Casirivimab and imdevimab: Cost-effectiveness analysis of the treatment based on monoclonal antibodies on outpatients with Covid-19

Background and objectives: In 2020, the world was profoundly affected by the spread of SARS-CoV-2, a novel coronavirus first identified in December 2019, that was the causative agent of coronavirus disease 2019 (Covid-19), a severe respiratory disease classified as a pandemic by the World Health Organization (WHO) in March 2020. Covid-19 had a significant negative impact on the healthcare facilities and the economies of many countries. A need for pharmacological treatments for Covid-19 patients rapidly emerged to limit the damage caused by the disease and allow for more efficient management of hospital resources. A possible alternative treatment that has achieved encouraging results on Covid-19 is the use of monoclonal antibodies. This research aims to evaluate the cost-effectiveness of a type of monoclonal antibody, specifically the combination of casirivimab and imdevimab, and assess its impact on the Italian healthcare system. Methods: The casirivimab and imdevimab treatment efficacy on outpatients with Covid-19 was tested using a predictive Markov model. Research endpoints include hospitalizations, Intensive Care Unit (ICU) admissions, and deaths. This was translated into terms of benefits (savings) and costs for the Italian National Health Service (NHS). The model operates on a predictive time frame of 20 weeks starting from September 2021 until January 2022. The data used to populate the model comes from international academic studies and open-access resources on online databases. Results: The model estimates the effects that can be achieved by administering casirivimab and imdevimab treatment on outpatients with Covid-19. According to the estimates, the treatment can prevent approximately 4,000 hospitalizations, 3,589 ICU admissions, and 1,500 deaths in the considered 20-week period. The potential cost savings amount to EUR 78 million, mainly attributable to the reduction in the number of hospitalizations and access to ICU. More specifically, a difference of EUR 15,4 million can be observed due to the reduction in the number of hospitalizations, a difference of EUR 59,3 million due to the reduction in the number in intensive care, and a difference of EUR 20,3 million due to the reduction in deaths as a consequence of the reduction of hospitalizations. These results are already very significant, considering that in Italy, only 4.76% of the population is eligible for monoclonal antibody treatment. Conclusion: The administration of casirivimab and imdevimab in outpatients with Covid-19 can accelerate recovery from the disease for patients, make hospital resource management more efficient and significantly reduce costs for healthcare facilities.