Receptagen Initiates Clinical Development of Growth Blockers Drug Candidate Demonstrates "Programmed Cell Death" in Cancer Cells
Seattle, WA, February 15, 1995--Receptagen Ltd. (TSE: RCG) today announced it has begun formal clinical development of its first "growth blocker" drug, as a result of recent company research demonstrating selective induction of programmed cell death, or "apoptosis," in cancer cells. Receptagen is developing growth-blocker drugs, a new class of minimally toxic biopharmaceuticals for the treatment of cancer and other life-threatening diseases marked by uncontrolled cell proliferation. With recent efficacy shown in cells, it has initiated development of the first generation of growth blockers that potentially lack the toxicities and immunosuppression of chemotherapy. "We have demonstrated for the first time that the simple detection of vitamin B 12--an essential enzyme cofactor for cell proliferation--can trigger programmed cell death in cancer cells without exposure to toxic chemotherapeutic drugs or radiation," said Dr. Charles A. Morgan, Jr., Ph.D., president and chief technical officer of Receptagen. Receptagen's therapeutic approach involves growth-blocker drugs designed to selectively deplete cancer cells of vitamin B12, an essential nutrient for cell growth and division. Vitamin B12 depletion is a treatment approach that has been used to successfully treat patient' s with acute leukemia. But until now, drugs capable of B 12 depletion have not been in existence. "We have designed monoclonal antibodies that target the B12-carrier protein, transcobalamin II," explained Dr. Morgan. "We have shown that these special antibodies can block the B 12 carder from deliver-
ing the essential cofactor into the cell, thereby depleting the cells of vitamin B12, halting proliferation and triggering programmed cell death in cancer cells." B12-inhibiting monoclonal antibodies have been undergoing feasibility evaluation at research centers under the Receptagen Research Network. One class of inhibitory antibody, reacting to the receptor-binding site of the carder protein for vitamin B12, will be the first form of growth blockers to undergo clinical testing. This groups has been shown to be the most potent in triggering death of cancer cells. Prior to entry into clinical trials, the antibodies will undergo "humanization" to reduce the potential for an adverse reaction to the administered antibody. Receptagen has already initiated clinical development of an inhibitor of apoptosis for the treatment of the accelerated cell death of CD-4 T-cells induced by the HIV virus in AIDS. The drug is based on Coenzyme Q10, an important cofactor that regulates the production of energy by the body's cells. Receptagen Ltd. is a biotechnology company operating through its wholly owned Seattle subsidiaries, Receptagen Corp., and Ryan Pharmaceuticals, to develop proprietary growth-blocker drugs and Coenzyme Q10 as regulators of cell death in the treatment of cancer and other life-threatening diseases. In Western Canada, Receptagen distributes pharmaceutical drugs through its division, VWD Distributors, based in Vancouver. Contacts:
A. Charles Morgan, Jr., Ph.D. President, Chief Technical Officer Tel: 206-778-5260 Charles Versaggi, Ph.D. Versaggi Biocommunications Tel: 415-395-7830