Bayer Terminates CAR-T Collaboration with Atara Therapeutics

Bayer_Volker Hartmann/Getty Images

Courtesy of Volker Hartmann/Getty Images

Bayer has terminated a two-year-old partnership with Atara Biotherapeutics that included the development of off-the-shelf T-cell immunotherapy for high mesothelin-expressing tumors. Shares of Atara were falling Friday morning following the Thursday afternoon announcement.

In December 2020, South San Francisco-based Atara and life sciences giant Bayer entered into a collaboration valued at nearly $700 million to develop the T-cell immunotherapy for high mesothelin-expressing tumors. Mesothelin is a tumor-specific antigen commonly expressed at high levels on the cell surface in many aggressive solid tumors, including mesothelioma, non-small cell lung cancer, ovarian cancer and pancreatic cancer. 

When the deal was announced, it included two developmental candidates from the Atara pipeline, ATA3271, an armored allogeneic T-cell immunotherapy, and an autologous version, ATA2271, for high mesothelin-expressing tumors such as malignant pleural mesothelioma and non-small-cell lung cancer.

But on Thursday, Atara announced that Bayer had terminated the agreement that was an early cornerstone of its cell and gene therapy strategy. The deal's termination comes about two months after Atara announced a study of ATA2271 was paused following the revelation of a patient's death

In that particular trial, Atara was working with Memorial Sloan Kettering to assess the cell therapy in patients diagnosed with malignant pleural mesothelioma, an aggressive disease typically fatal within 17 months. Although the patient had "a history of multiple malignancies and other comorbidities," an investigation will be conducted to determine if the Atara cell therapy played any role in the death, the company noted at the time. 

Jakob Dupont, head of global research and development at Atara, said the collaboration was ended following a strategic review conducted by Bayer of its rapidly-expanding cell and gene therapy pipeline. While Bayer has terminated the partnership, Dupont noted that preclinical and clinical data already generated provide the company with confidence in the potential of ATA2271 and ATA3271 to address patients' needs in solid tumors. Dupont added that Atara is reassessing its strategy to determine how to best generate value from those programs in the future. 

The Bayer collaboration will be terminated in September. At that time, all rights to ATA2271 and ATA3271 will return to Atara. Both ATA2271 and ATA3271 incorporate Atara's novel inclusion of armoring in the form of a PD-1 DNR construct in order to overcome checkpoint inhibition. 

ATA3271 leverages Atara's EBV T-cell platform and is currently in Investigational New Drug-enabling studies. Atara's allogeneic CAR T therapy is designed to improve current CD19 targeted CAR T therapies by leveraging 1XX CAR signaling technologies built on the company's novel EBV T-cell platform. Regarding the paused Phase I study of ATA2271, Atara anticipates an update in the second half of the year.

In the meantime, Atara will remain focused on its Phase II Embold study of ATA188, Chief Executive Officer Pascal Touchon said in a statement. An interim analysis of that study is expected in June. Also, Touchon said the company will continue to progress its study of tab-cel, which will include a review from the European Medicines Agency and the U.S. Food and Drug Administration regarding an appropriate pathway for a potential Biologics License Application. 

"Given the exciting developments on ATA188 and tab-cel, and our continued progress toward submitting an IND for ATA3219 in Q4 2022, we plan to focus our resources accordingly while we reassess our strategy for our mesothelin CAR T program. Consequently, we will postpone the anticipated IND filing for ATA3271 beyond the fourth quarter of 2022," Touchon said.

Despite the termination of the Bayer agreement, Atara will maintain its cash runway guidance into the fourth quarter of 2023, Touchon said.

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