Ninety-six-week efficacy of combination therapy with lamivudine and tenofovir in patients coinfected with HIV-1 and wild-type hepatitis B virus

In vitro Study on Synergistic Interactions Between Free and Encapsulated Q-Griffithsin and Antiretrovirals Against HIV-1 Infection

Introduction

Human immunodeficiency virus (HIV) remains a persistent global challenge, impacting 38 million people worldwide. Antiretrovirals (ARVs) including tenofovir (TFV), raltegravir (RAL), and dapivirine (DAP) have been developed to prevent and treat HIV-1 via different mechanisms of action. In parallel, a promising biological candidate, griffithsin (GRFT), has demonstrated outstanding preclinical safety and potency against HIV-1. While ARV co-administration has been shown to enhance virus inhibition, synergistic interactions between ARVs and the oxidation-resistant variant of GRFT (Q-GRFT) have not yet been explored. Here, we co-administered Q-GRFT with TFV, RAL, and DAP, in free and encapsulated forms, to identify unique protein-drug synergies.

Methods

Nanoparticles (NPs) were synthesized using a single or double-emulsion technique and release from each formulation was assessed in simulated vaginal fluid. Next, each ARV, in free and encapsulated forms, was co-administered with Q-GRFT or Q-GRFT NPs to evaluate the impact of co-administration in HIV-1 pseudovirus assays, and the combination indices were calculated to identify synergistic interactions. Using the most synergistic formulations, we investigated the effect of agent incorporation in NP-fiber composites on release properties. Finally, NP safety was assessed in vitro using MTT assay.

Results

All active agents were encapsulated in NPs with desirable encapsulation efficiency (15–100%), providing ~20% release over 2 weeks. The co-administration of free Q-GRFT with each free ARV resulted in strong synergistic interactions, relative to each agent alone. Similarly, Q-GRFT NP and ARV NP co-administration resulted in synergy across all formulations, with the most potent interactions between encapsulated Q-GRFT and DAP. Furthermore, the incorporation of Q-GRFT and DAP in NP-fiber composites resulted in burst release of DAP and Q-GRFT with a second phase of Q-GRFT release. Finally, all NP formulations exhibited safety in vitro.

Conclusions

This work suggests that Q-GRFT and ARV co-administration in free or encapsulated forms may improve efficacy in achieving prophylaxis.

Hepatitis B and HIV co-infection is still treated using lamivudine-only antiretroviral therapy combination in Uganda

BACKGROUND

Hepatitis B virus (HBV) and HIV are endemic in Uganda. Co-infection is common and leads to rapid progression of liver disease. Burden of co-infection is unknown yet most patients are on lamivudine-only ART where resistance is frequent. Most patients are initiated on antiretroviral therapy (ART) without knowing their HBV status.

OBJECTIVES

To determine burden of co-infection and HBV viral suppression among patients on ART in Northern Uganda.

METHODS

We recruited HIV infected adult patients on ART in a cross-sectional study. Age, sex, ART regimen and duration were recorded. Hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBcAb) and liver panel were performed. For those HBsAg+, hepatitis B e antigen (HBeAg) and HBV DNA were performed. CD4 cell count was recorded.

RESULTS

Three hundred patients were recruited. Twenty (6.7%) were co-infected, while 41% were anti-HBcAb+. Overall 188 (62.7%) were on lamivudine- only HBV active drug. Median ART duration 2 years (IQR 1-5), mean CD4+ cell count 317 cells/microlitre (SD 255-557). Of 20 HIV/HBV co-infected, 11/20 (55%) were on lamivudine-only ART, median duration 1.5 years. Nineteen (95%) had undetectable HBV DNA. Seventeen (85%) were HBeAg negative. Mean CD4+ cell count 327 cells/microlitre (SD 197-482).

CONCLUSION

A large proportion of patients were on lamivudine- only HBV-active ART. Resistance may occur long term thus testing for HBV and correct ART is recommended.

Treatment outcomes in a cohort of patients with chronic hepatitis B and human immunodeficiency virus co-infection in Mumbai, India

Treatment experiences with patients co-infected with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) in resource-limited settings remain poorly documented. This study aimed to evaluate the treatment outcomes in a cohort of HIV/HBV co-infected individuals receiving tenofovir/lamivudine (TDF/3TC)-based antiretroviral therapy (ART) in a programmatic setting in Mumbai, India. Additionally, a cross-sectional laboratory study was carried out measuring serologic and virologic parameters. A total of 57 patients who received TDF/3TC were included in the study. Of these, 52 (91%) were male and the mean age was 38.7 years. The median follow-up period was 16.8 months (IQR:7.9-37.9). Forty-three patients were included in the cross-sectional laboratory study, of whom 38 (67%) were HBeAg(+) positive. Four patients had serum HBsAg conversion to negative and had developed anti-HBs-antibodies. HBV-DNA became undetectable (<1.3 log10 copies/ml or <20 IU/ml) in 35.5% and 75% of the HBeAg(+) and HBeAg(-) patients, respectively. Overall, 46.5% of patients had undetectable HBV-DNA and 90.7% had adequately suppressed HBV-DNA (<3.3 log10 copies/ml or <2000 IU/ml). The median reduction in serum HBV-DNA was 6 log10 copies/ml. In 29 patients (63%) HIV viral load was undetectable. Outcomes included seven (12%) deaths, four (7%) lost to follow-up, one (2%) transferred out and 45 (79%) alive and on treatment. In conclusion, good treatment outcomes were achieved in a cohort of HIV/HBV co-infected patients in India. In regions with a high HIV/HBV burden, all HIV-infected individuals should be tested for chronic hepatitis B. A TDF/3TC-backbone could be considered as first-line standardized ART regimen in these settings.

