Primary or secondary failure of adefovir dipivoxil (ADV) therapy of chronic hepatitis B is not infrequent. The reasons for suboptimal responses are not well defined. In HIV and hepatitis C virus infection, failure of antiviral drug therapy has been linked with low blood drug levels. We have studied 20 well-defined patients with chronic hepatitis B who were treated with ADV for drug and virus kinetics. Importantly, neither Cmax levels (mean 26 ng/mL, range 14-59 ng/mL) nor the time to maximal drug levels (mean 4 h, range 2-8 h) differed between patients showing a complete virological response to adefovir (n = 10), patients with secondary treatment failure (n = 7) and patients with suboptimal primary response (hepatitis B virus-DNA >10 000 IU/mL after 6 months of treatment; n = 3). Thus, adefovir treatment failure is unlikely to be due to an inability to mount sufficient drug levels in the blood.

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Journal of Viral Hepatitis
Erasmus MC: University Medical Center Rotterdam

Deterding, K., Naesens, L., Buti, M., Janssen, H., Kirschner, J., Guerrero, A., … Wedemeyer, H. (2011). Adefovir serum levels do not differ between responders and nonresponders. Journal of Viral Hepatitis (Vol. 18). doi:10.1111/j.1365-2893.2010.01404.x