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Atara Biotherapeutics and Pierre Fabre Laboratories Announce Publication of ALLELE Tab-cel® Phase 3 Data in The Lancet Oncology

First Phase 3 Results of Allogeneic T-Cell Therapy Published

Significant objective response rate of 51.2% and median duration of response of 23.0 months in patients with relapsed or refractory EBV PTLD

US BLA on track for submission in Q2 2024 based on strong clinical record

CASTRES, France and THOUSAND OAKS, Calif., Feb. 2, 2024 /PRNewswire/ — Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leader in T-cell immunotherapy, leverages its novel allogeneic Epstein virus T-cell platform -Barr (EBV) to develop transformative therapies for patients with cancer and autoimmune diseases, and Pierre Fabre Laboratories, a global player in oncology and responsible for the global commercialization of tabelecleucel (tab-cel® or EBVALLO®), today announced that the data from the pivotal phase 3 ALLELE study of tabelecleucel, approved in the European Union in adults and children aged two years and older with relapsed or refractory (r/r) Epstein-Barr virus-positive post-transplant lymphoproliferative disease (EBV PTLD) after solid organ transplantation (SOT) or hematopoietic cell transplantation (HCT), were first published online in TheLancet Oncology.

The data were published in an article titled “Tabelecleucel for allogeneic hematopoietic stem cell or solid organ transplant recipients with Epstein-Barr virus-positive post-transplant lymphoproliferative disease after failure of rituximab or rituximab and chemotherapy (ALELO): a phase 3 , multicenter and open trial”, and can be accessed at the following link: https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(23)00649-6/fulltext

“The results of the ALLELE study highlight the clinical value of tab-cel, which is now approved by the EMA and MHRA, and is being made available to patients in Europe through our partner Pierre Fabre Laboratories as the first treatment of its kind for those with a devastating disease who previously had limited treatment options,” said Pascal Touchon, President and CEO of Atara. “As we prepare for our tab-cel BLA submission in the second quarter of 2024, we look forward to engaging with the FDA to move toward approval based on our strong clinical data.”

As reported in The Lancet Oncology, the ALLELE study met its primary endpoint: 22 of 43 patients with PTLD with EBV achieved an objective response (51.2% objective response rate or ORR). Those who responded to tab-cel had longer survival, with an estimated one-year overall survival of 84.4% (95% CI: 58.9, 94.7) for responders vs. 34.8% (95% CI: 14.6, 56.1) for non-responders. The median duration of response was 23.0 months and the median overall survival was 18.4 months. Tab-cel was well tolerated and there were no reports of tumor exacerbation reaction, cytokine release syndrome, or immune effector cell-associated neurotoxicity syndrome, and no events of graft-versus-host disease or SOT rejection in association with tab-cel. . These data were previously presented at the 2022 American Society of Hematology (ASH) Annual Meeting.

These pivotal trial data are supported by a more recent updated data analysis from the ALLELE study that continued to demonstrate a statistically significant ORR of 49% (p<0.0001), consistent durability of response, estimated OS, and survival profile. favorable safety in the population anticipated for the proposed US label. Additionally, real-world results from the European Expanded Access Program multicenter study demonstrated an ORR of 66.7% in 24 patients with EBV PTLD and were previously presented at the American Society of Clinical Oncology (ASCO) Annual Meeting of 2023.

“Patients with relapsed or refractory EBV PTLD have limited treatment options and poor overall survival measured in just weeks or months,” noted Susan Prockop, MD, principal investigator at Boston Children’s Hospital-Dana Farber Cancer Institute. “These clinically significant data reinforce tabelecleucel’s potential to save lives for these patients, for whom there are no approved therapies in the US, and help address an urgent unmet medical need.”

Tab-cel received marketing authorization under the brand name EBVALLO® in December 2022 by the European Commission (EC) as a monotherapy for the treatment of adult and pediatric patients two years of age and older with r/r EBV PTLD who have received at least one prior therapy. For solid organ transplant patients, prior therapy includes chemotherapy, unless chemotherapy is inappropriate. In the United States, Atara plans to submit a biologics license application (BLA) to the US Food and Drug Administration for tab-cel for the treatment of EBV PTLD in the second quarter of 2024. Additionally, in December 2023 , Atara revealed early results from the ongoing Phase 2 EBVision trial, which has the potential to further expand the clinical experience and potential of tab-cel to broader indications.

In December 2023, Atara announced the closing of the expanded global partnership with Pierre Fabre Laboratories for the United States and the remaining global commercial markets for tabelecleucel, building on an initial partnership covering Europe, the Middle East, Africa and other select emerging markets.

