New York, NY, October 2, 1997 - Researchers at the Center for Immunotherapy of Cancer and Infectious Diseases at the University of Connecticut School of Medicine announced today the publication of a scientific report in the current issue of Science (vol. 278, n. 5335) that describes a powerful new approach to using immunotherapy for the treatment of a variety of cancers, including metastatic disease. With this approach, the individual's own immune cells are stimulated to eliminate cancerous cells from the body.
The paper, entitled "Immunotherapy of Tumors with Autologous Cancer-Derived Heat Shock Protein Preparations," describes the use of protein complexes purified from tumor cells in the treatment of cancer and metastasis. Heat shock proteins (HSPs) are a family of molecular chaperones present in all cells. In this study, 80% of HSP-treated mice survived for longer than 250 days compared to fewer than 20% of control mice.
The approach to immunotherapy of cancer described in the report is medically significant because it is applicable to virtually all forms of cancer. Heat shock proteins can be purified from a tumor specimen removed by surgery or biopsy. The paper describes the treatment of five different kinds of cancers in mice, including metastatic lung cancer, melanoma and colon carcinoma.
The versatility of heat shock proteins in the treatment of cancer derives from their normal physiological role in cells. HSPs play a role in protein trafficking, whereby they keep other proteins in their correct shape and location. When these molecular chaperones are purified from cells, they bring along with them small fragments, or peptides, derived from other proteins expressed in that cell, providing a molecular "fingerprint" of the cell's content. Vaccination with the HSP-peptide complexes purified from cancer cells has the potential to specifically stimulate the immune system to attack cells bearing those peptides, i.e., the cancer cells themselves.
"The HSP-peptide complex vaccination is perhaps the first general principle of immunization which now has shown to be effective against a wide variety of pre-existing cancers," said Pramod K. Srivastava, Ph.D., of the University of Connecticut School of Medicine and Principle Investigator for the project. "Decades of research suggests that tumors are distinct from one individual to another, with each tumor containing its own unique set of mutations. The task of identifying each of these mutations in individual cancer patients -- with the intent of targeting them immunotherapeutically -- is therefore impractical. In contrast, the process of purifying HSPs is the same for each patient's tumor and is relatively simple."
This immunotherapeutic approach can target the cancer-specific antigens of any cancer cell without the need to identify what those antigens are. Moreover, the results from this paper demonstrate that the vaccine is effective against the primary tumor and its metastases. In human clinical settings, metastatic cancer is frequently untreatable and fatal even if the primary cancer has been removed successfully.
Antigenics, L.L.C., holds the commercial rights to the HSP-based vaccines against cancer and infectious diseases. "We have initiated a Phase I trial in pancreatic cancer where HSP-based vaccines are being prepared from individual cancer patients' tumors. Phase Ib clinical trials for the treatment of melanoma and renal cell carcinoma are expected to start in the fourth quarter 1997," said Garo Armen, Ph.D., Chief Executive Officer of Antigenics.
"We anticipate that vaccinating cancer patients with purified chaperone-peptide complexes will lead to a decrease in the size of the tumor and will treat metastasis. This approach, alone or in combination with surgery and chemotherapeutic treatments should extend and improve the quality of life for patients with a wide variety of cancers." Further, Armen said, "heat shock protein technology provides Antigenics with a platform that also has applications for the treatment of many infectious diseases.
The Center for Immunotherapy of Cancer and Infectious Diseases within the University of Connecticut School of Medicine at Farmington, CT is involved in basic and clinical research on immune responses to cancer and infectious diseases, and on problems in autoimmunity.
Antigenics, L.L.C., is a privately-held biopharmaceutical company developing treatments for cancer, infectious diseases and other disorders. These treatments are based on the Company's proprietary technology which utilizes the ability of heat shock proteins, the body's natural adjuvants, to modulate the immune system selectively.
Editor's notes: Dr. Pramod Srivastava will be available for interviews while currently in India, through the contacts listed above.