AAV9-mediated gene therapy for treating mucopolysaccharidosis type I
A co-therapeutic regimen comprising AAV9-mediated intrathecal/intracisternal and/or systemic delivery of an expression cassette containing a hIDUA gene and two or more immunosuppressants is provided herein. Also provided are methods useful for treating hIDUA deficiency (MPSI) and the symptoms associated with Hurler, Hurler-Scheie and Scheie syndromes.
1. A therapeutic regimen useful for treatment of an alpha-L-iduronidase deficiency in a human patient, wherein the regimen comprises administering to a patient:
(a) a recombinant adeno-associated virus (rAAV) having an AAV9 capsid and a nucleic acid comprising a sequence encoding human α-L-iduronidase (hIDUA) under control of regulatory sequences which direct expression thereof in the patient, wherein the hIDUA coding sequence has the nucleotide sequence of nucleotides 1 to 1962 of SEQ ID NO: 1 or a sequence at least 80% identical to nucleotides 1 to 1962 of SEQ ID NO: 1 which encodes a functional hIDUA, wherein the regulatory sequences comprise a cytomegalovirus immediate early (CMV IE) enhancer, a chicken beta-actin promoter, a chicken beta actin intron, and a rabbit beta globin polyadenylation (poly A) signal sequence,
(b) at least a first immunosuppressive agent which is an intravenous corticosteroid; and
(c) at least a second immunosuppressive agent which is an oral corticosteroid,
wherein administration of at least one immunosuppressive agent begins prior to or on the same day as delivery of the rAAV; and
wherein administration of at least one of the immunosuppressive agents continues for at least 8 weeks post-rAAV administration.
2. The therapeutic regimen according to claim 1 , wherein the therapeutic regimen comprises further administering to a patient one or more immunosuppressive agents comprising one or more macrolides.
3. The therapeutic regimen according to claim 2 , wherein the one or more macrolides comprises tacrolimus, sirolimus, or combination of tacrolimus and sirolimus.
4. The therapeutic regimen according to claim 1 , wherein corticosteroids administration is discontinued 12-weeks post rAAV administration.
5. The therapeutic regimen according to claim 2 , wherein the immunosuppressive agent which is tacrolimus is administered on day 2 post-rAAV administration.
6. The therapeutic regimen according to claim 2 , wherein the immunosuppressive agent which is sirolimus is administered on day −2 prior to rAAV administration.
7. The therapeutic regimen according to claim 2 , wherein when the immunosuppressive agents comprise both tacrolimus and sirolimus, a low dose of each is used to maintain a blood trough level of (i) 2 ng/ml to 4 ng/ml, or about 4 ng/ml to about 8 ng/ml, or a total of about 8 ng/ml to about 16 ng/ml of tacrolimus, and (ii) 1 ng/ml to 3 ng/ml of sirolimus.
8. The therapeutic regimen according to claim 2 , wherein when the immunosuppressive agents comprise only one of tacrolimus or sirolimus, the total dose is in the range of about 16 ng/ml to about 24 ng/ml.
9. The therapeutic regimen according to claim 2 , wherein when the immunosuppressive agents comprise both tacrolimus and sirolimus, the initial loading dose of sirolimus is about 1 mg/m 2 .
10. The therapeutic regimen according to claim 1 , wherein the immunosuppressive therapy is started at about day −14 to day −1 prior to rAAV administration.
11. The therapeutic regimen according to claim 1 , wherein the encoded hIDUA has the sequence of:
(a) amino acids 1 to 653 of SEQ ID NO: 2 (Genbank NP_000193); or
(b) a synthetic human enzyme comprising a heterologous leader sequence fused to amino acids 27 to 653 of SEQ ID NO: 2.
12. The therapeutic regimen according to claim 1 , wherein the rAAV is in a suspension having a pH of 6 to 9.
13. The therapeutic regimen according to claim 12 , wherein the rAAV is delivered via intrathecal injection.
14. The therapeutic regimen according to claim 13 , further Comprising co-administering an rAAV comprising the hIDUA gene intravenously.
15. The therapeutic regimen according to claim 1 , wherein the efficacy of therapy is assessed by measuring auditory capacity changes, optionally by auditory brainstem testing.
