Aims: To examine the efficacy and safety of pegfilgrastim in patients with congenital neutropenia (CN).
Methods: Seventeen patients enrolled in the French Severe CN Register received pegfilgrastim.
Results: Median age at pegfilgrastim introduction was 19.1 years (range 3.9-52.3 years). In 14 cases pegfilgrastim replaced GCSF (filgrastim or lenograstim), after a median of 6.9 years of GCSF therapy. The dose of pegfilgrastim was usually one full vial per injection (except in five children, who received 1/6 to 1/2 a vial), resulting in a dose of between 50 and 286 microg/kg. The pegfilgrastim schedule ranged from two injections every 7 days to one injection every 30 days, with treatment-free periods. The median interval between the first and last dose of pegfilgrastim was 0.8 years (0.01-4.1 years). The absolute neutrophil count tended to increase more strongly on pegfilgrastim than on GCSF, but the difference was not statistically significant. During pegfilgrastim therapy, a severe infection occurred in two patients and recurrent ENT infections in two other patients. Bone pain was reported by nine patients, anemia and thrombocytopenia occurred in one patient (WHO grade III), chronic urticaria occurred in one patient (WHO grade III), and a single pegfilgrastim injection was followed by respiratory distress and death 15 days later in a patient with GDSIb. At the last update, 10 patients had stopped receiving pegfilgrastim and seven patients were still receiving pegfilgrastim.
Conclusion: Compared to conventional GCSF, pegfilgrastim is more difficult to use in congenital neutropenia, with more frequent adverse events and sometimes poor efficacy.