Atara Bio Announces Pricing of Its $180.0 Million Offering of Common Stock

SOUTH SAN FRANCISCO, Calif., July 9, 2015 (GLOBE NEWSWIRE) -- Atara Biotherapeutics, Inc. (Nasdaq:ATRA), a biopharmaceutical company with a focus on developing innovative therapies for patients with debilitating diseases, today announced the pricing of its underwritten public offering of 3,461,538 shares of its common stock at a public offering price of $52.00 per share. In addition, Atara Bio granted the underwriters a 30-day option to purchase up to an additional 519,230 shares of common stock at the public offering price. All of the shares in the offering will be sold by Atara Bio. The offering is expected to close on July 15, 2015, subject to customary closing conditions.

Goldman, Sachs & Co. and Citigroup Global Markets Inc. are acting as joint book-running managers for the proposed offering. William Blair & Company, L.L.C., Canaccord Genuity Inc. and JMP Securities LLC are acting as co-managers.

A registration statement relating to these securities was declared effective by the U.S. Securities and Exchange Commission on July 9, 2015.

The offering is being made only by means of a written prospectus forming part of the effective registration statement. Copies of the final prospectus relating to the offering may be obtained, when available, from Goldman, Sachs & Co., Attention: Prospectus Department, 200 West Street, New York, New York 10282, by telephone at (866) 471-2526, by facsimile at (212) 902-9316, or by email at prospectus-ny@ny.email.gs.com, or from Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY, 11717, by email at prospectus@citi.com or by phone at (800) 831-9146.

This press release shall not constitute an offer to sell or a 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 Atara Biotherapeutics, Inc.

Atara Biotherapeutics, Inc. is a biopharmaceutical company focused on developing innovative therapies for patients with debilitating diseases. Atara Bio's programs include molecularly targeted product candidates and T-cell product candidates. Molecularly targeted product candidates include PINTA 745, STM 434 and ATA 842, members of the TGF-beta family of proteins that target myostatin and activin, and have demonstrated the potential to have therapeutic benefit in a number of clinical indications. T-cell product candidates include EBV-CTL, CMV-CTL and WT1-CTL.

CONTACT: INVESTOR & MEDIA CONTACT:
         Tina Gullotta, Atara Biotherapeutics, Inc.
         650-741-1613
         tgullotta@atarabio.com

         MEDIA CONTACT:
         Susan Heins, Pure Communications, Inc.
         864-286-9597
         susan@purecommunicationsinc.com

Released July 9, 2015