Suppression of HBV by tenofovir in HBV/HIV coinfected patients: a systematic review and meta-analysis

BACKGROUND

Hepatitis B coinfection is common in HIV-positive individuals and as antiretroviral therapy has made death due to AIDS less common, hepatitis has become increasingly important. Several drugs are available to treat hepatitis B. The most potent and the one with the lowest risk of resistance appears to be tenofovir (TDF). However there are several questions that remain unanswered regarding the use of TDF, including the proportion of patients that achieves suppression of HBV viral load and over what time, whether suppression is durable and whether prior treatment with other HBV-active drugs such as lamivudine, compromises the efficacy of TDF due to possible selection of resistant HBV strains.

METHODS

A systematic review and meta-analysis following PRISMA guidelines and using multilevel mixed effects logistic regression, stratified by prior and/or concomitant use of lamivudine and/or emtricitabine.

RESULTS

Data was available from 23 studies including 550 HBV/HIV coinfected patients treated with TDF. Follow up was for up to seven years but to ensure sufficient power the data analyses were limited to three years. The overall proportion achieving suppression of HBV replication was 57.4%, 79.0% and 85.6% at one, two and three years, respectively. No effect of prior or concomitant 3TC/FTC was shown. Virological rebound on TDF treatment was rare.

INTERPRETATION

TDF suppresses HBV to undetectable levels in the majority of HBV/HIV coinfected patients with the proportion fully suppressed continuing to increase during continuous treatment. Prior treatment with 3TC/FTC does not compromise efficacy of TDF treatment. The use of combination treatment with 3TC/FTC offers no significant benefit over TDF alone.

Long-term outcome of primary non-responders to tenofovir therapy in HIV/HBV-co-infected patients: impact of HBV genotype G

AIM

To evaluate the early virological response (EVR) to combined tenofovir-lamivudine or emtricitabine regimen in HBV/HIV-co-infected patients and the long-term efficacy of tenofovir.

METHODS

In this retrospective monocentric study, among the 166 HIV/HBV-co-infected patients regularly followed from 2003 to 2008 at Bichat Claude Bernard Hospital, 61 patients had received, either de novo combination therapy with tenofovir and lamivudine or emtricitabine (group I, n = 15) or add-on tenofovir to lamivudine therapy (group II, n = 46). The HBV polymerase region was sequenced and analysed for all patients with available samples.

RESULTS

All 15 group I patients achieved EVR vs 32 (82%) of group II patients (P = 0.15). Seven adherent group II patients met criteria for primary non-response, but achieved delayed response (DR) to therapy. In these seven patients, when compared with the 39 group II patients, there was a trend to longer duration of lamivudine pre-treatment and to higher rate of lamivudine-resistant mutants; and HBV genotype-G proportion was higher (P = 0.026). No virological breakthrough occurred after a median of 46 months follow up.

CONCLUSION

In these HBV/HIV-co-infected patients, first-line HBV therapy with tenofovir and emtricitabine or lamivudine was associated with EVR. However, DR to tenofovir was observed in 15% of patients who added tenofovir to lamivudine therapy, of whom four of seven (57%) had genotype G-HBV infection. No resistance was evidenced after 46 months of therapy even in patients with DR to tenofovir. At last, a good renal safety profile of TDF was observed after a median follow-up of 4 years of therapy.

Occult hepatitis B infection in patients infected with HIV: report of two cases of hepatitis B reactivation and prevalence in a hospital cohort

Patients co-infected with human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are particularly at risk of hepatitis B reactivation. Two cases of patients infected with HIV with isolated anti-HBc antibodies who had experienced an HBV reactivation are described. In the two cases HBV reactivation occurred after withdrawal of anti-retroviral treatment with anti-HBV activity from the patients' highly active antiretroviral therapy (HAART), in accordance with HIV genotypic resistance profiles. Consequently, plasma samples from 383 patients infected with HIV were tested to assess the prevalence of occult HBV infection in the Infectious Diseases Department Unit of Nancy Hospital by investigating serological patterns and HBV replication. Forty-five percent (172/383) of patients had had previous contact with HBV. Isolated anti-HBc antibodies were observed in 48 patients (48/383, 12%) and, among these, 2 were HBV-DNA positive. Since 75% (288/383) of the patients were treated with HAART, including at least one drug active against HBV, occult HBV infection was perhaps unrecognized. In cases of HIV infection, all patients should be screened for HBV infection and the knowledge of HBV status as well as the monitoring of HBV viral load are essential in preventing HBV reactivation. Consideration should be given to the continuation of drugs with anti-HBV activity in co-infected patients receiving HAART, as cessation of therapy is associated with a risk of HBV reactivation. At least, close monitoring of the HBV viral load is warranted in such situations.

