Sofosbuvir, velpatasvir, and voxilaprevir for patients with failure of previous direct-acting antiviral therapy for chronic hepatitis C: Results from the German Hepatitis C-Registry (DHC-R).

Despite the high effectiveness of direct-acting antivirals for the treatment of hepatitis C, a small proportion of patients do not respond to approved regimens. The combination regimen of SOF/VEL/VOX was recently approved for patients with failure to prior NS5A-based treatment. In this German real-world cohort including patients with cirrhosis (27.3 %) and previous decompensation events, 12 weeks of SOF/VEL/VOX resulted in high virologic response rates irrespective of disease severity and prior DAA regimen. Adverse events were mostly mild or moderate and comparable to those seen in the approval studies.

Therapeutic DNA vaccination using in vivo electroporation followed by standard of care therapy in patients with genotype 1 chronic hepatitis C.

Clearance of infections caused by the hepatitis C virus (HCV) correlates with HCV-specific T cell function. We therefore evaluated therapeutic vaccination in 12 patients with chronic HCV infection. Eight patients also underwent a subsequent standard-of-care (SOC) therapy with pegylated interferon (IFN) and ribavirin. The phase I/IIa clinical trial was performed in treatment naive HCV genotype 1 patients, receiving four monthly vaccinations in the deltoid muscles with 167, 500, or 1,500 µg codon-optimized HCV nonstructural (NS) 3/4A-expressing DNA vaccine delivered by in vivo electroporation (EP). Enrollment was done with 2 weeks interval between patients for safety reasons. Treatment was safe and well tolerated. The vaccinations significantly improved IFN-γ-producing responses to HCV NS3 during the first 6 weeks of therapy. Five patients experienced 2-10 weeks 0.6-2.4 log10 reduction in serum HCV RNA. Six out of eight patients starting SOC therapy within 1-30 months after the last vaccine dose were cured. This first-in-man therapeutic HCV DNA vaccine study with the vaccine delivered by in vivo EP shows transient effects in patients with chronic HCV genotype 1 infection. The interesting result noted after SOC therapy suggests that therapeutic vaccination can be explored in a combination with SOC treatment.

Lack of variant specific CD8+ T-cell response against mutant and pre-existing variants leads to outgrowth of particular clones in acute hepatitis C.

BACKGROUND: CTL escape mutations have been described during acute hepatitis C in patients who developed chronic disease later on. Our aim was to investigate the mutual relationship between HCV specific CD8+ T cells and evolution of the viral sequence during early acute HCV infection. RESULTS: We sequenced multiple clones of NS3 1406 epitope in 4 HLA-A*02 patients with acute hepatitis C genotype 1b infection. Pentamers specific for the variants were used to monitor the corresponding CD8+ T cell response. We observed outgrowth of mutations, which induced only a weak and thus potentially insufficient CD8+ T cell response. In one patient we observed outgrowth of variant epitopes with similarities to a different genotype rather than de novo mutations most probably due to a lack of responsiveness to these likely pre-existing variants. We could show that in acute hepatitis C CTL escape mutations occur much earlier than demonstrated in previous studies. CONCLUSIONS: The adaption of the virus to a new host is characterized by a high and rapid variability in epitopes under CD8+ T cell immune pressure. This adaption takes place during the very early phase of acute infection and strikingly some sequences were reduced below the limit of detection at some time points but were detected at high frequency again at later time points. Independent of the observed variability, HCV-specific CD8+ T cell responses decline and no adaption to different or new antigens during the course of infection could be detected.

Inhibitory molecules that regulate expansion and restoration of HCV-specific CD4+ T cells in patients with chronic infection.

BACKGROUND & AIMS: Inhibitory receptors such as programmed death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen (CTLA)-4 mediate CD8+ T-cell exhaustion during chronic viral infection, but little is known about roles in dysfunction of CD4+ T cells. METHODS: We investigated the functions of inhibitory molecules on hepatitis C virus (HCV)-, influenza-, and Epstein-Barr virus (EBV)-specific CD4+ T cells in patients with chronic infections compared with patients with resolved HCV infection and healthy donors. Expression of PD-1, CTLA-4, CD305, and CD200R were analyzed on HCV-specific CD4+ T cells, isolated from peripheral blood using major histocompatibility complex class II tetramers. We investigated the effects of in vitro inhibition of various inhibitory pathways on proliferation and cytokine production by CD4+ T cells, and we compared these effects with those from inhibition of interleukin (IL)-10 and transforming growth factor (TGF)-ß1. RESULTS: PD-1 and CTLA-4 were up-regulated on virus-specific CD4+ T cells from patients with chronic HCV infections. PD-1 expression was lower on influenza- than on HCV-specific CD4+ T cells from subjects with chronic HCV infection, whereas CTLA-4 was expressed at similar levels, independent of their specificity. CD305 and CD200R were up-regulated in HCV resolvers. Blockade of PD-L1/2, IL-10, and TGF-ß1 increased expansion of CD4+ T cells in patients with chronic HCV, whereas inhibition of IL-10 and TGF-ß1 was most effective in restoring HCV-specific production of interferon gamma, IL-2, and tumor necrosis factor α. CONCLUSIONS: We characterized expression of inhibitory molecules on HCV-, influenza-, and EBV-specific CD4+ T cells and the effects of in vitro blockade on CD4+ T-cell expansion and cytokine production. Inhibition of PD-1, IL-10, and TGF-ß1 is most efficient in restoration of HCV-specific CD4+ T cells.

The immunoregulatory role of CD244 in chronic hepatitis B infection and its inhibitory potential on virus-specific CD8+ T-cell function.

UNLABELLED: Multiple inhibitory receptors may play a role in the weak or absent CD8+ T-cell response in chronic hepatitis B virus (HBV) infection. Yet few receptors have been characterized in detail and little is known about their complex regulation. In the present study, we investigated the role of the signaling lymphocyte activation molecule (SLAM)-related receptor CD244 and of programmed death 1 (PD-1) in HBV infection in 15 acutely and 66 chronically infected patients as well as 9 resolvers and 21 healthy controls. The expression of CD244, PD-1, and T-cell immunoglobulin domain and mucin domain 3 (TIM-3) was analyzed in virus-specific CD8+ T-cells derived from peripheral blood or liver using major histocompatibility complex class I pentamers targeting immunodominant epitopes of HBV, Epstein-Barr-virus (EBV), or influenza virus (Flu). In chronic HBV infection, virus-specific CD8+ T-cells expressed higher levels of CD244 both in the peripheral blood and liver in comparison to the acute phase of infection or following resolution. CD244 was expressed at similarly high levels in EBV infection, but was low on Flu-specific CD8+ T-cells. In chronic HBV infection, high-level CD244 expression coincided with an increased expression of PD-1. The inhibition of the CD244 signaling pathway by antibodies directed against either CD244 or its ligand CD48 resulted in an increased virus-specific proliferation and cytotoxicity as measured by the expression of CD107a, interferon-γ, and tumor necrosis factor-α in CD8+ T-cells. CONCLUSION: CD244 and PD-1 are highly coexpressed on virus-specific CD8+ T-cells in chronic HBV infection and blocking CD244 or its ligand CD48 may restore T-cell function independent of the PD-1 pathway. CD244 may thus be another potential target for immunotherapy in chronic viral infections.

Barriers to initiation of hepatitis C virus therapy in Germany: A retrospective, case-controlled study.

Despite the availability of highly effective and well-tolerated direct-acting antivirals, not all patients with chronic hepatitis C virus infection receive treatment. This retrospective, multi-centre, noninterventional, case-control study identified patients with chronic hepatitis C virus infection initiating (control) or not initiating (case) treatment at 43 sites in Germany from September 2017 to June 2018. It aimed to compare characteristics of the two patient populations and to identify factors involved in patient/physician decision to initiate/not initiate chronic hepatitis C virus treatment, with a particular focus on historical barriers. Overall, 793 patients were identified: 573 (72%) who received treatment and 220 (28%) who did not. In 42% of patients, the reason for not initiating treatment was patient wish, particularly due to fear of treatment (17%) or adverse events (13%). Other frequently observed reasons for not initiating treatment were in accordance with known historical barriers for physicians to initiate therapy, including perceived or expected lack of compliance (14.5%), high patient age (10.9%), comorbidities (15.0%), alcohol abuse (9.1%), hard drug use (7.7%), and opioid substitution therapy (4.5%). Patient wish against therapy was also a frequently reported reason for not initiating treatment in the postponed (35.2%) and not planned (47.0%) subgroups; of note, known historical factors were also common reasons for postponing treatment. Real-world and clinical trial evidence is accumulating, which suggests that such historical barriers do not negatively impact treatment effectiveness. Improved education is key to facilitate progress towards the World Health Organization target of eliminating viral hepatitis as a major public health threat by 2030.

