Coinfection

CROI 2012: Long-term Tenofovir Promotes HBsAg Decline in HIV/HBV Coinfected People

Hepatitis B surface antigen (HBsAg) levels declined steadily in HIV/HBV coinfected patients treated with tenofovir for up to 8 years, especially those with rising CD4 T-cell counts, researchers reported at the 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012) this month in Seattle.

HIV positive people coinfected with hepatitis B virus (HBV) tend to experience more severe liver disease progression than individuals with hepatitis B alone. Tenofovir (Viread, also in the Truvada and Atripla coformulations) -- which is active against both HIV and HBV -- has been shown to reduce HBV viral load in coinfected people, but its effect on HBsAg levels in this population has been less extensively studied. HBsAg clearance, generally considered a cure, is uncommon.

Theodora de Vries-Sluijs from Erasmus Medical Center in Rotterdamand colleagues measured HBsAg changes in 104 HIV/HBV coinfected patients who received ART regimens containing tenofovir for at least 6 months.

Most participants (about 90%) were men, about 60% were white, and the average age was bout 42 years. They had been HBsAg positive -- indicating current HBV infection -- for at least 6 months. Two-thirds were hepatitis B "e" antigen (HBeAg) positive at baseline and 63% had HBV genotype A. The researchers measured HBsAg levels at baseline, at 6 months, and then annually, with a median follow-up duration of 56 months.

Results

• At baseline, HBsAg was significantly higher among HBeAg positive patients compared with HBeAg negative people (4.6 vs 2.8 log IU/mL).
• HBsAg levels decreased steadily among HBeAg positive participants, while HBeAg negative patients experienced only "limited" surface antigen decline.
• At 6 years, HBsAg had declined by 2.2 log IU/mL on average among HBeAg positive people compared with 0.6 IU/mL among HBeAg negative patients.
• Among HBeAg positive participants, immune reconstitution -- indicated by rising CD4 cell counts -- was significantly correlated with HBsAg decline.
• Higher HBsAg and HBV DNA levels at baseline were also significant predictors of HBsAg decline, while genotype A (vs non-A) showed a trend.
• HBsAg decline of 2 log IU/mL or more was highly predictive of HBsAg seroclearance, which mainly occurred during the first year on tenofovir.

"[Tenofovir] for HIV/HBV [coinfected] patients up to 6 years leads to significant HBsAg decline in the HBeAg positive population," the researchers concluded. "Early HBsAg kinetics were predictive for HBsAg seroclearance in HBeAg positive patients and correlated with [increased] CD4 cell count."

These findings, they suggested, "underline the importance of immune restoration in HBV clearance.

3/20/12

Reference

Tde Vries-Sluijs, R Zoutendijk, H Zaaijer, et al. TDF Treatment for Up To Eight Years Results in Pronounced HBsAg Decline in HBeAg positive HIV/HBV Coinfected Patients. 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012). Seattle, WA. March 5-8, 2012. Abstract 53.