Tenofovir Active in Previously Treated Chronic Hepatitis B, Including Adefovir-Resistant Virus: Presented at EASL

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Title: Tenofovir Active in Previously Treated Chronic Hepatitis B, Including Adefovir-Resistant Virus: Presented at EASL
URL: http://www.pslgroup.com/dg/220606.htm
Doctor's Guide
April 29, 2008

By Emma Hitt, PhD

MILAN, Italy -- April 29, 2008 -- Tenofovir disoproxil fumarate (TDF) induces high rates of virologic response in previously treated patients with hepatitis B virus (HBV), including those patients with adefovir resistance, according to 1-year findings presented here at the 43rd Annual Meeting of the European Association for the Study of the Liver (EASL).

Lead author Florian van Bömmel, MD, Physician, Hepatology and Gastroenterology Clinic, Charité Campus Virchow-Klinikum, Berlin Medical University, Berlin, Germany, presented the findings from a retrospective cohort analysis that included 131 HBV-monoinfected patients treated with TDF 300 mg once daily. Patients from 16 centres in Germany and the Netherlands were included. The median time of treatment observation was 23 months (range, 6-57 months).

All patients had a history of treatment with nucleos(t)ide analogues, including treatment with TDF for more than 6 months and an HBV deoxyribonucleic acid (DNA) level at baseline of more than 104 copies/mL. Of the 131 patients, 93% were lamivudine-experienced, 85% were adefovir-experienced, 61% had tyrosine-methionine-aspartate-aspartate mutations, and 19% had adefovir-resistance mutations.

After 12 months of TDF treatment, 85% of 101 evaluable patients had HBV DNA levels of less than 400 copies/mL. Patients with genotypic resistance to adefovir at baseline also achieved HBV DNA suppression during treatment, although to a lesser extent than those without resistance (30% vs 90%, P = .001).

Overall, 80% of patients had ALT normalisation. Hepatitis B e antigen (HBeAg) seroconversion occurred in 17% of patients, and hepatitis B surface antigen (HBsAg) loss occurred in 2% of patients.

No HBV virologic breakthrough was observed with TDF, and no clinically significant side effects related to TDF were observed during treatment. "One patient showed temporary mild creatinine elevation at month 12, but levels remained normal in all other patients," Dr. van Bömmel noted in his presentation here on April 25.

"TDF in this cohort of treatment-experienced patients resulted in potent suppression of HBV DNA," he concluded.

Another analysis, presented during the same session, indicated that TDF was comparably effective in lamivudine-naive (n = 377) versus lamivudine-experienced (n = 49) patients with chronic hepatitis B. The difference in mean HBV DNA log₁₀ copies/mL was comparable between groups (P = .675).

"No mutations associated with TDF resistance were observed in either lamivudine-experienced or -naive patients," said lead author, Michael P. Manns, MD, Professor, Chairman and Director, Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany. "In addition, TDF was well tolerated in both lamivudine-experienced and lamivudine-naive patients."

TDF is a nucleoside analogue currently approved in combination with other agents for the treatment of human immunodeficiency virus, and was approved last week by the European Commission for the treatment of adult chronic HBV patients with compensated liver disease in all member states of the European Union. Marketing applications are currently awaiting regulatory review in the United States, Canada, and Australia.

Funding for both of these studies was provided in part by Gilead Sciences, Inc.

[Presentation title: A Multicenter Analysis of Antiviral Response After One Year of Tenofovir Monotherapy in HBV-Monoinfected Patients With Prior Nucleos(t)ide Analogue Experience. Abstract 73. The Antiviral Response to Tenofovir Disoproxil Fumarate (TDF) is Comparable in Lamivudine (Lam)-Naïve and Lam-Experienced Subjects Treated for Chronic Hepatitis B (CHB). Abstract 74]

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