Anti-hepatitis B virus activity in vitro of combinations of tenofovir with nucleoside/nucleotide analogues

BACKGROUND

Long-term management of some chronic hepatitis B patients might require combination therapy using drugs with distinct resistance profiles to sustain viral suppression and to reduce the resistance-associated failure. Tenofovir disoproxil fumarate (TDF), approved for hepatitis B virus (HBV) and HIV-1 treatment, is active against wildtype HBV and HBV containing YMDD mutations, which confer resistance to emtricitabine (FTC), lamivudine (3TC) and telbivudine (LdT) and contribute to entecavir (ETV) resistance. We therefore evaluated the in vitro anti-HBV activity of tenofovir (TFV), the active parent drug of TDF, combined with FTC, 3TC, ETV, LdT and adefovir (AFV).

METHODS

The anti-HBV activities of the compounds were tested using the AD38 cell line that expresses wild-type HBV from a tetracycline-controllable promoter. Intracellular HBV DNA levels were quantified using real-time PCR assay and cytotoxicities were assessed with XTT assays. The antiviral data of the drug combinations were evaluated using MacSynergy analyses on the basis of the Bliss independence model as well as isobologram analyses on the basis of the Loewe additivity theory.

RESULTS

All drug combinations tested, FTC+TFV, 3TC+TFV, ETV+TFV, LdT+TFV and AFV+TFV, showed additive antiviral interactions as analysed by MacSynergy. Isobologram analyses revealed that these combination pairs were additive, with the exception of FTC+TFV, which demonstrated slight synergistic activity. No cytotoxic or antagonistic effects were observed with any of the combinations tested.

CONCLUSIONS

The combination of TFV with FTC, 3TC, ETV, LdT or AFV had additive to slightly synergistic anti-HBV effects in vitro. These results support the use of TDF as a component in combination regimens with currently available anti-HBV nucleoside analogues.

Prevention and management of drug resistance for antihepatitis B treatment

Emergence of drug resistance in antiviral therapy for chronic hepatitis B negates treatment benefits. There is a lower chance for emergence of resistance for drugs with rapid and potent viral suppression and a high genetic barrier for resistant mutations. Measurement of viral load at 24 weeks' treatment to aid decision making is mandatory for patients receiving drugs that are associated with a higher resistance rate. Combination treatment with drugs that belong to different groups is associated with a lower chance of resistance. To ensure better control of viral replication in patients with drug resistance, the addition of another drug without an overlapping resistance profile should be given as early as possible, preferably at the time when genotypic resistance emerges. With such strategies, most patients can be maintained in clinical remission. However, because of the mechanism of viral persistence, research efforts should continue to anticipate and prevent the emergence of multidrug-resistant strains.

New approaches in the management of chronic hepatitis B: role of tenofovir

In the field of HIV management, tenofovir disoproxil fumarate (TDF) plays a pivotal role and has been demonstrated to be a safe and well-tolerated antiviral agent. Recent data showed the efficacy of TDF in the treatment of chronically hepatitis B virus (HBV)-infected patients. TDF was superior to adefovir dipivoxil (ADV) in both nucleos(t)ide-naïve HBeAg-positive and HBeAg-negative HBV patients, and appeared to be one of the most potent antiviral agents so far. In addition, several reports showed that TDF was also effective in the nucleos(t)ide-experienced population, although conflicting results have been presented concerning patients with genotypic resistance to ADV. TDF seems to have a good resistance profile as well. The rtA194T mutation in association with lamivudine resistance may confer resistance to TDF, although both in vivo and in vitro studies regarding this mutation demonstrate conflicting results. As treatment with TDF may be associated with nephrotoxicity, all TDF-treated patients should be monitored for renal function at baseline and periodically thereafter. While the relative roles of interferon vs nucleos(t)ide analogues (NA) as initial anti-HBV therapy remains unclear, TDF will probably become one of the key factors in HBV management both as first-choice NA for nucleos(t)ide-naïve patients and as rescue therapy for nucleos(t)ide-experienced patients.

Long-term outcome of tenofovir disoproxil fumarate use against hepatitis B in an HIV-coinfected cohort

OBJECTIVES

Tenofovir disoproxil fumarate (TDF) is active against hepatitis B virus (HBV) and HIV. However, the long-term efficacy of tenofovir disoproxil fumarate (TDF) is not well known and the appearance of resistance is a major concern. We have studied the efficacy of TDF against HBV in patients treated at an Infectious Diseases Unit.

METHODS

We carried out a retrospective observational study of the efficacy of TDF against HBV replication in a cohort of 52 HIV-coinfected patients who received TDF for at least 6 months.

RESULTS

The median duration of follow-up of TDF treatment was 34 months. Forty-one patients (79%) were positive for HBV envelope antigen (HBeAg) and 35 had received previous lamivudine monotherapy for a median duration of 32 months. Virological breakthrough was observed in nine cases (17%). At the end of the follow-up period, HBV DNA levels were <1000 copies/mL in 42 patients (81%) and <200 copies/mL in 31 patients (60%). There were no significant differences between the lamivudine-naïve and lamivudine-experienced groups. In the lamivudine-experienced group, the duration of previous lamivudine monotherapy was associated with failure to achieve HBV DNA levels <200 copies/mL (P=0.036). Adding lamivudine or emtricitabine to TDF did not improve virological suppression. In 39 patients who achieved <200 HBV DNA copies/mL during TDF treatment, virological breakthrough was seen only in two patients (5%) after a median follow-up duration of 39.7 months.

