The therapies are directed against Prostate Specific Membrane Antigen (PSMA), a molecular cancer marker that is abundantly expressed on the surface of prostate cancer cells.
The developments, presented today at the 91st Annual Meeting of the American Association for Cancer Research (AACR), are the result of work being conducted under a joint venture between Progenics and Cytogen to develop prostate cancer immunotherapies based on PSMA.
Novel approaches for the creation and preclinical testing of therapeutic antibodies and vaccines to PSMA were reported by Gerald P. Donovan, Ph.D., Progenics’ Senior Staff Scientist, and Robert J. Israel, M.D., Progenics’ Vice President of Medical Affairs.
The therapeutic vaccine program includes recombinant PSMA protein immunogens as well as novel and proprietary viral vectors which deliver the PSMA gene to the immune system.
In animal studies, the vaccines have generated potent and specific immune responses to cell- surface PSMA.
The therapeutic antibody program includes both “naked” and radiolabelled monoclonal antibodies directed specifically to PSMA on the surface of prostate cancer cells.
“We have developed strategies for producing novel therapeutic antibodies as well as vaccines which elicit robust immune responses to PSMA,” said Dr. Donovan.
“These findings constitute an important step towards identifying the optimal therapeutic product candidates to advance into human clinical testing.” The PSMA gene was first identified by scientists at Memorial Sloan- Kettering Cancer Center in New York City.
PSMA was identified as a cell- surface protein that is abundantly expressed in prostate cancer cells and therefore is an attractive target for vaccine and antibody- based cancer immune therapies.
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 results indicate that PSMA- targeted therapies may have anti-angiogenesis effects and may prove valuable in treating a broad range of cancers.
“Through our joint venture with Cytogen and collaborations with leading academic researchers, we have been successful in rapidly advancing several promising product candidates into animal testing,” said Ronald J. Prentki, President of Progenics.
“This progress reflects our commitment to this exciting new technology, which we anticipate will lead to the first PSMA products entering human trials within the next twelve months.”
“By capitalizing on the unique characteristics of PSMA, we believe that our joint venture with Progenics can develop a range of new immunotherapies for prostate cancer,” said H. Joseph Reiser, Ph.D., Cytogen’s Chief Executive Officer.
“In addition, we intend to evaluate these therapies, as an anti- angiogenesis approach, in other cancers where PSMA is expressed.” Progenics Pharmaceuticals is a biopharmaceutical company focusing on the development and commercialization of products for the treatment and prevention of cancer, viral diseases, and neurological disorders.
Cytogen Corporation is an established biopharmaceutical company in Princeton, NJ, with two principal lines of business, proteomics and oncology.