Development of CD33-Targeted Dual Drug-Loaded Nanoparticles for the Treatment of Pediatric Acute Myeloid Leukemia.

Paediatric acute myeloid leukemia (AML) is a heterogeneous hematological malignancy still heavily reliant on traditional chemotherapeutic approaches. Combination treatments have shown to be a superior approach, but their success is often hindered by side effects and different drugs' pharmacokinetics. Here, we investigated ABT-737 and Purvalanol A as a potential drug pairing for pediatric AML and described the development of CD33-targeted polymeric nanoparticles (NPs) to enable their simultaneous targeted codelivery. Separate drug encapsulation within poly(lactic--glycolic acid) (PLGA) NPs was optimized prior to coencapsulation of both drugs at a synergistic ratio in PEGylated PLGA NPs. The therapeutic effects of formulations were evaluated in a panel of pediatric AML cells, and dual drug-loaded NPs (dual NPs) demonstrated significantly enhanced apoptotic cell death. Moreover, conjugation to gemtuzumab resulted in improved NP binding and internalization in CD33-positive cells. Finally, CD33-targeted dual-loaded NPs showed enhanced cytotoxicity to CD33-positive AML cells via CD33-mediated targeted drug delivery.