16. The therapeutic regimen according to claim 1 , wherein the rAAV is formulated for intrathecal injection to a human subject, to administer a total flat dose of:
(i) about 1.2×10 12 to about 6.0×10 12 GC or about 6.0×10 12 to about 3.0×10 13 GC to a human subject ≥4 months to <9 months of age;
(ii) about 2×10 12 to about 6.0×10 13 or about 1.0×10 13 to about 5.0×10 13 GC to a human subject ≥9 months to <18 months of age; or
(iii) about 2.2×10 12 to about 1.1×10 13 GC or about 1.1×10 13 to about 5.5×10 13 GC to a human subject ≥9 months to <18 months of age.
17. The therapeutic regimen according to claim 1 , wherein the patient is pre-dosed initially with the intravenous immunosuppressive agent which is a corticosteroid prior to rAAV administration.
18. The therapeutic regimen according to claim 1 , wherein the patient is dosed with the oral immunosuppressive agent which is a corticosteroid following rAAV administration.
19. The therapeutic regimen according to claim 1 , wherein the rAAV comprises a vector genome comprising a nucleic acid sequence having the sequence of nucleotides 1 to 4344 of SEQ ID NO: 3.
20. The therapeutic regimen according to claim 5 , wherein administering the patient with tacrolimus is discontinued 32-weeks post rAAV administration.
21. The therapeutic regimen according to claim 6 , wherein administering the patient with sirolimus is discontinued 48-weeks post rAAV administration.
22. The therapeutic regimen according to claim 2 , wherein when the immunosuppressive agents comprise both tacrolimus and sirolimus, the initial dose of tacrolimus is 0.05 mg/kg twice daily.
23. The therapeutic regimen according to claim 1 , wherein the hIDUA coding sequence comprises a nucleic acid sequence having the sequence of nucleotides 1 to 1962 of SEQ ID NO: 1.
24. The therapeutic regimen according to claim 23 , wherein the regimen comprises dosing the patient with tacrolimus to a blood trough level of about 4 ng/mL to about 8 ng/ml.
25. The therapeutic regimen according to claim 23 , wherein the regimen comprises dosing the patient with sirolimus to a blood trough level of about 1 ng/mL to about 3 ng/ml.
26. The therapeutic regimen according to claim 1 , wherein the rAAV is administrable by intracerebroventricular or intracisternal delivery.
27. The therapeutic regimen according to claim 1 , wherein the rAAV is administrable by intrathecal injection at a dose of about 10 9 to 10 11 GC/g brain mass.
28. The therapeutic regimen according to claim 1 , wherein the rAAV comprises an expression cassette comprising a nucleic acid sequence having the sequence of nucleotides 198 to 4126 of SEQ ID NO: 3.
29. The therapeutic regimen according to claim 28 , wherein the rAAV is administrable by intracerebroventricular or intracisternal delivery.
30. The therapeutic regimen according to claim 29 , wherein the regimen comprises dosing a patient with tacrolimus to a blood trough level of about 4 ng/mL to about 8 ng/ml.
31. The therapeutic regimen according to claim 29 , wherein the regimen comprises dosing the patient with sirolimus to a blood trough level of about 1 ng/mL to about 3 ng/ml.
32. The therapeutic regimen according to claim 29 , wherein the patient is predosed initially with the intravenous corticosteroid prior to rAAV delivery.
33. The therapeutic regimen according to claim 29 , wherein the intravenous corticosteroid is methylprednisolone given at 10 mg/kg on Day 1 prior to rAAV delivery.
34. The therapeutic regimen according to claim 33 , wherein the patient is dosed with the oral corticosteroid following rAAV delivery.
35. The therapeutic regimen according to claim 34 , wherein the oral corticosteroid is prednisone given starting at 0.5 mg/kg/day on Day 2 after rAAV delivery.
36. The therapeutic regimen according to claim 1 , wherein the intravenous corticosteroid is methylprednisolone given at 10 mg/kg once on Day 1 prior to rAAV delivery.
37. The therapeutic regimen according to claim 1 , wherein the oral corticosteroid is prednisone given starting at 0.5 mg/kg/day on Day 2 after rAAV delivery.