Molecular characterization of hepatitis B virus (HBV) isolated from a pediatric case of acute lymphoid leukemia, with a delayed response to antiviral treatment: a case report.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is effectively used as the first-line antiviral for chronic hepatitis B virus (HBV) infection in adults and children older than 12 years. To date, no confirmed case of virologic breakthrough (VBT) in a pediatric case has been reported. CASE PRESENTATION: Here we describe a case of a 5-year old, asymptomatically infected with HBV infection two months after chemotherapy for precursor B acute lymphoblastic leukemia (ALL). Although the 5-year old male is South African, his family originated from Guinea. At the end of the one-year follow-up, the infection progressed to chronic HBV infection, with a high viral load. At 36 weeks (8 months) post-treatment with lamivudine (LAM), there was a partial virologic response (PVR) and after 61 weeks (14 months), he was switched to TDF rescue monotherapy. Even with TDF treatment, he still experienced VBT and subsequent PVR. The full-length genome of HBV isolated 78 weeks after the switch to rescue TDF monotherapy was sequenced and belonged to genotype E. In addition to the LAM mutations (rtS256G and rtM267L), missense mutations in B-cell, T-cell, HLA class I and II-restricted epitopes emerged, which were to evade and escape host surveillance, leading to delayed viral clearance, persistence and disease progression. Two further events of VBT occurred between weeks 113 and 141 of TDF rescue-therapy. Viral loads and liver enzymes are normalizing progressively with long-term therapy. CONCLUSION: Although the host immune reconstitution may be delayed, prolonged TDF treatment was effective in treating this pediatric case of HBV infection with VBT and PVR.

Tenofovir monotherapy versus tenofovir plus entecavir combination therapy in HBeAg-positive chronic hepatitis patients with partial virological response to entecavir.

AIMS: The aim of this retrospective study was to compare the efficacy and safety of tenofovir disoproxil fumarate (TDF) monotherapy and TDF + entecavir (ETV) combination therapy for chronic hepatitis B (CHB) patients with the partial virological response (PVR) to ETV. METHODS: CHB patients with PVR to ETV were switched to TDF monotherapy or TDF + ETV combination therapy. The primary efficacy outcome was a virological response (VR), and the secondary efficacy outcomes were hepatitis B e antigen (HBeAg) seroconversion and alanine aminotransferase (ALT) normalization. The primary safety outcomes were changes in serum creatinine and serum phosphorus levels. RESULTS: A total of 143 patients were investigated, including 63 patients in the TDF monotherapy group and 80 patients in the TDF + ETV combination therapy group. Baseline demographics and clinical characteristics were comparable between groups. The median age of patients was 44.5 years, and 76.2% of them were male. The VR rate in TDF + ETV group was higher than that of the TDF group at 48 weeks (88.8% vs 71.4%; P = .009). At 48 weeks, the HBeAg seroconversion rate of TDF + ETV group was higher than that of the TDF group (30% vs 15.9%; P = .049). There was no significant difference in the proportion of patients with elevated ALT in the TDF group and TDF + ETV group at 48 weeks (9.5% vs 7.5%; P = .665). After adjusting the treatment regimen, serum creatinine levels increased slightly and serum phosphorus level decreased slightly in both groups. CONCLUSIONS: TDF + ETV combination therapy for 48 weeks had a higher VR rate than TDF monotherapy in CHB patients with PVR to ETV.

Switching to tenofovir vs continuing entecavir for hepatitis B virus with partial virologic response to entecavir: a randomized controlled trial.

Entecavir 0.5 mg (ETV) is widely used among treatment-naïve chronic hepatitis B (CHB) patients. However, 10%-30% of patients show partial virologic response (PVR) to the drug. If the hepatitis B virus (HBV) continues to replicate, the underlying liver disease may progress. Herein, we compared the efficacy of switching to tenofovir disoproxil fumarate (TDF) with that of continuing ETV in CHB patients with PVR to ETV. This was an open-label randomized controlled trial including CHB patients who had been receiving 0.5 mg of ETV for >12 months, but who still had detectable HBV DNA levels of >60 IU/mL without known resistance to ETV. Sixty patients were enrolled and 45 qualified for the study: Twenty-two patients were randomly assigned into the TDF group and 23 into the ETV group. After 12 months of treatment, the virologic response rate (HBV DNA <20 IU/mL) was significantly higher in the TDF group than in the ETV group, as measured using per-protocol analysis (55% vs 20%; P = .022) and intention-to-treat analysis (50% vs 17.4%; P = .020). The reduction in HBV DNA was greater (-1.13 vs -0.67 log10 IU/mL; P = .024), and the mean HBV DNA level was lower (1.54 vs 2.01 log10 IU/mL; P = .011) in the TDF group than in the ETV group. In conclusion, to achieve optimal response in CHB patients with PVR to ETV, switching to TDF would be a better strategy than continuing ETV. Appropriate modification of therapy would further improve the outcome of chronic HBV infection.

Clinical Course of Partial Virologic Response with Prolonged Tenofovir Therapy in Nuclos(t)ides-Naïve Patients with Chronic Hepatitis B.

