Printer Friendly

IMMUNOGEN'S BLOCKED RICIN TECHNOLOGY INCREASES POTENCY OF CANCER THERAPEUTICS 1,000-FOLD: RESEARCHERS REPORT DATA IN CANCER RESEARCH

IMMUNOGEN'S BLOCKED RICIN TECHNOLOGY INCREASES POTENCY OF CANCER THERAPEUTICS 1,000-FOLD: RESEARCHERS REPORT DATA IN CANCER RESEARCH
 CAMBRIDGE, Mass., Dec. 3 /PRNewswire/ -- In the Dec. 1, 1991 issue of Cancer Research, researchers from ImmunoGen, Inc. (NASDAQ: IMGN) report success in the development of a highly potent, therapeutic immunotoxin derived from ricin, a powerful plant toxin. The company's proprietary "blocked ricin" technology has enabled the production of anti-cancer drugs that are up 1,000-times more potent than conventional chemotherapeutics or other ricin-based compounds. ImmunoGen has three blocked ricin-based immunotoxins in clinical trials. The first product, Oncolysin B, is in multicenter Phase II and Phase I/II trials in the treatment of a variety of B-cell-related cancers.
 "The data in this paper confirm the fundamental premise on which our Oncolysin portfolio of products is based," comments ImmunoGen President and CEO Mitchel Sayare. "Both high potency and high specificity are essential properties of immunotoxins for use in the treatment of cancer," Sayare explains. "By linking blocked ricin to monoclonal antibodies which specifically target markers found on the surface of tumor cells, we are able to develop products that harness the toxicity of whole ricin to destroy cancer cells, while leaving normal tissue unaffected."
 Ricin is a naturally occurring plant toxin comprised of two chains. The A-chain is responsible for cell killing, while the B-chain enables ricin to bind to a simple sugar that is found on the surface of almost all human cells. Such nondiscriminate binding to cell surfaces is an undesirable property of toxins, when targeted by monoclonal antibodies. The B-chain also facilitates entry by the A-chain into the cell, where it kills the cell by catalytically inactivating ribosomes, the cell's protein synthesis machinery. ImmunoGen's blocked ricin inhibits the B-chain's ability to bind to cell surfaces, therby allowing the monoclonal antibody to target tumor cells exclusively.
 In describing the significance of the Cancer Research paper, co-author Dr. Walter Blattler, ImmunoGen's vice president of research, notes that "Historically, to prevent nonspecific binding of the B-chain, immunotoxins have been comprised of monoclonal antibodies linked either to ricin A-chain or to similar, single-chain toxins. Such immunotoxins may possess the requisite specificity of the component antibody, but they are far less potent than native ricin. We have demonstrated that an immunotoxin comprised of a highly specific monoclonal antibody, anti-B4, and blocked ricin is approximately 1,000-times more potent than immunotoxins comprised of the same antibody and ricin A-chain. Immunotoxins using blocked ricin incorporate all three essential functions of the natural toxin; namely, binding to cells, transport through the cell membrane, and catalytic inactivation of an essential cellular process."
 The paper, entitled "An Immunotoxin Prepared with Blocked Ricin: A Natural Plant Toxin Adapted for Therapeutic Use," describes a method of blocking the two galactose-binding sites of native ricin by chemical modification with affinity ligands, thereby maintaining both the translocation function of the B-chain and the catalytic activity of the A-chain, and eliminating nonspecific binding to cell surfaces. As described in the paper, blocked ricin was then conjugated to the anti-B4 (CD19) antibody, which targets an antigen found on the surface of tumor cells of B-cell lineage, to form an immunotoxin. The linkage between antibody and blocked ricin involves only the B-chain of blocked ricin, and thus does not disturb the covalent and noncovalent interactions between A-chain and B-chain. This stable antibody-blocked ricin linkage thereby ensures that the A-chain does not dissociate from the B-chain until it is inside the cell membrane of the target tumor cell, where it can kill the cell.
 The paper is co-authored by researchers at ImmunoGen and Dr. Lee M. Nadler of the Division of Tumor Immunology of Dana-Farber Cancer Institute in Boston, Mass., where much of the company's early-stage research has been conducted. Dr. Nadler is the discoverer of the anti-B4 antibody. Patents on blocked ricin technology are held by Dana-Farber Cancer Institute, which has licensed rights exclusively to the company.
 Oncolysin B is the product name for anti-B4 blocked ricin. It was the first ImmunoGen product to enter the clinic, and currently is in trials in the treatment of B-cell leukemias and lymphoma, AIDS- related lymphoma, multiple myeloma and as a purging agent in autologous bone marrow transplant.
 ImmunoGen, Inc. is a Cambridge, Mass.-based biotechnology company that develops biopharmaceuticals, primarily for the treatment of cancer. The company has developed proprietary toxins, drugs and biologicals conjugated to highly specific monoclonal antibodies which search out and destroy cancer cells. Each of ImmunoGen's first four products -- the Oncolysin portfolio of immunotoxins -- consists of a highly specific monoclonal antibody linked to blocked ricin. ImmunoGen currently has three Oncolysin products in human clinical trials in the United States, Canada and Europe.
 -0- 12/3/91
 /CONTACT: Mark Ratner of ImmunoGen, 617-661-9312/
 (IMGN) CO: ImmunoGen, Inc. ST: Massachusetts IN: MTC SU:


KM-DH -- NE002 -- 8634 12/03/91 09:39 EST
COPYRIGHT 1991 PR Newswire Association LLC
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Publication:PR Newswire
Date:Dec 3, 1991
Words:804
Previous Article:TECHNOLOGY APPLICATIONS, INC., ANNOUNCES REORGANIZATION
Next Article:NATIONAL GYPSUM COMPANY SIGNS WALLBOARD LICENSING AGREEMENT WITH ISRAELI COMPANY
Topics:


Related Articles
IMMUNOGEN'S BLOCKED RICIN TECHNOLOGY INCREASES POTENCY OF CANCER THERAPEUTICS 1,000-FOLD: RESEARCHERS REPORT DATA IN CANCER RESEARCH
IMMUNOGEN'S PHASE I CLINICAL TRIALS DATA WITH ONCOLYSIN B PRESENTED AT AMERICAN SOCIETY OF HEMATOLOGY MEETING
IMMUNOGEN ANNOUNCES SECOND QUARTER FISCAL YEAR 1992 RESULTS
CLINICAL TRIALS OF IMMUNOGEN'S ONCOLYSIN B EXPANDED; NCI TO BEGIN MULTICENTER STUDY IN CHILDREN WITH LEUKEMIA AND LYMPHOMA
IMMUNOGEN, INC. ENGINEERS HUMANIZED MONOCLONAL ANTIBODY USING NOVEL RESURFACING TECHNIQUE
RESULTS OF IMMUNOGEN'S PHASE I CLINICAL TRIAL USING ONCOLYSIN B SUBSEQUENT TO BONE MARROW TRANSPLANTATION PUBLISHED IN BLOOD
ONCOLYSIN(R) CD6, IMMUNOGEN'S FOURTH PRODUCT, ENTERS PHASE I HUMAN CLINICAL TRIALS
IMMUNOGEN OPENS A NEW MANUFACTURING FACILITY IN CANTON, MASSACHUSETTS
IMMUNOGEN SUBSIDIARY, APOPTOSIS TECHNOLOGY, INC., AND IMPERIAL CANCER RESEARCH FUND ANNOUNCE RESEARCH COLLABORATION
ImmunoGen Compound Eradicates Human Small-Cell Lung Cancer Tumors in Mice

Terms of use | Copyright © 2016 Farlex, Inc. | Feedback | For webmasters