Targeting Two Antigens Associated with B-ALL with CD19-CD123 Compound Car T Cell Therapy

The recent FDA approval of the first CAR immunotherapy marks a watershed moment in the advancement toward a cure for cancer. CD19 CAR treatment for B cell acute lymphocytic leukemia has achieved unprecedented remission rates. However, despite success in treating previously relapsed and refractory patients, CD19 CAR faces similar challenges as traditional chemotherapy, in that malignancy can adapt and overcome treatment. The emergence of both antigen positive and negative blasts after CAR treatment represents a need to bolster current CAR approaches. Here, we report on the anti-tumor activity of a CAR T cell possessing 2 discrete scFv domains against the leukemic antigens CD19 and CD123. We determined that the resulting compound CAR (cCAR) T cell possesses consistent, potent, and directed cytotoxicity against each target antigen population both in vitro and in vivo. Our findings indicate that targeting CD19 and CD123 on B-ALL cells may be an effective strategy for augmenting the response against leukemic blasts and reducing rates of relapse.