Epidemiological and economic impact of pre-exposure prophylaxis with targeted immunotherapies for COVID-19 among immunosuppressed patients in Argentina

Abstract

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Some immunosuppressive disorders have shown substantially lower protection after COVID-19 vaccination against severe outcomes. Therefore, pre-exposure prophylaxis is proposed. Targeted immunotherapy with monoclonal antibodies represents an option for preventing severe COVID-19. However, there is a lack of epidemiological and economic information on pre-exposure prophylaxis with targeted immunotherapies against COVID-19 among immunosuppressed patients. Thus, this study aims to identify and estimate the size of target population and direct medical costs related to pre-exposure prophylaxis with targeted immunotherapies against COVID-19 among the immunosuppressed adult population, and to explore the short-term economic impact of introducing tixagevimab–cilgavimab (AZD7442) for pre-exposure prophylaxis from the social security perspective in Argentina. This perspective was chosen due to the broad coverage of Argentina’s social security system, ensuring a representative framework for cost and access analysis. Through a four-step approach, we: 1) identified the immunosuppressed adult potential target population that could be eligible for pre-exposure prophylaxis with targeted immunotherapies in Argentina; 2) estimated direct medical costs associated with pre-exposure prophylaxis and COVID-19 management using a micro-costing approach; and 3) explore a cost analysis for the case of tixagevimab–cilgavimab 600 mg (assuming an ex-factory price of $950 per pack) from the social security perspective in Argentina, considering 0% and 100% pre-exposure prophylaxis uptake scenarios. Costs were expressed in American dollars ($) as of November 2022 (exchange rate: 130.8 Argentinian pesos = 1 American dollar). We estimated that 12,788 patients with target conditions (approximately 40 per 100,000 adults) would be candidates for receiving this therapy in Argentina. In terms of costs, the 100% uptake scenario accounts for total annual savings of approximately $ 121,902.7 in outpatient and hospitalization COVID-19-related costs. Also, tixagevimab–cilgavimab acquisition and administration costs represented an annual incremental cost of $24,415,617 ($1,918.5 per patient year). Finally, the net cost difference between the 100% and 0% uptake scenarios were estimated at $24,254,732.3 ($1,896.6 per patient year). This study provides crucial information for local and regional decision-makers to guide informed assessment of a potential coverage of pre-exposure prophylaxis with targeted immunotherapy among the immunosuppressed population.