BACKGROUND/AIMS: The clinical course of chronic hepatitis B (CHB) patients with partial virologic response (PVR) during tenofovir disoproxil fumarate (TDF) therapy remains unclear. METHODS: We retrospectively investigated the long-term clinical outcomes of TDF treatment in nucleos(t)ides-naïve CHB patients, particularly in those with PVR. RESULTS: A total of 391 patients treated with TDF therapy for more than 12 months were included. Virologic response (VR) was achieved in 341 patients (87.2%). PVR was evident in 127 (45.3%) of the 391 patients. Multivariate logistic regression analysis using selected baseline factors identified absolute HBV DNA levels at baseline (OR 0.496; 95% CI 1.369-1.969) and HBeAg positivity (OR 0.622; 95% CI 1.096-3.167) as factors significantly associated with PVR. During continuous prolonged TDF therapy, 127 (71.8%) of 177 patients with PVR achieved VR. The cumulative rates of VR in patients with PVR at 12, 24, and 36 months were 42.4, 79.7, and 90.2%, respectively. Serum HBV DNA level at week 24 was significantly associated with VR in patients with PVR. CONCLUSIONS: The vast majority of CHB patients with PVR achieved VR through prolonged TDF therapy, although the time to achieve VR was delayed in those with PVR. This suggests that adjustment of TDF therapy in patients with PVR is unnecessary.

Efficacy of long-term tenofovir disoproxil fumarate therapy in chronic hepatitis B patients with partial virologic response in real practice.

BACKGROUND/AIMS: The optimal management of chronic hepatitis B (CHB) patients with partial virologic response (PVR) to tenofovir disoproxil fumarate (TDF) remains unclear. We aimed to evaluate the long-term efficacy of prolonged TDF therapy in treatment-naïve CHB patients with PVR to TDF therapy in real practice. METHODS: We retrospectively investigated the efficacy of prolonged TDF therapy in treatment-naïve CHB patients with PVR to TDF. PVR was defined as a decrease in serum hepatitis B virus (HBV) DNA over 2 log10 IU/mL from baseline, with detectable HBV DNA by real-time polymerase chain reaction at week 48. RESULTS: We included 232 patients who underwent TDF therapy for over 48 weeks. Forty-two patients (18.1%) showed PVR. In multivariate analysis, hepatitis B e antigen (HBeAg) positivity, and high levels of serum HBV DNA at baseline and week 12 were independent predictive factors for PVR during TDF therapy. Out of 42 patients with PVR, 39 (92.9%) achieved virologic response (VR) during continuous TDF treatment; the cumulative VR rates at 24, 36, and 48 months were 79.8%, 88.2%, and 95.6%, respectively. With an additional 12 months of therapy, VR was achieved in 28/31 (90.3%) patients with HBV DNA < 100 IU/mL, compared to 5/11 (45.5%) patients with HBV DNA ≥ 100 IU/mL, at week 48. CONCLUSION: The vast majority of patients achieved VR through prolonged TDF therapy, thus TDF treatment can be maintained in nucleos(t)ide-naïve patients with PVR at week 48, especially in those with low viremia.

Efficacy of prolonged entecavir monotherapy in treatment-naïve chronic hepatitis B patients exhibiting a partial virologic response to entecavir.

BACKGROUND/AIMS: The optimal management of patients exhibiting a partial virologic response (PVR) to entecavir (ETV) has not been determined. The aim of this study was to determine the long-term efficacy of prolonged ETV monotherapy in treatment-naïve chronic hepatitis B (CHB) patients exhibiting a PVR to ETV therapy. METHODS: This study included 364 treatment-naïve CHB patients treated with ETV for ≥48 weeks and who received continuous ETV monotherapy for ≥96 weeks. PVR was defined as a decrease in serum hepatitis B virus (HBV) DNA of more than 2 log(10) IU/mL from baseline but with detectable HBV DNA by real-time PCR assay at week 48. RESULTS: Fifty-two of the 364 patients (14.3%) showed a PVR. Among them, 41 patients received continuous ETV monotherapy for ≥96 weeks (median duration 144 weeks, range 96-312 weeks), and 40 of these patients (95%) achieved a virologic response (VR, HBV DNA <20 IU/mL) during prolonged ETV monotherapy (median duration 78 weeks, range 60-288 weeks). The cumulative probabilities of a VR at weeks 96, 144, and 192 from treatment initiation were 78.0%, 92.7%, and 95.1%, respectively. The VR rate was 97.2% (35/36) in HBeAg-positive patients and 100% (5/5) in HBeAg-negative patients. In multivariate analysis, HBeAg positivity (odds ratio [OR], 9.231; 95% confidence interval [CI], 1.03-82.91; P=0.047) and a high baseline HBV DNA level (OR, 0.170; 95% CI, 0.08-0.37; P=0.000) were independently associated with a delayed virologic response. No patient developed genotypic resistance to ETV during follow-up. CONCLUSIONS: Long-term ETV monotherapy is effective for achieving a VR in treatment-naïve CHB patients exhibiting a PVR to ETV. HBeAg positivity and high baseline HBV DNA level were independently associated with a delayed virologic response.