UPDATE: New Abstract Links -- Atara Bio Announces Presentations of Clinical Data from EBV-CTL and STM 434 Product Candidates at the Upcoming 2016 American Society of Clinical Oncology (ASCO) Annual Meeting

SOUTH SAN FRANCISCO, Calif., May 18, 2016 (GLOBE NEWSWIRE) -- Atara Biotherapeutics, Inc. (Nasdaq:ATRA), a biopharmaceutical company focused on developing meaningful therapies for patients with severe and life-threatening diseases that have been underserved by scientific innovation, today announced presentations of clinical data from two of the Company’s clinical-stage programs at the upcoming ASCO 2016 Annual Meeting, which will take place in Chicago, IL, June 3-7, 2016. The Company’s collaborating investigators at Memorial Sloan Kettering Cancer Center (MSK) will deliver clinical results in an oral presentation for Atara’s allogeneic Epstein-Barr virus Cytotoxic T-Lymphocyte (EBV-CTL) product candidate in the treatment of patients with nasopharyngeal carcinoma (NPC). Also at ASCO, Atara will highlight in a poster presentation the initial clinical experience with the Company’s molecularly targeted product candidate, STM 434, currently in an ongoing Phase 1 dose escalation trial in patients with ovarian cancer or other advanced solid tumors.

Details of the presentations are as follows:

EBV-CTL

Oral Presentation Title: Treatment of EBV+ Nasopharyngeal Carcinoma with Banked EBV-Specific Cytotoxic T Cells
Date & Time: Monday, June 6^th, 2016; 3:48 - 4:00 p.m. Central Time
Session Title: Adoptive T-Cell Therapies for Cancer
Location: Hall D2, McCormick Place, Chicago, IL
Authors: S. Prockop, E. Doubrovina, S. S. Baxi, V. Escobedo, S. Suser, V. Szenes, D. G. Pfister, R. J. O'Reilly; Memorial Sloan Kettering Cancer Center
Abstract: #3012, full text of abstract can be found here

STM 434

Poster Presentation Title: Preliminary results from the first in human study of activin-A inhibitor, STM434, in patients with granulosa cell ovarian cancer and other advanced solid tumors
Date & Time: Monday, June 6^th, 2016; 1:00 - 4:30 p.m. Central Time
Session Title: Gynecologic Cancer
Location: Hall A, McCormick Place, Chicago, IL
Authors: D. Hyman,¹ D. Rasco,² J. R. Infante,³ J. Liu,⁴ E. Welkowsky,⁵ D. Thai,⁵ and C. Haqq⁵; Memorial Sloan Kettering Cancer Center,¹ South Texas Accelerated Research Therapeutics,² Sarah Cannon Research Institute,³ Dana Farber Cancer Institute,⁴ Atara Biotherapeutics⁵
Abstract: #5536, full text of abstract can be found here

About EBV-CTL

T-cells are a critical component of the body's immune system and can be harnessed to counteract viral infections and some cancers. By focusing the T-cells on specific proteins involved in cancers and infections, the power of the immune system can be employed to combat these diseases. Atara Bio's EBV-CTL utilizes a technology in which T cells are collected from the blood of third-party donors and then exposed to EBV antigens. The resulting activated T cells are then expanded, characterized, and stored for future therapeutic use in an appropriate partially human leukocyte antigen, or HLA, matched patient, providing an "off-the-shelf," allogeneic, cellular therapeutic option for patients.  EBV-CTLs are designed to find cancer cells expressing EBV and kill them. Phase 2 clinical results from trials conducted at MSK have been reported in multiple peer-reviewed forums. Atara Bio plans to commence two pivotal clinical trials of EBV-CTL for rituximab-refractory EBV Post-Transplant Lymphoproliferative Disorder (EBV-PTLD) following hematopoietic cell transplant (HCT), as well as solid organ transplant (SOT), towards the end of 2016.

About STM 434

STM 434, one of Atara Bio's molecularly targeted product candidates, is a fusion protein that binds Activin A and other ligands of the ActR2B receptor. Activin has been shown to be involved in the growth and proliferation of ovarian cancer and other tumors, with published evidence of its role at both the genetic, or messenger RNA, and protein levels. Activin expression is one of a few biomarkers associated with larger tumor volume and poorer outcomes, including shortened survival, in a variety of malignancies including ovarian cancer.

We are currently testing STM 434 in a three-part Phase 1 clinical trial designed to enroll patients with advanced ovarian cancer and other solid tumors.  Part 1 is a dose escalation in patients with advanced solid tumors; Part 2 is a monotherapy dose expansion in patients with advanced granulosa cell ovarian cancer; and Part 3 is designed to study STM 434 both as a monotherapy and in combination with other therapies in patients with advanced ovarian cancer.

About Atara Biotherapeutics, Inc.

Atara Biotherapeutics, Inc. is a biopharmaceutical company focused on developing meaningful therapies for patients with severe and life-threatening diseases that have been underserved by scientific innovation, with an initial focus on immunotherapy and oncology. Atara Bio’s programs include T cell product candidates and molecularly targeted product candidates. The T cell product candidates include EBV-CTL, CMV-CTL and WT1-CTL and harness the power of the immune system to recognize and attack cancer cells and cells infected with certain viruses. The molecularly targeted product candidates include STM 434. These product candidates target activin and myostatin, members of the TGF-beta family of proteins, and have demonstrated the potential to have therapeutic benefit in a number of clinical indications.

INVESTOR & MEDIA CONTACT:

Investors:
Steve Klass
212-213-0006 x331
sklass@burnsmc.com

Media:
Justin Jackson
212-213-0006 x327
jjackson@burnsmc.com

Released May 18, 2016