In November 2025, the US Food and Drug Administration (FDA) officially approved Kygevvi oral solution powder for the treatment of thymidine kinase 2 deficiency (TK2d) in adults and children with onset age ≤ 12 years old. Kygevvi is the first and only targeted therapy approved for the treatment of TK2d, consisting of two types of pyrimidine nucleosides, doxecitine and doxribtimine. Its function is to integrate doxecitine and doxribtimine into skeletal muscle mitochondrial deoxyribonucleic acid (DNA), thereby bypassing defective thymidine kinase 2 (TK2) and helping to repair and increase the quantity of mitochondrial DNA, and fundamentally improving cellular energy supply. Here is an introduction to its mechanism of action, pharmacodynamics, pharmacokinetics, clinical research, and safety.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |