Research on clozapine safety: Big-data evidence on rare blood cancer cases

An inter-departmental research team has conducted an analytic real-world cohort study on the association of clozapine, a highly efficacious antipsychotic drug, with the incidence of blood cancer. Their findings show that the risk of blood cancer associated with the use of clozapine is very low, with an average increase of less than six cases per 10,000 persons using clozapine for one year. Therefore, the clinical significance of such a risk is plausibly low. While previous preliminary Western studies have shown a potentially significant increase in risk, this study suggests that with stringent blood monitoring measures before and during clozapine use in Hong Kong and around the world, it may not be necessary to further restrict the use of clozapine or issue special warnings by the Department of Health or local drug regulatory authorities, thus facilitating early and effective treatment of mental illness.