Antiviral Therapy

In China, the clinical management of chronic hepatitis B (CHB) is complicated by the use of various-nucleoside/nucleotide analogue (NUC) regimens in treatment-naive patients, including NUCs with low genetic barriers to resistance, with/without add-on therapy and de novo NUC combinations. This longitudinal observational study therefore investigated the real-world clinical management and efficacy of NUC therapy in treatment-naive CHB patients in China.

Treatment-naive CHB patients initiated on NUC therapy were enrolled from 63 hospitals in tier-2 Chinese cities. Demographic and treatment-specific data were collected, with the objective of reporting real-world treatment patterns and comparing the effectiveness of entecavir (ETV) treatment and lamivudine (LAM)-based treatment. We herein report the first-year data.

3,408 NUC-naive patients were enrolled and treated with NUCs (53% ETV, 18% LAM-based, 29% other). Overall, 6.6% of patients modified their initial treatment, with ETV having lower rates of treatment modification than other major NUCs (P<0.05). At week 52, the virological response rate was higher with ETV than with LAM-based treatment (77.0% versus 61.4%; P<0.0001). LAM-based treatment was associated with a higher probability of virological breakthrough and genotypic resistance (21.4% and 19.6%, respectively) than ETV (1.6% and 0.1%, respectively; P<0.0001). Treatment-related adverse events or serious adverse events were uncommon.

In this nationwide observational study, more than 50% of patients with CHB in tier-2 city hospitals in China initially received ETV therapy. Consistent with clinical trial results, ETV was more effective than LAM-based treatments in a real-world setting, with the rate of treatment modification being relatively low in ETV-treated patients. ClinicalTrials.gov Identifer: NCT01726439.

The introduction of highly potent direct-acting combination therapies for HCV have negated the role of response-guided therapy and reduced the role of treatment monitoring. However, there remains a need to identify patients who are actively infected with HCV and discriminate those who have achieved sustained virological response (SVR) from those who fail to achieve SVR.

A total of 1,678 plasma samples from the 631 subjects enrolled in AbbVie's SAPPHIRE I trial (NCT01716585) were tested in a blinded fashion with Abbott HCV core antigen (cAg) assay and results were compared with Roche High-Pure system/COBAS® TaqMan HCV RNA 2.0 assay.

Using 10 fmol/l as the clinical cutoff for cAg, the HCV RNA and cAg tests were in 100% agreement for true negative samples and 99.6% agreement for truly positive samples. One discordant (screening) sample was identified. This sample was target not detected by HCV RNA method but positive by anti-HCV and highly positive by ARCHITECT core antigen (7,912 fmol/l). Seventeen samples had cAg levels in the ‘grey zone’ >3 but <10 fmol/l at initial testing and were re-tested per package insert. All of these samples gave a result of <3 fmol/l upon retest. These results were in alignment with target not detected HCV RNA result. One sample had a cAg >3 but <10 fmol/l when tested on three consecutive occasions (5.8, 5.5 and 4.4) but had a target not detected RNA result.

In this study cAg, with a 10 fmol/l cutoff, accurately identified 99.6% of patients with active viraemia and discriminated all subjects who achieved SVR from those who failed therapy.

A complete virological response is closely related to the long-term outcome of patients with chronic hepatitis B and prevention of emerging HBV mutations. We aimed to evaluate the efficacy of tenofovir disoproxil fumarate (TDF) monotherapy compared to entecavir-adefovir dipivoxil (ETV-ADV) combination therapy in patients with suboptimal responses to long-term lamivudine-adefovir dipivoxil (LAM-ADV) therapy for nucleoside analogue-resistant chronic hepatitis B.

Patients (n=60) were randomized to TDF monotherapy or ETV-ADV combination therapy for 96 weeks. All patients had the rt204I/V mutation and serum HBV DNA was measured (>60 IU/ml) during LAM-ADV therapy. The primary end point was a complete virological response (HBV DNA <20 IU/ml) at week 96.

The median duration of prior LAM-ADV rescue therapy was 43 (7–108) months. A complete virological response was achieved in 86.6% and 53.3% of patients in the TDF and ETV-ADV groups, respectively, at week 96 (P=0.005). Reduction in serum HBV DNA was significantly greater in the TDF group than in ETV-ADV group (-3.2 ±1.2 versus -2.6 ±1.2; P=0.01). Hepatitis B e antigen loss (22.2% versus 16.6%; P=0.731) and biochemical responses (76.7% versus 73.3%; P=0.766) were not different between the TDF and ETV-ADV groups. No newly emerged mutations were detected. Both therapies demonstrated favourable safety profiles.

TDF therapy achieved a better complete virological response than ETV-ADV therapy in chronic hepatitis B patients with suboptimal response to long-term LAM-ADV rescue therapy. (KCT0000627).

