HBV Treatment

 

Tenofovir

 

985. Combination of Entecavir and Tenofovir as a Rescue Therapy Is Safe and Highly Efficient in Cirrhotic HBV Mono-infected Patients with the History of Multiple Previous Treatment Failures

J. Schollmeyer; M. Lutgehetmann; T. Volz; A. W. Lohse; P. Buggisch; T. H. Meyer; S. Polywka; M. Dandri; J. Petersen

 

 

Background:

Treatment of chronic HBV infected individuals with nucleos(t)ide analogs using sequential monotherapy has led to the selection of multiple resistant mutations, endangering patients with advanced liver disease due to hepatic flares. The aim of this cohort study was to investigate the efficacy and safety of tenofovir (245mg) and entecavir (1mg) in treatment experienced cirrhotic patients. Combination therapy was initiated as a recue therapy in 12 compliant HBV mono-infected patients with multidrug resistant HBV or only partial responses to previous lines of therapy and advanced liver disease.

 

Methods:

Open label monocentric cohort study. Quantitative HBV-DNA measurement with a LLOD <400 copies/ml was used. Resistance und genotyping was done using Innolipa line-probe assay DR V.2 and direct sequencing. ALT and HBV-DNA was measured at baseline and every 3 months. Results: 12 male patients(9 HBeAg positive) with a median age of 48.5 years and with 3 lines of pretreatment (median, range 2-6) were included. At baseline median ALT was 1.6 ULN (range 0.38-5.32) and HBV-DNA was 5x106 copies/ml (range 7x104- 7x109 copies/ml). The median treatment duration after initiating the combination therapy was 6 months (range 3-15 months), without significant clinical side effects. The median HBV-DNA level dropped highly significant by 4.6 logs (range 1.7-7.8 log; p<0.0001) and 9/12 patients became HBV DNA undetectable (<400 copies/ml). This was accompanied by a significant decline in ALT (median 1.2 ULN; range 0.44-4.2; p=0.001). No patient showed clinical decompensation due to complications of cirrhosis or development of HCC. Besides previous long-term antiviral treatment (median 55 months), six patients became HBV DNA negative (<400 cop/ml) for the first time, demonstrating a high antiviral efficacy of this combination therapy despite pre-existing mutations or only partial responses in earlier therapies. Although viral activity was strongly suppressed in all patients no HBeAg or HBsAg loss was observed.

 

Discussion:

The rescue therapy with entecavir and tenofovir in cirrhotic HBV mono-infected patients harbouring complex viral resistance patterns or showing only partial antiviral responses earlier was highly efficient, safe, and well tolerated. There was no significant change in adherence before and after initiation of combination therapy with entecavir and tenofovir. More data are certainly needed to judge about the long-term safety, long-term antiviral efficacy and prevention of emergence of new viral mutations and prevention of clinical decompensation or HCC using this therapeutical approach in HBV patients with advanced liver disease.

 

983. A Prospective Study of Tenofovir Disoproxil Fumarate for Patients with Chronic Hepatitis B Who Have Previously Failed Lamivudine and Have Significant Viral Replication Despite at Least 24 Weeks of Adefovir Dipivoxil Therapy

S. Patterson; J. George; S. I. Strasser; A. U. Lee; W. Sievert; A. J. Nicoll; P. V. Desmond; S. K. Roberts; P. W. Angus

 

Tenofovir disoproxil fumarate (TDF) is a nucleotide analogue with potent activity against hepatitis B virus (HBV), including lamivudine (LAM) resistant HBV. Its efficacy in the treatment of patients with LAM resistance who have sub-optimally responded to adefovir (ADV) has not been defined. We therefore performed the first large prospective study of tenofovir in this difficult to treat population.

 

Methods:

This was a prospective multicentre study. Adults with HBV mono-infection who had previously failed LAM and had clinically significant viral replication after at least 24 weeks of ADV (HBV DNA >105 copies/mL if eAg positive, >104 copies/mL if eAg negative) were switched to TDF 300mg daily. Patients receiving combination ADV/LAM at baseline were switched to TDF/LAM. Pregnant or lactating females and patients with decompensated liver disease, creatinine clearance <70 mL/minute, or ALT >10x the upper limit of normal were excluded. TDF monotherapy subjects with persistent viral replication at 24 weeks were switched to combination TDF/LAM. The primary outcome measure was the median change in HBV DNA from baseline to 12 weeks. Secondary outcomes were safety and proportion of patients with undetectable HBV DNA. HBV DNA was measured using the Roche COBAS TaqMan assay.

