RXi Pharmaceuticals Nominates Dermal Anti-Scarring RNAi Product Candidate to Advance into Development

WORCESTER, Mass., Dec 17, 2010 (BUSINESS WIRE) --

RXi Pharmaceuticals Corporation (Nasdaq: RXII | PowerRating), a recognized leader in RNAi-based therapeutic discovery and development, today announced the selection of its first RNAi therapeutic product candidate to advance into development.

The development candidate, RXI--109, is a self-delivering RNAi compound (sd-rxRNA(TM)) that will initially be evaluated for the reduction of dermal scarring in planned surgeries. The selected lead candidate and several backups silence a gene target known to modulate fibrosis and thus may be applicable in the treatment of numerous indications with a fibrotic component, including scar formation. sd-rxRNA compounds are RNAi-based therapeutics that have demonstrated efficient cellular uptake without a delivery vehicle in preclinical studies.

"Dermal anti-scarring is an excellent match for RXi's expertise and our novel RNAi therapeutic platform," said Anastasia Khvorova, Ph.D., Chief Scientific Officer at RXi. "The disease biology is well understood, the targets are well validated, and intradermal injection is an acceptable administration route. Preclinical results using intradermal injection of sd-rxRNAs demonstrate robust, dose dependent, long lasting target specific silencing. This is a very exciting time for the company, and we look forward to advancing this program and filing an IND in the second half of 2011."

Dermal anti-scarring is an attractive lead indication for RXi with a clear development precedent and the ability to employ innovative clinical trial design with early efficacy endpoints. This indication represents an area of significant unmet medical need, with no approved drugs. The generation of early clinical proof of concept data in anti-scarring may support further expansion into other indications which contain a fibrotic component. Secondary clinical applications may include pulmonary fibrosis, liver fibrosis, acute spinal cord injury, ocular scarring and restenosis, which together encompass a potential market size of more than $16 billion.

"Selecting this first development candidate is a significant milestone for RXi and demonstrates the company's commitment to achieving our corporate goals and executing on our strategy," said Noah D. Beerman, President and Chief Executive Officer of RXi. "In early June, we designated dermal anti-scarring and retinal disorders as core focus areas and throughout 2010 we have made substantial progress in transitioning RXi from a research-focused company to one that is leveraging our strategy, platform and collaborations to advance our therapeutic pipeline. In addition to accomplishing our goal of nominating RXI-109 as our first development candidate, our partnering efforts also remain a priority for the company, and we are focused on completing a corporate partnership, which we anticipate being able to execute on in the coming months."

About Dermal Anti-Scarring

Scarring is a result of the natural process of wound repair. In the initial phase of this healing process, the wound is closed quickly to prevent infection and often results in visible scar tissue composed primarily of collagen. Dermal scars can range from fine lines to pronounced, painful scars that constrict the area and/or interfere with motion. Scar prevention and reduction is a therapeutic area of unmet medical need, with no universal standard of care and no approved drugs for the prophylactic reduction of scarring. The US potential market for skin scarring is estimated to be up to $4 billion with approximately 42 million surgical procedures conducted annually.

Anti-scarring/anti-fibrotic treatments are being developed to help prevent unsightly and debilitating dermal scars as well as to treat other medical conditions where excess scarring and/or fibrosis may occur. For the skin, these prophylactic treatments involve agents that are administered locally at the time of surgery or injury, and may lead to long-term improvements in scarring.

About Self-delivering rxRNA (or sd-rxRNA)

RXi's sd-rxRNA compounds are a novel class of RNAi therapeutics that are designed specifically for therapeutic use, and contain many of the properties that are required to advance RNAi based drugs into the clinic. The drug-like properties of sd-rxRNA include high potency, target specificity, serum stability, reduced immune response activation, and efficient cellular uptake.

An sd-rxRNA compound is a hydrophobically modified, stabilized hybrid that combines the best properties of both conventional RNAi and antisense technologies. sd-rxRNAs have a single-stranded phosphorothioate region, a short duplex region, and contains a variety of nuclease-stabilizing and lipophilic chemical modifications. The combination of these features allows sd-rxRNAs to achieve efficient spontaneous cellular uptake and potent, long-lasting intracellular activity.

sd-rxRNAs have shown in vivo silencing in preclinical studies in several tissues upon local and systemic administration and provide the foundation of our therapeutic platform that may be used to build a pipeline of RNAi-based therapeutics.

About RXi Pharmaceuticals Corporation

RXi Pharmaceuticals is a recognized leader in RNAi-based therapeutic discovery and development with a comprehensive therapeutic platform that includes both RNA interference (RNAi) compounds and delivery methods. The company is leveraging this broad and integrated RNAi therapeutic platform to build a pipeline of RNAi therapeutics for the treatment of a number of disease areas, including its core focus of developing treatments for dermal anti-scarring and retinal disorders as well as a continued interest in oncology and indications accessible by spinal cord delivery. RXi Pharmaceuticals believes it is well positioned to compete successfully in the RNAi therapeutics market based on the strength of its next generation therapeutic platform, experienced management team, accomplished Scientific Advisory Board, including Nobel Laureate, Dr. Craig Mello, and its broad intellectual property position in RNAi chemistry and delivery. www.rxipharma.com