Engineered Adenovirus INGN 07 Boasts Multiple Cancer-Killing Properties

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New Technology Accelerates Development Of Introgen's Novel Anti-

Cancer Candidate INGN 007

12/12/2003

Source: Introgen Therapeutics, Inc.

Significant advances related to the development of Introgen

Therapeutics, Inc.'s novel anti- cancer product candidate, INGN 007

(VRX 007) were presented today at the 12th International Conference

on Gene Therapy of Cancer, which is being held in San Diego. INGN

007, which Introgen licensed from VirRx, Inc. earlier this year, is a

proprietary, engineered adenovirus with multiple cancer killing

properties. New data related to the development of novel animal

models of cancer in which to test the potential efficacy and safety

of INGN 007 were presented by Introgen's collaborator, Dr.

S.M. Wold, founder and CEO of VirRx and chairman of the Department of

Molecular Microbiology and Immunology at St. Louis University School

of Medicine.

The study, titled " Adenovirus oncolytic vectors that overexpress

ADP, " reviewed previously presented data on oncolytic viruses and

described the production of novel animal models that allow these

viruses to be tested in a setting that more accurately reflects human

cancer.

Dr. Wold said, " Oncolytic viruses have demonstrated significant

potential in the treatment of cancer, and provide a new focus for

drug development efforts. Having generated a robust body of proof-of-

concept data in existing animal models, we now have the tools we need

to advance this promising technology more quickly toward the clinic.

With the model we presented today, the animals retain a functioning

immune system and also permit infection by and replication of these

novel adenoviral vectors. We believe that this model will further our

understanding of how oncolytic viruses may be used to treat cancer in

humans. "

Studies of tumor responses to oncolytic viruses to date have been

conducted in mice that lack a functioning immune system. These models

allow human tumors to be implanted into the mice without stimulating

the mouse immune system to attack the implanted tissue. Oncolytic

viruses have demonstrated a powerful ability to suppress tumor growth

in these models. However, mouse cells do not support replication of

these adenoviral vectors and the lack of a functioning immune system

makes it difficult to draw direct parallels between effects observed

in these models and potential effects in human cancers.

INGN 007 (VRX-007) is a replication competent adenovirus vector that

over- expresses an adenoviral gene (ADP) that causes rapid disruption

(oncolysis) of tumor cells in which it replicates. The ability to

overexpress the ADP gene sets this technology apart from other

existing oncolytic viruses and has been shown to provide a powerful

antitumor effect. Introgen holds an exclusive license to this

technology from VirRx. INGN 007 and related vectors have been

genetically engineered to increase their safety. In addition, some

vectors incorporate certain genetic features that permit the vectors

to replicate selectively in tumor cells. Additionally, some of these

vectors have been further modified by the addition of genes that

specifically kill cancer cells. These vectors have been extensively

tested in cell and animal models and shown to be very highly active

in killing tumor cells.

Introgen is a leading developer of biopharmaceutical products

designed to induce therapeutic protein expression using non-

integrating gene agents for the treatment of cancer and other

diseases. Introgen maintains integrated research, development,

manufacturing, clinical and regulatory departments and operates a

commercial-scale, CGMP manufacturing facility.

Certain statements in this press release that are not strictly

historical may be " forward-looking " statements, which are based on

current expectations and entail various risks and uncertainties. Such

forward-looking statements include, but are not limited to, those

relating to Introgen's future success with its clinical development

program for oncolytic viruses in the treatment of cancer or other

diseases. There can be no assurance that Introgen will be able to

commercially develop gene-based drugs, that necessary regulatory

approvals will be obtained or that any clinical trials or studies

undertaken will be successful or that the proposed treatments will

prove to be safe and/or effective. The actual results may differ from

those described in this press release due to risks and uncertainties

that exist in Introgen's operations and business environment,

including, but without limitation, Introgen's stage of product

development and the limited experience in the development of gene-

based drugs in general, Introgen's dependence upon proprietary

technology and current competition, history of operating losses and

accumulated deficits, reliance on collaborative relationships, and

uncertainties related to clinical trials, the safety and efficacy of

Introgen's product candidates, the ability to obtain the appropriate

regulatory approvals, patent protection and market acceptance, as

well as other risks detailed from time to time in Introgen's filings

with the Securities and Exchange Commission, including its annual

report on Form 10-K filed on March 31, 2003 and its quarterly report

on Form 10-Q filed on November 14, 2003, and its prospectus

supplement filed with the SEC pursuant to Rule 424((2) on November

26, 2003. Introgen undertakes no obligation to publicly release the

results of any revisions to any forward-looking statements that

reflect events or circumstances arising after the date hereof.

Editor's Note: For more information on Introgen Therapeutics, or for

a menu of archived press releases, please visit Introgen's Website

at: http://www.introgen.com/ .