Clozapine and Cancer Risk: New Data
Recently read about that long-term treatment with clozapine is associated with a small, but significant, risk of hematological malignancies in individuals with schizophrenia. Is it true?
@anjali-1 Investigators found long-term clozapine use of more than 5 years was linked to a 2.7-fold increased risk of hematological malignancies in a dose-dependent manner compared with other antipsychotics. Study results suggest long-term clozapine use is associated with increased risk of hematological malignancy, but the absolute risk is small compared with the absolute risk reduction in all-cause mortality associated with clozapine treatment compared with other antipsychotics. The study was published online March 22 in Lancet Psychiatry.
An Unresolved Issue
Clozapine is more effective than other antipsychotics for managing symptoms and suicidal behavior in schizophrenia, with the lowest mortality compared with other antipsychotics, but its use is restricted in many countries, the researchers note. Reports of nine deaths associated with clozapine use — eight due to agranulocytosis and one due to leukemia — in southwestern Finland in 1975 resulted in worldwide withdrawal of the drug. In 1990, clozapine was relaunched with stipulations for strict blood count control. The cumulative incidence of clozapine-induced agranulocytosis or severe neutropenia is estimated at about 0.9%.
Several small studies from Australia, Denmark, and the United States, and a large pharmacovigilance study suggest that clozapine treatment might be associated with an increased risk of hematological malignancies. Previous studies have suggested a possible risk of hematological malignancies associated with clozapine, but due to methodological issues, the question had remained unsettled.