Compounds targeting dmpk for the treatment of myotonic dystrophy

dsRNAi agent of the structure of formula (II):

• or a pharmaceutically acceptable salt thereof,
• wherein A is a double stranded nucleic acid having suppressing activity of DMPK gene expression, comprising a sense strand and an antisense strand forming a duplex with the sense strand, wherein each of the antisense strand and the sense strand is independently 10 to 30 nucleotides in length,
• L3 is independently selected from:
• (i) a bond;
• (iii) —OP(O)(OH)O—;
• (iv) —OP(S)(OH)O—;
• and
• (v) —O—;
• L4 is independently selected from:
• (i) substituted or unsubstituted 2 to 20 membered heteroalkylene;
• (ii) -L7-NH—C(O)— or -L7-C(O)—NH—, wherein L7 is substituted or unsubstituted C1-C20 alkylene;
• L5 is substituted or unsubstituted 2 to 20 membered heteroalkylene, or -L5AL5BL5CL5DL5E-, wherein L5A is independently unsubstituted C1-C8 alkylene;
• L5B is independently —NHC(O)—;
• L5C is independently a bond;
• L5D is independently a bond or unsubstituted C1-C8 alkylene;
• and L5E is independently a bond or —NHC(O)—;
• L6 is —NHC(O)—;
• R1 and R2 are independently unsubstituted C1-C19 alkyl or unsubstituted C1-C19 alkenyl;
• R3 is hydrogen;
• and
• t is 1.