CONCLUSIONS

TDF was able to control HBV replication in most HIV-coinfected patients after a median follow-up duration of 34 months, regardless of previous lamivudine treatment. However, a sizeable proportion of patients developed virological breakthrough.

Tenofovir Disoproxil Fumarate Tablets

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Prolonged use of tenofovir in HIV/hepatitis B virus (HBV)-coinfected individuals does not lead to HBV polymerase mutations and is associated with persistence of lamivudine HBV polymerase mutations

OBJECTIVES

The aim of the study was to identify and characterize hepatitis B virus (HBV) polymerase gene mutations associated with ongoing HBV replication in HIV/HBV-coinfected individuals receiving tenofovir (TDF).

METHODS

This retrospective cross-sectional study identified 28 HIV/HBV-coinfected individuals who had received TDF for at least 3 months. All patients had samples available while receiving TDF (on-TDF), and 24 also had samples available prior to treatment (pre-TDF). Case records were reviewed to obtain clinical and virological data at the times of sampling (+/-3 months). The HBV DNA of all samples was amplified using polymerase chain reaction (PCR), and the polymerase region of PCR-positive samples was sequenced and compared with reference HBV data.

RESULTS

Of the pre-TDF samples, 15 of 24 (63%) were HBV PCR positive. Of the on-TDF samples, four of 28 (14%) were HBV PCR positive (mean time on TDF 13.5 months; range 3-23 months). Lamivudine (3TC)-resistance mutations were detected in three of four (75%) of these viraemic samples. The previously identified putative TDF-resistance mutations, rtA194T+rtL180M+rtM204V, were not detected in any individual.

CONCLUSIONS

Unique mutations in the HBV polymerase gene associated with TDF resistance are rare in HIV/HBV coinfection. 3TC-resistance mutations persist and a significant proportion of patients are HBV PCR positive despite the addition of TDF.

[Combination therapy in chronic hepatitis B]

The HBV genome variability is responsible for the complexitiy of the viral quasi-species and its evolution during the course of the infection. During antiviral therapy, the persistence of infected cells is another important determinant involved in the selection of drug resistant strains. The development of nucleoside analogs with complementary resistance profiles has provided the rationale for add-on strategies in case of virologic breakthrough. The current trend is to add antivirals earlier, before the rebound of viral load, especially in case of partial virologic response. Clinical trials are required to determine if a de novo combination of nucleoside analogs provides an added benefit compared to an early add-on strategy. However, de novo combination is recommended in patients whose liver functions cannot tolerate treatment failure, and in patients with a high risk of developing viral resistance because of a complex viral quasi-species prior to therapy.

Current therapy for hepatitis C or D or immunodeficiency virus concurrent infection with chronic hepatitis B

Concurrent hepatitis C virus (HCV), hepatitis delta virus (HDV), or human immunodeficiency virus (HIV) infection with chronic hepatitis B virus (HBV) appears to increase the risk of progressive liver disease including liver cirrhosis and hepatocellular carcinoma. There is a 10% prevalence of HCV infection in chronic HBV or HDV infection. Serological evidence of previous exposure to HBV is found in more than 80% of HIV-positive patients in the high risk group. Notably, the most recently acquired virus tends to suppress the pre-existing virus. In chronic HBV infection acquired perinatally or in early childhood, usually HCV is dominant and may suppress or even displace HBV and HDV. Less frequently, HBV or HDV suppresses HCV. It is generally agreed that the dominant virus should be identified in order to make appropriate treatment decisions. Studies with standard interferon (IFN) to treat patients with HCV dominantly dual HBV/HCV infection have showed only limited virological response. But high dose of IFN has been demonstrated with better response rate. Combined ribavirin with standard or pegylated IFN therapy could achieve a sustained HCV clearance rate comparable with those infected with HCV alone. On the contrary, patients with HBV dominantly dual viral infection might indicate more appropriate addition of lamivudine to IFN than ribavirin. Additionally, patients with concurrent infection of HBV and HDV, IFN seems to be the only effective agent. However, the efficacy of IFN is related to the dose. High dose of IFN [9 MU tiw (thrice per week)] and longer treatment duration (at least 2 years) have been shown to achieve adequate virological response. In patients with concurrently infected HBV and HIV, anti-HBV therapy should be considered for all patients with evidence of liver disease, irrespective of the CD4 cell count. In patients not requiring antiretroviral therapy, HBV therapy should be preferentially based on IFN, adefovir, or telbivudine. In contrast, in patients with CD4 cell counts <350 cells/mul or those already on antiretroviral therapy, agents with double anti-HBV and anti-HIV activity are preferred. At present, the evidence of therapeutic efficacy is not sufficient to make a recommendation in treating patients with dual HBV/HCV or HBV/HDV or HBV/HIV infection. Further studies of the well-designed, larger scale are needed to elucidate the role of different regimens or combination in the treatment of dual viral infection.

