RXi Pharmaceuticals presents new preclinical data from its advanced RNAi therapeutic platform

RXi Pharmaceuticals Corporation (Nasdaq: RXII), a biopharmaceutical company pursuing the development and commercialization of proprietary therapeutics based on RNA interference (RNAi), today announced the presentation of new preclinical data from its advanced RNAi therapeutic platform at its Annual Investor Event held in New York City on Monday, October 5, 2009.

The presented data include results with novel self-delivering (sd-rxRNA™) RNAi compounds, which do not require an additional delivery vehicle to enter cells. The data show significantly improved pharmacological properties of these molecules, with applicability in a broad range of therapeutic applications.

“We are excited about the progress we are making in our sd-rxRNA™ research efforts,” said Tod Woolf, Ph.D. President and CEO of RXi Pharmaceuticals. “A key highlight from our presentation was that recently obtained data with our proprietary sd-rxRNA™ markedly improves the delivery of systemically and locally administered RNAi compounds. RXi and our collaborators in RNAi consider advances in the delivery to be the most important factor for the successful commercialization of RNAi therapeutics. ”

RXi’s therapeutic platform leverages its Next Generation rxRNA™ compounds and advanced delivery technologies to enable its internal programs and external collaborations. This provides RXi with multiple opportunities for the potential development of a sustainable pipeline of RNAi based products for unmet medical needs.

Key findings and highlights from the event include the following:

• Dr. Craig Mello, Nobel Laureate and RXi’s co-founder and Chairman of its Scientific Advisory Board, provided novel insights into the RNAi mechanism which have aided in the design of RXi’s novel rxRNA™ compounds.
• Data presented on the length of compounds showed that reducing the size of RNAi compounds could be important for cellular uptake.
• sd-rxRNA™ compounds were shown to have improved pharmacological and drug-like properties compared to unmodified classic siRNA (short interfering RNA). Research findings on sd-rxRNAs show:
  • Increased serum stability
  • Improved retention in the circulation
  • Minimal immune response activation
  • Efficient cellular uptake and internalization to many diverse cell types
  • Systemic delivery to the liver with effective gene silencing
  • Local delivery via intradermal injection with effective gene silencing
• An update to the status of indications currently being pursued by RXi was provided:
  • Compromised skin – RXi is performing animal studies based on positive data showing spontaneous uptake and enhanced tissue penetration with sd-rxRNA compounds.
  • Inflammatory diseases – RXi is working with researchers from the University of Massachusetts to deliver rxRNA™ compounds using an advanced delivery vehicle that targets macrophage cells.
  • Liver diseases – RXi is exploring sd-rxRNA™ delivery to the liver upon subcutanteous administration to animal models without the use of an additional delivery vehicle. Delivery to the liver may have many applications such as controlling hypercholesterolemia as well as several other metabolic indications.
  • Ocular diseases – RXi has shown spontaneous cellular uptake of its sd-rxRNA™ compounds by retinal cells and is working with an academic collaborator to further address retinal diseases.
  • Amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease) – RXi has established an academic collaboration with one of the leading ALS researchers to explore delivery of sd-rxRNA compounds to the spinal cord.
  • Oncology – RXi has an active pharmaceutical collaboration to explore the potential of using the rxRNA™ therapeutic platform in this area.

• RXi summarized its intellectual property position including its alternative path to RNAi based on the length of rxRNA™ duplexes and distinct end-structures and multiple layers of patent protection for both rxRNA™ compounds and delivery vehicles.