Pt(II) drugs are a widely used chemotherapeutic, yet their side effects can be severe. Here we show that the radiation-induced reduction of Pt(IV) complexes to cytotoxic Pt(II) drugs is rapid, efficient and applicable in water, that it is mediated by hydrated electrons from water radiolysis and that the X-ray-induced release of Pt(II) drugs from an oxaliplatin prodrug in tumours inhibits their growth, as we show with nearly complete tumour regression in mice with subcutaneous human tumour xenografts. The combination of low-dose radiotherapy with a Pt(IV)-based antibody–trastuzumab conjugate led to the tumour-selective release of the chemotherapeutic in mice and to substantial therapeutic benefits. The radiation-induced local reduction of platinum prodrugs in the reductive tumour microenvironment may expand the utility of radiotherapy.

Pt（II） 药物是一种广泛使用的化疗药物，但其副作用可能很严重。在这里，我们表明辐射诱导的 Pt（IV） 复合物还原为细胞毒性 Pt（II） 药物是快速、有效且适用于水的，它是由水辐射分解的水合电子介导的，并且 X 射线诱导的 Pt（II） 药物从奥沙利铂前药释放肿瘤抑制了它们的生长，正如我们在皮下人肿瘤异种移植物小鼠中几乎完全的肿瘤消退所显示的那样。低剂量放疗与基于 Pt（IV） 的抗体-曲妥珠单抗偶联物的结合导致化疗药物在小鼠体内的肿瘤选择性释放，并产生实质性的治疗益处。在减瘤微环境中辐射诱导的铂前药局部减少可能会扩大放疗的效用。