Comparison of 3 quantitative HCV RNA assays - Accuracy of baseline viral load to predict treatment outcome in chronic hepatitis C

The correlation between 3 assays for hepatitis C virus (HCV) RNA quantifica tion and their respective accuracy in predicting the response to interferon and interferon/ribavirin therapy was evaluated by analysing pre-treatment sera from 100 patients. A total of 97%, 100%, and 98% of the patients teste d positive by the branched DNA 2.0 assay (Quantiplex(R)), a multi-cycle rev ersed transcriptase polymerase chain reaction quantitative assay (Superquan t(R)) and the Roche Amplicor Monitor assay, respectively, The correlations between the assays, in all patients and in the major genotypes 1, 2, and 3, were significant, although the levels detected by the Amplicor Monitor ass ay were more than 1 log lower than by the other assays. Sustained virologic al responders to interferon therapy, but not to combination therapy, had lo wer baseline viral levels than long-term non-responders (p = 0.002 by Quant iplex 2.0; p = 0.008 by Superquant; p = 0.06 by Roche Amplicor Monitor), Pr e-treatment viral load greater than 3 x 10(6) Eq or copies/ml by the Quanti plex 2.0 and Superquant assays and greater than 100,000 copies/ml by the Am plicor Monitor assay predicted long-term non-response in 94%, 93% and 91% o f the interferon treated patients, respectively. In conclusion, acceptable correlations between available commercial quantitative assays were found. H igh baseline viral load predicted long-term non-response to interferon mono therapy,,whereas it did not to interferon/ribavirin combination therapy.