Avaliação econômica de tenofovir para o tratamento da hepatite B crônica sob a perspectiva do sistema público de saúde brasileiro

Abstract

Chronic hepatitis B is a high prevalence disease with 350 million cases estimated worldwide and one million deaths per year. Chronic hepatitis B patients can develop progressive hepatic disease that can result cirrhosis and hepatocellular carcinoma. Brazilian Ministry of Health updated, in October 2009, the Clinical Protocol and Therapeutical Guidelines for Chronic Viral Hepatitis B and Coinfections, incorporating the drugs adefovir dipivoxil, entecavir and tenofovir. The spending with Pharmaceutical Services Specialized Component has risen in the last years. This dissertation presents, in two studies, an economic evaluation of tenofovir compared to adefovir dipivoxil, entecavir and lamivudine for the treatment of adults chronic hepatitis B patients without HIV coinfections in Brazil. The first one evaluates the efficacy and safety of tenofovir through a scientific literature systematic review. The studied outcomes were undetectable viral DNA levels, hepatic enzymes levels normalization, histological improvement, HBeAg/Anti-HBe soroconversion, viral resistance, adverse effects and death. Six tenofovir efficacy and safety studies for the treatment of patients chronically infected by hepatitis B virus were included. Tenofovir demonstrated DNA levels reduction and no drug associated viral resistance. All the studies included were funded by tenofovir manufacturer laboratory. The second study is a cost-effectiveness analysis of adefovir dipivoxil, entecavir, lamivudine and tenofovir, from SUS perspective, aiming to support the discussion on drugs for the treatment of chronic hepatitis B. The initial treatment with entecavir or tenofovir showed better clinical outcomes. The lowest cost-effectiveness ratio was presented by entecavir in HBeAg-positive (R$4,010.84/LY) and lamivudine for HBeAg-negative (R$6,205.08/LY). For HBeAg-negative patients, the incremental cost-effectiveness ratio of entecavir (R$14,101.05/LY) is below the threshold recommended by the World Health Organization. Sensitivity analysis showed that the cost variation of the drugs can make tenofovir a cost-effective alternative for both HBeAg-positive and HBeAg-negative patients. Embased on the two studies, it was possible to perform an economic evaluation of chronic hepatitis B treatment. Considering the clinical evidence and the study assumptions, entecavir was the most cost-effective alternative for HBeAg-positive patients. However, sensitivity analysis showed that tenofovir can be the most cost-effective alternative if the drugs cost are changed. Treatment with entecavir was cost-effective compared to lamivudine for HBeAgnegative, although the sensitivity analysis showed that tenofovir can be cost-effective if the drugs cost are changed. The results showed that the incremental investment is economically recommended to achieve a better effectiveness in treatment. In conclusion, from the SUS perspective, we reiterate the use of tenofovir for the treatment of chronic hepatitis B in adult patients without HIV coinfection.