Kim Philipp, Zhang Chengcheng Christine, Thoröe-Boveleth Sven, Buhl Eva Miriam, Weiskirchen Sabine, Stremmel Wolfgang, Merle Uta, Weiskirchen Ralf
Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, D-52074 Aachen, Germany.
Department of Internal Medicine IV, Heidelberg University Hospital, D-69120 Heidelberg, Germany.
Biomedicines. 2021 Dec 8;9(12):1861. doi: 10.3390/biomedicines9121861.
Bis-choline-tetrathiomolybdate, introduced as WTX101 (now known as ALXN1840), is a first-in-class copper-protein-binding agent for oral therapy of Wilson's disease. In contrast to other decoppering agents such as trientine or D-penicillamine it acts by forming a tripartite complex with copper and albumin, thereby detoxifying excess liver and blood copper through biliary excretion. Preclinical animal experimentation with this drug was typically done with the alternative ammonium salt of tetrathiomolybdate, which is expected to have identical properties in terms of copper binding. Here, we comparatively analyzed the therapeutic efficacy of ALXN1840, D-penicillamine and trientine in lowering hepatic copper content in mouse. Liver specimens were subjected to laser ablation inductively conductively plasma mass spectrometry and electron microscopic analysis. We found that ALXN1840 caused a massive increase of hepatic copper and molybdenum during early stages of therapy. Prolonged treatment with ALXN1840 reduced hepatic copper to an extent that was similar to that observed after administration of D-penicillamine and trientine. Electron microscopic analysis showed a significant increase of lysosomal electron-dense particles in the liver confirming the proposed excretory pathway of ALXN1840. Ultrastructural analysis of mice treated with dosages comparable to the bis-choline-tetrathiomolybdate dosage used in an ongoing phase III trial in Wilson's disease patients, as well as D-penicillamine and trientine, did not show relevant mitochondrial damage. In contrast, a high dose of ALXN1840 applied for four weeks triggered dramatic structural changes in mitochondria, which were notably characterized by the formation of holes with variable sizes. Although these experimental results may not be applicable to patients with Wilson's disease, the data suggests that ALXN1840 should be administered at low concentrations to prevent mitochondrial dysfunction and overload of hepatic excretory pathways.
双胆碱四硫代钼酸盐，最初称为WTX101（现称为ALXN1840），是用于威尔逊病口服治疗的一类首创的铜蛋白结合剂。与曲恩汀或D-青霉胺等其他排铜剂不同，它通过与铜和白蛋白形成三方复合物发挥作用，从而通过胆汁排泄使肝脏和血液中过量的铜解毒。该药物的临床前动物实验通常使用四硫代钼酸盐的替代铵盐进行，预计其在铜结合方面具有相同的性质。在此，我们比较分析了ALXN1840、D-青霉胺和曲恩汀在降低小鼠肝脏铜含量方面的治疗效果。肝脏标本进行了激光烧蚀电感耦合等离子体质谱分析和电子显微镜分析。我们发现，在治疗早期，ALXN1840导致肝脏铜和钼大量增加。长期使用ALXN1840治疗可使肝脏铜含量降低到与给予D-青霉胺和曲恩汀后观察到的程度相似。电子显微镜分析显示肝脏中溶酶体电子致密颗粒显著增加，证实了ALXN1840的排泄途径。对接受与正在进行的威尔逊病患者III期试验中使用的双胆碱四硫代钼酸盐剂量相当的剂量治疗的小鼠，以及接受D-青霉胺和曲恩汀治疗的小鼠进行超微结构分析，未发现相关的线粒体损伤。相比之下，高剂量的ALXN1840应用四周会引发线粒体的显著结构变化，其显著特征是形成大小不一的孔洞。尽管这些实验结果可能不适用于威尔逊病患者，但数据表明，应低浓度使用ALXN1840以防止线粒体功能障碍和肝脏排泄途径过载。
