OBJECTIVES: Clozapine is widely used for treatment-resistant schizophrenia (TRS). Clozapine manufacturers are required to implement a patient support program, but not all are equal. The objective of this study was to estimate the economic impact of clozapine persistence on brand vs. generic clozapine, in Quebec, Canada.

METHODS: A retention analysis of brand clozapine versus generic clozapine products was performed using IQVIA Canada’s Régie de l’assurance maladie du Québec (RAMQ) data. Patients identified were followed for the subsequent 18 months. Costs considered were those associated with treatment acquisition, hospitalization, suicide attempts, emergency room and physician visits, and withdrawal symptoms. Costs were obtained from literature and Canadian governmental sources.

RESULTS: The 18-month persistence rate of patients on brand clozapine was 32.5% better than patients on generic clozapine, with the absolute percentages being 69.2% vs 55.4% (p=0.049). The improved persistence on brand clozapine compared to generic translates into savings of $3,158 per patient, per year, despite higher treatment acquisition costs on brand clozapine (+$2,097) and the longer retention, mainly owing to the reduced hospitalization (-$4,825). When applying these savings to the total Quebec TRS patient population on clozapine, this represents total savings of $25.6 million.

CONCLUSIONS: The results support, that if one assumes two different formulations may have the same clinical benefits, the support programs associated with the manufacturer’s registries and support systems have an impact on improving overall persistence on treatment.