 

Results:

Of 65 patients screened for the study, 59 were enrolled. 44 (75%) were male with a median age was 48 years (range 21-80). 38 (65%) patients were of Asian ethnicity. Duration of prior LAM or ADV therapy was a median of 38 and 23 months, respectively. At baseline, median viral load was 6.45 log10 copiesl/mL (range 4.0-8.8) and 38 subjects (64%) were HBeAg positive. 37 (63%) were switched from ADV monotherapy to TDF, the remaining 22 (37%) were switched from combination ADV/LAM to TDF/LAM. Baseline viral load and eAg status were similar in both groups. The fall in median HBV DNA from baseline to week 12 was 2.15 log10 copies/mL. This was similar independent of eAg status or ongoing LAM therapy. One patient ceased TDF at 10 days due to rash. There were no other adverse events. The proportion of patients with HBV DNA >103 copies/mL at 12, 24 and 48 weeks of therapy was 80%, 68% and 56%, respectively.

 

Conclusion:

TDF shows significant antiviral activity against HBV in patients who have failed lamivudine and are sub-optimal responders to ADV. This response is independent of eAg status and concomitant LAM therapy. However, in contrast to the experience in nucleos(t)ide naïve patients, the majority of patients (56%) have detectable HBV DNA following 48 weeks of TDF therapy.

 

920. Higher Frequency of Selection of Tenofovir-resistant Mutations in Lamivudine Exposed Compared to Naïve CHBV Patients During Tenofovir Antiviral Therapy

R. Chauhan; S. S. Hissar; A. K. Singh; S. K. Mishra; M. D. Kumar; S. K. Sarin

 

Introduction:

Tenofovir (PMPA) has been reported to be an effective antiviral agent for patients (pts) with chronic hepatitis B (CHB) with raised as well as normal ALT. It is also recommended in patients with prior Lamivudine (LMV) exposure or resistance. However, there is limited data on the frequency and profile of Tenofovir associated mutations in Lamivudine (LAM) exposed vs. naïve patients. We undertook to study the mutation profile in Tenofovir treated patients.

 

Methods:

Thirty three histologically proven pts with CHB were prospectively treated with PMPA 300 mg daily for 6 or more months. Seven pts had prior exposure to LMV and two to Adefovir (ADV). Nested PCR with sensitivity of amplifying <400 copies/ml of viral load was used, a amplicon of 766 bp was generated sequenced at baseline and at the follow up during treatment. Sequences were analyzed for emergence of mutations within and outside the catalytic domain (CD).

 

Results:

Of the 33 CHB pts, 28 were males with mean age of 35.7±12.1 years, 20 (60%) were HBeAg positive and 13 (40%) were HBeAg negative. ALT levels were raised in all except 3 pts. The baseline median (range) HBV DNA was 1x107 (4.5x104-4.4x108) copies/ml and ALT was 65 (27-321) IU/L. The median duration of therapy was 12 months (Range:6-24 mo). Eight (24%) pts were found to have resistant mutations and median (range) time of development of resistance was 10.5 (6-18) months; 5 of them were detected in CD and 3 outside it. Mutations were detected in all five (A-E) CD. Profile of Mutations are S81L (n=1), K168Stop (1), A181T (2), S202T (1), K241R (1), F248L (1) in CD and L146F (1), V84L (1), S85P (1) and N139K (1) outside the CD. The frequency of mutations was significantly higher in HBeAg positive than negative pts [7/20 (35%) vs. 1/13 (7.7) p = 0.003]. In HBeAg +Ve group, the mutations were detected in 5/20 (25%) patients, in CD-B in 2, CD-E in 1, CD-A+B in 1 and CD- C+D in 1 pts; and 2/20 (10%) outside the CD. Whereas one HBeAg -Ve patient was harboring mutation outside the CD. Mutations were more common in LMV exposed than naïve pts [3/7 (42.9%) vs. 5/26 (19.2%) p=0.003].

 

Interestingly, HBeAg-positive pts with normal ALT had higher frequency of mutations than raised ALT [2/3 (66.7%) vs. 5/17 (29.4%) p = NS] though the difference was not significant. No mutations were detected in pts with prior exposure to ADV.

 

Conclusions:

Tenofovir therapy is associated with a high frequency of selection of resistant mutants, more often in HBeAg positive subjects and those with prior exposure to Lamivudine. Novel mutations were detected in catalytic domain. Tenofovir should be carefully used in CHB patients with normal ALT.

 

913. Detection of Mutations Associated with Resistance to Nucleos(t)ide Analogs in Patients with HBV Infection During Treatment with Tenofovir

F. Boemmel; H. Feucht; B. Schlosser; V. Weich; E. Schott; B. Wiedenmann; T. Berg

 

Background:

Tenofovir disoproxil fumarate (TDF) is a recently licensed potent inhibitor of HBV replication. TDF was shown to be effective in wild type and lamivudine (LAM)-resistant HBV infections. Genotypic resistance to adefovir (ADV, mutations rtA181T/V or rtN236T) confers modest decreased sensitivity to TDF in vitro and may be associated with decreased efficacy of TDF in some patients. However, a breakthrough of HBV replication during TDF treatment due to genotypic resistance has not been observed yet. We have studied the development of mutations in HBV during TDF treatment.

