Atara Biotherapeutics, Inc. announced plans to complete the Biologics License Application (BLA) submission for patients with EBV+ PTLD in second quarter of 2022. U.S. approval of BLA for patients with EBV+ PTLD anticipated in first quarter of 2023. Following successful interactions with EMA, Atara submitted a Marketing Authorization Application (MAA) for tab-cel in patients with EBV+ PTLD, the first ever for an allogeneic, off-the-shelf T-cell therapy, in November 2021.

With the granting of Accelerated Assessment, the Company anticipates a decision regarding EU approval in fourth quarter of 2022. First presentation of positive data from the pivotal Phase 3 ALLELE study, reinforcing the transformative potential of tab-cel, as an oral session at the 63rdAmerican Society of Hematology (ASH) Annual Meeting in December 2021. Data demonstrated a 50% objective response rate (ORR) and durability of response with 89% of patients responding to treatment surviving after one year, compared with 32% in non-responders.

In a second oral presentation at ASH, longer term data from Phase 2 and Expanded Access Protocol (EAP) studies showed two-year survival benefit of over 86% in responders whether they achieved a complete response (CR) or partial response (PR) and median OS of 54.6 months. Continued favorable tab-cel safety profile and no new safety signals with more than 180 PTLD patients treated to date. EBV+ PTLD is a rare and potentially life-threatening cancer that may occur following a solid organ transplant (SOT) or allogeneic hematopoietic cell transplant (HCT).

For patients with EBV+ PTLD, the median survival is only 0.7 to 4.1 months after failure of initial therapy. There are currently no EMA- or FDA-approved treatments indicated for these patients. Tab-cel for Potential Additional Indications: Enrollment is continuing at sites in the potential label expansion multi-cohort Phase 2 study evaluating six patient populations within EBV+ immunodeficiency-associated lymphoproliferative diseases (IA-LPDs) and other EBV-driven diseases.

First data from the multi-cohort study planned to be presented in 2023. ATA188 for Progressive Multiple Sclerosis (MS). FDA has granted Fast Track designation for ATA188 in non-active primary progressive multiple sclerosis (PPMS) and non-active secondary progressive multiple sclerosis (SPMS), two populations with high unmet medical need and limited treatment options.

A Fast Track designation expedites the review of drugs filling an unmet medical need to treat serious conditions to get important therapies to patients faster; once received, this designation allows early and frequent communication with FDA throughout the development and review process. Atara is continuing to make good progress enrolling the Phase 2 randomized, double-blind, placebo-controlled dose-expansion EMBOLD study evaluating the efficacy and safety of ATA188 in patients with progressive MS. A formal interim analysis is planned for second quarter of 2022, including efficacy and safety, to optimize the likelihood of success in Phase 2 and confirm current development strategy. Following the interim analysis, the Company will communicate next steps for the program, including rationale, while still maintaining the integrity of the study.

Atara plans to conduct pivotal Phase 3 studies at the conclusion of the Phase 2 study and is actively exploring partnership opportunities. One Phase 3 study will focus on non-active SPMS, for which no approved therapies currently exist in U.S. or EU. A separate study will focus on non-active PPMS, which has very few treatment options in most countries and approved therapies are of limited efficacy.

The vast majority of people with PPMS and SPMS have non-active disease. Overall, increasing research activity and support within the academic community for the hypothesis of EBV as a driver of MS pathogenesis. CAR T Programs: Atara continues to advance CAR T programs in liquid and solid tumors, which include a differentiated approach to allogeneic cell therapy, with no gene editing of the T-cell receptor (TCR) and next generation CAR technologies to enhance expansion and persistence of functional T cells.

ATA2271/ATA3271 (Solid Tumors Over-Expressing Mesothelin). Global strategic collaboration for ATA2271 and ATA3271 with Bayer continues to progress well with advancement of the mesothelin-partnered CAR T immunotherapy programs. Data presented at ESMO-IO in December 2021 showed promising early safety and persistence of armored CAR T, ATA2271, in patients with advanced mesothelioma; infusions for the first two patient cohorts have now been completed. Atara is continuing to make progress on IND-enabling studies for ATA3271, an off-the-shelf, allogeneic CAR-T therapy targeting mesothelin using next-generation PD-1 dominant negative receptor (DNR) and 1XX CAR co-stimulatory signaling domain technologies for patients with advanced mesothelioma, and expects a filing in fourth quarter of 2022.

ATA3219 (B-cell Malignancies): Atara continues to advance development of ATA3219, a potential best-in-class allogeneic CD19 CAR T therapy that does not require TCR or human leukocyte antigen (HLA) gene editing, leveraging next-generation 1XX CAR co-stimulatory signaling domain and allogeneic EBV T-cell platform. New pre-clinical data (on file) demonstrated optimized version of ATA3219 with an enhanced memory phenotype, leads to both strong proliferative potential and potent antitumor activity supporting a best-in-class profile. Atara expects to submit an IND for B-cell malignancies in fourth quarter of 2022.