New antiviral choice for chronic hepatitis B: tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is an oral prodrug of tenofovir, a novel, acyclic nucleotide analogue with in vitro activity against HIV-1 and HIV-2. TDF is licensed by American Food and Drug Administration (FDA) in 2001 for the treatment of HIV infection. TDF is currently one of the most widely used nucleotide reverse transcriptase inhibitors (NRTIs) for the treatment of HIV infection. Its efficacy, favorable toxicity profile, and convenient dosing have made this drug one of the most popular first-line treatment. Numerous studies have demonstrated the use of TDF in the treatment of HIV infection. It also has been shown to be effective in HIV/HBV coinfected patients and in patients with wild-type and lamivudine-resistant strains. Accumulating evidence suggests that TDF is more potent in suppressing HBV replication. In this review, we summarize the study progress of TDF in treating HBV infection.

Treatment of chronic hepatitis B: recommendations from an Italian workshop

The changing scenario of hepatitis B virus therapy has encouraged the organisation of a workshop, endorsed by three Italian scientific societies, aimed at defining the current recommendations for hepatitis B virus treatment. Liver histology and stage of disease remain fundamental for treatment decisions; interferon and nucleoside/nucleotide analogues-based therapy represent different strategies for different phases of the hepatitis B virus disease. The recommendations defined: new and lower cut-off of hepatitis B virus-DNA for eligibility to therapy according to disease stage, how to optimise the use of nucleoside/nucleotide analogues and to individualise the monitoring of response and what to do with treatment failures. Specific recommendations have also been given for cirrhosis patients, those immune suppressed and co-infected with HIV and other hepatitis viruses.

The case for combination antiviral therapy for chronic hepatitis B virus infection

The treatment of hepatitis B virus (HBV) infection has been revolutionised in the past decade by the increased availability of effective antiviral agents. Many studies have shown the benefits of single agent therapy, but there is an alarming and rising rate of viral resistance, and clear evidence that viruses that harbour resistant mutations can cause liver disease and death. Current national guidelines for the treatment of HBV recommend a programme that starts with monotherapy, followed by sequential monotherapy or add-on therapy for those infections in which mutations have arisen. Very few studies starting with combination therapy have been undertaken, so there is little evidence of the clinical benefit of this approach to treatment. The studies that have been done have been short term and have concentrated on clinical parameters rather than virological resistance, which is likely to be the key determinant in the longer term. We argue that we should not wait for the evidence to use combination therapy for the treatment of HBV, since such trials may never be done and it would take several years for a benefit to become apparent. In the meantime, multidrug-resistant strains continue to hinder HBV control.

Role of tenofovir in the treatment of chronic HBV infection

Nucleoside analogues revolutionized the treatment of chronic HBV infection and have become the most important therapeutic option within the last decade. Currently, the nucleoside analogues lamivudine, telbivudine and entecavir, and the nucleotide analogue adefovir dipivoxil, are licensed. Tenofovir disoproxil fumarate (TDF) is another acyclic nucleotide analogue that has been successfully used in the treatment of HIV-infected patients, but has demonstrated significant antiviral activity in wild-type and lamivudine-resistant HBV infections. The use of TDF 300 mg/day leads to marked suppression of HBV replication below the detection limit in different patients groups with HBV mono- or HIV/HBV co-infection in most instances, and a remarkably high rate of hepatitis B e antigen loss and even hepatitis B surface antigen loss was found in small, uncontrolled studies. Belonging to the substance class of acyclic nucleotide analogues, TDF is not cross-resistant to nucleoside analogue resistance-associated mutations. In equal dosages, TDF has comparable antiviral potency as compared with its congender adefovir dipivoxil, but in clinical studies exhibits higher antiviral efficacy and generates a higher genetic barrier against the development of genotypic HBV resistance due to its approximately 24-fold higher dosage. Owing to the numerous newly developed compounds and as a consequence of the emerging problem of drug resistance, treatment concepts for chronic hepatitis B will certainly be modified in the future. Because of its quite favorable antiviral and safety properties, TDF will likely be highly regarded in the management of HBV infections in the future.

Antiviral therapy of chronic hepatitis B: prevention of drug resistance

The emergence of viral resistance during treatment is becoming an important clinical issue for hepatitis B virus (HBV) antiviral therapy. Considerable progress has been achieved in the efficacy of treatment, with the development of new drugs that allow a sustained suppression of HBV replication, or at least maintain the viral load below a clinically relevant threshold. Although most drugs currently registered for the treatment of chronic hepatitis B are effective in suppressing viral load, long-term therapy is required to avoid viral reactivation and progression of liver disease. Because of the variability of the HBV genome, such long-term treatments are associated with the emergence of resistant viral strains, which may compromise the initial clinical benefit of the treatment.

Emerging drugs for hepatitis B

Chronic hepatitis B remains a treatment challenge despite the availability of new nucleoside analogs. This is due to the persistence of viral infection during therapy, which exposes the patient to the risk of developing antiviral drug resistance. Therefore, new polymerase inhibitors are needed to manage resistance to existing drugs and new trials of combination therapy are required to delay drug resistance. In the future, antiviral agents targeting other steps of the viral life cycle will be needed to achieve antiviral synergy and prevent antiviral drug resistance. Immune modulators are also expected to enhance antiviral response and to achieve sustained response. Discovery of new antiviral drugs and design of new treatment strategies are, therefore, needed to manage this disease, which is still the main cause of cirrhosis and hepatocellular carcinoma worldwide.

