NIH Scientists Report TB4 Effective in Dermal Wound Repair in Diabetic and Aged Animals; RegeneRx's Thymosin Beta 4 Subject of New Scientific Paper.

Business Editors/Health/Medical Writers

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BETHESDA, Md.--(BUSINESS WIRE)--Feb. 13, 2003

RegeneRx Biopharmaceuticals, Inc. (OTCBB:RGRX, www.regenerx.com) announced that Thymosin Beta 4 (TB4), a molecule found in high concentrations in blood platelets (amongst the first cells to enter a wound), plays an important role in the repair and remodeling of tissue in diabetic and aged animals, according to the most recent findings published in the current issue of the Journal of Wound Repair and Regeneration, Vol. 11:1, pp. 19-24.

Previously, it was reported that TB4 was effective in accelerating the healing of wounds in normal and steroid-suppressed laboratory animals.

According to Dr. Hynda Kleinman, Chief of the Laboratory of Cell Biology at the National Institute of Dental and Craniofacial Research in Bethesda, Maryland and the senior author of the paper, "In diabetic mice, where healing is delayed, we find that wound contracture and collagen deposition are significantly increased in mice treated with Thymosin B4."

A second key finding was the effectiveness of TB4 in speeding up the healing process in aged (26-month-old) mice where wound healing is significantly delayed.

Dr. Kleinman reported that, "Thymosin B4 accelerated wound healing in these aged mice, with increases in keratinocyte migration, wound contracture, and collagen deposition." Dr. Kleinman went on the state, "Together, these data show that TB4 is a potent, naturally occurring wound healing factor."

TB4 is a naturally occurring 43-amino acid peptide whose gene is up-regulated following tissue injury and during the remodeling and differentiation of cells.

TB4 represents a new class of wound healing compound and is different from other wound repair factors, such as growth factors, in that it promotes endothelial 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.

One of its key mechanisms of action is TB4's ability to regulate the cell-building protein, actin, a vital component of the cytoskeleton. It has been the subject of a significant amount of research at the NIH and other academic institutions, having been reported to effectively repair dermal and corneal wounds in numerous animal models under a variety of conditions.

Further, it has been delivered both topically and systemically with both routes of administration showing similar activity for dermal wounds. The fact that TB4 is active across a broad spectrum of wounds with various underlying causes would indicate that it is a necessary component of the wound repair process.

Dr. Kleinman is a foremost authority in the areas of wound healing and angiogenesis and has trained many of the leading scientists in these fields.

Dr. Kleinman, Dr. Deborah Phillip, a research fellow in Dr. Kleinman's laboratory, and their colleagues at the NIH have, over the past several years, made important contributions to the understanding of the role of TB4 in the healing and remodeling of mammalian tissues. Their discoveries have stimulated additional research programs on the role of TB4 in wound healing and tissue repair.

The current research in diabetic and aged mice was headed by Dr. Philp, whose expertise is in wound healing, angiogenesis and proteases.

RegeneRx Biopharmaceuticals, Inc. is developing TB4 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 patent applications pending.

The company received an IND to begin human clinical trials, which it anticipates will begin shortly using TB4 for the treatment of chronic wounds.

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 regulatory approval process and the ongoing and prospective development and commercialization of TB4 and possible future benefits to the Company, its shareholders, and patients.

Due to the nature of clinical trials, product development and the regulatory approval process, the forward-looking statements contained in this press release 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.