Company: ATRA
Filing Date: 2025-03-07
Form Type: 10-K
Source: 0000950170-25-035507
Chunk: 16

Company: Atara Biotherapeutics, Inc.
Filing Date: 2025-03-07
Form: 10-K
Item: Item 1
Chunk 16
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 or solid organ transplants (SOT) have a reduced ability to control EBV. Left without appropriate immune surveillance, EBV-transformed cells can, in some patients, proliferate and cause an aggressive, life-threatening cancer called EBV+ PTLD. Nearly all cases of PTLD that occur following HCT are EBV positive while approximately 60% of PTLD cases that occur following SOT are EBV positive.

Historical studies suggest a high unmet medical need for improved therapies in patients with EBV+ PTLD who have failed rituximab or rituximab plus chemotherapy, with approximately 40% to 60% of patients either not responding to or progressing following this first line of therapy. Expected median overall survival in patients with EBV+ PTLD following HCT who have failed rituximab-based first line therapy is approximately 1.7 months, and for patients with EBV+ PTLD following SOT who have failed rituximab-based first line therapy, the median overall survival is approximately 3.3 months. The use of chemotherapy in patients with EBV+ PTLD who have failed rituximab is frequently associated with significant rates of treatment-related mortality due to the frailty of the patients and severe toxicities associated with chemotherapy. Based on our market research, we estimate there were several hundred EBV+ PTLD patients who failed rituximab or rituximab plus chemotherapy in the U.S. in 2019. 

Tab-cel® (Ebvallo™) for EBV+ PTLD

In June 2015, we licensed certain patent rights, know-how and a library of T cells and cell lines specific to EBV from MSK under an exclusive license agreement. In accordance with the license agreement, we agreed to use commercially reasonable efforts to commercialize the licensed products and to make milestone payments with respect to the licensed programs and to make royalty 

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payments to MSK to the extent product candidates arising from the collaboration are commercialized. Our first commercial product, Ebvallo, is part of this MSK collaboration and targets EBV. 

Tab-cel® (Ebvallo™) is an allogeneic EBV-specific T-cell immunotherapy that is approved in the EU and UK and currently in Phase 3 development in the U.S. for the treatment of patients with EBV+ PTLD who have failed rituximab or rituximab plus chemotherapy. Tab-cel is also under development for other EB