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Adefovir therapy for chronic HBV safely, effectively discontinued after 4 to 5 years

Most hepatitis B e antigen-negative patients with chronic HBV experienced sustained response to adefovir after 4 to 5 years of treatment, with many experiencing hepatitis B surface antigen loss, in a recent study.

In a prospective, cohort observational study, researchers evaluated 33 hepatitis B e antigen-negative (HBeAg-negative) patients with chronic HBV (CHB). All participants had undetectable HBV DNA levels and normal aminotransferase levels and had recently completed 4 to 5 years of treatment with adefovir dipivoxil (ADV). Alanine aminotransferase (ALT), hepatitis B surface antigen (HBsAg) and HBV DNA levels were recorded monthly for 6 months and then every 3 to 6 months for a median of 69 months (range 67-72 months).

Shortly after treatment discontinuation, virological relapse occurred in all participants, with 25 patients also experiencing biochemical relapse. For most participants, HBV DNA levels were highest in either the first (n=22) or second (n=7) month after treatment. Fifteen patients who relapsed subsequently received treatment with ADV or lamivudine and showed no evidence of liver decompensation. One patient experienced HBsAg loss.

No deaths occurred within the cohort, and no patients developed cirrhosis or hepatocellular carcinoma. Sustained response occurred in 18 patients during follow-up, including 13 who cleared HBsAg. Follow-up at 6-month intervals continued in patients who experienced HBsAg loss, with no reversal to positivity and nine participants seroconverting to antibody to HBsAg.

Multivariate analysis indicated associations between HBsAg clearance and higher ALT levels before (OR=1.02; P=.027) and after treatment (OR=1.29; P=.019); no re-treatment after ADV stoppage (OR=.027; P=.002), and lower HBsAg levels upon stopping treatment (OR=0.99; P=.033). Subsequent analyses with a model including the most significant variables indicated no statistically significant associations. Among 18 patients who did not receive additional antiviral therapy during ADV follow-up, only ALT levels after ADV treatment (OR=1.31; 95% CI, 1.02-1.69) were associated with HBsAg loss.

“Our study shows that effective 4- to 5-year treatment with ADV followed by drug discontinuation leads to HBsAg loss in approximately 40% of patients with well-compensated HBeAg-negative CHB,” the researchers wrote. “This is the highest rate of off-treatment HBsAg loss that has been achieved with any type of antiviral therapy in patients with CHB so far.”