The Novel Imiqualine EAPB02303 Is a Potent Drug for Treating Acute Myeloid Leukemia

Although 60% of AML patients respond well to standard chemotherapy, most patients eventually relapse, develop chemoresistance, and do not survive more than five years. Targeted therapies, including analogs of imiquimod belonging to the family of imiqualines, emerged as promising agents against AML. Notably, the first-generation imiqualine EAPB0503 proved selective potency against nucleophosmin-1-mutant (NPM1c) AML. Recently, chemical modifications of EAPB0503 led to the development of the lead compound from the second generation, EAPB02303. Here, we demonstrate that EAPB02303 displays 200-fold greater potency, broader activity across AML subtypes, and, importantly, a distinct mechanistic profile when compared to EAPB0503. Unlike EAPB0503, which primarily targeted <i>NPM1c</i> AML cells, EAPB02303 exhibits broad-spectrum activity across various AML subtypes. Remarkably, EAPB02303 anti-leukemic activity was attributed to the inhibition of PI3K/AKT/mTOR signaling activity. Nevertheless, NPM1c AML cells were more sensitive to EAPB02303, likely due to its ability to promote NPM1c protein degradation. In vivo, EAPB02303 potently reduced the leukemic burden and improved organ tumor infiltration in both wt-<i>NPM1</i> and <i>NPM1c</i> AML xenograft mice. Yet, the significant prolonged survival was exclusive to <i>NPM1c</i> AML xenografts, likely due to superior response conferred by NPM1c degradation. Overall, these findings highlight the potential of EAPB02303 as a powerful therapeutic agent for a range of AML subtypes, supporting its further development for broader clinical use.