Atara Biotherapeutics to Present 12-Month Data from All Four Cohorts in the Phase 1a Study of ATA188 in Progressive Multiple Sclerosis at MSVirtual2020

Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a pioneer in T-cell immunotherapy leveraging its novel allogeneic EBV T-cell platform to develop treatments for patients with severe diseases, including solid tumors, hematologic cancers and autoimmune disease, today announced the Company will present for the first time 12-month data from all four cohorts in the Phase 1a study of ATA188 for the treatment of progressive forms of multiple sclerosis (MS) at MSVirtual2020: 8th Joint ACTRIMS-ECTRIMS Meeting, held September 11-13, 2020.

In addition to safety, sustained disability improvement (SDI) was assessed, defined as improvement in Expanded Disability Status Scale (EDSS) or Timed 25-Foot Walk (T25W) at ≥2 consecutive time points. Other measures evaluated include Fatigue Severity Score (FSS), 12-item Multiple Sclerosis Walking Scale (MSWS-12), Multiple Sclerosis Impact Scale (MSIS-29), and whole brain volume (via magnetic resonance imaging, MRI).

As reported in the abstract available today, data indicate ATA188 is well-tolerated at all dose levels. Patients who achieved SDI at any time point maintained it at all future time points; these patients also showed a trend toward improvement in fatigue, physical function, and MRI whole brain volume at 12 months. As of June 2020, open-label extension (OLE) data from the 15-month time point was also available for four patients in cohorts 1-3; the three patients that achieved SDI at six and 12 months, maintained it at 15 months. The 12-month data for cohort 4 and updated OLE data will be presented in an e-poster on September 11.

In addition, Atara will present in an e-poster data reinforcing the proposed mechanism of action (MOA) of ATA188 by targeting EBV antigens, which further supports the role of EBV in MS. The Company will also present study design details for the currently enrolling Phase 1b randomized, double-blind, placebo-controlled portion of the study.

Abstracts are available on the MSVirtual2020 Website on Tuesday, September 1 at 7:00 a.m. ET. E-posters will be made available on Friday, September 11 at 8:00 a.m. ET.

Details of the MSVirtual2020 e-Poster Presentations:
Title: Phase I study of ATA188, an off-the-shelf, allogeneic Epstein-Barr virus-targeted T-cell immunotherapy for progressive forms of multiple sclerosis
Poster #: P0226
Abstract #: 1635

Title: Phase I, multicenter, two-part study of ATA188, an open-label, dose-escalation and double-blind, placebo-controlled dose-expansion study
Poster #: P0227
Abstract #: 1691

Title: Gene expression profiling and TCR diversity of ATA188, an off-the-shelf, allogeneic EBV-targeted T-cell immunotherapy for progressive MS (encore from AAN 2020)
Poster #: P0084
Abstract #: 1770

Atara Conference Call and Webcast Information

Atara will hold a conference call at 8:30 a.m. ET/5:30 p.m. CEST for analysts and investors to review the Phase 1a data and Atara’s continued plans for the ATA188 program. The call will include:

• Pascal Touchon, President and Chief Executive Officer, Atara Biotherapeutics
• Jakob Dupont, MD, Executive Vice President, Global Head of Research and Development, Atara Biotherapeutics
• AJ Joshi, MD, Senior Vice President and Chief Medical Officer, Atara Biotherapeutics

Analysts and investors can participate in the conference call by dialing (888) 540-6216 for domestic callers and (734) 385-2715 for international callers, using the conference ID 6694633. A live audio webcast can be accessed by visiting the Investors & Media – News & Events section of atarabio.com. An archived replay will be available on the Company's website for 30 days following the live webcast.

About ATA188

Epstein-Barr Virus (EBV) is associated with a wide range of hematologic malignancies and solid tumors, as well as certain autoimmune conditions such as multiple sclerosis (MS). T cells are a critical component of the body’s immune system and can selectively target EBV believed to be important in the pathogenesis of MS.

Off-the-shelf, investigational ATA188, has the potential to target EBV-infected B cells and plasma cells in the central nervous system that may catalyze autoimmune responses and MS pathophysiology.

Atara is advancing a Phase 1 ATA188 clinical study in patients with progressive MS across clinical sites in the U.S. and Australia.

About Atara Biotherapeutics, Inc.

Atara Biotherapeutics, Inc. (@Atarabio) is a pioneer in T-cell immunotherapy leveraging its novel allogeneic EBV T-cell platform to develop transformative therapies for patients with severe diseases including solid tumors, hematologic cancers and autoimmune disease. With our lead program in Phase 3 clinical development, Atara is the most advanced allogeneic T-cell immunotherapy company and intends to rapidly deliver off-the-shelf treatments to patients with high unmet medical need. Our platform leverages the unique biology of EBV T cells and has the capability to treat a wide range of EBV-associated diseases, or other severe diseases through incorporation of engineered CARs (chimeric antigen receptors) or TCRs (T-cell receptors). Atara is applying this one platform to create a robust pipeline including: tab-cel® (tabelecleucel) in Phase 3 development for Epstein-Barr virus-driven post-transplant lymphoproliferative disease (EBV+ PTLD); ATA188, a T-cell immunotherapy targeting EBV antigens as a potential treatment for multiple sclerosis; and multiple next-generation chimeric antigen receptor T-cell (CAR-T) immunotherapies for both solid tumors and hematologic malignancies. Improving patients’ lives is our mission and we will never stop working to bring transformative therapies to those in need. Atara is headquartered in South San Francisco and our leading-edge research, development and manufacturing facility is based in Thousand Oaks, California. For additional information about the company, please visit atarabio.com and follow us on Twitter and LinkedIn.

Forward-Looking Statements

This 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 potential benefits, safety and efficacy of ATA188; the results and data from the Phase 1a study of ATA188; and Atara’s ability to successfully advance the development of ATA188. These forward-looking statements are subject to risks and uncertainties, including, without limitation, risks and uncertainties associated with the costly and time-consuming pharmaceutical product development process and the uncertainty of clinical success; the COVID-19 pandemic, which may significantly impact (i) our business, research, clinical development plans and operations, including our operations in South San Francisco and Southern California and at our clinical trial sites, as well as the business or operations of our third-party manufacturer, contract research organizations or other third parties with whom we conduct business, (ii) our ability to access capital, and (iii) the value of our common stock; the sufficiency of Atara’s cash resources and need for additional capital; and other risks and uncertainties affecting Atara’s and its development programs, 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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20200901005427/en/