Regulus Announces Pricing of Public Offering of Common Stock of 4.5 Million Shares at $9.50

Regulus Therapeutics Inc.

, a biopharmaceutical company leading the discovery and development of innovative medicines targeting microRNAs, announced today the pricing of a public offering of 4,500,000 shares of its common stock at a price of $9.50 per share. The gross proceeds to Regulus from this offering are expected to be approximately $42.8 million, before deducting underwriting discounts and commissions and estimated offering expenses payable by Regulus. The offering is expected to close on or about July 22, 2013, subject to customary closing conditions. Regulus has also granted the underwriters a 30-day option to purchase up to an additional 675,000 shares at the public offering price to cover overallotments, if any. Lazard Capital Markets LLC, Cowen and Company, LLC and BMO Capital Markets Corp are acting as joint book-running managers for the offering. Needham & Company, LLC and Wedbush PacGrow Life Sciences are acting as co-managers. A registration statement relating to these securities was declared effective by the Securities and Exchange Commission on July 16, 2013. The offering is being made only by means of a prospectus, copies of which may be obtained from Lazard Capital Markets LLC, Attn: Syndicate Department, 30 Rockefeller Plaza, 48th Floor, New York, NY 10112, Telephone: (800) 542-0970; from Cowen and Company, LLC (c/o Broadridge Financial Services, 1155 Long Island Avenue, Edgewood, NY 11717, Attn: Prospectus Department, Telephone: (631) 274-2806, Fax: 631-254-7140); or from BMO Capital Markets Corp, Attention: Equity Syndicate Department, 3 Times Square New York, NY 10036, Telephone: (800) 414-3627, E-mail: bmoprospectus@bmo.com. This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other jurisdiction. About Regulus Regulus Therapeutics Inc. is a biopharmaceutical company leading the discovery and development of innovative medicines targeting microRNAs. Regulus is leveraging a mature therapeutic platform based on technology that has been developed over 20 years. Regulus works with a broad network of academic collaborators and leverages the oligonucleotide drug discovery and development expertise of its founding companies, Alnylam Pharmaceuticals and Isis Pharmaceuticals. Regulus is developing RG-101 for the treatment of HCV and is advancing other microRNA therapeutics toward clinical development in several areas, including oncology, fibrosis and metabolic diseases. Regulus has formed strategic alliances with AstraZeneca, GlaxoSmithKline and Sanofi and a research collaboration with Biogen Idec.