Exhibit 99.1
RXi Pharmaceuticals Announces $8.3 Million Public Offering
Worcester, MA, July 31, 2009 — RXi Pharmaceuticals Corporation (Nasdaq: RXII), a biopharmaceutical
company pursuing the development and commercialization of proprietary therapeutics based on RNA
interference (RNAi), announced today that it has entered into definitive agreements for the
purchase of 2,385,715 shares of its common stock at $3.50 per share and warrants to purchase up to
954,286 shares of common stock at an exercise price of $4.50 per share, which will be exercisable
beginning on or about February 4, 2010.
The
offering is expected to close on or about August 4, 2009, subject to the satisfaction of
customary closing conditions. RXi will receive approximately $7.8 million in net proceeds from the
offering. Proceeds from the transaction will be used to meet working capital needs and for general
corporate purposes.
All of the securities were offered pursuant to an effective shelf registration statement. Rodman &
Renshaw, LLC, a subsidiary of Rodman & Renshaw Capital Group, Inc. (Nasdaq: RODM) acted as the
exclusive placement agent for the offering. Griffin Securities, Inc. and Natixis Bleichroeder Inc.
acted as financial advisors to RXi in this placement.
A shelf registration statement relating to the shares of common stock and warrants issued in the
offering (and the shares of common stock issuable upon exercise of the warrants) has been filed
with the Securities and Exchange Commission (the “SEC”) and has been declared effective. A
prospectus supplement relating to the offering will be filed with the SEC. Copies of the prospectus
supplement and accompanying prospectus may be obtained directly from
RXi by contacting RXi
Pharmaceuticals Corporation, 60 Prescott Street, Worcester, MA 01605. This announcement is neither
an offer to sell nor a solicitation of an offer to buy any of our shares of common stock or
warrants. No offer, solicitation or sale will be made in any jurisdiction in which such offer,
solicitation or sale is unlawful.
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 technology 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). rxRNA™
compounds are designed specifically for therapeutic use and may 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,