Nucleoside triphosphate and nucleoside triphosphate analogue prodrugs

The invention relates to nucleoside triphosphate and nucleoside triphosphate analogue prodrugs. It is an object of the present invention to provide improved nucleoside triphosphate or nucleoside triphosphate analogue prodrugs. To achieve the object, the present invention provides in one aspect non-symmetrically double modified nucleoside triphosphate compounds, or their analogues, wherein the modification is carried out at the terminal, i.e. the y-phosphate, or the corresponding analogous group, and wherein the first modification is adding a moiety A being intracellular stable, and the second modification is adding an intracellular labile mask B, which is cleaved within the cell, such that a nucleoside triphosphate or analogue thereof mono-modified with the intracellularly stable moiety A is released in the cell.