BRISBANE, CA, Atara Biotherapeutics, Inc., a drug development company with a focus on innovative therapies for patients with debilitating diseases, announced today a second closing of its recently announced Series B financing, bringing the total raised this round to $52 million. Investors in the Series B include Alexandria Venture Investments, Amgen Ventures, The Baupost Group, Celgene Corporation (Nasdaq: CELG), DAG Ventures, Domain Associates, EcoR1 Capital and Kleiner Perkins Caufield & Byers.

Proceeds will be used to accelerate the clinical development of Atara's two lead programs, PINTA 745 and STM 434, which are expected to generate new clinical data within the next 18 months. PINTA 745 is a myostatin inhibiting peptibody in Phase 2 development as a potential treatment for protein energy wasting (PEW), a form of inflammation, malnutrition and muscle wasting in patients with end-stage renal disease. STM 434, an inhibitor of activin, represents a novel targeted approach for the treatment of ovarian cancer as well as other solid tumors. The Atara team plans to submit an investigational new drug (IND) application to the U.S. Food and Drug Administration to conduct a first-in-human, Phase 1 study of STM 434.

In addition, Atara announced that Isaac Ciechanover, M.D., chief executive officer, is scheduled to present at the 32nd Annual J.P. Morgan Healthcare Conference on Wednesday, January 15, 2014 at 3:30 p.m. PST in San Francisco.

About Atara Biotherapeutics

Atara Biotherapeutics, Inc. is a privately-held drug development company with a focus on innovative therapies for patients with debilitating diseases. The research of Atara and its family of companies is based on groundbreaking discoveries regarding the ability of activin, myostatin and other biological targets to change the course of disease progression. Atara has three novel biologics in development, including PINTA 745 (Phase 2) for protein energy wasting in end-stage renal disease, STM 434 (IND-ready) for ovarian cancer and other solid tumors, and NINA 842 (pre-clinical) for cancer-related cachexia. Atara and its family of companies were launched in 2012 by a proven team of drug developers, Amgen, and Kleiner Perkins Caufield & Byers. For more information, please visit www.atarabio.com.