Cost-effectiveness of atazanavir/ritonavir compared with lopinavir/ritonavir in treatment-naive human immunodeficiency virus-1 patients in Sweden

Objective: The aim of this study was to estimate the cost-effectiveness of atazanavir/ritonavir (atazanavir/r) versus lopinavir/ritonavir (lopinavir/r) in treatment-nai < ve human immunodeficiency virus-1 (HIV-1) patients in Sweden for whom efavirenz is not suitable. Methods: A Markov model was developed to predict the lifetime outcomes of atazanavir/r and lopinavir/r in terms of quality-adjusted life years (QALYs) and total costs. The model was structured to focus on treatment lines -- how patients progress from first- to second-, and then to third-line treatment. Model inputs were derived directly from clinical trials, such as the CASTLE study (a 96-week head-to-head trial in first-line therapy), and from the Framingham risk-equation. The analysis was conducted from a payer perspective and included extensive scenario and probabilistic sensitivity analyses. Results: The model predicted atazanavir/r to save 0.16 (95% confidence interval (CI) 0.00 to 0.33) QALYs and reduce total costs by --202,896 SEK (95% CI --332,156 to --81,644 SEK) over a lifetime horizon. Probabilistic sensitivity analyses showed that atazanavir/r had a 100% probability to be cost-effective at a willingness to pay of 200,000 SEK per QALY. Conclusion: The results indicate that atazanavir/r is cost-saving and more effective compared to lopinavir/r for patients who have previously not been exposed to antiretroviral drugs in Sweden.