RegeneRx Completes Patient Enrollment of First Phase II Clinical Trial

Business Wire, August 20, 2008

BETHESDA, Md. -- REGENERX BIOPHARMACEUTICALS, INC. (AMEX:RGN) (www.regenerx.com) announced today that it completed enrollment of its first of four ongoing Phase II clinical trials. The trial is a double-blind, placebo-controlled, dose-escalating clinical trial evaluating the safety and efficacy of the Company's topical drug candidate, RGN-137, in seventy-two patients with pressure ulcers who are being treated for up to 84 days or less if fully healed. RGN-137 is a formulation of thymosin beta 4 specifically for topical delivery to dermal wounds. Twenty-two wound care centers and hospitals in the United States have participated in the study. The Company expects to report results in the fourth quarter of 2008.

"Clearly, we are excited about reaching this important milestone. While each of our Phase II trials will stand on its own and give us valuable information in separate medical indications, this trial will give us the first information on RGN-137's safety and efficacy in dermal wound healing. Currently there are no pharmacological agents approved for improving the healing of pressure ulcers and we look forward to reporting the results once they are available," stated David Crockford, RegeneRx's vice president for clinical and regulatory affairs.

About RegeneRx Biopharmaceuticals, Inc.

RegeneRx is focused on the discovery and development of novel peptides to accelerate tissue repair and protection. Currently, RegeneRx is developing three product candidates, RGN-137, RGN-259 and RGN-352 for dermal, ophthalmic, and cardiovascular tissue repair, respectively. These product candidates are based on T4, a 43-amino acid, naturally occurring peptide, in part, under an exclusive world-wide license from the National Institutes of Health. RegeneRx holds or has filed over 60 world-wide patents related to its drug candidates and is currently sponsoring three Phase II chronic dermal wound-healing clinical trials, a Phase II ophthalmic wound-healing clinical trial, and a Phase I parenteral (injectable) clinical trial supporting systemic delivery of RGN-352 for acute cardiovascular indications.

RegeneRx Technology Background

T4 is a synthetic version of a naturally occurring peptide present in virtually all human cells. It is a first-in-class multi-faceted molecule that promotes endothelial cell differentiation, angiogenesis in dermal tissues, keratinocyte migration, collagen deposition, and down-regulates inflammation. RegeneRx has identified several molecular variations of T4 that may affect the aging of skin, among other properties, and could be important candidates as active ingredients in pharmaceutical and consumer products. Researchers at the National Institutes of Health, and at other academic institutions throughout the U.S., have published numerous scientific articles indicating T4's in vitro and in vivo efficacy in accelerating wound healing and tissue protection under a variety of conditions. Key publications related to T4's cardio-protective effects have been published in Nature and Circulation. Abstracts of these and other scientific papers related to T4's mechanisms of action may be viewed at RegeneRx's website: www.regenerx.com.

Forward-Looking Statements

Any statements in this press release that are not historical facts are forward-looking statements made under the provisions of The Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the words "project," "believe," "anticipate," "plan," "expect," "estimate," "intend," "should," "would," "could," "will," "may" or other similar expressions and include statements regarding the safety and efficacy of RGN-137, RGN-259 and RGN-352 and the status and prospects of any ongoing pre-clinical studies and clinical trials, including the Phase II clinical trial related to RGN-137 in patients with pressure ulcers. Actual results may differ materially from those indicated or implied by such forward-looking statements because the Company's product candidates may not demonstrate safety and/or efficacy in current or future clinical trials or as a result of various important factors described in the Company's filings with the Securities and Exchange Commission ("SEC"), including those identified in the "Risk Factors" sections of the annual report on Form 10-K for the year ended December 31, 2007 filed with the SEC on March 28, 2008 and other periodic reports filed with the SEC. Any forward-looking statements in this press release represent the Company's views only as of the date of this release and should not be relied upon as representing its views as of any subsequent date. The Company anticipates that subsequent events and developments may cause its views to change, and the Company specifically disclaims any obligation to update this information, as a result of future events or otherwise, except as required by applicable law.