- I saw this article about a possible new cancer vaccine. According to the
text, it may also work on lymphomas, which might include Waldenstrom's disease
and low grade lymphomas. --Matt--
Results Presented of First Multivalent Cancer Vaccine at AACR Annual Meeting
NEW ORLEANS, March 31 /PRNewswire/ -- Progenics Pharmaceuticals, Inc.
(Nasdaq: PGNX) today announced that initial results of randomized Phase I/II
clinical trials of its second cancer vaccine, MGV, were presented at the
American Association for Cancer Research Annual Meeting in New Orleans,
Louisiana. MGV is the first vaccine combining two defined cancer antigens to
be tested in humans and has potential in treating a wide range of cancers.
Additionally, the Company's collaborators presented new data showing that
vaccination with MGV can eradicate cancer micrometastases in a mouse tumor
The MGV vaccine is designed to stimulate a patient's immune system to control
or eradicate residual cancer cells after surgery, radiation or chemotherapy.
The vaccine is based on the GM2 and GD2 gangliosides, cancer antigens that are
present in many cancer types, including colorectal and gastric cancers, small
cell lung cancer, lymphoma, sarcoma, and neuroblastoma. MGV contains the GM2
and GD2 antigens separately coupled to the carrier protein keyhole limpet
hemocyanin (KLH) and mixed with QS-21 adjuvant (an immune system stimulant).
Vaccination of patients with MGV is designed to destroy cancer cells without
damaging healthy tissue by stimulating the formation of antibodies to GM2 and
The clinical study presented at the conference evaluated thirty patients with
high-risk melanoma and sarcoma immunized with MGV over a period of nine
months. Patients were randomly assigned to five groups receiving a fixed dose
of GM2-KLH and QS-21 adjuvant and one of a number of escalating doses of GD2-
KLH. The primary objectives of the trial are to evaluate the tolerability of
the vaccine, and to determine the optimal dose of GD2-KLH by measuring
circulating antibodies to GD2 as well as GM2. Optimal dosing with GM2-KLH was
previously determined during the development of Progenics' first cancer
vaccine, GMK. Initial findings from the twenty-four patients in the first
four cohorts indicate that twenty-three of twenty-four subjects produced
antibodies to GM2 and fifteen of twenty-four subjects developed antibodies to
GD2. A dose-response to GD2-KLH was observed, with ten of eleven patients
developing antibodies to GD2 in the groups receiving the higher doses.
Additionally, no vaccine-related toxicities were reported. The trial
continues to evaluate the final group of patients currently receiving the
highest dose of GD2-KLH.
A separate presentation described the results of a preclinical study with
Progenics' vaccine containing GD2-KLH and QS-21 adjuvant. The study used a
mouse model of liver metastases that is usually lethal within 40 days.
Administration of the vaccine to mice prevented outgrowth of micrometastases,
resulting in complete protection in the majority of animals as measured by
number of liver metastases or survival as end-points. Vaccine regimens
inducing the highest antibody concentrations provided the greatest protection,
and 100% protection was observed even when vaccination was initiated after
tumor challenge. This is the first demonstration that vaccination against a
specific ganglioside cancer antigen can eradicate micrometastases resulting in
protection from tumor challenge.
"These studies provide significant information supporting the mechanism of
action of our MGV cancer vaccine," said Dr. Paul J. Maddon, Progenics'
Chairman and Chief Executive Officer. "By using defined cancer antigens in
our vaccines, we can study the immunological response to the vaccine and then
correlate that response with patient outcome. We are very pleased that the
patients in the Phase I/II study developed measurable levels of antibodies to
both GM2 and GD2 without experiencing significant toxicity, and the animal
data are extremely promising. In most cancers, it is the metastases that are
most difficult to treat and usually lead to mortality. The animal studies
suggest that MGV may have significant impact on eradicating metastatic cells
even after they have generated new tumors. This vaccine has the potential to
reduce or eliminate the growth of metastases and may provide improved quality
of life and extended survival time to patients with a variety of cancers."
Progenics Pharmaceuticals, Inc. is a biotechnology company focusing on the
development and commercialization of products for the treatment and prevention
of cancer and viral diseases. The Company's lead product, GMK, is a cancer
vaccine in pivotal Phase III clinical trials for the treatment of malignant
melanoma. A second cancer vaccine, MGV, with broad application to a variety
of cancers, is in Phase I/II trials. Progenics has a collaboration with
Bristol-Myers Squibb Company in the area of cancer vaccines. Progenics' lead
HIV product, PRO 542, is in Phase I/II clinical trials, and a follow-on HIV
product, PRO 367, is expected to commence Phase I/II trials in 1998. Progenics
also has a collaboration with F. Hoffmann-La Roche Ltd in the area of HIV
therapeutics which target fusion co-receptors.
This news release contains forward-looking statements that involve risks and
uncertainties. The Company's actual results may differ materially from those
anticipated in these forward-looking statements. Factors that may cause such
differences include, but are not limited to, those discussed in the Company's
prospectus, dated November 19, 1997, as filed with the Securities and Exchange
Commission, including the uncertainties associated with product development,
the risk that clinical trials will not commence when planned, the risks and
uncertainties associated with dependence upon the actions of government
regulatory agencies and the risk that products that appeared promising in
early clinical trials do not demonstrate efficacy in larger-scale clinical
trials. In particular, there can be no assurance that the Company's cancer
programs will result in the commercialization of a product.
SOURCE Progenics Pharmaceuticals, Inc.
CO: Progenics Pharmaceuticals, Inc.
03/31/98 12:41 EST http://www.prnewswire.com
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