Shares of RegeneRx Biopharmaceuticals Inc. plunged 40 percent Friday after a Phase II study of lead product RGN-137 failed to show it significantly improved the healing of pressure ulcers compared to placebo.
The study compared three concentrations of RGN-137 to placebo in 72 patients with chronic Stage III or IV pressure ulcers. RGN-137 met its primary endpoint of demonstrating tolerability, and there were no drug-related serious adverse events, but the efficacy data fell short as the drug failed to significantly outperform placebo in improving the completion or rate of wound healing.
J.J. Finkelstein, RegeneRx's president and CEO, said in a news release that the company will "continue to analyze the data" but will not make any decisions about the future of the program until it sees data from an ongoing Phase II trial in venous stasis ulcers.
The venous stasis data are expected this quarter. RegeneRx also is conducting a Phase II trial of RGN-137 for wound healing in patients with epidermolysis bullosa, and data are expected later this year.
The pressure ulcer data do not bode well for the other two ulcer trials, but RegeneRx noted that the mid-dose of RGN-137 did offer more rapid initiation of wound healing than placebo, although the difference was not statistically significant. The company also emphasized that pressure ulcers are different from venous stasis ulcers, which result from venous insufficiency, and from epidermolysis bullosa ulcers, which result from genetic factors.
RGN-137 is a topical formulation of the peptide thymosin beta 4 (TB4), which promotes endothelial cell differentiation, among other activities. The rest of the company's pipeline also focuses on TB4, including the Phase II ophthalmic wound healing drug RGN-259 and the Phase I injectable RGN-352 for acute cardiovascular indications and cardiac tissue repair.
RegeneRx had about $5.4 million in cash, equivalents and short-term investments at the end of the third quarter, after posting a quarterly loss of about $2.3 million. A stock sale to Sigma-Tau Group, RegeneRx's largest shareholder, brought in $3 million in December.
Shares of Bethesda, Md.-based RegeneRx (AMEX:RGN) fell 70 cents, or to close at $1.05 Friday.