Epidemiology, diagnosis and treatment of chronic hepatitis B in HIV-infected patients (EPIB 2005 STUDY)

OBJECTIVE

To describe the characteristics of hepatitis B (HBV) infection in HIV-infected patients and the impact of anti-HBV treatments.

PATIENTS AND METHODS

All the patients with past or present chronic HBV infection seen in October 2005 in 17 French hospitals were included. Data were retrospectively collected from their first visit in a time-dependent manner, through a detailed standardized questionnaire.

RESULTS

Among 477 HBV-infected patients, 261 (55%) were co-infected with HIV. The HBV-HIV co-infected patients underwent fewer serological, virological and histological evaluations. Initial positive HBe antigenemia (HBe Ag) was more frequent in these patients (57.9 versus 28.6%; P < 10), as was cirrhosis on the initial liver biopsy (17.9 versus 7.6%; P = 0.05). Throughout the mean 5-year follow-up, HBe Ag loss was less frequent (P = 0.04), as was HBe seroconversion (incidence rate 2.6 versus 10/100 patient-years; P < 10). HBe Ag loss was associated with fibrosis improvement (METAVIR score -0.5 +/- 0.4 versus +0.2 +/- 0.6 if persistent positive HBe Ag, P = 0.01). In co-infected patients on tenofovir, adefovir or interferon, HBe seroconversions were seen in patients on combined HBV treatment, the use of which is increasing (58% in 2005). Nevertheless, no significant difference in virological, immunological or biochemical evolution was observed between these different treatments.

CONCLUSIONS

In HBV-HIV co-infected patients, the assessment of HBV infection still needs to be improved, the HBV wild-type remains predominant, and HBe Ag loss is rare and associated with a better histological evolution. There is insufficient evidence of the superiority of combined HBV treatment, and this still needs be demonstrated in long term studies.

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.

Treatment of hepatitis B with lamivudine and tenofovir in HIV/HBV-coinfected patients: factors associated with response

As therapy for human immunodeficiency virus (HIV) infection evolves, optimizing hepatitis B virus (HBV) treatment and identifying factors that impact its response in the HIV/HBV-coinfected population is critical. We identified retrospectively 45 HBV/HIV-coinfected patients with detectable HBV DNA by the Bayer VERSANT HBV 3.0 bDNA assay (limit of quantification 2000 copies/mL) at baseline and/or year 1 of therapy. Patients were divided into three groups based on the active HBV agent in their antiretroviral regimen: group 1 (n = 15) received lamivudine; group 2 (n = 10), lamivudine plus tenofovir and group 3 (n = 20), lamivudine followed by lamivudine plus tenofovir. HBV genotypes and resistance profiles were determined by the Bayer Trugene HBV 1.0 assay. More patients in group 2 achieved HBV DNA suppression below 2000 copies/mL (80%), loss of HBe antigen (HBeAg) (40%) and loss of HBeAg and gain of anti-HBe (20%) than did patients in group 1 or 3. More patients with HBV genotype A, achieved HBV DNA suppression <2000 copies/mL than did patients with non-A genotypes [74% (26/35) vs 20% (2/10)], respectively (P = 0.003). Risk for virological nonresponse was significant in those with non-A genotypes [odds ratio (OR) 11.1; 95% CI: 2.0-50], previous HIV therapy (OR 6.5; 95% CI: 1.2-35) and <90% compliance (OR 3.7; 95% CI: 0.99-14.3). Simultaneous therapy with lamivudine/tenofovir suppresses HBV DNA more effectively than lamivudine or tenofovir added to lamivudine. More patients infected with HBV genotype A responded than the non-A patients, regardless of therapeutic regimen, compliance or prior HIV therapy.

Treatment options in HBV

The available evidence on interferon-alpha (IFN) treatment for chronic hepatitis B is sufficient to conclude that in patients with HBeAg positive chronic hepatitis, standard IFN therapy significantly improves clearance of HBeAg (number needed to treat [NNT] = 4), loss of HBV-DNA (NNT = 4) and clearance of HBsAg (NNT = 18). HBeAg positive patients with normal or slightly raised ALT should be treated only if there is histological evidence of progressive disease. In patients with HBeAg negative chronic hepatitis, less than 20% of subjects who have achieved an end-of-treatment virological response after a course of standard IFN maintain a sustained virological response in the long-term. IFN treatment could help to delay or prevent disease decompensation and liver-related deaths but further large studies are needed. Lamivudine is effective at reducing, and sometimes clearing, HBV replication in heavily immunosuppressed patients and can be safely administered to patients with advanced liver disease. Lamivudine should be continued over an undefined extended period of time, with a switch from lamivudine to adefovir if there is an HBV-DNA breakthrough under therapy. Adefovir, excluding cost, is preferable to lamivudine as a first-choice because there is less chance of inducing resistance. The long-term benefit of lamivudine and adefovir and the role of combinations is under investigation.

