The deal covered the US biotech’s next-generation mesothelin-directed CAR-T cell therapies for treatment of solid tumors including ATA3271, an armored allogeneic next generation allogeneic T-cell immunotherapy, and an autologous version, ATA2271.

Atara said on May 19 it had received notification of Bayer’s intention to end the agreement, following the German pharma and agrochemicals group’s “strategic review and asset level prioritization of its pipeline,” including cell and gene therapy.

Bayer’s decision to quit the pact came three months after a death was recorded during clinical trials with ATA2271 – for which Atara had responsibility. The Memorial Sloan Kettering Cancer Center then paused enrollment.

The deceased patient reportedly was in a higher-dose cohort of the dose-escalation study investigating ATA2271 as a treatment for people with malignant pleural mesothelioma. Atara said the patient had a history of multiple malignancies and other comorbidities. No dose-limiting toxicities were reported in the two lower dose cohorts.

On termination of the agreement, which will take effect in September this year, Bayer will return the rights and licenses granted by Atara in full to the US partner.

As part of the deal, Atara had secured $60 million upfront from Bayer, along with up to $610 million in milestones for worldwide rights to an early-phase autologous CAR-T and a preclinical off-the-shelf asset. For a limited time, Bayer was to have a nonexclusive right to negotiate a license for additional Atara CAR-T product candidates.

Jakob Dupont, Atara’s global research & development head, said that, based on the clinical and pre-clinical data generated to date, the South San Francisco-based biotech remains confident in the potential of ATA2271 and ATA3271 to address patient need in solid tumors and is reassessing its strategy on how best to generate value from the programs moving forward. The company, however, has abandoned plans to submit a request to the FDA in the 2022 fourth quarter for a clinical trial of ATA3721.

Author: Dede Williams, Freelance Journalist