TB4 Decreases Inflammation & Bleeding in Eye After Injury; Molecule Also Modulates Expression of Key Remodeling Proteins.

Business Editors/Health/Medical Writers

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BETHESDA, Md.--(BUSINESS WIRE)--April 26, 2004

It was reported today at the Association of Research in Vision and Ophthalmology (ARVO) annual meeting in Ft. Lauderdale, Florida that TB4-treated corneas of laboratory animals demonstrated decreased inflammation and hyphema (bleeding in the anterior chamber of the eye) at 7 days after injury when compared to placebo, as well as modulation of certain other important proteins associated with wound-healing.

Dr. Gabriel Sosne and his colleagues at Wayne State University and Kresge Eye Institute in Detroit, Michigan, concluded that TB4 promotes corneal wound healing and the expression of key tissue remodeling molecules, thus, suggesting a mechanism of action for its effects on corneal wound repair.

TB4 is a naturally occurring molecule being developed for dermal, ocular and other wound-healing indications by RegeneRx Biopharmaceuticals, Inc., Bethesda, Maryland, (OTCBB:RGRX) (www.regenerx.com).

Dr. Allan Goldstein, Chairman of Biochemistry and Molecular Biology at the George Washington University School of Medicine in Washington, DC and Chief Scientific Advisor to RegeneRx stated, "The key to this study is that it further defines and confirms certain biological mechanisms for TB4's actions in ocular wound repair. The reduction of inflammation, hemorrhaging and expression of important 'remodeling molecules' with topical administration of TB4, compared to a placebo, helps us understand why we see accelerated healing and decreased inflammation in various tissues after injury. Clearly, we look forward to testing these findings in other sites beyond the skin and eyes."

TB4 is a naturally occurring 43-amino acid peptide present in virtually all human cells. It represents a new class of wound healing drug and is different from other wound repair factors, such as growth factors, in that it promotes endothelial cell differentiation and keratinocyte cell migration, down-regulates a number of inflammatory cytokines and chemokines, and has a very low molecular weight, allowing it to diffuse relatively long distances through tissues. A key mechanism of action is TB4's ability to regulate the cell-building protein, actin, a vital component of the cytoskeleton. Additionally, it has recently been reported that TB4 directly influences the production of laminin-5, a protein necessary for proper adhesion of certain types of mammalian cells and an important component of the wound healing process. TB4 has been the subject of a significant amount of research at the NIH and a number of other academic institutions, and has been reported to be effective in the repair of dermal and corneal wounds in numerous animal models under a variety of conditions.

RegeneRx is a biopharmaceutical company developing TB4 as a platform technology for the treatment of acute and chronic wounds and for the treatment of a variety of human diseases involving tissue and organ repair under an exclusive world-wide license from the NIH. The Company holds several patents related to the technology and has numerous world-wide patent applications pending. RegeneRx successfully completed Phase I human clinical trials with TB4 for the treatment of chronic dermal wounds and expects Phase II trials to begin in the second quarter of 2004.

The information in this press release may include certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements concern the Company's current expectations regarding future events, including the ongoing and prospective development of TB4 and possible future benefits to the Company, its shareholders, and patients. Due to the nature of product development and the regulatory approval process, the forward-looking statements are subject to risks and uncertainties, including those reflected in the Company's filings with the Securities and Exchange Commission, particularly its most recent Annual Report on Form 10-KSB. The Company assumes no obligation to update or revise any forward-looking statements made herein or any other forward-looking statements made by the Company.