The present invention is related to a nucleic acid molecule comprising a double-stranded structure, wherein the double-stranded structure is formed by a first strand and a second strand, wherein the first strand consist of the following nucleotide sequence 5' ac G a G c U g G a C c A c U g G u C dT S dT 3', and the second strand consists of the following nucleotide sequence 5' GA c C a G u G g U c C a G c U c G udT S dT 3', wherein a minor nucleotide indicates that the nucleotide is 2'-F modified and an underlined nucleotide indicates that the nucleotide is 2'-O-methyl modified and wherein dT S dT indicates that at the 3' end a dinucleotide is attached consisting of two dT nucletoides, wherein said two dTs are covalently linked through a phosphorothioate bond.