GENEVA, Sept. 30 /PRNewswire-FirstCall/ -- Immunomedics, Inc.
(Nasdaq: IMMU) today reported that its therapeutic product candidates, as well
as those of its subsidiary company, IBC Pharmaceuticals, Inc., were the
subject of five presentations made at the "Molecular Targets and Cancer
Therapeutics" International Conference sponsored by the European Organization
for Research and Treatment of Cancer (EORTC), the American Association for
Cancer Research (AACR), and the National Cancer Institute (NCI).
Three of the poster presentations involved the humanized anti-CD74
monoclonal antibody conjugated with the anticancer drug, doxorubicin (DOX).
The first one evaluated the in vitro efficacy of the drug conjugate on
CD74-expressing cell lines of non-Hodgkin's lymphoma (NHL) and multiple
myeloma (MM). The drug conjugate was found to bind specifically to
CD74-expressing NHL and MM cell lines with sub-nanomolar affinity. More
importantly, unlike non-specific antibody-DOX conjugate, the CD74-DOX
conjugate internalized inside the cells producing a cytotoxicity level
approaching that of free DOX. The pharmacokinetics and tissue biodistribution
of the drug conjugate in mice and the acute toxicological potential of the
naked antibody in monkeys were presented in the second poster. In naive
BALB/c mice, with regards to blood clearance or normal tissue uptake, no
significant difference was observed between the drug conjugate and the naked
antibody. Moreover, neither had a significant association with any normal
body tissue suggesting that coupling DOX to the CD74 antibody does not alter
the pharmacokinetic or biodistribution profile of the antibody component in
the conjugate. The naked antibody displayed a short serum half-life and fast
clearance from the circulation, and was well tolerated in cynomolgus monkeys.
Tolerability studies of the drug conjugate are ongoing. The third
presentation on CD74-DOX conjugate examined its in vivo efficacy in a mouse MM
model. Given as a single injection, the drug conjugate was shown to be
efficacious with doses as low as 35 micrograms and administration as late as
ten days after tumor cell inoculation.
"We are very encouraged by these preclinical results," commented Dr. Ivan
D. Horak, a coauthor of all the studies and is the Executive Vice President of
Research and Development, and Chief Scientific Officer. "Antibody-targeted
selective delivery of anticancer drugs against antigens expressed on cancer
cells can potentially improve the therapeutic index of anticancer drugs. CD74
is a rapidly internalizing transmembrane chaperone molecule, and has high
expression on human NHL and MM. At 8 drug molecules per antibody molecule,
our CD74 antibody-DOX conjugate represents a rational choice for clinical
development as a therapeutic against CD74-expressing tumors," Dr. Horak added.
The fourth poster described the construction, characterization, and in
vitro cytotoxiciy of a novel immunotoxin fusion protein consisting of two
ranpirnase (rpRNase) molecules fused to an anti-CD74 humanized antibody.
rpRNase is a protein that specifically degrades RNAs upon internalization.
Previous studies indicated that cytotoxicity of rpRNase can be enhanced more
than 10,000-fold when the enzyme is chemically conjugated to an internalizing
antibody. The fusion protein has retained the RNA degradation activity of
rpRNase and the binding affinity of the CD74 antibody, and demonstrated potent
toxicity to CD74 expressing cells.
The final presentation outlined the production of a trivalent bispecific
fusion protein, hBS14, in myeloma cells for improved pretargeting and therapy
of carcinoembryonic antigen (CEA)-expressing cancers. Pretargeting
radioimmunoimaging and radioimmunotherapy involves uncoupling of the
radionuclide from the tumor-targeting antibody, which allows antibody
localization and clearance to occur prior to a very rapid and highly specific
delivery of the radioactive payload carried on a small molecule, such as a
peptide. hBS14 is a fusion protein consisting of two binding sites for CEA
and one binding site for histamine-succinyl-glycine. The efficacy of hBS14 for
tumor pretargeting was evaluated in nude mice bearing CEA-expressing human
colonic tumor. The results indicate that hBS14 is an attractive candidate for
use in a variety of pretargeting applications, particularly tumor therapy with
radionuclides and drugs.
"These presentations clearly underscore our strength in research and
development. We continue to bring new ideas in antibody design from the
laboratory and new antibodies into the clinic. We plan to submit an
Investigational New Drug Application to the FDA for the CD74-DOX conjugate and
we look forward to commence its testing in human," remarked Cynthia L.
Sullivan, President and Chief Executive Officer.
Immunomedics, Inc. is a biopharmaceutical company focused on the
development, manufacture and commercialization of diagnostic imaging and
therapeutic products for the detection and treatment of cancer and other
serious diseases. Integral to these products are highly specific monoclonal
antibodies and antibody fragments designed to deliver radioisotopes and
chemotherapeutic agents to tumors and other sites of disease. Immunomedics
has therapeutic product candidates in clinical development and has two
marketed diagnostic imaging products. Our most advanced therapeutic product
candidate is epratuzumab, for which certain Phase II clinical trials for the
treatment of non-Hodgkin's lymphoma have already been completed.
This release, in addition to historical information, contains forward-
looking statements made pursuant to the Private Securities Litigation Reform
Act of 1995. Such statements, including statements regarding clinical trials,
involve significant risks and uncertainties and actual results could differ
materially from those expressed or implied herein. Factors that could cause
such differences include, but are not limited to, risks associated with new
product development (including clinical trials outcome and regulatory
requirements/actions), competitive risks to marketed products and availability
of financing and other sources of capital, as well as the risks discussed in
the Company's Annual Report on Form 10-K for the year June 30, 2004. The
Company is not under any obligation, and the Company expressly disclaims any
obligation, to update or alter any forward-looking statements, whether as a
result of new information, future events or otherwise.
Company Contact: Chau Cheng, Associate Director, Investor Relations &
Business Analysis, (973) 605-8200, extension 123. Visit the Company's web site
at http://www.immunomedics.com.
SOURCE Immunomedics, Inc.
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Related links:
http://www.immunomedics.com
Company News On-Call:
http://www.prnewswire.com/comp/113121.html
CONTACT:
Chau Cheng, Associate Director, Investor
Relations & Business Analysis of Immunomedics, Inc.,
+1-973-605-8200, ext. 123
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