Biotechnology company RXi Pharmaceuticals Corporation has completed dosing with their first drug, in its first phase I study. RXI-109 is being developed to prevent or reduce dermal scarring following surgery or trauma, as well as for the management of hypertrophic scars and keloids.

Over the past 3 months, 15 subjects who are scheduled to undergo abdominoplasty in the coming months, were enrolled in a double-blind dose, escalation study during which single intradermal injections were administered in a dose dependent manner to five cohorts of three subjects each. Subjects received an injection of RXI-109 in two separate areas on the abdomen and placebo injections in two other areas of the abdomen. Data on safety and tolerance were collected and evaluated for each cohort before moving to the next cohort with a higher dose level.

RXI-109 was well tolerated by intradermal injection. No serious local or systemic side effects were observed in the subjects at any of the doses administered. Local erythema (redness) around the injection site was somewhat more pronounced in the cohort that received the highest dose, but these instances of redness disappeared usually within 72 hours after the injection, and did not give rise to significant subjective complaints from the study subjects.

“These are exciting times for RXi Pharmaceuticals,” said Dr Geert Cauwenbergh, president and CEO of the company. “These results show that sd-rxRNA, as a technology, can be used locally over a range of concentrations in a safe and well-tolerated manner. In the past, concerns have been raised over the tolerability of RNAi compounds in clinical trials for systemic organ diseases. These clinical data in skin and dermis confirm our earlier observations in animal studies that RXi’s self delivering (sd) technology can be used safely for disease indications where local delivery is appropriate.” Dr Cauwenbergh added that, “the subjects continue to be followed with photographic documentation of their incision sites for a direct visual comparison, and biopsies of these sites at the time of the scheduled abdominoplasties, will allow direct comparison of RXI-109 versus placebo treated sites on a histological level. We are looking forward to these data becoming available in the coming months.”

With cosmetic surgical procedures becoming increasingly more common to improve appearance, or to correct skin imperfections as a result of trauma or disease, scarring has become a much more significant side effect of such interventions. In humans, scarring of the skin after surgery, trauma, or burns can cause debilitating aesthetic, functional and psychological effects. Medical treatment for scarring remains limited. Often with severe scarring, acceptable treatment plans include scar revision surgery which may alter the scar initially, but may also result in further exacerbation of the surgically-intervened area. Such exacerbation of a scar can often be a debilitating and painful experience for the patient and, to date, there are no FDA-approved therapeutics for the treatment of post-operative scars.  RXI-109 has been shown in cell culture and animal models to reduce CTGF, a growth factor that is essential in the wound healing cascade. Elevated levels of CTGF-dependent signaling can prolong the tissue repair process and lead to pathological scarring.

RXi Pharmaceuticals first clinical programme centres around RXI-109, a self-delivering RNAi compound (sd-rxRNA) developed by RXi for the reduction of dermal scarring in planned surgeries. RXI-109 is designed to reduce the expression of CTGF (connective tissue growth factor), a critical regulator of several biological pathways involved in fibrosis, including scar formation in the skin. The first clinical trial of RXI-109, initiated in June 2012, will evaluate the safety and tolerability of several dose levels of RXI-109 in humans and may provide preliminary evidence of surgical scar reduction. As there are currently no FDA-approved drugs to prevent scar formation, a therapeutic of this type could have great benefit for trauma and surgical patients (especially relating to raised or hypertrophic scarring), as a treatment during the surgical revision of existing unsatisfactory scars, and in the treatment, removal and inhibition of keloids (scars which extend beyond the original skin injury).

RXi’s sd-rxRNA compounds are designed for therapeutic use and have drug-like properties, such as high potency, target specificity, serum stability, reduced immune response activation, and efficient cellular uptake. They are hybrid oligonucleotide molecules that combine the beneficial properties of both conventional RNAi and antisense technologies. The sd-rxRNAs have a single-stranded phosphorothioate region, a short duplex region, and contain a variety of nuclease-stabilizing and lipophilic chemical modifications. The combination of these features has been shown in vitro and in animal tissues, to allow sd-rxRNAs to achieve efficient spontaneous cellular uptake and potent, long-lasting intracellular activity.

RXi Pharmaceuticals Corporation is a biotechnology company focused on discovering, developing and commercializing innovative therapies based on its proprietary, next-generation RNAi platform.