 

Methods:

The efficacy of TDF monotherapy was retrospectively evaluated in 48 HBV monoinfected patients (m/f 38/10, mean age 49 [22-74] years, 39 HBeAg positive, mean HBV DNA 7.1 [4.8-9.6] log copies/mL) who where treated with TDF 300 mg/d for a duration ≥ 12 (mean 25 [12-52]) months in our centre. Prior to TDF treatment, 43 patients had been treated with LAM and 33 patients with ADV for a mean duration of 27 [1-57] and 13 [1-56] months. HBV DNA levels were measured every 3 months (HBV Monitor, Roche, detection limit 400 copies/mL). At start and during TDF treatment the HBV polymerase gene was sequenced from codon rt88 to rt282 in all patients at time points when HBV DNA was still detectable (total 126, mean 2.6 [1-6] samples/patient). Results: At baseline TDF, 20 patients had HBV wild type, 22 patients genotypic resistance to LAM and 6 genotypic resistance to ADV.

 

In all patients with initial ADV resistance, mutations associated with ADV resistance remained detectable during TDF treatment and only 1 patient achieved HBV DNA levels < 400 copies/mL at month 12 (p<0.0001). In four patients without genotypic resistance to ADV at baseline TDF (three were pre-treated with ADV and one with LAM), by population sequencing ADV resistant variants (rtA181T, rtA181V, rtA181T+rtN236T) became detectable between month 5 and 11 of TDF treatment. After 12 months of TDF treatment, 3 of the 4 patients had achieved HBV DNA levels < 400 copies/mL (p=n.s.). In none of the patients new mutations or a re-increase of HBV DNA levels was observed during TDF treatment.

 

Conclusion:

HBV variants associated with resistance to ADV and also to LAM (rtA181T) can become transiently detectable during TDF treatment by population sequencing in some patients where the mutation was not detected at baseline, but seem not to influence response to TDF.

 

980. Tenofovir Disoproxil Fumarate (TDF) Versus Adefovir Dipivoxil (ADV) in Asians with HBeAg-positive and HBeAg-negative Chronic Hepatitis B Participating in Studies 102 and 103

S. S. Lee; E. Heathcote; W. Sievert; H. N. Trinh; K. D. Kaita; Z. M. Younossi; J. George; M. L. Shiffman; P. Marcellin; J. Sorbel; J. Anderson; E. Mondou; J. Quinn; F. Rousseau

 

Background:

TDF, a nucleotide analogue and obligate chain terminator, has potent activity against hepatitis B virus (HBV). An analysis of efficacy and safety was performed among Asian patients enrolled in two Phase 3 pivotal trials, Studies 102 (HBeAg-negative patients) and 103 (HBeAg-positive patients). Evaluation in Asians was considered important given the endemnicity of HBV infection in this population.

 

Methods:

Patients were randomized 2:1 to double-blind TDF 300 mg or ADV 10 mg once daily for 48 weeks. Eligibility criteria required abnormal ALT and HBV DNA >100,000 (HBeAg-) or > 1,000,000 (HBeAg+) copies/mL (Roche COBAS TaqMan; LLQ=169 copies/mL [29 IU/mL]). Virological (HBV DNA <400 copies/mL [69 IU/mL]), biochemical (ALT normal), and histologic response (at least 2-point decrease in Knodell necroinflammation without worsening fibrosis) were prospectively evaluated among patients of self-reported Asian ethnicity using an intent-to-treat analysis where missing data were considered as failure.

 

Results:

Among 189 Asian patients enrolled across both studies (127 TDF; 62 ADV), 94 were HBeAg-negative and 95 were HBeAg+. Mean age among Asians was 40 years (TDF and ADV) and 68% were male. Mean baseline HBV DNA was 7.55 (TDF) and 7.88 (ADV) log copies/mL. Mean baseline Knodell necroinflammatory score was 8.6 TDF vs 8.7 ADV, and cirrhosis was present in 18% of Asians randomized to TDF and 21% randomized to ADV. As expected most patients were infected with HBV genotype B or C (89% TDF; 90% ADV); a minority had genotype A or D (11% TDF; 8% ADV). At Week 48 treatment with TDF produced suppression of HBV DNA to <400 copies/mL in 85% of patients compared with 42% on ADV, p<0.001; normal ALT in 72% vs 65% on ADV; and histologic response in 77% vs 71% on ADV. Sixteen percent of Asian patients treated with TDF or ADV experienced HBeAg seroconversion over the first 48 weeks of study (observed data). TDF and ADV were well tolerated and had a similar safety profile in Asian patients with chronic hepatitis B.

 

Conclusion:

TDF demonstrated superior efficacy compared with ADV with similar safety and tolerability in Asian patients following 48 weeks of randomized treatment. Efficacy and safety were congruent with the results of the overall studies.

