Tailoring interferon dose and monitoring viral load in hepatitis C virus genotype 1b infected patients: a pilot study

Background and aims. Complete (biochemical and virological) primary respons e remains the first goal of any antiviral therapy and its early assessment could be particularly useful in the management of the high viral load, geno type 1b infected patients, who have the worst chance of response. We evalua ted whether tailoring interferon dose according to pre-treatment viral load and early monitoring of quantitative HCV-RNA could either improve or predi ct the results of recombinant alpha-2a interferon treatment in these patien ts. Patients. Fifty-three consecutive genotype 1b HCV-infected patients, strati fied in two groups by viral load (cut off 6 MEq/ml), received randomly 6 or 9 MU of recombinant alpha-2a interferon twice weekly for 6 months, followe d by 6 MU for another 6 months. Methods. HCV-RNA was measured (b-DNA) assay two months apart prior to thera py, at baseline, after 2 weeks of therapy and monthly thereafter. Results. in the high viraemic group, complete primary response was observed in 80% of patients treated with high dose recombinant alpha 2a interferon and only in 14.3% of low dose treated patients (p<0.03). In low viraemic pa tients, complete primary response was 53.8% in low dose patients and 80% (8 out of 10) in the high dose group. Sustained response was 60% in high vira emic patients treated with high dose and absent in those treated with low d ose (p<0.05). One log viral load decrease at 2 or 4 weeks showed 0.87 and 0 .80 positive predictive values, 0.95 and 1.0 negative predictive values wit h 96% and 100% sensitivities and 83% and 70% specificities. Conclusions. 6 MU recombinant alpha-2a interferon thrice weekly schedules w ere completely ineffective in the large majority (85.7%) of patients with v iral load above 6 million HCV-RNA copies/ml and the treatment failure could be predicted by lack of one log viral load decrease after 2-4 weeks of tre atment.