RXi Pharmaceuticals to present in vivo data of rxRNA compounds

RXi Pharmaceuticals Corporation (Nasdaq: RXII), a biopharmaceutical company pursuing the development and commercialization of proprietary therapeutics based on RNA interference (RNAi), today announced that it will be presenting new in vivo data on its self-delivering rxRNA™ compounds at a number of upcoming scientific conferences, detailed below.

The presentations will include in vivo data showing dramatic improvements to the pharmacological properties of RNAi compounds when using the proprietary chemistries of RXi’s self-delivering rxRNA™ (sd-rxRNA™). The improvements increase the blood circulation time of such compounds 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 could dramatically advance the field of RNAi therapeutics and the development of many novel disease treatments.

Delivery is a key factor in RNAi drug development and the vast majority of companies developing RNAi therapeutics, including RXi, have been trying to use delivery vehicles to deliver RNAi drugs to desired tissues and cells within the body. Historically, RNAi drug compounds not encapsulated by a delivery vehicle were typically cleared by the kidneys almost immediately. Through the creation and development of sd-rxRNA™ compounds, RXi has addressed one of the major issues in RNAi drug development. Since sd-rxRNA™ compounds do not require an additional delivery vehicle, they may potentially provide significant competitive advantages in efficacy, toxicity, ease of administration and manufacturing cost.

The conference presentations by management include the following events:

--Tod Woolf, Ph.D., President and CEO of RXi Pharmaceuticals, will present the data in his keynote presentation at the 2009 Life Science Regional Technology Symposium being held at the Woodbridge Hilton in Iselin, New Jersey on Tuesday, September 15, 2009 at 10:15 am ET.

--Dmitry Samarsky, Ph.D., Vice President of Technology Development for RXi will also be presenting the data at the Select Biosciences RNAi Europe conference in Berlin, Germany on September 18^th at 10:45 am local time and at the Biologics Drug Delivery & Beyond conference in Boston, MA on Thursday September 24, 2009 at 4:15 pm ET.