 

842. Precore and Basal Core Promoter Mutations Restore the Reduced Replication Efficacy of Tenofovir-resistance Associated rtA194T Polymerase Mutations of the Hepatitis B Virus

S. Amini-Bavil-Olyaee; J. Sheldon; C. Trautwein; F. Tacke

 

Background & Aims:

Tenofovir (TDF) is a new effective treatment option for patients chronically infected with the hepatitis B virus (HBV), but could potentially be hampered by polymerase mutations conferring drug resistance. The rtA194T mutation has been found in patients coinfected with HBV and HIV during TDF administration. Furthermore, the rtA194T mutation can occur in conjunction with polymerase mutants associated with lamivudine (LAM)-resistance and/or with mutations associated with HBeAg-negative HBV infection, namely precore (PC) and basic core promoter (BCP) mutations. We aimed at characterising the replication efficiency of TDF-resistant mutants, alone and in combination with LAM, PC or BCP mutations.

 

Methods:

Replication-competent HBV constructs harbouring rtA194T alone or in addition to LAM resistance(rt180M+rtM204V), PC and BCP mutations were generated and transiently transfected in Huh7 human hepatoma cells. Viral replication fitness was assessed quantifying intracellular HBV RNA (Northern Blot) and HBV Progeny DNA (immunoprecipitation and Southern Blot) as well as HBV copy number (real-time qPCR), HBsAg and HBeAg in the supernatant.

 

Results:

The rtA194T mutation alone reduced the replication efficiency as compared to wildtype (WT) HBV. LAM-resistance in addition to rtA194T further decreased the replication capacity. In contrast, combination of rtA194T (with or without additional LAM-resistance) with HBeAg-negative PC or BCP mutants increased the replication efficiency of the drug-resistant polymerase mutants, thereby restoring the viral replication to similar levels as WT clones. Clones haboring rtA194T showed resistance to TDF in vitro.

 

Conclusions:

The rtA194T mutation, associated with tenofovir drug resistance, negatively impacts replication competence of HBV constructs. Additional lamivudine-resistant polymerase mutations further decrease HBV replication. Viral replication, however, can be restored to WT levels, if these polymerase mutations occur together with precore or basic core promoter substitutions as found in HBeAg negative hepatitis B. Patients with HBeAg negative chronic HBV infection may therefore be at particular risk when developing drug resistance to tenofovir and/or lamivudine.

 

866. Immunological Profile of Peripheral Blood Mononuclear Cells, NK T Cells and Dendritic Cells in Chronic HBV-infected Patients Treated with Tenofovir Disoproxil Fumarate

N. T. Pati; S. Kottilil; S. S. Hissar; S. Kumari; S. K. Mishra; K. Madan; S. K. Sarin

 

Background:

The immunological mechanisms responsible for chronicity of HBV infection and liver disease are still poorly understood. Viral suppression with nucleoside analogues is associated with limited response and only partial immune restoration. There is also very limited data on the cellular immune responses in HBeAg positive and negative patients.

 

Aims:

We studied in detail the profile of of PBMCs, NK T cells and dendritic cells in chronic HBV-infected patients treated with Tenofovir. Methods: Twenty seven histologically proven chronic hepatitis B patients treated with Tenofovir 300 mg per day were included; HBeAg positive high ALT (n= 15 ) and HBeAg negative high ALT ( n=12 ). HBV DNA (Cobas Amplicor, Roche Diagnostics), serum ALT, immune profile were measured at baseline and 4, 12, 24 weeks. Immuological marker profiling for T cell activation, central and effector memory, T-regulatory cells, Toll-like receptor expression, Natural Killer cell activation, and dendritic cell activation were measured using flow cytometric analysis. Wilcoxon analysis and Spearman correlations were performed to make statistical significance.

 

Results:

More than 80% of patients in both groups had virologic response (more than 2 log reduction) to therapy. HBV DNA was significantly higher in HBeAg positive patients (p<0.01) but the DNA levels declined in both the groups significantly at 24 weeks. HBeAg negative patients had reduced CD8 frequencies (p<0.006) and expressed a greater percentage of CD4+ CCR5+ T , CD4+ CD25 FoxP3+ cells than HBeAg positive (22.6% vs. 7.8%. p<0.04) (17.9%, vs. 3.3% p <0.05), patients. In HBeAg positive group, in first 4 weeks, there was an increased expression of CD8 and CD4+ CD25 FoxP3+ and which declined over time. Expression of CCR5, CCR6, TLR3, TLR 9 was increased at 12 wks. However, in HBeAg negative group expression of TLR3 and TLR9 was significantly increased at 4 wk (p<0.04) and showed continued increase expression at 12 and 24 wk (p<0.0005).

 

Conclusions:

Increase in activated CD4+and T regulatory cells and decrease in CD8 T cells is seen in HBeAg negative CHB individuals, suggesting a pathogenic role of these cells in the development of chronicity of infection. HBV DNA suppression with tenofovir results in increased frequencies of CD8 T cells in HBeAg negative group and increased expression of CCR5, CCR6, TLR3, TLR9 expression in both the groups.