FOXP3 expression in hepatitis C virus-specific CD4+ T cells during acute hepatitis C.

BACKGROUND & AIMS: Down-regulation of hepatitis C virus (HCV)-specific CD4(+) T-cell responses is a hallmark of chronic viral persistence in acute hepatitis C. FOXP3(+)CD25(+)CD4(+) regulatory T cells can modulate HCV-specific immune responses in vitro, but the role of virus-specific regulatory T cells in the pathogenesis of chronic viral persistence is unknown. METHODS: Two novel HLA-DR15 tetramers were synthesized to study the kinetics and phenotype of FOXP3(+)-expressing HCV-specific CD4(+) T cells from 10 patients with acute hepatitis C and 15 patients with chronic hepatitis C. RESULTS: In acute hepatitis C, generally only a low percentage of HCV-specific CD4(+) T cells expressed FOXP3(+) (mean of 2.5% in patients with self-limited acute hepatitis C vs 2.4% in patients with evolving chronic hepatitis C). Although distinct but short-lived increases in virus-specific FOXP3(+)CD4(+) T cells occurred in 3 patients (30%, 26%, and 7% of tet(+) CD4(+) T cells, respectively), these did not correlate with the evolution of chronic hepatitis C. HCV-specific FOXP3(+)CD4(+) T cells displayed a distinct phenotype, with only 10% expressing CD25 and 40% being CD127low. Interestingly, this phenotype of FOXP3(+)CD4(+) T cells was already expanded in bulk CD4(+) T cells in patients with chronic hepatitis C. CONCLUSIONS: Although short-lived increases in HCV-specific FOXP3(+)CD4(+) T cells occur during the course of acute hepatitis C, we could not demonstrate an association of HCV-specific regulatory T cells and persistent viremia.

Risk factors for resistance development against lamivudine during long-term treatment of chronic hepatitis B virus infections.

BACKGROUND/AIM: The use of lamivudine for the treatment of chronic hepatitis B (CHB) is limited by high rates of lamivudine resistance. However, it is still in use in many regions. Factors associated with lamivudine resistance development have been studied in only a few European cohorts. The aim of our study was to assess the rate and risk factors for lamivudine resistance in a large real-life European cohort. PATIENTS AND METHODS: We retrospectively analyzed patients with CHB treated in three German University centers over up to 12 years. Lamivudine resistance was defined as virologic breakthrough and presence of genotypic lamivudine resistance. The probability of resistance was estimated by Kaplan-Meier analysis and resistance predictors by Cox regression. RESULTS: A total of 227 patients were included into the analysis (hepatitis B envelope antigen positive or negative). Rates of lamivudine resistance by years 1-7 were 7, 26, 35, 41, 46, 53, and 55%, respectively. Interestingly, two hepatitis B envelope antigen-negative patients developed resistance during the year 12 of treatment. Independent risk factors for resistance development were hepatitis B virus DNA levels of at least 10 copies/ml before and detectable hepatitis B virus DNA by month 6 of treatment. CONCLUSION: Even after long-term response to lamivudine more than 10 years, resistance may still develop. Our findings further discourage the use of lamivudine for the treatment of CHB.

Antiviral therapy for recurrent hepatitis C after liver transplantation: sustained virologic response is related to genotype 2/3 and response at week 12.

OBJECTIVES: Recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) is a major cause of transplant failure in HCV-positive patients. We retrospectively assessed the efficacy and safety of antiviral therapy and determined the factors influencing sustained virologic response (SVR) in LT recipients. METHODS: Between 1998 and 2007, we treated 36 LT recipients for hepatitis C cirrhosis and subsequent HCV recurrence (27 genotype 1 and 9 genotypes 2/3) with pegylated interferon alpha-2a (180 microg/week), pegylated interferon alpha-2b (1.5 microg/kg per week), or standard interferon alpha-2b (3 MIU 3X/week) plus ribavirin (600-1200 mg/day) for 48 weeks. RESULTS: SVR was achieved in seven of 27 (26%) of genotype 1 patients versus nine of nine (100%) genotype 2/3 patients (P=0.0001). Early virologic response at week 12 was associated with permanent viral clearance. Side effects included cytopenia and acute hearing loss, but rate of therapy withdrawal and dose reduction was low. CONCLUSION: Combination therapy in patients with HCV reinfection after LT yields an excellent SVR rate in genotype 2/3 patients, but remains unsatisfactory in genotype 1 patients. Virologic response at week 12 (early virologic response) can determine whether therapy should be continued or not.

