多药物联合化疗的进展使得急性淋巴细胞白血病（ALL）患者的生存率有所提高。然而，相当一部分患者对一线化疗无反应，或在以后复发，并伴随有复发性疾病，此后的长期生存率仍然较低。为了为这些患者开发新的有效治疗选项，我们进行了一系列高通量的联合药物筛选实验，以确定与MRX-2843有协同作用的化疗药物，MRX-2843是一种目前正在临床测试中用于治疗复发/难治性白血病和实体瘤的小分子双重MERTK和FLT3激酶抑制剂。通过实验和计算方法，我们发现MRX-2843与长春碱在B-ALL和T-ALL细胞系的扩增抑制上呈现强烈的、比例相关的协同作用。基于这些发现，我们开发了这些药物的多组分脂质纳米粒子配方，不仅在T-ALL细胞内传递了定义的药物比例，而且在药物封装后也提高了抗白血病活性。通过MRX-2843和长春碱纳米粒子配方处理，我们证实了在T-ALL患者原始细胞样本中的协同和加成作用，提示了它们在临床上的相关性。此外，纳米粒子配方在ETP-ALL的正位移小鼠异种移植模型中减轻了疾病负担并延长了生存时间，两种药物以剂量依赖的方式对治疗活性做出了贡献。与之相反，MRX-2843单独为主的纳米粒子在该模型中无效。因此，MRX-2843在体内增加了ETP-ALL细胞对长春碱的敏感性。在这种情况下，含有剂量更高的MRX-2843的加成纳米粒子提供了比协同纳米粒子更有效的疾病控制。与之相反，含有更高的、对抗性的MRX-2843和长春碱比例的纳米粒子则效果较差。因此，在体内，MRX-2843的药物剂量和比例相关相互作用都显著影响治疗活性。综上所述，这些发现提供了一种系统的高通量联合药物筛选和多药物传递方法，以最大限度地发挥MRX-2843和长春碱在T-ALL中联合应用的治疗潜力，并描述了一种新的转化剂，可用于增强T-ALL患者对长春碱的治疗反应。这种广泛适用的方法还可以应用于开发其他对癌症和其他疾病的治疗具有成熟协同作用的组合产品。版权所有 © 2023 Elsevier B.V.发表。

Advances in multiagent chemotherapy have led to recent improvements in survival for patients with acute lymphoblastic leukemia (ALL); however, a significant fraction do not respond to frontline chemotherapy or later relapse with recurrent disease, after which long-term survival rates remain low. To develop new, effective treatment options for these patients, we conducted a series of high-throughput combination drug screens to identify chemotherapies that synergize in a lineage-specific manner with MRX-2843, a small molecule dual MERTK and FLT3 kinase inhibitor currently in clinical testing for treatment of relapsed/refractory leukemias and solid tumors. Using experimental and computational approaches, we found that MRX-2843 synergized strongly-and in a ratio-dependent manner-with vincristine to inhibit both B-ALL and T-ALL cell line expansion. Based on these findings, we developed multiagent lipid nanoparticle formulations of these drugs that not only delivered defined drug ratios intracellularly in T-ALL, but also improved anti-leukemia activity following drug encapsulation. Synergistic and additive interactions were recapitulated in primary T-ALL patient samples treated with MRX-2843 and vincristine nanoparticle formulations, suggesting their clinical relevance. Moreover, the nanoparticle formulations reduced disease burden and prolonged survival in an orthotopic murine xenograft model of early thymic precursor T-ALL (ETP-ALL), with both agents contributing to therapeutic activity in a dose-dependent manner. In contrast, nanoparticles containing MRX-2843 alone were ineffective in this model. Thus, MRX-2843 increased the sensitivity of ETP-ALL cells to vincristine in vivo. In this context, the additive particles, containing a higher dose of MRX-2843, provided more effective disease control than the synergistic particles. In contrast, particles containing an even higher, antagonistic ratio of MRX-2843 and vincristine were less effective. Thus, both the drug dose and the ratio-dependent interaction between MRX-2843 and vincristine significantly impacted therapeutic activity in vivo. Together, these findings present a systematic approach to high-throughput combination drug screening and multiagent drug delivery that maximizes the therapeutic potential of combined MRX-2843 and vincristine in T-ALL and describe a novel translational agent that could be used to enhance therapeutic responses to vincristine in patients with T-ALL. This broadly generalizable approach could also be applied to develop other constitutively synergistic combination products for the treatment of cancer and other diseases.Copyright © 2023. Published by Elsevier B.V.