 

880. Presence of rtA194T at Baseline Does Not Reduce Efficacy to Tenofovir(TDF) in Patients with Lamivudine(LAM)-resistant Chronic Hepatitis B

S. K. Fung; T. Mazzulli; M. Sherman; V. Popovic; E. Sablon

 

Background:

Antiviral-resistant mutations associated with virologic breakthrough on TDF therapy have not been fully characterized. rtA194T has been reported in TDF-treated HIV-HBV coinfected patients with breakthrough infection. However, the clinical significance is unknown in HBV monoinfected patients

 

Aim:

To determine the effect of rtA194T on treatment response to TDF 300 mg daily in patients with LAM-resistant HBV.

 

Patients and Methods:

Adult HBV patients receiving oral antiviral therapy at University Health Network Liver Clinics (Toronto, Canada) were monitored for genotypic antiviral resistance. Routine bloodwork, HBV serology and HBV DNA were measured every 3 months. Resistance testing was performed on all patients who developed virologic breakthrough (rise in HBV DNA by > 1 log IU/ml compared to nadir) and in those who failed to achieve undetectable HBV DNA 6 months after starting therapy. Genotyping and detection of resistance mutations were performed using a line probe assay InnoLiPA HBV DR v2/v3 (InnoGenetics, Ghent, Belgium). HBV DNA was measured using real-time PCR (Roche, TaqMan 48, LLQ 6 IU/ml).

 

Results:

Of the 283 consecutive treatment-experienced adult patients with chronic hepatitis B tested for antiviral resistance, 10 were found to harbor rtA194T (all in association with rtL180M + rtM204V/I). This group of patients (mean age 48±17 yrs, 6 Asians, 7 males, 4 HBeAg-positive, mean HBV DNA 5.5±2.5 log IU/ml, 7 with cirrhosis) was treated with LAM 100 mg daily (mean treatment duration 42±21 months) and none had previously received TDF. 6 patients developed virologic breakthrough, while 4 had a suboptimal response. 5 patients received salvage therapy – 4 with TDF 300 mg daily, 1 with TDF + emtricitabine 200 mg daily. All patients on salvage TDF had > 3 log IU/ml reduction in HBV DNA 3 months after starting therapy with improvement in ALT levels; 4 had undetectable HBV DNA and normal ALT at last follow-up (mean follow-up time 5.8±1.1 months). 1 patient with rtL180M + rtM204V/I + rtA194T developed hepatic decompensation before salvage therapy was started.

 

Conclusions:

This is the first study to report rtA194T detected among LAM-experienced but TDF-naïve HBV patients. rtA194T does not appear to be associated with reduced efficacy among LAM-resistant HBV patients salvaged with TDF in short term follow-up. These findings suggest that rtA194T may represent a viral polymorphism or compensatory mutation rather than a signature mutation leading to nucleotide resistance. Further clinical studies are required to fully characterize genotypic mutations associated with TDF resistance.

 

907. Tenofovir-based Highly Active Antiretroviral Therapy (HAART) Is Associated with High Rates of HBV DNA Suppression and HBeAg Seroconversion in Thai HIV-HBV Coinfected Patients

G. Matthews; A. Avihingsanon; S. Lewin; J. Sasadeusz; P. Marks; P. A. Revill; A. Ayres; S. Bowden; S. Locarnini; C. L. Thio; K. Ruxrungtham; G. J. Dore

 

Two randomized clinical trials of HBV-active HAART in antiretroviral naive HIV-HBV coinfected subjects were initiated in Thailand in 2004-2005. Randomisation of the nucleos(t)ide analogues was to i) zidovudine(AZT)/lamivudine(LAM) or ii) AZT/tenofovir (TDF) or iii) TDF/LAM in the TICO study (n=36) and to i)AZT/emtricitabine (FTC) or ii)TDF/FTC in HIV NAT 023 (n=18), All subjects also received efavirenz (EFV).

 

Clinical trial primary endpoints were at 48 weeks after which subjects continued follow-up in an HIV-HBV cohort study; subjects on LAM or FTC HBV monotherapy added TDF. The aim of this analysis was to determine long-term HBV virological and serological responses in HIV-HBV coinfected subjects receiving TDF containing HAART.

Forty-seven of 54 HIVHBV coinfected subjects had post-48 week follow-up. Mean age was 38 years and 31/47 (66%) were male. Pre-HAART HIV disease was generally advanced with median CD4 count of 42 cells/mm3 and 45% with prior AIDS illnesses, median HBV DNA was 8.0 log10 IU/ml (IQR 7.5-8.7 log10 IU/ml) and 30/47 (64%) were HBeAg positive. HBV genotype was C in 85% of subjects. At last follow-up, a median of 27 months (range 14-40m) after HAART initiation, all patients were on TDF-containing regimens: 19 in initial combination (TDF+LAM/FTC), 17 with late combination after AZT→TDF switch at 48 w, and 11 on TDF monotherapy for HBV.

 

Median duration of TDF was 25, 8 and 32 months respectively. All patients had HIV RNA suppression < 50 c/ml and median CD4 count was higher at 342 cells/mm3. 72% of subjects had HBV DNA < 20 IU/ml with 94% HBV DNA < 400 IU/ml. No subject had HBV DNA > 1000 IU/ml. No significant differences were seen in proportion of patients <20 IU/ml by type of TDF-regimen (p=0.236). HBeAg loss occurred in 46% (n=14) of HBeAg positive subjects with an anti-HBe seroconversion rate of 33% (n=10). HBeAg loss was not associated with age (p=0.08), CD4 nadir (p=0.71), change in CD4 count (p=0.53), or baseline HBV DNA (p=0.48) but was associated with pre-HAART ALT. HBeAg loss was observed in 23% of subjects with normal ALT at baseline compared to 65% of those with abnormal ALT pre-HAART (p=0.02).

 

The cumulative rate of HBeAg loss was 13% at 3m, 30% at 6m, 40% at 12m, 50% at 18m and 67% at 24 months. HBsAg loss occurred in 13% overall (n=6) of whom 4 were HBeAg positive and 2 HBeAg negative pre-HAART.

 

Conclusion:

In conclusion TDF-containing HAART is highly successful in achieving HIV and HBV-related virological suppression in coinfected subjects initiating HAART in Thailand, irrespective of regimen. Further work is needed to understand the mechanism(s) of the high rates of HBeAg loss and HBsAg seroconversion.

 

977. Week 96 Resistance Surveillance for HBeAg Positive and Negative Subjects with Chronic HBV Infection Randomized to Receive Tenofovir DF 300 MG QD

A. Snow-Lampart; B. J. Chappell; M. Curtis; Y. Zhu; E. Heathcote; P. Marcellin K. Borroto-Esoda

 

Aim:

To evaluate amino acid changes within HBV pol/RT following 96 weeks (wks) of treatment with tenofovir DF 300 mg QD (TDF) and to determine the potential association of the changes with resistance to TDF.

 

Methods:

Subjects were enrolled in one of two studies [GS-US-174-0102 (HBeAg-) or GS-US-174-0103 (HBeAg+)]. Population di-deoxy sequencing of the serum HBV pol/RT was attempted for all subjects at baseline (BL) and for viremic subjects (HBV DNA ≥ 400 copies/mL) at Wk 96/time of discontinuation of TDF monotherapy. Virologic breakthrough (VB) was defined as confirmed HBV DNA values >1 log10 from nadir or confirmed HBV DNA ≥400 copies/mL after having been <400 copies/mL.

 

Results:

389 of 426 subjects originally randomized to receive TDF for 48 wks entered the second year of the studies [GS-0102 n=235; GS-0103 n=154]. Five subjects with HBV DNA ≥400 copies/mL at Wk 96 and 19 subjects who discontinued TDF monotherapy between Wk 48 and Wk 96 with HBV DNA ≥400 copies/mL (median time on TDF among these 19 subjects was 80 4ks) were evaluated for genotypic resistance (n=24 total). The remaining subjects had HBV DNA <400 copies/mL at their last visit through Wk 96 and were not evaluable for genotyping. Genotypic evaluation of the last TDF monotherapy sample for the 24 subjects with HBV DNA ≥400 copies/mL demonstrated the presence of conserved site changes in HBV pol/RT in 2/24 subjects (rtL101L/F in one and rtL180M + rtM204V in the other) in the absence of VB. Both subjects achieved >6 log10 decline from BL in HBV DNA and were still declining at the time the changes were detected. No changes in HBV pol/RT were observed in 13/24 subjects and 6/24 subjects had polymorphic site changes as compared to BL. PCR amplification failed for the remaining 3/24 subjects.

 

Five of the 24 subjects experienced VB during the second year of the studies; 3/5 had no changes in HBV pol/RT from BL and 2/5 had polymorphic site changes; one with rtP215P/S and one with rtF221Y/F. The incidence of these polymorphisms in patients at BL in these studies ranged from 6% to 60% and did not have an impact on the antiviral response to TDF. The majority of the subjects with VB (3/5) had a history of non compliance. Phenotypic analysis is ongoing for those subjects harboring conserved site changes and for those experiencing VB.

 

Conclusions:

Development of conserved site changes in HBV pol/RT was rare and did not result in VB among subjects treated with up to 96 wks of TDF monotherapy. Virologic breakthrough was infrequent and not associated with the development of conserved site changes in HBV pol/RT with the majority of VB subjects having a history of non-compliance.

 

976. Cost-effectiveness Simulation Analysis of Tenofovir Disoproxil Fumarate (TDF), Lamivudine (LAM), Adefovir Dipivoxil (ADV) and Entecavir (ETV) in HBeAg-negative (-) Patients with Chronic Hepatitis B (CHB) in the USA

H. B. Deniz; F. Everhard

 

Background:

As new oral antiviral treatments for chronic hepatitis B (CHB) virus are available, it is important to understand their impact on pharmacy and medical costs as well as on patient quality of life.

 

Aim:

To estimate the impact of initiating treatment with TDF, LAM, ADV and ETV on cost and quality of life in HBeAg(-) patients in the United States (US).

