Abstract 1548: CO-1008, an ADC program targeting leukemic progenitor and blast AML cells, but not normal hematopoetic progenitor cells

The overall survival of patients diagnosed with Acute Myeloid Leukemia (AML) remains low. While initial responses to therapy are favorable, the duration of response is short, and overcoming therapeutic resistance has proven difficult. The presence of chemoresistant leukemic stem cells (LSCs), among other mechanisms, has been implicated as a driver in the observed relapse. Antibody-drug conjugates (ADC) are targeted cancer therapeutics that leverage antigen specificity to deliver a potent cytotoxic payload. Recently, ADCs have shown promise in the clinic, but can also present safety and efficacy concerns. Mylotarg, an FDA approved CD33-directed ADC used to treat Acute Myeloid Leukemia, was the first ADC to be approved. The therapeutic is active against most AML tumors but can lead to severe myelotoxicity given the expression of CD33 on normal myeloid progenitor cells. We leveraged a pharmaco-pheno-multiomic analysis of primary AML tumors to uncover a previously unexplored target expressed on both LSCs and AML blasts, but not normal hematopoetic progenitor cells or other normal tissue. The target also showed capacity to rapidly internalize and has activity of well-established oncogenic kinases associated with expression. A novel monoclonal antibody (IgG1) with favorable binding and biophysical characteristics was established against this novel target and conjugated to a highly potent cytotoxic agent, creating a novel ADC. This ADC shows strong binding across AML tumors with effective internalization and highly potent killing of AML tumors. Citation Format: Garima Kaushik, Bandana Vishwakarma, Marina Bell, Kakajan Komurov. CO-1008, an ADC program targeting leukemic progenitor and blast AML cells, but not normal hematopoetic progenitor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1548.