Data on persistence of NS5A resistance-associated substitutions (RASs) may have implications for resistance testing approaches and selection of initial and retreatment strategies.

Long-term persistence of NS5A RASs in HCV genotype (GT) 1 infected subjects (n=76) who did not achieve sustained virological response after receiving ledipasvir (LDV) without sofosbuvir (SOF) and were subsequently enrolled in an ongoing 3-year follow-up registry study was investigated by population or deep sequencing.

Of the 76 subjects enrolled, 67 and 9 subjects had GT1a and GT1b infection, respectively. At pretreatment, NS5A RASs were detected in 14% of subjects (11/76) by population sequencing, with three subjects having >1 RAS. All RASs that were detected at pretreatment persisted and were observed at the 96 week visit in the follow-up study (FU96). For the remaining subjects with no detectable RASs at pretreatment, RASs were detected in 98% (63/64) of subjects at virological failure in the parent study and persisted at detectable levels through FU96 in 86% of subjects by deep sequencing (1% cutoff). However, a decline in the quasispecies frequency of most RASs and the number of RASs per subject was observed over time. Phenotypic analysis demonstrated that the majority of NS5A RASs confer similar levels of resistance to LDV and daclatasvir.

The majority of NS5A RASs can persist at detectable levels for >96 weeks post-treatment in subjects who failed treatment with regimens containing an NS5A inhibitor without SOF, suggesting relatively high fitness of NS5A RASs even in the absence of drug pressure.

Although nucleoside/nucleotide analogue therapy is thought to suppress chronic hepatitis B (CHB) via regulation of inflammatory cytokines/chemokines, the mechanism is still unclear. In this study, serum cytokine/ chemokine levels were measured in CHB patients treated with entecavir, and the association with antiviral response was analysed.

A total of 78 Japanese patients with CHB were enrolled, and serum cytokine/chemokine levels were measured at baseline and at 12, 24 and 48 weeks of entecavir treatment using the MULTIPLEX kit.

Antiviral response to entecavir treatment was significantly associated with hepatitis B surface antigen (HBsAg) titre and serum interferon-gamma-inducible protein 10 (IP-10) level (12w; P=0.0002; OR=0.020 [95% CI 0.002, 0.156], P=0.003; OR=0.042 [95% CI 0.005, 0.336], respectively). HBe-positive patients whose serum macrophage-derived chemokine (MDC) level was lower (<582.83 pg/ml) and IP-10 level was higher (≥1,323.13 pg/ml) achieved hepatitis B e antigen (HBeAg) loss earlier than those who remained HBeAg-positive (P=0.044). HBsAg reduction by entecavir treatment was significantly associated with higher initial tumour necrosis factor-alpha (TNF-α) level (≥15.20 pg/ml) and higher alanine aminotransferase level (≥73 IU/l; P=0.009; OR=18.460 [95% CI 2.044, 166.709], P=0.022; OR=7.709 [95% CI 1.341, 44.327], respectively).

Results of the present study indicate that changes in cytokine/chemokine levels following entecavir therapy are associated with response to antiviral therapy in CHB patients. Monitoring of serum cytokine/chemokine levels could be useful for predicting reduction of HBV DNA and HBsAg and HBe seroconversion.

Virological success (VS) and immunological reconstitution (IR) of antiretroviral-naive HIV-1-infected patients with pre-therapy viral load (VL) >500,000 copies/ml was assessed after 12 months of treatment according to initial drug-class regimens.

An observational multicentre retrospective study was performed. VS was defined as the first VL <50 copies/ml from treatment start. IR was defined as an increase of at least 150 CD4⁺ T-lymphocytes from treatment start. Survival analysis was used to estimate the probability and predictors of VS and IR by 12 months of therapy.

428 HIV-1-infected patients were analysed. Patients were grouped according to the different first-line drug-classes used: a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs; NNRTI-group; n=105 [24.5%]); a protease inhibitor (PI) plus two NRTIs (PI-group; n=260 [60.8%]); a four-drug regimen containing a PI-regimen plus an integrase inhibitor (PI+INI-group; n=63 [14.7%]).

Patients in the PI-group showed the lowest probability of VS (PI-group: 72.4%; NNRTI-group: 75.5%; PI+INI-group: 81.0%; P<0.0001). By Cox regression, patients in PI+INI and NNRTI-groups showed a higher adjusted hazard ratio (95% CI) of VS compared to those in the PI-group (PI+INI-group: 1.48 [1.08, 2.03]; P=0.014; NNRTI-group: 1.37 [1.06-1.78]; P=0.015). The probability of IR was 76.2%, and was similar among groups. Patients with AIDS showed a lower adjusted hazard ratio (95% CI) of IR compared to non-AIDS presenters (0.70 [0.54, 0.90]; P=0.005).

In this multicentre retrospective study, patients with viraemia >500,000 copies/ml who start a first-line regimen containing PI+INI or NNRTI yield a better VS compared to those receiving a PI-based regimen.