Assessment of treatment efficacy in HBV infection and disease

In patients co-infected with HIV and HBV viral load monitoring allows comparison of the efficacy of different antiviral drugs and determination of the initial response to therapy. Usually, the decline in viral load is associated with an improvement in ALT levels and liver histology scores, but some patients show transient elevations in ALT levels due to the restoration of the specific anti-HBV immune response. Analysis of liver histology is useful to determine the improvement of the inflammatory activity of the disease and liver fibrosis, and to make an accurate diagnosis when drug hepatotoxicity is suspected. HBe seroconversion and HBs loss have been described in some patients during anti-HBV therapy with lamivudine, adefovir or tenofovir, indicating that the control of viral replication by these agents may lead to a dramatic suppression of viral load. HBV drug resistant mutants can be diagnosed at an early stage with the monitoring of viral load. Future research directions include the determination of predictive factors of response, the effect of anti-HBV therapy on liver disease severity, the impact of long-term treatment on HBsAg clearance and intrahepatic cccDNA, the impact of HBV drug resistance on the liver disease, the role of cross-resistance testing of HBV strains in patients with HBV treatment failure.

Antiviral therapy of chronic hepatitis B

Treatment of chronic hepatitis B remains a clinical challenge. Long-term viral suppression is a major goal of antiviral therapy to improve the clinical outcome of the patients. Antiviral treatment of chronic hepatitis B relies currently on immune modulators such as interferon alpha and its pegylated form, and viral polymerase inhibitors. Because of the slow kinetics of viral clearance and the spontaneous viral genome variability, viral mutants resistant to nucleoside analogs may be selected. However, the development of new antiviral agents is rapidly improving the offing of therapy of chronic hepatitis B. These new therapeutic advances are reviewed in this manuscript.

Antiretroviral treatment of HIV infection: Swedish recommendations 2005

On 2 earlier occasions, in 2002 and 2003, the Swedish Medical Products Agency (MPA) and the Swedish Reference Group for Antiviral Therapy (RAV) have jointly publicized recommendations for the treatment of HIV infection. A working group from the same expert team that produced the 2002 report has now revised the text again. Since the publication of the last treatment recommendations, 4 new medicines have become available: emtricitabine, atazanavir, fosamprenavir, and enfuvirtid. The last-mentioned belongs to a new class of HIV medications called fusion inhibitors (Box 1). It is likely that tipranavir will also be on the market soon. Simultaneously, the drug zalcitabin has been deregistered. The following updated recommendations parallel the earlier ones, but increased knowledge allows us to be more specific in our recommendations. Thus, it is now suggested that the initial treatment for HIV infection consist of 2 nucleoside reverse transcriptase inhibitors (NRTIs) and 1 non-nucleoside reverse transcriptase inhibitor (NNRTI); or 2 NRTIs and 1 protease inhibitor (PI). In the group of the NRTIs, stavudine is no longer recommended for this purpose. In the NNRTI group, efavirenz should be preferred to nevirapine, except under special circumstances. Finally, PIs ought to be boosted with ritonavir (PI/r). Also new are recommendations regarding treatment choices for patients co-infected with hepatitis B virus (HBV) or tuberculosis (TB). As in the case of the previous publication, recommendations are evidence-graded in accordance with the Oxford Centre for Evidence Based Medicine, 2001 (see http://www.cebm.net/levels_of_evidence.asp#levels), and have been supplemented with references to newly-added sections and data not referred to in earlier background documentation.

Kidney transplantation in HIV-infected patients

Human immunodeficiency virus (HIV) infection has traditionally been considered an absolute contraindication to solid organ transplantation. With improvements in survival and increases in the prevalence of end-stage liver and kidney disease in HIV-positive patients treated with highly active antiretroviral therapy, many transplant centers have begun to reconsider the role of transplantation in patients with well-controlled HIV infection. This article reviews the literature on transplantation in HIV-infected patients, with a focus on kidney transplantation in the era of highly active antiretroviral therapy.

Anti-hepatitis B virus efficacy of tenofovir disoproxil fumarate in HIV-infected patients

Tenofovir disoproxil fumarate (TDF) has shown in vitro activity against both HIV and hepatitis B virus (HBV). We retrospectively evaluated the efficacy of TDF (300 mg/d), administered as a part of anti-retroviral therapy, in a large cohort of HIV/HBV-coinfected patients. Sixty-five HIV/HBV-coinfected patients who received TDF for at least 6 months with serum HBV DNA levels above 2.3 log10 copies/mL at TDF initiation and who had stored serum samples before and during TDF therapy were included. Serum HBV DNA was measured on stored samples. The median follow-up period was 12 (Q1-Q3: 8-17) months. Serum hepatitis B e antigen (HBeAg) was positive in 54 patients (83.1%). Fifty-two patients (80.0%) were receiving lamivudine (LAM) (150 mg twice a day), and 68.8% had documented LAM resistance at baseline. Among HBeAg-positive patients, the median reduction from baseline (8.17; Q1-Q3 = 7.30-8.30 log10 copies/mL) of serum HBV DNA was 4.56 log10 copies/mL (Q1-Q3 = 3.33-5.55) (P < .0001). In HBeAg-negative patients, serum HBV DNA decline from baseline (4.83; Q1-Q3 = 2.69-6.40 log10 copies/mL) was 2.53 log10 copies/mL (Q1-Q3 = 0.39-4.10). At the end of the study, HBV DNA became undetectable in 29.6% and 81.6% of the HBeAg-positive and HBeAg-negative patients, respectively. Serum HBeAg became negative in 4 patients, 2 of whom acquired serum hepatitis B e antibody. In conclusion, this retrospective analysis demonstrates the efficacy of TDF against wild-type, presumed precore mutants and LAM-resistant HBV when used as a part of anti-retroviral therapy in HIV-coinfected patients.

