RXi Pharmaceuticals this week announced that its lead drug candidate, the anti-scarring agent RXI-109, was safe and well tolerated in a phase I study, while producing a dose-dependent reduction of its target protein.
RXI-109 comprises siRNAs designed to inhibit connective tissue growth factor, or CTGF, a protein linked to wound healing and other fibrotic processes. It employs the company's proprietary self-delivering technology, which enables cellular uptake without the need for a delivery vehicle.
In the phase I study, 15 volunteers received a single dose of the drug, at doses ranging from 0.5 mg/cm to 5 mg/cm, in two 2-centimeter areas of the abdomen. Two other areas on the abdomen were treated with placebo injections.
A day after treatment, the four areas received an incision that was immediately closed. Patients were followed for three months, at which point they underwent abdominoplasty. Samples were taken from portions of the skin removed during the surgery for assessment.
“No significant side effects or toxicity were observed and the incisions did not appear to slow healing on the active or the placebo side, indicating that RXI-109 does not delay wound closure,” RXi said. “In addition, blood level measurements for RXI-109 indicated that the maximum systemic exposure was only about 5 percent of the intradermally administered dose.”
Further, there was a statistically significant reduction in the average CTGF protein concentration in RXI-109-treated sites versus placebo sites, with the highest reduction in target protein levels observed in the incision areas receiving the two highest doses.
Data from a second, ongoing phase I study testing multiple doses of RXI-109 are expected to be available in July.