Sirna Therapeutics, Inc. To Present At 2006 Biotechnology Industry Organization (BIO) InvestorForum

SAN FRANCISCO, Oct. 11 /PRNewswire-FirstCall/ -- Sirna Therapeutics, Inc. (“Sirna”) , a leading RNAi therapeutics company, announced today that senior management will give a company presentation at the 2006 Biotechnology Industry Organization InvestorForum on Wednesday, October 18, 2006 at 11:00 a.m. PT at the Palace Hotel in San Francisco, CA.

For more information on this conference, please log onto: http://investorforum.bio.org/opencms/bif/2006/index.jsp

About Sirna Therapeutics

Sirna Therapeutics is a clinical-stage biotechnology company developing RNAi-based therapies for serious diseases and conditions, including age-related macular degeneration (AMD), hepatitis C, dermatology, asthma, respiratory syncytial virus (RSV) and Huntington’s disease. Sirna Therapeutics completed its Phase 1 clinical trial for Sirna-027 in AMD in 2005 and with its strategic partner, Allergan, Inc., is moving Sirna-027 forward into Phase 2 clinical trials. Sirna has selected a clinical candidate for hepatitis C virus, Sirna-034, which the Company plans to bring into Phase 1 clinical trials by the end of 2006. Sirna has established an exclusive multi-year strategic alliance with GlaxoSmithKline for the development of siRNA compounds for the treatment of respiratory diseases. Sirna has a leading intellectual property portfolio in RNAi covering over 250 mammalian gene and viral targets and over 200 issued or pending patents covering other major aspects of RNAi technology, including the microRNA technology. More information on Sirna Therapeutics is available on the Company’s web site at http://www.sirna.com.

Safe Harbor Statement

Statements in this press release which are not strictly historical are “forward-looking” statements which should be considered as subject to many risks and uncertainties. For example, most drug candidates do not become approved drugs. The development of Sirna-027 and Sirna-034 as well as Sirna’s other programs are still at a relatively early stage. All of these programs, and Sirna’s ability to obtain milestone and royalty payments for them, are subject to significant risks and unknowns, are highly contingent upon future successes, and require significant funding. In addition, patent applications may not result in issued patents, and issued patents may not be enforceable or could be invalidated. Other risks and uncertainties include, among others, Sirna’s early stage of development, Sirna’s history and expectation of losses and need to raise capital, Sirna’s need to obtain clinical validation and regulatory approval for Sirna-027, Sirna-034 and Sirna’s other product candidates, any of which could have negative results, Sirna’s need to engage collaborators, Sirna’s need to obtain and protect intellectual property, and the risk of third-party patent infringement claims. These and additional risk factors are identified in Sirna’s Securities and Exchange Commission filings, including Forms 10-K and 10-Q and in other SEC filings. Sirna undertakes no obligation to revise or update any forward-looking statements in order to reflect events or circumstances that may arise after the date of this release.

Contacts: Stephan Herrera Executive Director, Investor Relations Sirna Therapeutics, Inc. +1 415 512 7200 herreras@sirna.com Stephanie Carrington The Ruth Group +1 646 536 7017 scarrington@theruthgroup.com

Sirna Therapeutics, Inc.

CONTACT: Stephan Herrera, Executive Director, Investor Relations of SirnaTherapeutics, Inc., +1-415-512-7200, herreras@sirna.com; or StephanieCarrington of The Ruth Group, +1-646-536-7017,scarrington@theruthgroup.com, for Sirna Therapeutics, Inc.

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