Safety and immunogenicity of a recombinant hepatitis B vaccine manufactured by a modified process in renal pre-dialysis and dialysis patients

BACKGROUND

Patients with renal insufficiency are hyporesponsive to vaccination, including to hepatitis B vaccines. A manufacturing process modification for a hepatitis B vaccine (mpHBV) was studied in renal pre-dialysis and dialysis patients.

METHODS

This randomized, open-label, multicenter, estimation study enrolled previously unvaccinated, HBV-seronegative adult dialysis and pre-dialysis patients (N=276, median age 72.0 years). At 0, 1, 6, and 8 months, group 1 received a 1 mL intramuscular dose of mpHBV (containing 40 μg HBsAg) as a single injection, while group 2 received a 1 mL intramuscular dose of a licensed hepatitis B vaccine as two injections (each containing 20 μg HBsAg; 40 μg HBsAg total). Serum antibody to HBsAg (anti-HBs) was measured predose 1, and 1 month postdose 3 and 4. Anti-HBs geometric mean concentration (GMC) and seroprotection rate (SPR, % of subjects with anti-HBs titer ≥10 mIU/mL) were estimated at months 7 and 9.

RESULTS

For group 1, month 7 SPR was 48.5% (49/101, 95% CI: 38.4%, 58.7%); with an additional dose, month 9 SPR increased to 66.7% (66/99, 95% CI: 56.5%, 75.8%). For group 2, month 7 SPR was 57.7% (64/111, 95% CI: 47.9%, 67.0%); with an additional dose, month 9 SPR increased to 69.2% (72/104, 95% CI: 59.4%, 77.9%). group 1 GMCs at months 7 and 9 were 27.5 mIU/mL (95% CI: 15.7, 48.0) and 61.7 mIU/mL (95% CI: 34.2, 111.5), respectively. group 2 GMCs at months 7 and 9 were 48.7 mIU/mL (95% CI: 28.7, 82.7) and 115.8 mIU/mL (95% CI: 65.2, 205.5), respectively. There were 22 serious adverse events; none were considered related to study vaccine.

CONCLUSIONS

Both formulations were immunogenic in this population but required more vaccinations to reach seroprotective levels than comparable regimens in healthy individuals, as expected. The relatively reduced SPRs seen in this population support the need for routine screening and re-dosing in this population.

The Oncogenic Potential of Hepatitis B virus rtA181T/ Surface Truncation Mutant

Background

Previously, a less prevalent lamivudine-resistant mutant (rtA181T) was discovered in Taiwanese patients, in which a stop codon in the surface gene concomitantly occurred, leading to impaired secretion of hepatitis B virus (HBV) surface antigen. The rtA181T mutant also conferred drug resistance to adefovir. We discovered a 39-year-old patient with advanced hepatocellular carcionoma, who was seropositive for HBV e antigen but seronegative for HBV surface antigen. Nucleotide sequence analysis revealed the presence of polymerase rtA181T/surface truncation mutant in both the serum and hepatoma samples. Surprisingly, this patient has never received lamivudine or adefovir antiviral therapy. Here, we aimed to evaluate the oncogenic potential of HBV rtA181T/surface truncation mutant.

Methods

Site-directed mutagenesis experiments followed by transactivation assays were performed in HepG2 cells to evaluate the transactivation activities of the corresponding pre-S/S truncation mutant for c-Myc, c-Fos and Simian virus 40 promoters. NIH3T3 cells stably expressing the mutant were used to assess the tumourigenicity in nude mice.

Results

Transactivation experiments revealed that the corresponding pre-S/S truncation mutant was capable of transactivating the Simian virus 40 and human c-Myc promoters but not the c-Fos promoter. NIH3T3 cells stably expressing this mutant were tumourigenic in four of the five nude mice tested.

Conclusion

Our data indicate that an HBV polymerase rtA181T/surface truncation mutant could emerge spontaneously without previous antiviral treatment. The presence of this mutant in a patient with advanced hepatocellular carcinoma as well as its oncogenic potential warrants careful re-evaluation of the current strategy of prolonged antiviral therapy.

Key reports from the 9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 2007

The 9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV provided a forum for the presentation of basic and clinical research focused on the pathogenesis and management of lipodystrophy and other adverse events associated with antiretroviral therapy. New data were reported on the contribution of both antiretroviral therapy and HIV infection itself on the development of metabolic abnormalities in patients with lipodystrophy, including insulin resistance and dyslipidaemia, which are associated with an increased risk of diabetes and cardiovascular disease. In addition, an emerging role of HIV and antiretroviral therapy in bone, liver and kidney disease were highlighted. A major focus of the data presented in these areas concerned the identification and evaluation of risk factors and appropriate surrogate markers for defining cardiovascular disease risk as well as other outcomes of long-term treatment. The complexity of defining such risk factors was underscored by data describing the impact of race, age and gender in the progression of metabolic disease and related complications among different HIV-infected populations. Finally, advances in the development of pharmacovigilance reporting systems in resource-limited settings and their impact upon healthcare policies and the provision of patient care were also described.

Special Considerations and Treatment of Patients with HBV-HIV Coinfection

Coinfection with HIV and hepatitis B virus (HBV) substantially alters the natural course of HBV infection as well as its management. Therapy for HBV infection in HIV-coinfected patients requires several factors to be taken into consideration, such as whether the antiviral activity of a particular agent is specific for HBV (that is, adefovir, entecavir, telbivudine and pegylated interferon) or for both viruses (that is, lamivudine, emtricitabine and tenofovir), whether the chosen drug has the potential for inducing drug resistance and cross-resistance, and whether use of the agent is associated with hepatotoxicity. For coinfected patients who do not require therapy for their HIV infection, clinicians should avoid prescribing monotherapy with agents that have activity against HIV (that is, tenofovir, entecavir, emtricitabine or lamivudine) so as not to compromise future HIV care. This review discusses the current status of treatment of hepatitis B in the setting of HIV infection. It describes emerging therapeutic strategies and addresses challenges in the treatment of coinfection.