 SOUTH SAN FRANCISCO, Calif.--BUSINESS WIRE--Atara Biotherapeutics, Inc. Nasdaq: ATRA, a pioneer in T-cell immunotherapy leveraging its novel allogeneic EBV T-cell platform to develop transformative therapies for patients with serious diseases including solid tumors, hematologic cancers and autoimmune diseases, today announced that it has commenced an underwritten public offering of 150,000,000 of shares of its common stock. In connection with the proposed offering, Atara Biotherapeutics ex 