 

Methods:

A simulation analysis using a Markov model was developed to predict incidence and cost of CHB-related complications according to levels of HBV DNA viral over time. Patients were assumed to be treatment-naïve at time of treatment initiation with TDF, LAM, ADV and ETV and were assigned levels of viral suppression and risk of developing viral resistance specific to their treatment. Patients who became resistant could switch or add-on another treatment. Patients who developed resistance to initial and subsequent treatments were assumed to discontinue treatment and incidence of complications was modeled assuming no further viral suppression. CHB-related complications included compensated cirrhosis, decompensated cirrhosis (DCC) and hepatocellular carcinoma (HCC). Patients who developed DCC or HCC were eligible for liver transplant. Costs of managing CHB and complications reflect clinical practice in the US. All clinical, epidemiologic and utility inputs were obtained from published literature. Analysis was conducted based on a population of 1,000 simulated patients per treatment over a period of 20 years. Cost and quality-adjusted life years were discounted at 3% per year.

 

Results:

Patients who initiated treatment with TDF were predicted to generate lower pharmacy and medical costs and have greater number of quality-adjusted life years than LAM, and ADV. Compared to ETV, patients with TDF were expected to generate lower pharmacy and medical costs while yielding similar number of quality-adjusted life years. These results were mostly driven by a low expected resistance rate for TDF compared to LAM and a lower acquisition cost than ETV and ADV.

 

Conclusions:

When considering initial treatment for CHB virus in the US, TDF is predicted to be one of the most cost-effective treatments compared to LAM, ADV and ETV.

 

TDF

LAM

ADV

ETV

Total pharmacy and medical cost per patient (US$)

117,794

152,336

138,950

141,409

Cost of inital and subsequent HBV treatments (US$)

94,781

101,990

105,449

117,648

Quality-Adjusted Life Years

10.28

8.93

9.72

10.28

 

932. Excellent Treatment Response to Tenofovir (TDF)Monotherapy in Chronic Hepatitis B (CHB) Patients with Prior Suboptimal Response to Entecavir (ETV) Monotherapy

C. Pan; K. Hu

 

Background:

Both ETV and TDF are potent anti-HBV agents, but it remains unclear if switching to TDF is a reasonable approach to those with suboptimal response to ETV treatment.

 

Aims:

To determine how CHB patients with suboptimal response to ETV respond to TDF monotherapy.

 

Methods:

Retrospective analysis of the antiviral effects of TDF in 7 cases with suboptimal responses to ETV treatment (<1 log10 DNA reduction in 6 months) among 236 (2.97%) CHB patients received ETV monotherapy for a mean 68 weeks (53-126) during 8/20/2005 - 5/20/2008.

 

Results:

All 7 cases were Chinese, mean age of 39.5 years (20-64); 5 were male; 5 were HBeAg+; 6 genotype C and 1 had B; prior to ETV, 2 had 12-18 month lamivudine (LAM) treatment but no antiviral resistance by Quest lab direct sequencing method (QLDSM). The mean HBV DNA level was 2.0 x 7 log10 (4.4 x 5 log10-2.5 x 9 log10) c/ml and ALT was 63.3 (34-443) IU/L. 5 cases had liver biopsy before ETV treatment, 4 reported stage 2; and 1, stage 3 fibrosis. The mean duration of ETV treatment was 77 (53-126) weeks, including 5 naïve cases on 0.5 mg/day, and 2 with prior LAM exposure on 1 mg/day. At the time of switching to TDF, the mean HBV DNA level was 2.6 x 4 log10 (1.2 x 3 log10 -7.9 x 4 log10) copies/ml; mean ALT was 33.4 (26-44) IU/L, none had antiviral resistance by QLDSM. All 7 cases achieved HBV DNA < 160 copies/ml after switching (2 in 12 weeks, 5 in 24 weeks). 1 of the 5 HBeAg+ cases has lost HBeAg after switching to TDF for 57 weeks. All 7 cases switched to TDF for a mean of 34.8 (16-76) weeks without evidence of virologic breakthrough.

 

Conclusion:

In our cohort, patients received ETV for a mean of 68 weeks, less than 3% (7 cases) have suboptimal virologic response. All 7 cases responded to TDF monotherapy well and 100% achieved HBV DNA < 160 copies/ml after 24 weeks of treatment. A larger study with longer follow up will be needed to verify our results.

 

955. Tenofovir is Equally Active In Vitro Against Wild-type HBV Clinical Isolates of Genotypes A−H

M. Curtis; J. Harris; K. Borroto-Esoda; J. Hinkle; Y. Zhu

 

Introduction:

HBV is a heterogeneous virus that is classified into eight different viral genotypes (A−H). The aim of this study was to evaluate the anti-viral activity of tenofovir (TFV), a nucleotide analog with potent activities against HIV and HBV, on wild-type HBV of different viral genotypes.

