Aduro Biotech Announces Close of Initial Public Offering, Including Full Exercise of Underwriters’ Option to Purchase Additional Shares, and Concurrent Private Placement

Aduro Biotech, Inc. (Nasdaq: ADRO) today announced the closing of its initial public offering of 8,050,000 shares of common stock at a price to the public of $17.00 per share, which included 1,050,000 shares sold pursuant to the exercise in full of the underwriters’ option to purchase additional shares. Aduro estimates the net proceeds from the public offering were approximately $124.3 million after deducting the underwriting discount and estimated offering expenses. Aduro also today announced the closing of its concurrent private placement of 1,470,588 shares of common stock at a price of $17.00 per share, for estimated net proceeds of approximately an additional $25.0 million.

BofA Merrill Lynch and Leerink Partners LLC acted as joint book-running managers for the offering. William Blair and Canaccord Genuity acted as co-managers.

A registration statement relating to these securities was declared effective by the U.S. Securities and Exchange Commission (SEC) on April 14, 2015.

This offering was made only by means of a prospectus. A copy of the final prospectus related to the offering may be obtained at no cost by visiting EDGAR on the SEC’s website (www.sec.gov), or from: BofA Merrill Lynch, 222 Broadway, New York, NY 10038, Attn: Prospectus Department, or by email at dg.prospectus_requests@baml.com; or Leerink Partners LLC, Attention: Syndicate Department, One Federal Street, 37th Floor, Boston, MA 02110, by email at syndicate@leerink.com, or by phone at (800) 808-7525 ext. 6142.

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 jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Aduro

Aduro Biotech, Inc. is a clinical-stage immuno-oncology company focused on the development of technology platforms to stimulate an immune response against cancer. Aduro’s lead platform is based on proprietary strains of live-attenuated, double-deleted (LADD) Listeria monocytogenes that induce a potent innate immune response and have been engineered to express tumor-associated antigens to induce tumor-specific T cell-mediated immunity. Aduro has received Breakthrough Therapy designation from the FDA for its lead LADD regimen, CRS-207 in combination with GVAX Pancreas in pancreatic cancer. The company is evaluating the proprietary immuno-oncology combination in the ongoing Phase 2b ECLIPSE clinical trial and has additional ongoing clinical trials with its LADD platform in mesothelioma and glioblastoma. The company is also developing clinical candidates using cyclic dinucleotide (CDN) synthetic small molecule immune modulators that are designed to activate the intracellular STING receptor, a central mediator of the innate immune response.