Rilpivirine (RPV), a non-nucleoside reverse transcriptase inhibitor drug, could be a favourable drug for maintenance therapy in HIV-infected adolescents because it has few long-term side effects. However, data among adolescents switching from efavirenz (EFV) to RPV are limited. This study investigated the pharmacokinetics (PK), safety and efficacy of RPV in virologically suppressed HIV-1-infected adolescents after switching from EFV.

Adolescents aged 12–18 years on EFV-based antiretroviral therapy (ART) were switched from EFV to RPV (25 mg, once daily). Intensive 24-h blood samplings at 0 (pre-dose), 1, 2, 4, 5, 6, 9, 12 and 24 h were performed 4 weeks after switching. PK parameters were calculated using a non-compartmental method and compared with published data from the PAINT and pooled ECHO/THRIVE substudies. HIV RNA level was measured at weeks 12 and 24. Biochemical profiles were measured at baseline and week 24.

From January to June 2016, 20 adolescents (12 male) were enrolled. Median (IQR) age was 16 (15–17) years and weight was 49 (42–59) kg. Mean (sd) AUC_{24 h}, C_{24 h} and C_max of RPV were 2,041 (745) ng•h/ml, 69 (29) ng/ml and 143 (65) ng/ml, respectively. Median (IQR) T_max was 5 (2–9) h. Four adolescents had C_{24 h} <40 ng/ml. All PK parameters were comparable with published data. All adolescents remained virologically suppressed at week 24. Significant decreases in fasting total cholesterol, triglyceride and low-density lipoprotein were observed (P-value <0.05).

Virologically suppressed HIV-infected adolescents had adequate RPV exposure and remained virologically suppressed after switching from EFV. RPV can be used as long-term maintenance ART in HIV-infected adolescents.

Myrcludex B is a first-in-class virus entry inhibitor for patients with chronic hepatitis B or B/D infections. In patients it will be coadministered with drugs needed for the disease or comorbidities. We aimed to define the risk of drug–drug interactions by characterizing the influence of myrcludex B on relevant drug transporting and metabolizing enzymes in vitro.

Inhibition of P-glycoprotein (P-gp; ABCB1), breast cancer resistance protein (BCRP/ABCG2), and the organic anion transporting polypeptides 1B1 and 1B3 (OATP1B1/SLCO1B1 and OATP1B3/SLCO1B3) was measured in cells over-expressing the respective transporter using fluorogenic substrates. Inhibition of cytochrome P450 enzymes (CYPs) was assessed with commercially available kits. mRNA induction of drug transporting and metabolizing enzymes was measured in LS180 cells after 4 days of treatment by quantitative real-time PCR. Pregnane X receptor (PXR) activation was assessed using a reporter-gene assay.

Whereas activities of P-gp and BCRP were not influenced by myrcludex B, OATP1B1 and OATP1B3 were specifically inhibited with a 50% inhibitory concentration (IC₅₀) of 0.5 and 8.7 μM, respectively. Myrcludex B weakly inhibited all CYPs tested at concentrations ≥10 μM except CYP2D6, which was not inhibited at concentrations up to 2 μM. Myrcludex B had no influence on mRNA expression of CYP1A1, CYP3A4, UGT1A3, ABCB1, ABCC2 and ABCG2, and on PXR activity.

Our in vitro study suggests that myrcludex B is not at major risk of acting as a perpetrator drug. A potential inhibition of the uptake transporters OATP1B1 and OATP1B3 and a previous clinical finding of potential CYP3A inhibition, requires further evaluation and should be carefully addressed in future trials.

Pre-analytical sample processing is often overlooked as a potential cause of inaccurate assay results. Here we demonstrate how plasma, extracted from standard EDTA-containing blood collection tubes, may contain traces of blood cells consequently resulting in a false low-level HIV-1 viral load when using Roche Cobas HIV-1 assays.

The presence of human DNA in Roche Cobas 4800 RNA extracts and in RNA extracts from the Abbott HIV-1 RealTime assay was assessed by quantifying the human albumin gene by means of quantitative PCR. RNA was extracted from plasma samples before and after an additional centrifugation and tested for viral load and DNA contamination. The relation between total DNA content and viral load was defined.

Elevated concentrations of genomic DNA were detected in 28 out of 100 Cobas 4800 extracts and were significantly more frequent in samples processed outside of the AIDS Reference Laboratory. An association between genomic DNA presence and spurious low-level viraemia results was demonstrated. Supplementary centrifugation of plasma before RNA extraction eliminated the contamination and the false viraemia.

Plasma isolated from standard EDTA-containing blood collection tubes may contain traces of HIV DNA leading to false viral load results above the clinical cutoff. Supplementary centrifugation of plasma before viral load analysis may eliminate the occurrence of this spurious low-level viraemia.