Phase I, Interventional, Single Arm, Open Label, Treatment Study to Evaluate The Safety and Tolerability of CLL1-CD33 cCAR in Patients With Relapsed and/or Refractory, High Risk Hematologic Malignancies.

AML bears heterogeneous cells that can consequently offset killing by single-CAR-based therapy, which results in disease relapse. Leukemic stem cells (LSCs) associated with CLL1 expression comprise a rare population that also plays an important role in disease progression and relapse for myeloid malignancies. CD33 is widely expressed in AML, high risk myelodysplastic syndromes (MDS) and myeloproliferative neoplasms. Targeting both CD33 and CLL1 surface antigens together may offer two distinct benefits. First, targeting both bulk disease and leukemic stem cells together allows for a more comprehensive ablation of the disease. Second, dual targeting of myeloid malignancies by both CD33 and CLL1 directed therapy overcomes the pitfalls of single-antigen therapy by preventing relapse due to antigen loss. While loss of a single antigen under antigen-specific selection pressure is possible, loss of two antigens simultaneously is much less likely.

CLL1-CD33 cCAR is a compound Chimeric Antigen Receptor (cCAR) immunotherapy with two distinct functional CAR molecules expressed on a T-cell, directed against the surface proteins CLL1 and CD33. cCAR intends to target the mechanisms of single-CAR relapse, specifically antigen escape and leukemic stem cells.