Methods of treatment using G-CSF protein complex

1. A method of preventing, alleviating, or treating neutropenia in a patient having compromised white blood cell production comprising administering to the patient a therapeutically effective amount of a protein complex comprising a modified human granulocyte-colony stimulating factor (hG-CSF) covalently linked to an immunoglobulin Fc region via a non-peptidyl polymer, wherein the non-peptidyl polymer is site-specifically linked to an N-terminus of the immunoglobulin Fc region and the modified hG-CSF comprises the amino acid sequence of SEQ ID NO: 1.

2. The method of claim 1 , wherein the neutropenia is severe chronic neutropenia or febrile neutropenia.

3. The method of claim 1 , wherein said compromised white blood cell production is a result of chemotherapy, radiation therapy, or idiopathic thrombocytopenia purpura.

4. The method of claim 1 , wherein the protein complex is administered after the patient is treated with adjuvant or neoadjuvant chemotherapy.

5. The method of claim 4 , wherein the protein complex is administered between 1 and 5 days after the patient is treated with adjuvant or neoadjuvant chemotherapy.

6. The method of claim 5 , wherein the adjuvant or neoadjuvant chemotherapy is a combination of docetaxel and cyclophosphamide.

7. The method of claim 1 , wherein a second dose of the protein complex is administered between 15 and 25 days after a first dose of the protein complex is administered to the patient.

8. The method of claim 1 , wherein the therapeutically effective amount is a unit dosage form selected from: 25 μg/kg, 50 μg/kg, 100 μg/kg, and 200 μg/kg.

9. The method of claim 1 , wherein the therapeutically effective amount is 13.2 mg of the protein complex in a 0.6 mL dosage volume.

10. The method of claim 1 , further comprising administering to the patient a therapeutically effective amount of a second agent.

11. The method of claim 10 , wherein the second agent is an anti-cancer agent.

12. The method of claim 1 , wherein the immunoglobulin Fc region comprises a polypeptide sequence of SEQ ID NO: 2.

13. The method of claim 12 , wherein both ends of the non-peptidyl polymer are respectively linked to the modified human G-CSF and the immunoglobulin Fc region through reactive groups by a covalent bond.

14. The method of claim 13 , wherein the reactive group of the non-peptidyl polymer is an aldehyde group.

15. The method of claim 14 , wherein:

(a) the aldehyde group is a propionaldehyde group or a butyraldehyde group; or

(b) the succinimide derivative is succinimidyl carboxymethyl, succinimidyl valerate, succinimidyl methylbutanoate, succinimidyl methylpropionate, succinimidyl butanoate, succinimidyl propionate, N-hydroxysuccinimide, or succinimidyl carbonate.

16. The method of claim 14 , wherein:

(a) the non-peptidyl polymer has an aldehyde group as a reactive group at both ends;

(b) the non-peptidyl polymer has an aldehyde group and a maleimide group as a reactive group at both ends, respectively; or

(c) the non-peptidyl polymer has an aldehyde group and a succinimide group as a reactive group at both ends, respectively.

17. The method of claim 1 , wherein the immunoglobulin Fc region consists of CH2 and CH3 domains.

18. The method of claim 17 , wherein the immunoglobulin Fc fragment is an IgG4 Fc fragment.

19. The method of claim 1 , wherein the non-peptidyl polymer is polyethylene glycol.

20. The method of claim 19 , wherein the polyethylene glycol has a molecular weight of 3.4 kDa.

21. The method of claim 1 , wherein each end of the non-peptidyl polymer is linked to the N-terminus of the immunoglobulin Fc region and an N-terminus, a C-terminus, or a free reactive group of a lysine residue, a histidine residue, or a cysteine residue of the modified human G-CSF, respectively.