“Current results from the first global, multicenter, open-label Phase 3 study of the novel allogeneic T-cell therapy, tabelecleucel, show significant clinical benefit and a favorable safety profile in a severely affected population. These results bring much hope for patients.” , and confirm the innovative nature of this treatment, also recognized through the Prix Galien award that we received in France. With the recent EU marketing authorization, EBVALLO® is the first EBV-specific allogeneic T cell therapy available for patients with r/ r EBV PTLD after TCH or TOS and their families. All of this resonates perfectly with our purpose of ‘every time we take care of just one person, we make the world better,'” said Núria Perez-Cullell, Director of Affairs Doctors, Patients and Consumers of Pierre Fabre Laboratories.

About Atara Biotherapeutics, Inc.

Atara is harnessing the natural power of the immune system to develop off-the-shelf cell therapies for difficult-to-treat cancers and autoimmune conditions that can be rapidly administered to patients in a matter of days. With cutting-edge science and a differentiated approach, Atara is the first company in the world to receive regulatory approval for an allogeneic T-cell immunotherapy. Our advanced and versatile Epstein-Barr virus (EBV) T-cell platform does not require editing of the T cell receptor or HLA gene and forms the basis of a diverse portfolio of investigational therapies that target EBV, the root cause of certain diseases, as well as next-generation AlloCAR-T designed to provide best-in-class opportunities in a wide range of hematologic malignancies and B cell-driven autoimmune diseases. Atara is based in Southern California. For more information, visit atarabio.com and follow @Atarabio on X and LinkedIn.

About Pierre Fabre Laboratories

Pierre Fabre Laboratories is a leading French medical and beauty care company with 4 decades of experience in innovation, development, manufacturing and marketing in oncology. The company dedicated about 80% of its R&D spending to oncology in 2022, focusing on targeted therapies. Its current commercial portfolio in oncology covers colorectal, breast and lung cancer, melanoma, hematology and precancerous skin conditions such as actinic keratosis.

In 2022, Pierre Fabre Laboratories recorded a turnover of 2.7 billion euros, of which 69% came from international sales in 120 countries. Established in the south-west of France since its creation in 1962, the group manufactures 90% of its products in France and employs around 10,000 people worldwide. The company is 86% owned by the Pierre Fabre Foundation, a government-recognized public interest foundation, and its own employees through an international employee share ownership plan. The sustainability policy of Pierre Fabre Laboratories has been evaluated by the independent certification body AFNOR with the “Exemplary” level of its CSR label (ISO 26,000 standard for sustainable development).

More information about Pierre Fabre Laboratories can be found at www.pierre-fabre.com, @PierreFabre.

Forward-looking statements

This press release contains or may involve “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 development, data, schedule and progress, as applicable, of: (1) the tab-cel program, including a possible BLA filing for tab-cel in the United States; (2) the features and potential benefits of tab-cel, including data and analyzes from the ALLELE study and the timing of such data will be received and reported; and (3) the amended and restated marketing agreement with Pierre Fabre. Because such statements relate to future events and are based on Atara’s current expectations, they are subject to various risks and uncertainties and Atara’s actual results, performance or achievements could differ materially from those described or implied by the statements herein. Press release. These forward-looking statements are subject to risks and uncertainties, including, but not limited to, risks and uncertainties associated with the costly and time-consuming process of pharmaceutical product development and the uncertainty of clinical success; the ongoing COVID-19 pandemic and the wars in Ukraine and the Middle East, which may significantly affect (i) our commercial, research and clinical development plans and operations, including our operations in Southern California and Denver and in 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 do business, (ii) our ability to access capital and (iii) the value of our common stock ; the adequacy of Atara’s cash resources and the need for additional capital; and other risks and uncertainties affecting Atara and its development programs, including those discussed in Atara’s filings with the Securities and Exchange Commission, including the sections “Risk Factors” and “Management’s Discussion and Analysis financial statements and results of operations” in the Company’s most recently filed periodic reports on Form 10-K and Form 10-Q and subsequent filings and in documents incorporated by reference therein. Except as otherwise required by law, Atara 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.

Atara Investor and Media Relations:

Alex ChapmanVice President, Corporate Communications and Investor Relationsachapman@atarabio.com

Jason Awe, Ph.D. Senior Director of Corporate Communications and Investor Relations jawe@atarabio.com

Pierre Fabre Laboratories Media Contact:

Laurence Marchallaurence.marchal@pierre-fabre.com

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