The Incidence of Leukemia and Mortality from Sepsis in Patients with Severe Congenital Neutropenia Receiving Long-Term G-CSF Therapy.

Background: In patients with severe congenital neutropenia (SCN), mortality from sepsis is reduced by treatment with granulocyte colony-stimulating factor (G-CSF), but myelodsyplastic syndrome and acute myeloid leukemia (MDS/AML) have been reported in treated and untreated patients.

Methods: We studied 374 patients with SCN and 29 patients with Shwachman-Diamond Syndrome (SDS) on long-term G-CSF enrolled in the Severe Chronic Neutropenia International Registry.

Results: In SCN, mortality from sepsis was stable at 0.9%/year. The hazard of MDS/AML increased significantly over time, from 2.9%/year after 6 years to 8.0%/year after 12 years on G-CSF. After 10 years, the cumulative incidence was 8% for mortality from sepsis and 21% for MDS/AML. The hazard of MDS/AML increased with the dose of G-CSF. Twenty-nine percent of SCN patients received more than the median dose of G-CSF (≥8 μg/kg/day), but achieved less than the median absolute neutrophil count (ANC) response (ANC <2188 cells/μL at 6–18 months). In these less responsive patients, the cumulative incidence of adverse events was highest: after 10 years, 40% developed MDS/AML and 14% died of sepsis, compared to 11% and 4%, respectively, of more responsive patients whose ANC was above the median on doses of G-CSF below the median. An intermediate group achieved an ANC above the median on doses of G-CSF above the median; among them, the 10 year cumulative incidence was 15% for MDS/AML and 3% for mortality from sepsis. In secondary analyses, we found that pre-treatment blood cell counts could not predict the subsequent clinical outcome. Furthermore, on therapy, patients who were less responsive vis-à-vis their neutrophil counts had similar increases in eosinophils, basophils, monocytes, and lymphocytes, and similar decreases in platelets, as other patients maintained on ≥8 μg/kg/day. Consistent with the SCN results, in SDS patients, the limited available data do not suggest that G-CSF therapy is a risk factor for MDS/AML in SDS.

Conclusions: The risk of MDS/AML was similarly low in all patients who achieved an ANC above the median on any dose of G-CSF. It appears that G-CSF has reduced mortality from sepsis, and revealed the underlying leukemic predisposition of SCN.