ATA2271 and ATA3271: Mesothelin CAR T Programs in Solid Tumors

ATA2271 – Autologous Mesothelin-Targeted CAR T Program in Solid Tumors
  • Mesothelin is a target associated with aggressive solid tumors
  • Expresses scFv that binds to mesothelin above cancer threshold
  • Incorporates next-generation CAR T technologies combining novel 1XX costimulatory domain and PD-1 Dominant Negative Receptor (DNR)
  • ATA3271: off-the-shelf, allogeneic EBV mesothelin CAR T


Autologous ATA2271 is in Phase 1 development and allogeneic ATA3271 is in preclinical development: both target solid tumors expressing the tumor antigen mesothelin and leverage novel next-generation 1XX co-stimulatory domain and PD-1 Dominant Negative Receptor technologies.

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  • ATA2271: Mesothelioma & other solid tumors
    Phase 1
  • ATA3271: Mesothelioma & other solid tumors

Atara’s Next-Generation Solid Tumor CAR T cells

T and B-cell fractions are separated from a healthy donor via leukapheresis. The CD19+ fraction is transformed with EBV, generating an EBV+ lymphoblastoid cell line (BLCL). T cells are stimulated with BLCLs prior to retroviral introduction of mesothelin (MSLN)-targeted CAR with 1XX signaling domain and PD1DNR. The mesothelin scFv is derived from human anti-MSLN antibody m912. Continued expansion of MSLN-1XX-PD1DNR CAR+ EBV T cells (ATA3271) occurs with BLCL stimulation prior to harvest and cryopreservation for later use.

Solid Tumor Cart Cells
EBV CAR T Cells Expressing MSLN-1XX CAR and PD1DNR

Next-Generation CAR T Technology

Our preclinical pipeline is rapidly expanding with novel technologies and next-generation, multi-targeted CAR T immunotherapies thanks to our collaborations with Moffitt Cancer Center and Memorial Sloan Kettering Cancer Center.