对于克服化疗耐药性、在耐受剂量下对增殖缓慢的肿瘤具有杀伤作用的新型ADC药物载荷具有很大需求。二氢卡米霉素是一种已知的高效细胞毒性药物类，具有DNA小沟结合和烷基化特性，同时对化疗耐药性肿瘤也具有活性。虽然多种二氢卡米霉素衍生物已在多年间用作ADC生产的药物载荷，但不利的理化性质妨碍了具有最佳特性的ADC制备。对毒素进行优化，平衡反应性和稳定性特征，并选择最佳连结体，使我们得以开发出新型类似二氢卡米霉素的药物载荷链NMS-P945，适于与mAbs结合，形成可重复的药物抗体比（DAR）>3.5。当与曲妥珠单抗结合时，生成的ADC具有良好的内吞特性，能够诱导旁观者效应和免疫原性细胞死亡。此外，与Her2表达的细胞株同时进行测试时，其显示出较曲妥珠单抗-曲妥珠汀（trastuzumab deruxtecan）更强的目标驱动活性和细胞毒性。在Her2驱动模型中，以耐受剂量治疗的治愈小鼠也观察到了较高的体内疗效。基于小鼠和恒河猴药代动力学和药效动力学（PK/PD）数据开发的模型预测，在给予0.5 mg/kg的曲妥珠单抗-NMS-P945-ADC 2剂量后，可以使患者的肿瘤退缩。因此，鉴于用于ADC制备的优越理化特性以及模型曲妥珠ADC在临床前获得的旁观者效应、免疫原性细胞死亡和对化疗耐药性肿瘤的活性，NMS-P945代表了一种高效的创新药物载荷，用于创造新一代ADC。

New ADC payloads overcoming chemoresistance and killing also poorly proliferating tumors at well tolerated doses are much desired. Duocarmycins are a well-known class of highly potent cytotoxic agents, with DNA minor groove binding and alkylation properties, active also in chemoresistant tumors. Although different duocarmycin derivatives have been used during the years as payloads for ADC production, unfavorable physico-chemical properties impaired the production of ADCs with optimal features. Optimization of the toxin to balance reactivity and stability features and best linker selection allowed us to develop the novel duocarmycin-like payload-linker NMS-P945 suitable for conjugation to mAbs with reproducible Drug Antibody Ratio (DAR) >3.5. When conjugated to trastuzumab it generated an ADC with good internalization properties, ability to induce bystander effect and immunogenic cell death. Moreover, it showed strong target-driven activity in cells and cytotoxic activity superior to trastuzumab deruxtecan tested, in parallel, in cell lines with Her2 expression. High in vivo efficacy with cured mice at well tolerated doses in Her2-driven models was also observed. A developed pharmacokinetic/ pharmacodynamic (PK/PD) model based on efficacy in mice and cynomolgus monkey pharmacokinetic data, predicted tumor regression in patients upon administration of 2 doses of trastuzumab-NMS-P945-ADC at 0.5 mg/kg. Thus, considering the superior physicochemical features for ADC production and preclinical results obtained with the model trastuzumab ADC, including bystander effect, immunogenic cell death and activity in chemoresistant tumors, NMS-P945 represents a highly effective, innovative payload for the creation of novel, next generation ADCs.