January 13, 2010
FOR IMMEDIATE RELEASE

RXI PHARMACEUTICALS AND THE UNIVERSITY OF MASSACHUSETTS MEDICAL SCHOOL ANNOUNCE RESEARCH COLLABORATION FOCUSED ON OCULAR DISEASE

WORCESTER, Mass. – RXi Pharmaceuticals Corporation (Nasdaq: RXII), a biopharmaceutical company pursuing the development and commercialization of proprietary therapeutics based on RNA interference (RNAi), today announced a collaboration with Shalesh Kaushal, M.D., Ph.D., Chairman of the Department of Ophthalmology at The University of Massachusetts Medical School (UMMS). The research collaboration will be focused on the application of RXi’s self-delivering RNAi (sd-rxRNA™) compounds for ocular diseases such as age-related macular degeneration, the leading cause of blindness in Americans over 55 years of age.

RXi previously presented encouraging data on spontaneous cellular uptake and potent activity of sd-rxRNA compounds in retinal cells. The collaboration with UMMS will further advance RXi’s therapeutic platform by evaluating the delivery and silencing activity of sd-rxRNAs in preclinical models of ocular disease.

Noah D. Beerman, President and CEO of RXi Pharmaceuticals commented, “We are eager to explore the use of our sd-rxRNA compounds in additional therapeutic areas, such as ocular disease, and to continue our successful relationship with the leading researchers at UMMS. Leveraging academic collaborations is an essential part of our business strategy and we are looking forward to collaborating with one of the top clinical research ophthalmologists in the U.S.”

Dr. Kaushal commented, “RXi’s next generation sd-rxRNA compounds incorporate many drug-like properties of a successful therapeutic and may improve the clinical success of RNAi therapeutics. I am enthusiastic about the opportunity to work with such promising technology from one of the leading RNAi therapeutics companies.”

About RNA Interference (RNAi) and Self-delivering rxRNA™ (sd-rxRNA™)
Regarded as a revolutionary discovery in biology, RNA interference (RNAi) is a naturally occurring mechanism whereby short, double-stranded RNA molecules interfere with the expression of genes in living cells. This mechanism has the potential to be harnessed to “silence” or specifically block the production of disease-causing proteins before they are made. This technology can potentially be used to treat human diseases by “turning-off” genes that lead to disease in the first place. RXi Pharmaceuticals is using RNAi technology to develop RNA-derived molecules targeting disease-causing genes.

Self-delivering rxRNA™ (sd-rxRNA™) is a proprietary technology developed at RXi which enables the efficient delivery of RNAi compounds without the requirement of an additional delivery vehicle. This technology has an immediate clinical application for diseases where localized delivery is an option and also has the potential to be applied for indications requiring systemic delivery of RNAi.

About RXi Pharmaceuticals Corporation
RXi Pharmaceuticals is a discovery-stage biopharmaceutical company pursuing the development and potential commercialization of proprietary therapeutics based on RNA interference (RNAi) for the treatment of human diseases. RXi has a comprehensive therapeutic platform that includes both RNAi compounds and delivery methods. RXi uses its own version of RNAi compounds -- rxRNA™ -- that provide an advanced alternative to conventional small interfering RNAs (siRNAs) and define the next generation of RNAi technology. rxRNA™ compounds are designed specifically for therapeutic use and contain many of the properties needed to move RNAi based drugs into the clinic. 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 early intellectual property position in RNAi chemistry and delivery. www.rxipharma.com

About the University of Massachusetts Medical School
The University of Massachusetts Medical School, one of the fastest growing academic health centers in the country, has built a reputation as a world-class research institution, consistently producing noteworthy advances in clinical and basic research. The Medical School attracts more than $240 million in research funding annually, 80 percent of which comes from federal funding sources. The mission of the Medical School is to advance the health and well-being of the people of the commonwealth and the world through pioneering education, research, public service and health care delivery with its clinical partner, UMass Memorial Health Care. For more information, visit www.umassmed.edu.

CONTACT:
RXi Pharmaceuticals
Donna Falcetti
508-929-3615
ir@rxipharma.com

or

Investors
S. A. Noonan Communications
Susan Noonan
212-966-3650
susan@sanoonan.com

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Media
Rx Communications Group
Eric Goldman
917-322-2563
egoldman@rxir.com