Exhibit 99.1
RXi Pharmaceuticals Obtains Direct Ownership of Previously Licensed RNAi
Delivery Intellectual Property
Delivery Intellectual Property
Strengthens Position in RXi Proprietary Self-delivering rxRNA™
Worcester, MA, September 25, 2009 — 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 has recently acquired direct
ownership of technology for which it had previously exercised its option to exclusively license
from Advirna LLC. The novel acquired technologies potentially enable in vivo delivery of RNAi
therapeutics. Terms of the agreement were not disclosed.
Tod Woolf, Ph.D., President and Chief Executive Officer of RXi, stated, “RXi’s self-delivering
rxRNA™ (sd-rxRNA™) technology platform, which is based on a combination of this technology acquired
from Advirna and RXi internally developed technology, has shown extremely promising results in
pre-clinical studies. This prompted us to acquire direct ownership of the technology instead of
merely licensing it. By combining this newly acquired technology into RXi’s own portfolio and
gaining full control of the patent prosecution, we enhance the potential of obtaining broader
claims that would further strengthen RXi’s intellectual property position.”
The broad clinical potential of Advirna’s technology in combination with RXi’s rxRNA™ platform,
which includes sd-rxRNA’s, may enable RXi to develop a robust and sustainable RNAi therapeutic
platform with significant competitive advantages in efficacy, toxicity, ease of administration and
manufacturing costs when compared to traditional RNAi compounds. The unique capabilities of this
technology are generating substantial interest in the scientific and business community.
About RNA Interference (RNAi)
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.
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