An inter-departmental research team at the LKS Faculty of Medicine of the University of Hong Kong conducted a real-world cohort study on the association of the antipsychotic drug clozapine with the incidence of blood cancer. Their findings suggest that the risk of blood cancer associated with clozapine use is very low, with an average increase of less than six cases per 10,000 persons using the drug for one year. Previous Western studies had indicated a potentially significant increase in risk, but with stringent blood monitoring measures, it may not be necessary to further restrict the use of clozapine. The study was published in PLOS Medicine and supports the safe and effective use of clozapine in treating mental illness.
Clozapine is the only antipsychotic drug approved by the FDA for treatment-resistant schizophrenia and is known for its high efficacy in reducing symptoms and relapse rates. Recent Finnish and American studies suggested an increased risk of blood cancer associated with clozapine use, but the clinical significance of this risk was unclear. The research team in Hong Kong utilized territory-wide electronic health records to construct a retrospective cohort of patients diagnosed with schizophrenia and followed them for seven years. Their findings showed a slight association between clozapine use and blood cancer, in line with previous studies, but no increased risk for other cancer types.
The study provides reliable evidence supporting the safety of clozapine for patients and healthcare professionals, given the rarity of the association between the drug and blood cancer. With comprehensive blood monitoring measures in place, patients do not need to be overly concerned about the risk of blood cancer. Clinicians are advised to weigh the risks and benefits of clozapine and make appropriate decisions based on individual patient needs. The research team highlights the strengths of Hong Kong’s healthcare big data and its potential application in drug safety monitoring, enabling better understanding of clinically meaningful healthcare issues.
The research team is currently investigating potential adverse effects of other psychotropic drugs, particularly cancer risks, to improve overall long-term safety and effectiveness in treating mental illness. By utilizing interdisciplinary efforts and big data, they aim to provide valuable information for clinical decision-making and make medication use in patients with mental illness safer and more effective. The study on clozapine and blood cancer sets a precedent for using real-world data to assess drug safety and supports the continued use of the drug for treating schizophrenia, with appropriate monitoring and consideration of individual patient needs.