To the editor:

Severe congenital neutropenia (SCN) of infancy is a rare disorder with onset very early in life. Until the introduction of bone marrow transplantation as a curative strategy, and more recently with the introduction of recombinant granulocyte colony-stimulating factor (G-CSF), this was often a lethal disorder. Although G-CSF has prolonged survival, patients continue to die of infectious complications at a rate of 0.9% per year.1  Pegfilgrastim, the pegylated, covalent conjugate of G-CSF, is a longer acting form of filgrastim, making once-per-chemotherapy-cycle administration possible. It has been used in adult cancer patients to shorten the duration of chemotherapy-induced neutropenia2-4  and more recently also as adjuvant treatment in the pediatric population.5,6  The safety and efficacy profile of pegfilgrastim has been shown to be comparable with filgrastim and, due to its single dose administration, has improved patient quality of life.

We describe the case of an African American female who was found to be neutropenic at 7 weeks of age. A bone marrow aspirate performed at 10 weeks of age showed hypocellularity with decreased myeloid precursor cells and few mature myeloid cells, and she was diagnosed with SCN. Treatment with daily G-CSF was started at 5 months, and until she was 15 and a half years old she received daily G-CSF injections, with average doses of 20 μg/kg/day. Treatment compliance was a major concern, as evidenced objectively by admission and discharge absolute neutrophil count (ANC; Table 1). Since birth, she has been hospitalized 95 times (average of 6 times/year, with a range of 3-11). The average length of stay has been 7 days per admission due to significant infected and unremitting ulcerations and abscesses. At the age of 14 years and 8 months, she developed a right breast abscess that was positive for both methicillin-resistant Staphylococcus aureus and Proteus mirabilis. For the next 10 months, she was hospitalized a total of 53 days for this unremitting lesion and, although she was treated with various antibiotics, the recurrent right breast abscess continued to ulcerate and would not completely heal. At 15 and a half years, she was started on pegfilgrastim at a dose of 3 mg subcutaneously weekly, which was slowly increased to 4.5 mg weekly and then to a maximum of 6 mg subcutaneously weekly. Since starting this regimen 16 months ago, she has been hospitalized 3 times (average hospitalization of 3 days/admission) and the recurrent right breast abscess has completely healed. Pegfilgrastim given once to a 48-year-old patient with SCN has been previously reported,7  but to our knowledge, this is the first reported pediatric case of weekly pegfilgrastim usage for the treatment of SCN. Although this is limited to only one case, the treatment has been feasible and well tolerated. Given the fact that survival of patients with SCN has dramatically increased in recent years, we propose that the use of pegfilgrastim can improve quality of life as well as increase compliance, particularly in the adolescent population. Further studies to evaluate long-term outcomes, however, are warranted.

Table 1

Admissions, hospitalization-days, and treatments

YearAdmissions, no. per year per treatment typeHospitalization-days, no. per year per treatment typeTreatment typeANC at admission, × 109/LANC at discharge, × 109/L
1990 32 None 0.15 0.20 
1990 GM-CSF 
1990 10 G-CSF 6.0 
1991 47 G-CSF 0.40 2.0 
1992 36 G-CSF 0.30 1.7 
1993 21 G-CSF 0.15 3.0 
1994 35 G-CSF 0.18 2.7 
1995 43 G-CSF 0.45 4.1 
1996 25 G-CSF 0.20 1.8 
1997 11 52 G-CSF 0.10 2.1 
1998 27 G-CSF 0.15 1.5 
1999 30 G-CSF 0.10 1.0 
2000 19 G-CSF 0.12 3.5 
2001 G-CSF 0.50 2.5 
2002 27 G-CSF 0.05 2.3 
2003 11 G-CSF 0.10 3.8 
2004 31 G-CSF 0.50 3.5 
2005 55 G-CSF 0.30 5.0 
2006 10 G-CSF 1.6 
2006 Pegfilgrastim 0.50 3.0 
2007 Pegfilgrastim 3.50 3.5 
YearAdmissions, no. per year per treatment typeHospitalization-days, no. per year per treatment typeTreatment typeANC at admission, × 109/LANC at discharge, × 109/L
1990 32 None 0.15 0.20 
1990 GM-CSF 
1990 10 G-CSF 6.0 
1991 47 G-CSF 0.40 2.0 
1992 36 G-CSF 0.30 1.7 
1993 21 G-CSF 0.15 3.0 
1994 35 G-CSF 0.18 2.7 
1995 43 G-CSF 0.45 4.1 
1996 25 G-CSF 0.20 1.8 
1997 11 52 G-CSF 0.10 2.1 
1998 27 G-CSF 0.15 1.5 
1999 30 G-CSF 0.10 1.0 
2000 19 G-CSF 0.12 3.5 
2001 G-CSF 0.50 2.5 
2002 27 G-CSF 0.05 2.3 
2003 11 G-CSF 0.10 3.8 
2004 31 G-CSF 0.50 3.5 
2005 55 G-CSF 0.30 5.0 
2006 10 G-CSF 1.6 
2006 Pegfilgrastim 0.50 3.0 
2007 Pegfilgrastim 3.50 3.5 

ANC counts are averages.

GM-CSF indicates recombinant granulocyte-macrophage-colony-stimulating factor.

Authorship

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Correspondence: Michael F. Guerrera, MD, Division of Hematology-Oncology, 4th Floor, West Wing, Children's National Medical Center, 111 Michigan Avenue, NW, Washington, DC 20010, E-mail:MFGUERRE@cnmc.org.

References

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