Atara Biotherapeutics, Inc., a drug development company with a focus on innovative therapies for patients with debilitating diseases, announced today that it has secured $38.5 million in initial closings under its Series B financing. In this round, investors Amgen Ventures (Nasdaq: AMGN), Celgene Corporation (Nasdaq: CELG), and EcoR1 Capital, joined existing investors Alexandria Venture Investments, DAG Ventures, Domain Associates, 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.

'We founded Atara with the goal of accelerating the development of novel biologic compounds to bring meaningful therapeutic advances to conditions underserved by innovation in recent years,' said Isaac Ciechanover, MD, chief executive officer of Atara. 'This financing allows us to advance our pipeline and moves us closer to achieving our mission of addressing substantial unmet medical needs.'

Within only 15 months of its founding, the Atara team initiated a Phase 2 pilot trial of PINTA 745, a myostatin inhibiting peptibody, being investigated as a potential treatment for protein energy wasting (PEW), a form of inflammation, malnutrition and muscle wasting in patients with end-stage renal disease. PEW is a condition that correlates with adverse outcomes and increased mortality in patients with chronic renal disease receiving dialysis. This condition affects a significant proportion of the 400,000 patients in the US who annually undergo treatment with dialysis. The goals of this Phase 2 trial are to assess PINTA 745 potential effects on lean body mass, physical function, quality of life and other outcomes for these patients.

In addition, the Atara team plans to submit an investigational new drug (IND) application to the US Food and Drug Administration to conduct a first-in-human, Phase 1 study of STM 434, an inhibitor of activin. STM 434 represents a novel targeted approach for the treatment of ovarian cancer as well as other solid tumors. Considered the deadliest cancer for women, ovarian cancer kills approximately 125,000 globally each year. Pre-clinical data with Atara's activin inhibitors suggest an anti-tumor effect as a single agent and additive benefit in combination with chemotherapy.

In conjunction with the financing, Atara announced that it has appointed Joel Marcus, chairman, chief executive officer, and founder of Alexandria Real Estate Equities, Inc. (NYSE: ARE) / Alexandria Venture Investments to the board of directors of the Atara family of companies.

'Atara has moved quickly to build a pipeline of innovative, targeted therapies designed to address the underlying mechanisms of disease, and disease states for which there are few therapeutic options today,' said Mr. Marcus. 'The company has employed a strategic business structure that provides optionality for value creation. I am honored to join the board and the world-class team that Isaac is assembling.'

The financing described above relates to three biotechnology entities - Nina Biotherapeutics, Inc., Pinta Biotherapeutics, Inc., and Santa Maria Biotherapeutics, Inc. - in the Atara family of companies. Atara's unique structure was designed to help enable investors to preserve optionality and maximize potential value creation. Atara has raised more than $58 million to date for this family of companies.

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.