Evaluation of safety switches in HA-1 TCR2–transduced T cells. Comparison of survival of CD8⁺ T cells transduced with LV constructs, including HA-1 TCR2, and various safety switches after exposure to a safety-switch–activating drug (blue bars) or no drug (gray bar). Survival percentage of iCasp9-TCR2–, tEGFR-TCR2–, RQR8-TCR2–, and Myc-TCR2–transduced CD8⁺ T cells was measured after 24 hours of incubation with the optimal concentration of the respective drug: chemical inducer of dimerization (AP1903), anti-EGFR mAb (cetuximab) + complement, anti-CD20 (rituximab) + complement, anti-myc mAb + complement, or media control only. Residual HA-1 TCR2–transduced T cells were quantified by flow cytometry.