Background: Patients infected with chronic hepatitis C virus (HCV) genotype 1 are the least responsive to peginterferon (pegIFN) and ribavirin therapy. The monitoring of early virological response (EVR) is therefore an important tool for quickly identifying non-responders, permitting therapy discontinuation and avoiding adverse effects and costs.
Objective: To analyse the financial impact, in treatment-naive patients infected with HCV genotype 1, of two different measurement techniques for evaluating the EVR during pegIFN-alpha-2b plus ribavirin therapy, and to compare the results of a 48-week standard course of therapy with pegIFN-alpha-2b plus ribavirin without measuring EVR.
Methods: A budget impact model was constructed using a decision-tree analysis. EVR was defined as a >2 log decline in HCV RNA levels at week 12 either tested with two quantitative HCV RNA tests or undetectable HCV core antigen (HCV core Ag) protein levels at week 12 (one HCV core Ag test). Clinical data were taken from multicentre trials and costs from the published literature (euro, 2003 values). The analysis was carried out from the perspective of the Spanish healthcare system and therefore only direct costs were considered. The base-case scenario assumed that a potential study population of 18,504 people in Spain with chronic HCV genotype 1 would be eligible for treatment with pegIFN-alpha-2b plus ribavirin.
Results: In the base case, the most effective strategy was testing EVR by HCV core Ag. This resulted in 12,745 patients reaching a sustained virological response (SVR) at an overall cost of 243.98 million euro (19,142 euro per SVR). Conversely, quantitative HCV RNA testing resulted in 11,776 patients with an SVR at a cost of 232.73 million euro ( 19,763 euro per SVR). The incremental cost per successfully treated patient with HCV core Ag testing versus quantitative HCV RNA testing was 11,597 euro. One-way sensitivity analyses demonstrated that changes in the study parameters did not modify the outcomes, except when increasing the EVR or SVR of strategy 2 or when decreasing the EVR or SVR of strategy 3.
Conclusion: This model suggests, with its underlying assumptions and data, that the assessment of EVR at week 12 by HCV core Ag testing in chronic HCV patients infected with genotype 1 permits identification of those patients expected to achieve an SVR with pegIFN-alpha-2b and ribavirin, resulting in a lower overall cost to the Spanish healthcare system than HCV RNA testing or no testing at all.