Progenics and Cytogen Select Therapeutic Prostate Cancer
Vaccine for Human Testing
LAKE TAHOE, Nev., Sept. 25 -- Progenics Pharmaceuticals, Inc.
(Nasdaq: PGNX) and Cytogen Corporation (Nasdaq: CYTO) announced a new
vaccine candidate that the companies will develop for the treatment of prostate
cancer. The vaccine is directed against prostate specific membrane antigen
(PSMA), a unique protein found on the surface of prostate cancer cells, and is
designed to stimulate a patient's immune system to recognize and destroy the
cancer cells. The preclinical findings were reported at the 7th Annual CaP CURE
Scientific Retreat, a gathering of more than 350 of the world's leading prostate
cancer researchers. This in vivo immunotherapy program is being conducted
under a joint venture between Progenics and Cytogen.
The new vaccine is a genetically-engineered, or recombinant, form of the PSMA
protein that comprises a portion of the protein that resides on the surface of
prostate cancer cells and is fully accessible to the immune system. It is believed
that the recombinant PSMA protein can be produced at large scale in a form
suitable for human clinical testing. A highly purified form of the recombinant
PSMA protein will be combined with a potent immunological stimulant, or
adjuvant, to form the final vaccine product. The findings were described in an oral
presentation by William C. Olson, Ph.D., Senior Director of Research &
Development at Progenics.
"Based on our recent scientific advances, we have successfully produced a
vaccine candidate that faithfully mimics the PSMA structure expressed on
prostate cancer cells," said Dr. Olson. "We believe that such a vaccine has the
potential to induce an immune response in patients that is capable of eliminating
prostate cancer cells. We expect to begin Phase I clinical studies next year."
In addition to the recombinant PSMA protein vaccine approach described above,
Progenics and Cytogen are also pursuing in parallel a vaccine strategy that
utilizes novel and proprietary viral vectors which are designed to deliver the PSMA
gene to the immune system. In animal studies, the vaccines have generated
potent and specific immune responses to cell-surface PSMA. In addition to their
two vaccine programs directed at stimulating a patient's immune system against
his own cancer, Progenics and Cytogen have a therapeutic antibody program that
includes "naked", radiolabelled, and toxin-conjugated monoclonal antibodies
directed specifically at PSMA. The companies anticipate that a viral vaccine
candidate as well as antibody-based therapies could also be tested in the clinic
next year.
The PSMA gene was first discovered by scientists at Memorial Sloan-Kettering
Cancer Center in New York City. PSMA is a cell-surface protein abundantly
expressed on prostate cancer cells and therefore is an attractive target for
vaccine and antibody-based cancer immunotherapies. Further work demonstrated
that PSMA is also present at high levels on newly formed blood vessels
(neovasculature) needed for the growth and survival of many types of solid
tumors. These observations suggest that if PSMA-targeted therapies exhibit
anti-angiogenesis effects, they may be valuable in treating a broad range of
cancers.
Progenics Pharmaceuticals, Inc. is a biopharmaceutical company focusing on
the development and commercialization of products for the treatment and
prevention of cancer, viral, and other life-threatening diseases. The Company's
most advanced 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 entering Phase II trials. GMK and
MGV are being developed in collaboration with Bristol-Myers Squibb Company.
The Company's lead HIV product, PRO 542, has completed two Phase I/II clinical
trials, and two follow-on HIV products, PRO 367 and PRO 140, are preparing to
commence Phase I/II trials. Progenics also has collaborations with F.
Hoffmann-La Roche Ltd in the area of HIV co-receptors, and with American Home
Products and Pharmacopeia, Inc. focusing on HIV attachment and fusion. The
Company is also developing a novel small-molecule antioxidant, DHA, to treat
stroke and other disorders.
Cytogen Corporation is a biopharmaceutical company in Princeton, NJ whose
mission is setting new standards in cancer care. Its two principal lines of
business, proteomics and oncology, are built upon its expertise in antibodies and
molecular recognition and are directed to development of novel products for the
diagnosis, imaging, staging and treatment of cancer and a proteomics-driven drug
discovery platform. The Company's cancer management franchise currently
comprises four FDA-approved products: ProstaScint(R), used to image the extent
and spread of prostate cancer; BrachySeed(TM) implants for prostate cancer
therapy; OncoScint CR/OV(R), a diagnostic imaging agent for colorectal and
ovarian cancer; and Quadramet(R), for the relief of cancer-related bone pain. The
Company has established a pipeline of product candidates based on its
proprietary antibody and prostate specific membrane antigen, or PSMA,
technologies, and holds worldwide exclusive license to PSMA. The Company
also has U.S. marketing rights to the late-stage product candidate Combidex(R),
a magnetic resonance imaging agent being developed by Advanced Magnetics for
the detection of lymph node metastases. The Company's wholly owned
subsidiary, AxCell Biosciences Corporation, is developing a proprietary protein
pathway database as a drug discovery and development tool for the
pharmaceutical and biotechnology industries. AxCell Biosciences has agreed to
enter into a collaboration with the Institute for Systems Biology to elucidate
aberrations in protein signaling pathways underlying the metastatic spread of
prostate cancer.
This press release contains forward-looking statements. Any statements
contained herein that are not statements of historical fact may be forward-looking
statements. The words 'anticipates,' 'plans,' 'expects' and similar expressions
identify forward-looking statements. Such forward-looking statements involve risks
and uncertainties which may cause the companies' actual results, performance
or achievements to be materially different from those expressed or implied by
forward-looking statements. Such factors include, among others, the
uncertainties associated with product development, the risk that clinical trials will
not commence when or proceed as planned, the risks and uncertainties
associated with dependence upon the actions of the companies' corporate,
academic and other collaborators and of government regulatory agencies, the risk
that products that appeared promising in early clinical trials do not demonstrate
efficacy in larger-scale clinical trials, the uncertainty of future profitability and
other factors set forth more fully in the companies' Annual Reports on Form 10-K
for the fiscal year ended December 31, 1999 and other periodic filings with the
Securities and Exchange Commission. In particular, there can be no assurance
that the companies' PSMA programs will result in a commercial product. The
companies do not have a policy of updating or revising forward-looking
statements, and thus it should not be assumed that the companies' silence over
time means that actual events are bearing out as expressed or implied in such
forward-looking statements.
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