Immunogenicity, Safety, and Efficacy of Zarzio®/Filgrastim HEXAL® in Patients With Severe Chronic Neutropenia

Inclusion criteria: 1. Patients with established congenital, cyclic or idiopathic severe chronic neutropenia having an indication for treatment with Sandoz' filgrastim according to the SmPC of the product 2. Patients ≥ 18 years of age at the day of inclusion 3. Written informed consent of patient Exclusion criteria:. 1. Chemotherapy-induced neutropenia 2. Neutropenia in combination with confirmed diagnosis of autoimmune disease, e.g. rheumatoid arthritis, Felty's syndrome, or systemic lupus erythematosus 3. Myelodysplastic syndrome or leukemia 4. Thrombocytopenia (platelets \< 50.000/mm3) or anemia (hemoglobin \< 8 g/dl) with the exception of patients with Shwachman-Diamond syndrome, glycogen storage disease 1b, or Barth's syndrome 5. Sickle cell disease 6. History of malignancy of any organ system, treated or untreated, with the exception of localized basal cell carcinoma of the skin 7. For patients with congenital severe chronic neutropenia only: Any cytogenetic aberrations in bone marrow aspirates with results not older than six months suspicious for malignant transformation. 8. Known or suspected hypersensitivity to rhG-CSF products 9. Known or suspected hypersensitivity to any of the excipients of Sandoz' filgrastim product 10. Positive result of anti-rhG-CSF antibody assessment at screening 11. Absolute and relative contraindications as specified in the SmPC of Sandoz' filgrastim 12. Drug abuse, substance abuse, or alcohol abuse 13. Use of any other investigational drug at the time of enrollment, or within 30 days or 5 half-lives prior to enrollment, whichever is longer 14. Patients unwilling and/or who are not capable of ensuring compliance with the provisions of the study protocol 15. Pregnant or breastfeeding women where pregnancy is defined as the state of a female after conception and until the termination of gestation, confirmed by a positive serum hCG laboratory test 16. Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, UNLESS they are using a highly effective method of birth control (i.e. one that results in a less than 1% per year failure rate when used consistently and correctly, such as implants, injectables, combined oral contraceptives and intrauterine devices (IUDs)). Periodic abstinence (e.g. calendar, ovulation, symptothermal, post-ovulation methods) is not acceptable.