RXi Pharmaceuticals Presents at AACR Conference, Highlighting the Potential for RNAi Therapeutics in Oncology

April 19, 2010

WORCESTER, Mass.--(BUSINESS WIRE)--RXi Pharmaceuticals Corporation (Nasdaq: RXII), a biopharmaceutical company pursuing the development and commercialization of proprietary therapeutics based on RNA interference (RNAi), today announced that Anastasia Khvorova, Ph.D., Chief Scientific Officer, is presenting at the 101^st annual American Association for Cancer Research (AACR) Conference on April 19, 2010. The presentation will not be webcast.

Dr. Khvorova’s presentation includes a broad overview of the mechanism of RNAi, as well as a description of current RNAi preclinical and clinical pipelines. In addition, in vivo data on RXi’s proprietary ‘self delivering’ (sd-rxRNA™) compounds will be presented, as well as the potential for the use of the company’s RNAi therapeutic platform in the treatment of a variety of oncology indications.

In contrast to conventional siRNAs, sd-rxRNA compounds have been shown by RXi in animal models to have the unique property of prolonged blood circulation, allowing them to reach the desired tissues before they are degraded in serum or cleared by the kidneys. The improved drug-like properties of sd-rxRNAs have the potential to dramatically advance the field of RNAi therapeutics and the development of many novel disease treatments, including a variety of oncology indications, for which treatments may be addressed using both local and systemic administration.

The American Association for Cancer Research Conference, which is taking place in Washington, DC from April 17^th through April 21^st, is expected to attract more than 17,000 attendees this year. This key scientific conference highlights critical cancer research issues widely being studied by academics as well as the pharmaceutical industry.

About RXi Pharmaceuticals Corporation

RXi Pharmaceuticals is a discovery-stage biopharmaceutical company pursuing the development and commercialization of proprietary therapeutics based on RNA interference (RNAi) for the treatment of human diseases. RXi has a comprehensive therapeutic platform that includes both novel RNAi compounds and advanced delivery methods that can potentially be applied for local and systemic applications, against targets that may be undruggable by other modalities. RXi uses its proprietary version of RNAi compounds -- rxRNA™ -- that provide an advanced alternative to conventional small interfering RNAs (siRNAs) and define the next generation of RNAi technology. These include rxRNAori™, rxRNAsolo™, and sd-rxRNA™ (or “self delivering” RNA), which are distinct from, and potentially convey significant advantages over, classic siRNAs. RXi Pharmaceuticals believes it is well positioned to compete successfully in the RNAi-based therapeutics market with its accomplished scientific advisors, including Dr. Craig Mello, recipient of the 2006 Nobel Prize for his co-discovery of RNAi; a management team that is experienced in developing RNAi products; and a strong and early, but broad, intellectual property position in RNAi chemistry and delivery. www.rxipharma.com

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements about future expectations, plan and future development of RXi Pharmaceutical Corporation's products and technologies. These forward-looking statements about future expectations, plans and prospects of the development of RXi Pharmaceutical Corporation's products and technologies involve significant risks, uncertainties and assumptions, including the risk that the development of our RNAi-based therapeutics may be delayed or may not proceed as planned and we may not be able to complete development of any RNAi-based product, the risk that the FDA approval process may be delayed for any drugs that we develop, risks related to development and commercialization of products by our competitors, risks related to our ability to control the timing and terms of collaborations with third parties and the possibility that other companies or organizations may assert patent rights that prevent us from developing our products. Actual results may differ materially from those contemplated by these forward-looking statements. RXi Pharmaceuticals Corporation does not undertake to update any of these forward-looking statements to reflect a change in its views or events or circumstances that occur after the date of this release.

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