Immunology of hepatitis B infection.

The immune response initiated by the T-cell response to viral antigens is thought to be fundamental for viral clearance and disease pathogenesis in hepatitis B virus (HBV) infection. The T-cell response during acute self-limited hepatitis B in people is characterised by a vigorous, polyclonal, and multispecific cytotoxic and helper-T-cell response. By contrast, the immune response in chronic carriers, not able to eliminate the virus, is weak or undetectable. Thus a dominant cause of viral persistence could be the existence of a weak antiviral immune response. Methodological progress in animal models allows more precise investigation of the mechanisms by which the immune system resolves viral infection or develops chronic infection. Although clearance of most virus infections is widely thought to indicate the killing of infected cells by virus-specific T cells, data suggest that non-cytolytic intracellular viral inactivation by cytokines released by virus-inactivated lymphomononuclear cells could have an important role in the clearance of this virus without killing the infected cell. Additional factors that could contribute to viral persistence, which have been partly proven in animal models, are viral inhibition of antigen processing or presentation, modulation of the response to cytotoxic mediators, immunological tolerance to viral antigens, viral mutations, and infection of immunologically privileged sites. In view of the central role of cellular immunity in disease pathogenesis, strategies have been proposed to manipulate this cellular immune response in favour of protection from disease.

Dysfunctional CD8+ T cells in hepatitis B and C are characterized by a lack of antigen-specific T-bet induction.

The transcription factor T-bet regulates the production of interferon-γ and cytotoxic molecules in effector CD8 T cells, and its expression correlates with improved control of chronic viral infections. However, the role of T-bet in infections with differential outcome remains poorly defined. Here, we report that high expression of T-bet in virus-specific CD8 T cells during acute hepatitis B virus (HBV) and hepatitis C virus (HCV) infection was associated with spontaneous resolution, whereas T-bet deficiency was more characteristic of chronic evolving infection. T-bet strongly correlated with interferon-γ production and proliferation of virus-specific CD8 T cells, and its induction by antigen and IL-2 stimulation partially restored functionality in previously dysfunctional T-bet-deficient CD8 T cells. However, restoration of a strong interferon-γ response required additional stimulation with IL-12, which selectively induced the phosphorylation of STAT4 in T-bet(+) CD8 T cells. The observation that T-bet expression rendered CD8 T cells responsive to IL-12 suggests a stepwise mechanism of T cell activation in which T-bet facilitates the recruitment of additional transcription factors in the presence of key cytokines. These findings support a critical role of T-bet for viral clearance and suggest T-bet deficiency as an important mechanism behind chronic infection.

Inhibitory phenotype of HBV-specific CD4+ T-cells is characterized by high PD-1 expression but absent coregulation of multiple inhibitory molecules.

BACKGROUND: T-cell exhaustion seems to play a critical role in CD8+ T-cell dysfunction during chronic viral infections. However, up to now little is known about the mechanisms underlying CD4+ T-cell dysfunction during chronic hepatitis B virus (CHB) infection and the role of inhibitory molecules such as programmed death 1 (PD-1) for CD4+ T-cell failure. METHODS: The expression of multiple inhibitory molecules such as PD-1, CTLA-4, TIM-3, CD244, KLRG1 and markers defining the grade of T-cell differentiation as CCR7, CD45RA, CD57 and CD127 were analyzed on virus-specific CD4+ T-cells from peripheral blood using a newly established DRB1*01-restricted MHC class II Tetramer. Effects of in vitro PD-L1/2 blockade were defined by investigating changes in CD4+ T-cell proliferation and cytokine production. RESULTS: CD4+ T-cell responses during chronic HBV infection was characterized by reduced Tetramer+CD4+ T-cell frequencies, effector memory phenotype, sustained PD-1 but low levels of CTLA-4, TIM-3, KLRG1 and CD244 expression. PD-1 blockade revealed individualized patterns of in vitro responsiveness with partly increased IFN-γ, IL-2 and TNF-α secretion as well as enhanced CD4+ T-cell expansion almost in treated patients with viral control. CONCLUSION: HBV-specific CD4+ T-cells are reliably detectable during different courses of HBV infection by MHC class II Tetramer technology. CD4+ T-cell dysfunction during chronic HBV is basically linked to strong PD-1 upregulation but absent coregulation of multiple inhibitory receptors. PD-L1/2 neutralization partly leads to enhanced CD4+ T-cell functionality with heterogeneous patterns of CD4+ T-cell rejunivation.

