Purpose: Antibody-drug conjugates (ADCs) have shown impressive clinical activity with approval of many agents in hematological and solid tumors. However, challenges remain with both efficacy and safety of ADCs. This study describes novel trastuzumab-auristatin conjugates with the hydrophilic MMAE prodrug MMAU, and optimization of a glycopeptide linker leading to a wider therapeutic window. Experimental Design: Trastuzumab was conjugated with auristatin payloads via a series of linkers using a stabilized maleimide handle. The ADCs were characterized in vitro and their relative in vivo anti-tumor efficacies were assessed in HER2+ xenograft models. Relative linker stabilities and the mechanism of linker cleavage were studied using in vitro assays. Toxicity and toxicokinetics of the best performing ADC were evaluated in cynomolgus monkey (cyno). Results: The trastuzumab-MMAU ADC with stabilized glycopeptide linker showed maleimide stabilization and higher resistance to cleavage by serum and lysosomal enzymes compared to a valine-citrulline conjugated trastuzumab ADC (trastuzumab-vc-MMAE). A single dose of 1 or 2 mg/kg of trastuzumab-MMAU at drug-to-antibody ratios (DAR) of 8 and 4 respectively resulted in xenograft tumor growth inhibition, with superior efficacy to trastuzumab-vc-MMAE. Trastuzumab-MMAU DAR4 was tolerated at doses up to 12 mg/kg in cyno, which represents 2- to 4-fold higher dose than that observed with vedotin ADCs, and had increased terminal half-life and exposure. Conclusions: The optimized trastuzumab-MMAU ADC showed potent antitumor activity and was well tolerated with excellent pharmacokinetics in non-human primates, leading to a superior preclinical therapeutic window. The data supports potential utility of trastuzumab-MMAU for treatment of HER2+ tumors.

中文翻译：

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曲妥珠单抗-MMAU 抗体-Auristatin 缀合物：缬氨酸-葡萄糖氨酸接头与稳定的马来酰亚胺缀合物可提高体内疗效和耐受性

目的：抗体药物偶联物（ADC）已显示出令人印象深刻的临床活性，许多药物已在血液学和实体瘤中获得批准。然而，ADC 的功效和安全性仍然存在挑战。这项研究描述了新型曲妥珠单抗-auristatin 与亲水性 MMAE 前药 MMAU 的缀合物，以及糖肽接头的优化，从而获得更宽的治疗窗。实验设计：曲妥珠单抗使用稳定的马来酰亚胺手柄通过一系列连接体与阿里他汀有效负载结合。 ADC 在体外进行了表征，并在 HER2+ 异种移植模型中评估了它们的相对体内抗肿瘤功效。使用体外测定研究了相对接头稳定性和接头裂解机制。在食蟹猴 (cyno) 中评估了性能最佳 ADC 的毒性和毒代动力学。结果：与缬氨酸-瓜氨酸缀合的曲妥珠单抗 ADC (trastuzumab-vc-MMAE) 相比，具有稳定糖肽接头的曲妥珠单抗-MMAU ADC 具有马来酰亚胺稳定性，并且对血清和溶酶体酶的裂解具有更高的抗性。单剂量 1 或 2 mg/kg 曲妥珠单抗-MMAU，药物抗体比 (DAR) 分别为 8 和 4，可抑制异种移植肿瘤生长，其疗效优于曲妥珠单抗-vc-MMAE。 Trastuzumab-MMAU DAR4 在食蟹猴中的耐受剂量高达 12 mg/kg，这比使用 vedotin ADC 观察到的剂量高 2 至 4 倍，并且终末半衰期和暴露量增加。结论：优化的曲妥珠单抗-MMAU ADC 在非人灵长类动物中表现出有效的抗肿瘤活性，并且耐受性良好，具有优异的药代动力学，从而实现了优越的临床前治疗窗。该数据支持曲妥珠单抗-MMAU 用于治疗 HER2+ 肿瘤的潜在用途。