 

Methods:

The full-length HBV genomes of wild-type virus populations from 11 patients with different viral genotypes (1 each of genotypes A, B, E, F, G and H, 3 genotype C, and 2 genotype D ) were amplified and cloned into a previously described pHY106 vector. In vitro drug susceptibility against TFV was tested by transient transfection of these patient-derived full-length HBV quasi-species populations into HepG2 cells. Intracellular HBV replication was assayed by Southern blot analysis, and levels of replicated signals were calculated using a full genome length HBV DNA marker. Regression analyses of antiviral data were performed with Table Curve 2D software to calculate EC50 values. Assays were performed a minimum of three times for each of the 11 virus constructs. Plasmid pHY92 that expresses a wild-type HBV strain served as a control. Mixed effect ANOVA models were fit to log-transformed EC50 and HBV DNA data across patients and lab strain samples with a fixed effect for genotype and a random effect for sample-within-genotype.

 

Results:

Transient transfection of the constructs containing genome length HBV clinical isolates of all currently identified genotypes (A−H) led to efficient HBV DNA replication in HepG2 cells. The levels of the intra-cellular replicated HBV DNA of the tested clinical isolates (excluding genotype D) were similar (mixed ANOVA, p = 0.15); with genotype D isolates (n = 2) having significantly higher levels of replication (mixed ANOVA contrast, p=0.006). The in vitro drug susceptibility analysis showed that the mean EC50 values for TFV against wild-type HBV clinical isolates ranged from 0.2 to 0.9 uM, with overall genotype mean (± SD) EC50 of 0.50 ± 0.26 uM. The mean (± SD) EC50 value for TFV against the pHY92 laboratory strain was 0.65 ± 0.28 uM. Statistical analysis indicated that all HBV genotypes had similar susceptibilities to TFV (mixed ANOVA, p = 0.30).

 

Conclusions:

The in vitro phenotypic results for TFV against HBV genotypes A−H are consistent with the observed clinical data from the two tenofovir DF phase III trials, in which HBV genotypes A−D responded to tenofovir DF treatment with similar efficacies (Gane et al. J Hepatol 2008. 48:S256-S257).

HBV Treatment – Hepatitis B and Children

1622. The Control of HBV Replication That Leads to HBeAg/anti-HBe Seroconversion Does Not Prevent the Emergence of Pre-Core Defective Variants in Genotype D-Infected Children

P. Colombatto; C. Barbera; F. Bortolotti; A. M. Maina; F. Moriconi; D. Cavallone; P. Calvo; M. Baldi; F. Oliveri; F. Bonino; M. Brunetto

 

 

Background & Aim:

The emergence of precore mutants (P-C mt) unable to produce HBeAg may account for the persistence of HBV infection and disease in genotype D infected children. We investigated the relationship between longitudinal changes of P-C mt populations and the virological and clinical outcomes in a paediatric cohort.

Patients. We enrolled 80 (50 male and 30 female) consecutive patients diagnosed with HBV infection at the median age of 11.4 years (range: 0.2-17 years), mostly with a vertical (66%) or intra-familial (16%) transmission, followed up for a median period of 12.5 years (range: 1-25 years).

 

Methods:

HBeAg/anti-HBe status was evaluated in all patients at the admission and then every 2 years in 47 (30 male and 17 female). HBV genotype was determined by direct sequencing (DS) of the pre-S/S regions. HBV-DNA levels were measured (Cobas Amplicor HBV, Roche) in 2-7 sera per patient and P-C dominant populations characterized by DS. P-C mt minority populations were detected by oligo-hybridization assay and allele specific PCR with a sensitivity of 10% and 0.1% of total viremia.

 

Results:

Genotype D infection was present in all but 5 (6.2%) genotype A patients. At the admission 64 were HBeAg positive. At the median age of 11.4 (range: 1.3-25.2) years 53 (82.8%) underwent HBeAg/anti-HBe Sc, 32 (60.4%) after IFN treatment. The mean baseline Log10 HBV-DNA levels (cp/ml) were significantly (ANOVA, P<0.05) lower in patients who seroconverted than in those who did not (7,26+2,54 vs 9,60+0,43). After seroconversion HBV-DNA levels remained below 10^4 cp/ml in 26 (49.1%) inactive carriers. Among the 7 (13.2%) patients who lost HBsAg after seroconversion, 5 remained with a P-C wild type (wt) dominant population. In the 53 seroconverted patients dominant wt-mixed-mt P-C populations were found in 96-4-0% of the sera before seroconversion (median 4.5 y; range 0-18 y), in 58-16-26% within 3 years after seroconversion and in 45-8-47% during the subsequent follow-up (median 9 y; range 4-22 y).

 

Conclusions:

In Italian HBeAg-positive children with genotype D infection HBeAg/anti-HBe seroconversion is a frequent event, occurring more often in those with lower viremia levels. Seroconversion is associated with transition to a low replicative phase where a progressive selection of P-C mt populations occur. However, HBsAg clearance, is more frequently observed in patients who maintain a predominant P-C wild type population.