Delayed versus immediate treatment for patients with acute hepatitis C: a randomised controlled non-inferiority trial.

BACKGROUND: Early treatment of acute hepatitis C virus (HCV) infection with interferon alfa monotherapy is very effective, with cure rates of greater than 85%. However, spontaneous clearance of HCV occurs in 10-50% of cases. We aimed to assess an alternative treatment strategy of delayed antiviral therapy in patients who do not eliminate the virus spontaneously compared with immediate treatment. METHODS: In our open-label phase 3 non-inferiority trial, we enrolled adults (≥18 years) with acute hepatitis C but no HIV or hepatitis B co-infection at 72 centres in Germany. We randomly allocated patients with symptomatic acute hepatitis C (1:1) to receive immediate pegylated interferon alfa-2b treatment for 24 weeks or delayed treatment with pegylated interferon alfa-2b plus ribavirin (for 24 weeks) starting 12 weeks after randomisation if HCV RNA remained positive. We used a computer-generated randomisation sequence and block sizes of eight, stratified by bilirubin concentration. We assigned all asymptomatic patients to immediate treatment with pegylated interferon alfa-2b for 24 weeks. The primary endpoint was sustained HCV RNA negativity in all randomly allocated participants who completed screening (intention-to-treat analysis), with a non-inferiority margin of 10%. For the primary analysis, we calculated the virological response of patients in the immediate and delayed treatment groups and an absolute risk difference stratified by bilirubin status. The trial was stopped early on advice from the study advisory committee because of slow recruitment of participants. This study is registered, number ISRCTN88729946. FINDINGS: Between April, 2004, and February, 2010, we recruited 107 symptomatic and 25 asymptomatic patients. 37 (67%) of 55 symptomatic patients randomly allocated to receive immediate treatment and 28 (54%) of 52 symptomatic patients randomly allocated to receive delayed treatment had a sustained virological response (difference 13·7%, 95% CI -4·6 to 32·0; p=0·071). 18 (72%) of 25 asymptomatic patients had a sustained virological response. 22 (42%) of 52 symptomatic patients allocated to receive delayed treatment did not complete follow-up compared with 20 (25%) of 80 symptomatic or asymptomatic patients assigned immediate treatment (p=0·037). 11 symptomatic patients (21%) assigned delayed treatment had spontaneous HCV clearance. 14 patients who received delayed pegylated interferon alfa-2b plus ribavirin treatment and completed follow-up achieved sustained virological response. INTERPRETATION: Delayed treatment is effective although not of equal efficacy to immediate treatment; coupled with the rate of spontaneous clearance it can reduce unnecessary treatment in closely monitored populations. Immediate treatment seems preferable in populations where loss to follow-up is great. FUNDING: German Network of Competence on Viral Hepatitis (HepNet, funded by the German Federal Ministry of Education and Research, grants 01KI0102, 01KI0401, and 01KI0601), MSD, Schering-Plough.

Recurrence of hepatitis C virus during leucocytopenia and spontaneous clearance after recovery from cytopenia: a case report.

INTRODUCTION: There is little information about the risk of HCV recurrence in immunosuppressed patients. Although the presence of antibodies to HCV and the absence of HCV-RNA is usually considered to indicate viral elimination, the virus may not be completely eliminated but may be under control of an effective immune response. CASE PRESENTATION: A 69 year old man presented with jaundice, elevated ALT, AST, lipase and concomitant abdominal pain. He was found to be positive for HCV-RNA (genotype 3a) and was diagnosed with acute hepatitis C. Six weeks later no HCV-RNA was detected, and the patient was diagnosed with hyperthyreosis and started on propylthiouracil. After 4 weeks of propylthiouracil treatment, the patient developed leucocytopenia, followed by liver function deterioration and reappearance of HCV-RNA. Propylthiouracil was discontinued and his leukocyte counts increased. Twenty-eight weeks after onset of acute hepatitis C, no HCV-RNA was detected. CONCLUSION: This case history shows the risk of recurrence of HCV during leucocytopenia. These findings indicate that patients who are anti-HCV positive but HCV-RNA negative may be at risk of cytopenia-induced HCV reactivation.

Characterization of sequence variations in immunodominant regions of the HBV-nucleocapsid protein as a prerequisite for the development of an epitope-based vaccine.

