Hematopoietic growth factors for the treatment of severe chronic neutropenia

Severe chronic neutropenia (SCN) is a rare but important cause of recurrent fevers, oropharyngeal ulcerations and severe infections. In three forms of SCN, i.e., congenital neutropenia (Kostmann's syndrome and related syndromes), idiopathic neutropenia (both childhood and adult), and cyclic neutropenia, it is now established that long-term treatment with the hematopoietic growth factor, recombinant human granulocyte colony stimulating factor (rHuG-CSF or Filgrastim), can elevate blood neutrophil counts to the normal range in most patients, with a concomitant reduction in infection-related events including fever, oral ulcerations, antibiotic use and symptoms of inflammation. Treatment with this growth factor causes an increase in the number and maturity of marrow cells of the neutrophilic series; other cell lines are largely unaffected. Marrow stimulation and expansion are reflected by the occurrence of bone pain early in therapy, as well as some increase in spleen size in most cases. Adverse effects of therapy are infrequent in both children and adults, and long-term treatment with daily or every-other-day s.c. injections of rHuG-CSF are well accepted. Because of the risk that some patients with chronic neutropenia may have or develop myelodysplasia and/or leukemia, careful pretreatment evaluations (blood, bone marrow and cytogenetics) and long-term observations are extremely important. An international registry for patients with SCN has been established to maintain records and further investigate these conditions.