Clozapine rechallenge following neutropenia using granulocyte colony-stimulating factor: A Quebec case series.

TitleClozapine rechallenge following neutropenia using granulocyte colony-stimulating factor: A Quebec case series.
Publication TypeJournal Article
Year of Publication2021
AuteursBéchard, L, Corbeil, O, Plante, M, Thivierge, M-A, Lafrenière, C-É, Roy, M-A, Demers, M-F
JournalJ Psychopharmacol
Date Published2021 Sep
KeywordsAdult, Aged, Antipsychotic Agents, Clozapine, Databases, Factual, Female, Filgrastim, Follow-Up Studies, Granulocyte Colony-Stimulating Factor, Humans, Male, Middle Aged, Neutropenia, Quebec, Retrospective Studies, Schizophrenia, Treatment-Resistant, Young Adult

BACKGROUND: Clozapine has a unique efficacy profile among individuals suffering from treatment-resistant schizophrenia, but is associated with hematological side effects. The use of granulocyte colony-stimulating factors (G-CSF) to allow clozapine continuation or rechallenge has emerged as a promising option, but evidence is still scarce.AIM: To describe the largest case series so far published regarding this practice.METHOD: A national clozapine hematological monitoring database was consulted to identify all patients who had had neutrophil count <1.5 × 10/L since 2004 in Quebec and was cross-referenced with hospital pharmacy software to identify patients who had received at least one dose of G-CSF, such as filgrastim, while being exposed to clozapine. All data were collected retrospectively, using patients' medical files, from January to July 2019.RESULTS: Using G-CSF, three out of eight patients could maintain clozapine despite neutropenia episodes that otherwise would have required treatment discontinuation. The only side effect reported was mild short-lived back pain, over a mean 3-year follow-up period. In all but one case, filgrastim was used on an "as-needed" basis at doses of 300 mcg administered subcutaneously.CONCLUSION: These results suggest that the "as-needed" use of G-CSF is well-tolerated and may allow clozapine rechallenge in some well-selected patients, adding to the paucity of data regarding long-term safety and efficacy of this strategy. More research may help to better define potential candidates and optimal regimen of such practice.

Alternate JournalJ Psychopharmacol
PubMed ID34229529
PubMed Central IDPMC8436292