Impact of tenofovir-containing antiretroviral therapy on chronic hepatitis B in a cohort co-infected with human immunodeficiency virus

OBJECTIVES

We studied the impact of tenofovir disoproxil fumarate, given as an antiretroviral medication, on patients with chronic hepatitis B virus (HBV) co-infection.

METHODS

The polymerase gene-sequence evolution and quantitative HBV loads (HBVL) were observed for 48 weeks in patients taking tenofovir-containing antiretroviral therapy. The patients were grouped according to baseline strata: high-replicative virus (>6 log copies/mL), low-replicative virus at detectable virus loads (<6 log) and HBs-antigen-positive, HBV-DNA-negative individuals.

RESULTS

Thirty-one patients were evaluated. The median decline in 20 patients with high-replicative HBV infection was -5.37 log (range: 3.57-7); 11 out of 20 decreased to undetectable levels (lower limit of detection = < 200 copies/mL) and another three were below 400 copies/mL. Out of six patients with detectable HBV-DNA at week 48 (HBVL result: range 3.36-4.32 log(10)), we were able to carry out a re-sequence in four patients. We did not observe relevant emerging resistance mutations, or a relevant virus load re-increase from nadir (>+0.5 log). The patients with low-replicative virus (n = 9) and the baseline DNA-negative patients (n = 2) had an undetectable HBV-DNA at week 48. Two patients became HBeAg-negative; one DNA-negative patient became HBsAg-negative.

CONCLUSIONS

Tenofovir is effective in treating HBV infection in HIV patients. Patients with high-replicative virus may benefit from this treatment strategy by a reduction in replicative status, a precondition for improved hepatic function. A few patients showed low-level HBV replication. Indicators for clinical HBV-resistance to tenofovir were not observed.

Acyclic nucleoside phosphonates: a key class of antiviral drugs

Almost 20 years after the broad antiviral activity spectrum of the first acyclic nucleoside phosphonates was described, several of these compounds have become important therapies for DNA virus and retrovirus infections. Here, we review the discovery and development of acyclic nucleoside phosphonates, focusing on cidofovir and its potential in the treatment of various herpes-, papilloma-, polyoma-, adeno- and pox-virus infections, adefovir for the treatment of hepatitis B and tenofovir for the treatment of AIDS and the prevention of HIV infections.

[GESIDA/GESITRA-SEIMC, PNS and ONT consensus document on solid organ transplant (SOT) in HIV-infected patients in Spain (March, 2005)]

Solid organ transplant may be the only therapeutic alternative in some HIV-infected patients. Experience in North America and Europe during the last five years shows that survival at three years after an organ transplant is similar to that observed in HIV-negative patients. The criteria agreed upon to select HIV patients for transplant are: no opportunistic infections (except tuberculosis, oesophageal candidiasis or P. jiroveci -previously carinii- pneumonia), CD4 lymphocyte count above 200 cells/.L (100 cells/.L in the case of liver transplant) and an HIV viral load which is undetectable or suppressible with antiretroviral therapy. Another criterion is a two-year abstinence from heroin and cocaine, although the patient may be in a methadone programme. The main problems in the post-transplant period are pharmacokinetic and pharmacodynamic interactions between antiretorivirals and immunosuppressors, rejection and the management of relapse of HCV infection, which is one of the main causes of post-liver transplant mortality. Up to now, experience with pegylated interferon and ribavirin is scarce in this population. The English version of the manuscript is available at http://www.gesidaseimc.com.

Selection of Hepatitis B Virus Polymerase Mutations in HIV-Coinfected Patients Treated with Tenofovir

Background

Tenofovir (TDF) is an adenosine nucleotide analogue that has been approved for the treatment of HIV-1 infection. It also shows activity against hepatitis B virus (HBV) in patients with or without lamivudine (LAM)-associated mutations. Development of clinical or virological HBV breakthrough during TDF therapy has not been reported so far. The aim of this study was to analyse the HBV polymerase (pol) from HIV/HBV-coinfected patients with detectable serum levels of HBV DNA during treatment with TDF for longer than 6 months.

Methods

The HBV pol was sequenced from 43 patient's serum before and during TDF therapy. Phenotypic analyses were performed using HBV replication-competent plasmids carrying unique mutations selected under TDF therapy.

Results

Mean exposure to LAM was 35.3 ±27.5 months and to TDF 11.2 ±6.7 months. Genotypic analyses from 21 of the patients revealed LAM-associated mutations, and a further two patients developed a novel mutation, rtA194T, along with LAM-resistance-associated mutations. Phenotypic analyses revealed that constructs harbouring rtA194T combined with rtL180M and rtM204V displayed an over 10-fold increase in the IC50 for TDF compared with the wild type.

Conclusion

The selection of HBV mutations in HBV/HIV-coinfected patients failing TDF therapy is an unlikely event within the first 12 months of treatment. However, HBV from two of the 43 patients treated with TDF for more than 12 months was found to contain one novel mutation located distal to the catalytic site of the HBV pol. In vitro, rtA194T conferred a reduced susceptibility to TDF in the presence of LAM-associated mutations.