New Clozapine Regulations May Widen Ethnic Disparities
Revised monitoring requirements for clozapine may inadvertently worsen existing inequalities in access to treatment for people of African ancestry
The use of clozapine, a highly effective antipsychotic for treatment-resistant schizophrenia, is restricted by mandatory haematological monitoring requirements. Although these monitoring programmes have reduced mortality associated with clozapine-induced agranulocytosis, they also contribute to delayed treatment initiation and clinician reluctance to prescribe clozapine. People of African ancestry are disproportionately affected by these challenges, resulting in longstanding ethnic inequalities in access to this treatment.
## Background Clozapine remains the most effective antipsychotic for treatment-resistant schizophrenia, yet its use is limited by monitoring requirements. A major factor underlying these disparities is the under-recognition of ACKR1/DARC-associated neutropenia, a common inherited haematological phenotype among individuals of African and some Middle Eastern ancestries. This condition results in lower baseline neutrophil counts without an increased risk of infection or clozapine-induced agranulocytosis.
## Monitoring Requirements Several countries and regulatory bodies have revised or proposed revisions to monitoring requirements, including the removal of white blood cell monitoring and updated absolute neutrophil count thresholds. The European Clozapine Task Force has recommended stepwise reductions in monitoring frequency after 1 and 2 years of stable counts, which have been formally adopted by the European Medicines Agency. Similar reforms are expected in the UK.
## Equity in Monitoring Reforms While these changes have the potential to reduce treatment burden and improve access to clozapine, there is a risk that they could inadvertently widen existing ethnic disparities. Eligibility for extended monitoring will depend on demonstrating sustained haematological stability during the first 2 years of treatment. For patients with unrecognised ACKR1/DARC-associated neutropenia, naturally lower neutrophil counts might trigger increased monitoring or temporary treatment interruptions despite the absence of any increased risk of infection or clozapine-induced agranulocytosis. To address this issue, routine genetic screening for ACKR1/DARC-associated neutropenia should be incorporated into clozapine monitoring frameworks to reduce unnecessary treatment interruptions and ensure that modernisation of clozapine monitoring benefits all patients equitably.
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