HKUMed’s Big Data Study Confirms Clozapine Safety Against Rare Blood Cancer Risks

Researchers at the LKS Faculty of Medicine at the University of Hong Kong have conducted a comprehensive study examining the safety of clozapine, an antipsychotic medication, concerning the risk of blood cancer. This study represents the first analytical real-world cohort investigation specifically focused on this association.

Study Findings

Published in *PLOS Medicine*, the study found that the risk of developing blood cancer from clozapine use is very low, estimated at fewer than six cases per 10,000 individuals using the medication over one year. These findings indicate that the clinical significance of the associated risk is minimal. Past research from Western countries suggested a possible increase in blood cancer risk; however, the findings from HKUMed propose that effective blood monitoring protocols might reduce the need for additional restrictions on clozapine use.

Clozapine Overview

Clozapine is the only antipsychotic drug approved by the U.S. Food and Drug Administration for the treatment of treatment-resistant schizophrenia. It is noted for its efficacy in managing symptoms while reducing the risk of relapse and mortality. Previous studies, particularly from Finland and the United States, implied a severe risk of blood cancer linked to clozapine use, but this research provides a clearer picture by analyzing an extensive dataset.

Research Methodology

The research team utilized electronic health records from the Hospital Authority of Hong Kong, reviewing around 400,000 patient files to establish a retrospective cohort of approximately 10,000 schizophrenia patients from 2001 to 2022, with a median follow-up period of seven years after the initiation of the drug. Key findings from the study include:

• Rare Incidence of Blood Cancer: Only 39 out of the 10,000 patients developed blood cancer during the study period.
• Increased Risk Correlating with Prior Studies: The incidence ratio of blood cancer among clozapine users compared to non-users indicated a slight association.
• No Association with Other Cancer Types: The study did not find an increased risk of other cancers related to clozapine use.

Implications for Healthcare Professionals

The project leader, Professor Francisco Lai Tsz-tsun, stated that this study provides healthcare professionals and patients with valuable evidence regarding the safety of clozapine under current blood monitoring protocols. He noted that the low incidence of blood cancer cases associated with clozapine should not prevent patients from receiving effective treatment for mental health conditions.

Future Research Directions

The research team plans to continue investigating various potential adverse effects linked to other psychotropic medications, aiming to enhance medication safety and efficacy for patients with mental health conditions by utilizing comprehensive healthcare data accessible in Hong Kong.

Funding and Contact

This research was partially supported by the Laboratory of Data Discovery for Health funded by the AIR@InnoHK and the Innovation and Technology Commission. Further inquiries can be directed to the LKS Faculty of Medicine at the University of Hong Kong.

(Source: University of Hong Kong)