Dr. Victor R. Ambros, Discoverer of microRNA, Joins RXi Pharmaceuticals’ Scientific Advisory Board

RXi Pharmaceuticals Corporation (RXi) (Nasdaq: RXII), today announced that Victor Ambros, Ph.D., Professor of Molecular Medicine at the University of Massachusetts Medical School, has been appointed to the Company’s Scientific Advisory Board, increasing the size of the Board to seven members.

Dr. Ambros is known for his groundbreaking 1993 discovery of the first microRNA (miRNA). MicroRNAs are natural RNA interference compounds that are now known to regulate genes involved in a vast array of biological processes, including human disease. Ambros’ discovery has been heralded as a fundamental discovery in physiology and medicine.

Commenting on today’s news, Dr. Tod Woolf, President and Chief Executive Officer of RXi, noted, “It is a pleasure, both professionally and personally, to welcome Victor to the RXi team. I have known Victor since he served on my thesis committee at Harvard. Coincidentally, he served as the Ph.D. thesis advisor to RXi’s founder, Dr. Craig Mello, so this appointment truly brings Victor full circle.”

Dr. Woolf continued, “We look forward to leveraging Victor’s knowledge of microRNAs and genetic pathways. Understanding the natural RNAi (microRNA) process is fundamental to the successful development of RNAi therapeutics and, in particular, the expanding field of microRNA therapeutics. We believe that having the father of microRNAs on our Scientific Advisory Board puts the Company in an even stronger position as we pursue the development of our proprietary therapeutic platform in the areas of neurology, inflammation, metabolic disease and oncology.”

Dr. Ambros earned his Bachelor of Science from the Massachusetts Institute of Technology (MIT) and completed his graduate work with Nobel Prize winner David Baltimore at MIT, studying poliovirus genome structure and replication. He began studying the genetic pathways controlling developmental timing in the nematode C. elegans during his post-doctoral fellowship in Nobel Prize winner H. Robert Horvitz’s lab at MIT, and continued those studies while on the faculty of Harvard from 1984 to 1992, at Dartmouth from 1992 to 2007, and most recently, at the University of Massachusetts Medical School, where he was appointed Professor of Molecular Medicine in early 2008.

It was in 1993 that Dr. Ambros and his team identified the first microRNA, the product of lin-4, a heterochronic gene of C. elegans. Since then, the role of microRNAs in development has been a major focus of his research and there is now a growing body of scientific literature which shows that microRNAs are involved in many diseases, including cancer, diabetes and heart disease.

Among Dr. Ambros’ distinguished recognitions, in April he was awarded the 2008 Gairdner International Award, one of the most prestigious international awards in medical research and dubbed the “Canadian Nobel.” Also in April, Dr. Ambros was one of nine individuals to receive the Benjamin Franklin Medal in Life Sciences. The Franklin Institute Awards are awarded for outstanding achievements that have directly and positively impacted and enhanced the quality of human life and deepened the understanding of the universe.

Dr. Ambros has also received the Brandeis University’s Lewis S. Rosenstiel Award and the Genetics Society of America Medal for outstanding contributions in the past 15 years. In 2002, he was awarded the Newcomb Cleveland Prize from the American Association for the Advancement of Science, of which he is a member. He is the author of numerous publications in the field of RNA and microRNA and is frequent lecturer on microRNA and gene regulatory pathways.

About RXI Pharmaceuticals

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 Pharmaceuticals’ rxRNA(TM) compounds are distinct from the siRNA compounds used by many other companies developing RNAi therapeutics and are believed by the Company, based on its internal research, to be up to 100x more active than conventional siRNA (depending on the target site), nuclease resistant and readily manufactured. 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. 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 $179 million in research funding annually, 80 percent of which comes from federal funding sources. The work of UMMS researcher Craig Mello, PhD, an investigator of the prestigious Howard Hughes Medical Institute (HHMI), and his colleague Andrew Fire, PhD, then of the Carnegie Institution of Washington, toward the discovery of RNA interference was awarded the 2006 Nobel Prize in Physiology or Medicine and has spawned a new and promising field of research, the global impact of which may prove astounding. UMMS is the academic partner of UMass Memorial Health Care, the largest health care provider in Central Massachusetts. For more information, visit www.umassmed.edu.

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, 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 RXi Pharmaceuticals Corporation 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.