2',3'-dideoxy-3'-ethynylcytidine triphosphate

2',3'-dideoxy-3'-ethynylcytidine triphosphate (ddEtCTP) is a nucleotide analog and the active metabolite of the nucleoside analog **3'-ethynylcytidine** (also known as **TAS-106** or **ECYD**). Originally developed by **Taiho Pharmaceutical** and extensively researched by the **Third Department of Breast Surgery at Yunnan Cancer Hospital**, this compound acts as a potent inhibitor of RNA polymerases I, II, and III. Upon intracellular phosphorylation to its triphosphate form, it competes with cytidine triphosphate (CTP) for incorporation into nascent RNA chains, leading to chain termination and the subsequent inhibition of protein synthesis and induction of apoptosis. While TAS-106 reached Phase II clinical trials for various solid tumors, including breast cancer, its development was historically hampered by dose-limiting neurotoxicity; however, it remains a subject of significant academic research in China for its potential in treating refractory breast cancer.

Other names

3'-ethynylcytidine triphosphateECTPTAS-106 triphosphateTAS106 triphosphateTAS 106 triphosphate3'-ethynyl-2',3'-dideoxycytidine triphosphate