Compositions and methods for stroke prevention in pediatric sickle cell anemia patients

1. A method of treating or ameliorating stroke in a sickle cell anemia (SCA) patient in need thereof, the method comprising administering to the patient a therapeutically effective amount of a compound of formula (I), or a salt or solvate thereof:

PROTEIN-Z-DOMAIN-X-Y (I),

wherein in (I):

PROTEIN comprises amino acid residues 23 to 849 (PSCAKE . . . to . . . QED) of SEQ ID NO:19;

DOMAIN is absent or at least one selected from the group consisting of a human IgG Fc domain (Fc), human serum albumin protein (ALB), and a fragment thereof;

X and Z are independently absent or a polypeptide comprising 1-20 amino acids; and

Y is absent.

2. The method of claim 1 , wherein the risk of developing stroke, or the severity of the stroke, is reduced in the SCA patient being administered the compound as compared to a SCA patient who has not been administered the compound.

3. The method of claim 1 , wherein the compound lacks a negatively-charged bone-targeting sequence.

4. The method of claim 1 , wherein the patient is administered the compound by at least one route selected from the group consisting of subcutaneous, oral, aerosol, inhalational, rectal, vaginal, transdermal, intranasal, buccal, sublingual, parenteral, intrathecal, intragastrical, ophthalmic, pulmonary, and topical.

5. The method of claim 1 , wherein the compound is intravenously or subcutaneously administered to the patient.

6. The method of claim 1 , wherein administering the compound to the patient increases, or prevents further decrease of, the patient's extracellular pyrophosphate concentrations.

7. The method of claim 1 , wherein the PROTEIN comprises an ecto-nucleotide pyrophosphate/phosphodiesterase-2 (ENPP2) transmembrane domain.

8. The method of claim 7 , wherein the ENPP2 transmembrane domain comprises amino acid residues 12-30 of SEQ ID NO:2, which corresponds to SEQ ID NO:23.

9. The method of claim 1 , wherein DOMAIN comprises ALB and the compound lacks a polyaspartic acid domain.

10. The method of claim 1 , wherein the PROTEIN lacks the ENPP1 transmembrane domain.

11. The method of claim 1 , wherein DOMAIN comprises an IgG Fc domain.

12. The method of claim 1 , wherein the compound is administered to the patient as a pharmaceutical composition further comprising at least one pharmaceutically acceptable carrier.

13. The method of claim 1 , wherein the patient is further administered at least one additional anti-stroke treatment.

14. The method of claim 13 , wherein the at least one additional anti-stroke treatment is selected from the group consisting of an anticoagulant medication, hydroxyurea, an antiplatelet medication, an antihypertensive medication, a tissue plasminogen activator (tPA), a surgical intervention, and an endovascular procedure.

15. The method of claim 13 , wherein the compound and the at least one additional anti-stroke treatment are co-administered to the patient.

16. The method of claim 13 , wherein the compound and the at least one additional anti-stroke treatment are co-formulated.

17. The method of claim 1 , wherein the compound is the only anti-stroke treatment administered to the patient.

18. The method of claim 1 , wherein the compound is the only anti-stroke treatment administered to the patient in an amount sufficient to treat or ameliorate stroke in the patient.

19. The method of claim 1 , wherein the patient is a mammal.

20. The method of claim 19 , wherein the mammal is a human.

21. A method of treating or ameliorating stroke in a SCA patient in need thereof, the method comprising:

measuring the amount of pyrophosphate (PPi) in a sample from the SCA patient,

comparing the amount of PPi in the sample from the SCA patient with the amount of PPi in a reference sample,

wherein, if the amount of PPi is lower in the sample from the SCA patient than in the reference sample, the patient is determined to be at risk for stroke, and

further administering to the patient at risk for stroke a therapeutically effective amount of a compound of formula (I), or a salt or solvate thereof:

PROTEIN-Z-DOMAIN-X-Y (I),

wherein in (I):

PROTEIN comprises amino acid residues 23 to 849 (PSCAKE . . . to . . . QED) of SEQ ID NO:19;

DOMAIN is absent or at least one selected from the group consisting of a human IgG Fc domain (Fc), human serum albumin protein (ALB) and a fragment thereof;

X and Z are independently absent or a polypeptide comprising 1-20 amino acids; and

Y is absent.

22. The method of claim 21 , wherein the patient is a mammal.

23. The method of claim 22 , wherein the mammal is a human.

24. The method of claim 21 , further comprising administering at least one additional anti-stroke treatment to the SCA patient.