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AASLD 2012: Entecavir Shows Good Efficacy for Black and Hispanic Hepatitis B Patients

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The nucleoside analog entecavir (Baraclude) worked as well for previously untreated African-American and Hispanic/Latino hepatitis B patients as it did for the majority white and Asian study populations in prior clinical trials, according to a poster presented at the American Association for the Study of Liver Diseases Liver Meeting (AASLD 2012) last month in Boston.

Entecavir is one of the most widely used treatments for chronic hepatitis B. The Phase 3 pivotal trials that led to the drug's approval enrolled mostly Caucasian and Asian patients, however, so there is limited information about its effectiveness for black or Hispanic people.

This is an important question because some drugs show racial/ethnic differences in effectiveness. Interferon-based therapy for chronic hepatitis C, for example, is less effective for people of African descent, due to their lower likelihood of carrying the favorable IL28B "CC" gene variant associated with good interferon response.

Lennox Jeffers from the University of Miami and colleagues assessed the safety and efficacy of entecavir for black and Hispanic hepatitis B patients who had not previously received treatment with nucleoside/nucleotide analogs.

This single-arm, open-label study included 46 nucleoside/nucleotide-naive patients with hepatitis B "e" antigen (HBeAg) positive or HBeAg negative chronic hepatitis B and compensated liver disease. Most (76%) were men, the mean age was 42 years, and 57% were HBeAg positive -- similar to the demographics of Phase 3 trial participants.

Within this group, 40 people (87%) self-identified as black or African-American. The researchers were only able to enroll 6 of the planned 40 Hispanic/Latino participants, which they suggested might be due to low hepatitis B prevalence and widespread HBV vaccination in these communities.

All participants were treated with 0.5 mg daily entecavir for 52 weeks. The primary efficacy endpoint was the proportion of people with HBV DNA <50 IU/mL (or approximately 300 copies/mL) at Week 48 using a non-completer = failure analysis. 

Results

  • At 48 weeks, 70% of participants overall achieved HBV DNA <50 IU/mL.
  • For black patients, the virological response rate was 73%.
  • The mean decrease in HBV DNA from baseline was -5.18 overall and -5.22 for black patients.
  • No participants experienced virological breakthrough during treatment.
  • 8 patients had HBV DNA >50 IU/mL at week 48 or at their last on-treatment visit, of whom 6 had virus samples available for resistance testing.
  • No entecavir resistance mutations were detected, but 1 person had an emergent lamivudine resistant variant (M204V/L180M).
  • About 68% of participants achieved ALT normalization (<1.0 x upper limit of normal).
  • 54% of all participants and 50% of black patients showed HBeAg loss.
  • 46% and 41%, respectively, experienced HBeAg seroconversion.
  • Hepatitis B surface antigen (HBsAg) loss was uncommon, at 7% overall and 5% for black patients.
  • HBsAg seroconversion was also rare, at 4% and 3%, respectively.
  • 4 participants (3 of whom were black) experienced serious adverse events, but none stopped treatment for this reason.

Based on these findings, the researchers concluded, "In this cohort of mostly Black/African-American [nucleoside/nucleotide-naive, HBeAg+ or HBeAg- chronic hepatitis B patients, entecavir demonstrated potent antiviral suppression similar to the experience in entecavir registrational trials, whereas HBeAg seroconversion rates appeared to be higher; however, the sample size was small."

"The safety profile of entecavir in this population was consistent with that observed in entecavir registrational trials," they added.

12/14/12

Reference

LJ Jeffers, CJ Van Rensburg, AT Banks, et al. Antiviral Efficacy of Entecavir in Black/African American and Hispanic Patients with Chronic Hepatitis B who are Nucleos(t)ide-Naive. 63rd Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2012). Boston, November 9-13, 2012. Abstract 433.