Compositions and methods for inhibiting expression of the ALAS1 gene

1. A double-stranded ribonucleic acid (dsRNA) for inhibiting expression of ALAS1, comprising:

(i) an antisense strand that comprises the sequence of SEQ ID NO: 1296;

(ii) a sense strand comprising at least 15 contiguous nucleotides from SEQ ID NO: 1295; and

(iii) a duplex region of 15-30 base pairs in length.

2. The dsRNA of claim 1 , wherein said dsRNA comprises at least one modified nucleotide.

3. The dsRNA of claim 1 , wherein each of the sense strand and the antisense strand is 19-24 nucleotides in length.

4. The dsRNA of claim 1 , wherein at least one strand comprises a 3′ overhang of at least 1 nucleotide.

5. The dsRNA of claim 4 , wherein the 3′ overhang is 2 nucleotides in length.

6. The dsRNA of claim 1 further comprising a ligand.

7. The dsRNA of claim 6 , wherein said ligand is a GalNAc ligand.

8. An isolated cell comprising the dsRNA of claim 1 .

9. A pharmaceutical composition for inhibiting expression of an ALAS1 gene, the composition comprising the dsRNA of claim 1 .

10. A method of inhibiting ALAS1 expression in a cell, the method comprising:

(a) introducing into the cell the dsRNA of claim 1 , and

(b) maintaining the cell of step (a) for a time sufficient to obtain degradation of the mRNA transcript of an ALAS1 gene, thereby inhibiting expression of the ALAS1 gene in the cell.

11. A method of treating a disorder related to ALAS1 expression comprising administering to a subject in need of such treatment a therapeutically effective amount of the dsRNA of claim 1 .

12. The method of claim 11 , wherein the subject is at risk for developing, or is diagnosed with, a porphyria.

13. The method of claim 11 , wherein the dsRNA is administered before, during, or after an acute attack of porphyria.

14. The method of claim 11 , wherein the method decreases a level of a porphyrin or a porphyrin precursor in the subject.

15. A method for decreasing a level of a porphyrin or a porphyrin precursor in a cell, comprising contacting the cell with the dsRNA of claim 1 , in an amount effective to decrease the level of the porphyrin or the porphyrin precursor in the cell.

16. A vector encoding at least one strand of a dsRNA of claim 1 .

17. An isolated cell comprising the vector of claim 16 .

18. The method of claim 11 , wherein said method

(i) ameliorates a symptom associated with an ALAS1 related disorder (e.g., a porphyria)

(ii) inhibits ALAS1 expression in the subject,

(iii) decreases a level of a porphyrin precursor or a porphyrin in the subject,

(iv) decreases frequency of acute attacks of symptoms associated with a porphyria in the subject, or

(v) decreases incidence of acute attacks of symptoms associated with a porphyria in the subject when the subject is exposed to a precipitating factor.

19. The dsRNA of claim 7 , wherein the GalNAc ligand is attached to the 3′ end of the sense strand.

20. The dsRNA of claim 1 , wherein the at least one modified nucleotide is chosen from a 2′-O-methyl modified nucleotide, 2′-fluoro modified nucleotide, or both.

21. The dsRNA of claim 19 , wherein the GalNAc ligand is attached to the 3′ end of the sense strand via a linker.

22. The dsRNA of claim 7 , wherein the GalNAc ligand is

23. The dsRNA of claim 21 , wherein the ligand and linker has the structure of:

24. The method of claim 11 , wherein the porphyria is a hepatic porphyria selected from acute intermittent porphyria (AIP) hereditary coproporphyria (HCP), variegate porphyria (VP), ALA deyhdratase deficiency porphyria (ADP), and hepatoerythropoietic porphyria.

25. The method of claim 11 , wherein the dsRNA is administered during a prodrome.

26. The method of claim 11 , wherein the subject has an elevated level of ALA, PBG, or both ALA and PBG.

27. A method of treating a subject with an elevated level of ALA, PBG, or both ALA and PBG, the method comprising administering to the subject the dsRNA of claim 1 .

28. The dsRNA of claim 5 , wherein one end of the dsRNA is blunt-ended.

29. The dsRNA of claim 28 , wherein the dsRNA comprises one or more phosphorothioate linkages.

30. The dsRNA of claim 1 , which comprises 20 or more modified nucleotides chosen from 2′-O-methyl modified nucleotides and 2′-fluro modified nucleotides.

31. The dsRNA of claim 30 , comprising 2′-O-methyl modified nucleotides and 2′-fluro modified nucleotides over the entire length of the sense and antisense strands.

32. A double-stranded ribonucleic acid (dsRNA) for inhibiting expression of ALAS1, comprising:

(i) an antisense strand that comprises the sequence of SEQ ID NO: 1296;

(ii) a sense strand comprising at least 15 contiguous nucleotides from SEQ ID NO: 1295;

(iii) a duplex region of 15-30 base pairs in length;

(iv) one strand comprising a 3′ overhang of at least 1 nucleotide;

(v) one end that is blunt-ended; and

(vi) at least one modified nucleotide chosen from a 2′-O-methyl modified nucleotide, 2′-fluoro modified nucleotide, or both.

33. A double-stranded ribonucleic acid (dsRNA) for inhibiting expression of ALAS1, wherein the dsRNA comprises:

(i) a sense strand comprising at least 15 contiguous nucleotides from SEQ ID NO: 1295;

(ii) an antisense strand complementary to at least nucleotides 871-889 of SEQ ID NO: 1; and

(iii) a ligand comprising one or more N-acetylgalactosamine (GalNAc) derivatives.

34. The dsRNA of claim 33 , wherein the dsRNA comprises at least one modified nucleotide, wherein at least one of the modified nucleotides is chosen from the group consisting of: a 2′-O-methyl modified nucleotide, a nucleotide comprising a 5′-phosphorothioate group, a terminal nucleotide linked to a cholesteryl derivative or dodecanoic acid bisdecylamide group, a 2′-deoxy-2′-fluoro modified nucleotide, a 2′-deoxy-modified nucleotide, a locked nucleotide, an abasic nucleotide, a 2′-amino-modified nucleotide, a 2′-alkyl-modified nucleotide, a morpholino nucleotide, a phosphoramidate, and a non-natural base comprising nucleotide.

35. The dsRNA of claim 33 , wherein the GalNAc derivative structure is as shown below and is attached to the 3′ end of the sense strand of the dsRNA

36. The dsRNA of claim 33 , comprising a duplex region of 15-30 base pairs in length.