Comparison of the antiviral activity of Adefovir ( ADV ) and Teno - fovir ( TDF ) on hepatitis B virus ( HBV ) in HIV - HBV co - infected pa - tients

Context: Characteristics and factors influencing viral decay under TDF and ADV need to be determined in HIV-HBV co-infected patients. Patients and methods: This non-randomized, open label study compared the HBV DNA decay in 85 HIV-HBV co-infected patients initiating a combined antiretroviral regimen either including TDF or associated with ADV. The first 6 monthchange in viral load was analyzed using mixed-linear models. The adjusted hazards rate ratio, comparing the rates of undetectable HBV-DNA between treatments, was calculated using Cox proportional hazard model. Results: The HBV-DNA decay, adjusted for baseline HBV viral load, was more pronounced in patients treated with TDF than with ADV (-66% versus -53% at 12 months, p=0.0001). Patients in the TDF group presented a steeper slope of decline, estimated at 1.1 (95% CI: 0.9, 1.3) compared to 0.8 (95% CI: 0.6, 1.0) in the ADV group (p=0.036). The mean time to HBV-DNA undetectability was 19.3 months (95% CI: 16.7 – 22.0) with TDF and 25.9 months (95% CI: 21.1 – 30.7) with ADV. When adjusted for HBe Ag, HBV-DNA and ALT levels at baseline, the influence of treatment on time to HBV-DNA undetectability re-mained in favor of TDF versus ADV (HR = 2.79; 95 % CI : 1.05-7.40, p=0.039) Conclusion: The early-phase HBV-DNA decay is more strongly influenced by TDF than by ADV. This is associated with a sustained antiviral activity in the TDF group, in which patients reach the threshold of HBV undetectability at a faster rate and at a larger proportion than those taking ADV. in se rm -0 03 25 81 2, v er si on 1 30 S ep 2 00 8