ontakrai_8864dd9cfb3b4dff9a913aede7a7c915-80x70.jpg)
St. Jude scientists identify new therapeutic target for high-risk pediatric leukemia