CytoGenix's `Universal' Expression System Encompasses Multiple Therapeutic Applications.

Business Editors & Health/Medical Writers

HOUSTON--(BUSINESS WIRE)--Sept. 18, 2000

CytoGenix Inc. (CYGX) announced that the company's growing Intellectual Property portfolio encompasses technology that may incorporate many existing therapeutic oligonucleotides.

Jonathan F. Elliston, Ph.D., J.D. CytoGenix's vice president responsible for R&D and IP summaries the CYGX IP portfolio, "As of September 2000, CytoGenix's proprietary expression technology platform includes, one issued U.S. Patent (No. 6,054,299), two published International Applications (Nos. WO 00/22113 & 00/22114), and numerous U.S. and international patents pending.

CytoGenix President and CEO, Malcolm Skolnick, Ph.D., J.D., elaborates, "The company's Intellectual Property portfolio includes filings for nucleic acid constructs (vectors) comprising elements needed to express many different oligodeoxynucleotide (ODN) sequences in a cell. The construct may be considered a unique patentable composition of matter distinct from the sequence it expresses. The expression systems together with the materials and methods for inserting the vector into specific cells are similarly considered patentably distinct from particular sequences and the methods described to deploy them."

Dr. Elliston explains, "The CytoGenix proprietary expression technology may have extremely broad application in the world of molecular therapies related to antisense, triplex and catalytic DNA among others. Initial studies have shown that several different ssDNA can be expressed in different cell lines at sufficient levels to alter protein expression. The results from on-going animal studies should prove very interesting."

The CytoGenix ssDNA intracellular expression systems (TroVec(R) and EnzSyn(R)) are specifically designed for the effective application of antisense and related therapies that interfere with the production of disease causing proteins at the cellular level.

Antisense therapy works by introducing into the cells therapeutic molecules of sequence specific DNA that bind and disable the messenger, mRNA. This prevents the production of disease-causing proteins just one step from their genetic points of origin.

The CytoGenix technology also has promise in triplex therapy that occurs in the genome itself. As the double helix of DNA "unzips" to accommodate the transcription of mRNA, the inserted ssDNA molecule binds with the genomic sequences forming a triple strand of DNA, or triplex which can no longer produce mRNA.

A third application, aptameric modulation of protein function, involves expressing ssDNA molecules in cells targeted to bind directly to the disease-causing proteins thus reducing or eliminating their harmful effects.

The list of ssDNA molecules that have been demonstrated to have therapeutic effects grows by the day against an ever expanding number of target diseases, as does the roster of biotechs who have studies and trials in progress.

Leaders in the field of identifying genomic therapies include Isis, Genta, Hybridon, Amgen, Aronex, Immunex, Genzyme, and AVI BioPharma to name a few. Clinical trials are in progress for drugs against a wide variety of conditions and diseases from catastrophic to cosmetic. They include cancer (breast, lung, prostate, skin) viral infections (HIV, hepatitis C, herpes, CMV) skin disease (psoriasis), plus many bacterial infections. It is believed that a majority of diseases known may respond to some type of pharmacogenomic therapy.

Numerous studies in the CytoGenix lab, and various university studies have demonstrated proof of concept of the CytoGenix expression system in cells. The manuscript describing the first eukaryotic version of the vector has been accepted for publication in the December issue of Antisense & Nucleic Acid Drug Development. A second manuscript, describing subsequent successful developments, is currently being reviewed by the CytoGenix Scientific Advisory Board prior to submission for publication. Additional animal studies are in progress to demonstrate proof of concept of the company's ssDNA intracellular expression system in vivo. An abstract entitled "Novel Intracellular Single-Stranded DNA Expression System: Production of c-raf RNA-cleaving Catalytic DNA" has been submitted to the January meeting of the Keystone Symposia on Gene Therapy 2001: A Gene Odyssey.

Except for statements of historical fact, the statements in this press release are forward-looking. Such statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from the statements made. These factors include, but are not limited to, general economic conditions, risks associated with the acceptance of new products, competition, and other factors more fully detailed in the company's filings with the Securities and Exchange Commission.