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Atara Biotherapeutics Presents Positive Efficacy and Safety Results for Patients with Epstein-Barr Virus-Associated Leiomyosarcoma (EBV+ LMS)

December 15, 2018

-- Second EBV‑associated solid tumor with encouraging responses to tab-cel® -- Tab-cel® safety appears consistent with a favorable risk profile and previous observations -- Results were presented today in an oral session at the European Society for Medical Oncology Immuno-Oncology Congress 2018

SOUTH SAN FRANCISCO, Calif., Dec. 15, 2018 (GLOBE NEWSWIRE) -- Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leading off-the-shelf, allogeneic T-cell immunotherapy company developing novel treatments for patients with cancer, autoimmune and viral diseases, today presented results indicating that tab-cel® (tabelecleucel) was generally well tolerated with responses for patients with Epstein-Barr virus-associated leiomyosarcoma (EBV+ LMS). EBV+ LMS is a rare soft tissue sarcoma that occurs in transplant and immunosuppressed patients and is typically an aggressive radiation- and chemotherapy-resistant disease with poor patient outcomes. The results were presented in an oral session at the European Society for Medical Oncology Immuno-Oncology (ESMO I‑O) Congress 2018 taking place in Geneva, Switzerland.

“The EBV+ LMS results presented at ESMO I-O are the second example, along with nasopharyngeal carcinoma (NPC), of a difficult-to-treat, EBV-associated solid tumor with encouraging responses to tab‑cel®,” said Dietmar Berger, M.D., Ph.D., Global Head of Research and Development of Atara Biotherapeutics. “Observations of responses based on standard-CT and metabolic PET-CT imaging, in the context of prolonged survival, further highlight the opportunity for tab‑cel® and off-the-shelf, allogeneic T-cell immunotherapy in EBV-associated cancers beyond our ongoing studies for patients with post‑transplant lymphoproliferative disease (PTLD) and NPC.”

The oral presentation summarized the evaluation of tab-cel® in an analysis of EBV+ LMS patients from three clinical studies, 2 single-center, open-label studies (NCT00002663, NCT01498484) and the multi‑center expanded access protocol (EAP) study (NCT02822495). Twelve patients with EBV+ LMS received one or more doses of tab-cel®, of whom 10 were assessed for responses with two patients not evaluable. Two of the 10 patients achieved a partial response via CT-based RECIST 1.1 criteria and eight patients achieved stable disease. In the two single-center studies with longer follow-up, six of eight patients survived more than 27 months and the estimated median survival was 77.4 months. At the time of this analysis, responses assessed by PET-CT imaging were available from the multi-center EAP study where 3 of the 4 patients achieved a metabolic response. Tab-cel® was generally well tolerated and the safety appeared consistent with a favorable risk profile and previous clinical studies.

About tab-cel® (tabelecleucel)Atara’s most advanced T-cell immunotherapy in development, tab-cel®, is a potential treatment for patients with Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (EBV+ PTLD) who have failed rituximab, as well as other EBV-associated hematologic and solid tumors, including nasopharyngeal carcinoma (NPC). In February 2015, the FDA granted tab-cel® Breakthrough Therapy Designation for EBV+ PTLD following allogeneic hematopoietic cell transplant (HCT), and in October 2016, tab-cel® was accepted into the EMA Priority Medicines (PRIME) regulatory pathway for the same indication, providing enhanced regulatory support. In addition, tab-cel® has orphan status in the U.S. and EU. Tab-cel® is in Phase 3 clinical development for the treatment of EBV+ PTLD following an allogeneic hematopoietic cell transplant (MATCH study) or solid organ transplant (ALLELE study), and Atara recently initiated a Phase 1/2 study in NPC.

About Atara Biotherapeutics, Inc. Atara Biotherapeutics, Inc. ( @Atarabio ) is a leading off-the-shelf, allogeneic T-cell immunotherapy company developing novel treatments for patients with cancer, autoimmune and viral diseases. Atara’s most advanced T-cell immunotherapy, tab-cel® (tabelecleucel), is in Phase 3 development for patients with Epstein-Barr virus-associated post-transplant lymphoproliferative disorder (EBV+ PTLD), as well as other EBV-associated hematologic and solid tumors, including nasopharyngeal carcinoma (NPC). Atara is also developing T-cell immunotherapies targeting EBV antigens believed to be important for the potential treatment of multiple sclerosis (MS). Atara’s pipeline also includes next-generation chimeric antigen receptor T-cell (CAR T) immunotherapies for patients with hematologic and solid tumors, autoimmune and infectious diseases. The company was founded in 2012 and is headquartered in South San Francisco, California.

Forward-Looking StatementsThis press release contains or may imply “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. For example, forward-looking statements include statements regarding: the safety of, and responses to, tab-cel®; the prospects of tab-cel® and off-the-shelf, allogeneic T-cell immunotherapy in EBV-associated cancers; and current clinical results. Because such statements deal with future events and are based on Atara Biotherapeutics’ current expectations, they are subject to various risks and uncertainties and actual results, performance or achievements of Atara Biotherapeutics could differ materially from those described in or implied by the statements in this press release. These forward-looking statements are subject to risks and uncertainties, including those discussed in Atara Biotherapeutics’ filings with the Securities and Exchange Commission (SEC), including in the “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of the Company’s most recently filed periodic reports on Form 10-K and Form 10-Q and subsequent filings and in the documents incorporated by reference therein. Except as otherwise required by law, Atara Biotherapeutics disclaims any intention or obligation to update or revise any forward-looking statements, which speak only as of the date hereof, whether as a result of new information, future events or circumstances or otherwise.

INVESTOR & MEDIA CONTACTS:

Investors:John Craighead, Atara Biotherapeutics650-410-3012 jcraighead@atarabio.com

John Grimaldi, Burns McClellan212-213-0006 x362 jgrimaldi@burnsmc.com

Media:Nancie Steinberg, Burns McClellan212-213-0006 x318 nsteinberg@burnsmc.com

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