As colorectal cancer (CRC) remains a leading cause of cancer-related death, identifying therapeutic targets and approaches is essential to improve patient outcomes. The EGFR ligand epiregulin (EREG) is highly expressed in RAS wildtype and mutant CRC with minimal expression in normal tissues, making it an attractive target for antibody-drug conjugate (ADC) development. In this study, we produced and purified an EREG monoclonal antibody (mAb), H231, that had high specificity and affinity for human and mouse EREG. H231 also internalized to lysosomes, which is important for ADC payload release. ImmunoPET and ex vivo biodistribution studies showed significant tumor uptake of 89Zr-labeled H231 with minimal uptake in normal tissues. H231 was conjugated to either cleavable dipeptide or tripeptide chemical linkers attached to the DNA-alkylating payload duocarmycin DM, and cytotoxicity of EREG ADCs was assessed in a panel of CRC cell lines. EREG ADCs incorporating tripeptide linkers demonstrated the highest potency in EREG-expressing CRC cells irrespective of RAS mutations. Preclinical safety and efficacy studies showed EREG ADCs were well-tolerated, neutralized EGFR pathway activity, caused significant tumor growth inhibition or regression, and increased survival in CRC cell line and patient-derived xenograft models. These data suggest EREG is a promising target for the development of ADCs for treating CRC and other cancer types that express high levels of EREG. While the efficacy of clinically approved anti-EGFR mAbs are largely limited by RAS mutational status, EREG ADCs may show promise for both RAS mutant and wildtype patients, thus improving existing treatment options.

中文翻译：

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靶向 EGFR 配体上皮调节蛋白的抗体-药物偶联物在结直肠癌中引发强大的抗肿瘤活性


由于结直肠癌 （CRC） 仍然是癌症相关死亡的主要原因，因此确定治疗靶点和方法对于改善患者预后至关重要。EGFR 配体上皮调节蛋白 （EREG） 在 RAS 野生型和突变型 CRC 中高度表达，在正常组织中表达最少，使其成为抗体-药物偶联物 （ADC） 开发的有吸引力的靶标。在这项研究中，我们生产并纯化了一种 EREG 单克隆抗体 （mAb） H231，该抗体对人和小鼠 EREG 具有高特异性和亲和力。H231 还内化到溶酶体中，这对 ADC 有效载荷的释放很重要。免疫 PET 和离体生物分布研究表明，肿瘤对 89Zr 标记的 H231 的摄取显著，在正常组织中的摄取最少。H231 与附着在 DNA 烷化有效载荷 duocarmycin DM 上的可切割二肽或三肽化学接头偶联，并在一组 CRC 细胞系中评估 EREG ADC 的细胞毒性。无论 RAS 突变如何，掺入三肽接头的 EREG ADC 在表达 EREG 的 CRC 细胞中均表现出最高效力。临床前安全性和有效性研究表明，EREG ADC 耐受性良好，中和 EGFR 通路活性，引起显着的肿瘤生长抑制或消退，并提高 CRC 细胞系和患者来源的异种移植模型的存活率。这些数据表明，EREG 是开发用于治疗 CRC 和其他表达高水平 EREG 的癌症类型的 ADC 的有前途的靶点。虽然临床批准的抗 EGFR mAb 的疗效在很大程度上受到 RAS 突变状态的限制，但 EREG ADC 可能对 RAS 突变型和野生型患者都有希望，从而改善现有的治疗选择。