Albumin nanocomplex of BCL-2/xL inhibitor reduced platelet toxicity and improved anticancer efficacy in myeloproliferative neoplasm and lymphoma.

The clinical application of BCL-2/xL inhibitors for cancer treatment is limited by the on-target thrombocytopenia. Although APG-1252 was designed to mitigate this issue, platelet toxicity at higher doses in clinical trials restricts dose escalation for greater efficacy. We have developed albumin nanocomplexes of APG-1252 (Nano-1252) to reduce platelet toxicity while improving drug efficacy through enhancing drug delivery to lymphoid organs. Nano-1252 forms stable nanoparticles due to the strong binding affinity between APG-1252 and albumin, reducing the platelet toxicity threshold by fourfold by limiting premature drug release and conversion to its active forms in circulation. Furthermore, Nano-1252 exhibited preferential accumulation in lymphoid organs, leading to enhanced anticancer efficacy in Mantle Cell Lymphoma (MCL) and Myeloproliferative Neoplasms (MPNs) mouse models. Our study not only develops a potential formulation to overcome the current translational barrier of APG-1252 but also reveals novel properties of the well-established albumin nanoformulation, thereby expanding its clinical applications.