BACKGROUND/AIMS: In hepatitis B virus infection, viral elimination is dependent on an efficient antiviral T cell response which is not detectable in chronic hepatitis B. Therefore, new therapeutic concepts focus on T cell activation, such as epitope-based T cell-targeted vaccines. However, with the development of peptide-based vaccines in mind, viral mutations frequently described in hepatitis B within known immunodominant helper epitopes may have an influence on peptide selection. METHODS: Mutant peptides within immunodominant epitopes (aa 1-20, aa 91-105, and aa 143-157) at position 12, 14, 93, 97, 147, 151, 153, and 155 were tested with peripheral blood mononuclear and specific clone cells for their ability to induce proliferation, produce cytokines, induce T cell receptor down-regulation or antagonize wild-type activity of the hepatitis B core antigen-specific CD4+ T cell clones. RESULTS: Five variants could not induce T cell proliferation or cytokine production when the variants were presented alone. Coincubation with wild-type epitopes leads to T cell activation showing that the variants do not act as T cell receptor antagonists for hepatitis B virus-specific CD4+ T cells. In contrast, five other variants and wild-type peptides stimulated CD4+ T cell proliferation and production of Th1 cytokines. CONCLUSIONS: Our data demonstrate that frequently occurring mutations within immunodominant epitopes have rather a nonstimulatory than a strengthening effect and thus should not included in a vaccine.

Tracking virus-specific CD4+ T cells during and after acute hepatitis C virus infection.

BACKGROUND: CD4+ T cell help is critical in maintaining antiviral immune responses and such help has been shown to be sustained in acute resolving hepatitis C. In contrast, in evolving chronic hepatitis C CD4+ T cell helper responses appear to be absent or short-lived, using functional assays. METHODOLOGY/PRINCIPAL FINDINGS: Here we used a novel HLA-DR1 tetramer containing a highly targeted CD4+ T cell epitope from the hepatitis C virus non-structural protein 4 to track number and phenotype of hepatitis C virus specific CD4+ T cells in a cohort of seven HLA-DR1 positive patients with acute hepatitis C in comparison to patients with chronic or resolved hepatitis C. We observed peptide-specific T cells in all seven patients with acute hepatitis C regardless of outcome at frequencies up to 0.65% of CD4+ T cells. Among patients who transiently controlled virus replication we observed loss of function, and/or physical deletion of tetramer+ CD4+ T cells before viral recrudescence. In some patients with chronic hepatitis C very low numbers of tetramer+ cells were detectable in peripheral blood, compared to robust responses detected in spontaneous resolvers. Importantly we did not observe escape mutations in this key CD4+ T cell epitope in patients with evolving chronic hepatitis C. CONCLUSIONS/SIGNIFICANCE: During acute hepatitis C a CD4+ T cell response against this epitope is readily induced in most, if not all, HLA-DR1+ patients. This antiviral T cell population becomes functionally impaired or is deleted early in the course of disease in those where viremia persists.

Immunogenicity and safety of an experimental adjuvanted hepatitis B candidate vaccine in liver transplant patients.

Patients with chronic liver disease are at higher risk of hepatitis B (HB) virus infection before and after liver transplantation, and they commonly have a suboptimal immune response to HB vaccines. In this randomized trial, we compared the immunogenicity of primary vaccination with 2 doses of an experimental adjuvanted HB vaccine (adjuvant system 04 containing aluminium and monophosphoryl lipid A [HB-AS04]) to that of 3 double doses of a licensed HB vaccine in 93 liver transplant candidates. Depending on the waiting list for liver transplantation, a booster dose of HB-AS04 or double booster dose of the licensed HB vaccine was given before or after surgery, at 6 to 12 months after initiation of the vaccination course. The percentage of subjects with seroprotective anti-HB surface antibody concentrations 1 month after booster was twice as high in the HB-AS04 group (60.0%), vs. patients in the comparator group (32.0%) (P = 0.035). In subjects who did not undergo liver transplantation before administration of the booster, better immunogenicity results were obtained: 80% of subjects were seroprotected after HB-AS04 vaccination vs. 60% with the comparator (P = 0.2302). Despite a slightly higher reactogenicity, the safety profile of the HB-AS04 vaccine was clinically acceptable. In conclusion, an improved antibody response was observed in liver transplant candidates with 3 doses of HB-AS04, as compared to 4 double doses of a comparator. Liver transplant candidates could benefit from the use of this experimental adjuvanted HB vaccine to further increase their protection against HB infection.