Clinical utility of entecavir for chronic hepatitis B in Chinese patients

Pharmacokinetic Study of Nalbuphine in Surgical Patients Undergoing General Anesthesia with Varying Degrees of Liver Dysfunction

Purpose

This study aimed to characterize the pharmacokinetics of nalbuphine in patients undergoing general anesthesia with varying degrees of liver dysfunction.

Patients and Methods

Twenty-four patients were enrolled and divided into three cohorts based on liver function: normal liver function (n = 13), mild liver dysfunction (n = 5), and moderate/severe liver dysfunction (n = 6). During the induction of anesthesia, they received 15 mg of nalbuphine intravenously. Venous blood samples were collected from each patient. The plasma concentration of nalbuphine was determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The pharmacokinetic parameters of nalbuphine were calculated by non-compartmental analysis (NCA) using Phoenix WinNonlin software.

Results

Compared with the normal liver function group, the plasma elimination half-life (T_1/2) of nalbuphine was increased by approximately 33% in the moderate/severe liver dysfunction group (2.66 h vs 3.54 h, P<0.05), and the volume of distribution (V_d) increased by approximately 85% (100.08 L vs 184.95 L, P<0.05). Multivariate analysis revealed that weight and platelet were associated with clearance (CL); total bilirubin as an independent factor was associated with T_1/2, and weight associated with area under the curve (AUC_(0→∞)) independently.

Conclusion

The T_1/2, mean residence time, and V_d of nalbuphine in patients with moderate/severe liver dysfunction were prolonged or increased significantly compared with those in the normal liver function group. These data suggest that it may need to be used with caution when nalbuphine is administered to patients with moderate or severe liver dysfunction.

Exploration of long-acting implant formulations of hepatitis B drug entecavir

Alternative formulations of entecavir, a once daily oral hepatitis B antiretroviral, may improve treatment adherence by patients. We explored the use of biocompatible polymers to control entecavir dissolution in two formats suitable for subcutaneous implantation. Hot melt extrudates were prepared by extruding entecavir-polymer blends at specified weight ratios. Dip-coated tablets were prepared by compressing entecavir in a multi-tip tooling. Tablets were dip-coated in solutions of polymer and dried. In rodents, entecavir-poly(caprolactone) extrudates demonstrated >180 days of continuous drug release, although below the estimated efficacious target input rate. Drug pharmacokinetic profiles were tunable by varying the polymer employed and implant format. The rank order trends of drug input rates observed in vitro were observed in vivo in the detected plasma concentrations of entecavir. In all dose groups entecavir was not tolerated locally at the site of administration where adverse event severity correlated with drug input rate. These polymer-based implantable formats have applicability to long-acting formulations of high solubility compounds beyond entecavir.

Adherence and perceived barriers to oral antiviral therapy for chronic hepatitis B

Background: Globally, of the 248 million people chronically infected with the hepatitis B virus (HBV), 74 million reside in China. Five oral nucleot(s)ide analogs (NUCs) have been approved for the treatment of chronic hepatitis B (CHB) in China.

Objectives: The aims of this study were to determine rates of adherence to NUC therapy in patients with CHB, to identify the self-perceived barriers to adherence, and to examine the factors associated with adherence.

Methods: Questionnaire-based interviews were administered among Chinese patients with CHB at hepatology clinics of a tertiary hospital in the city of Wuhan, China. Adults aged 18 years or older prescribed with NUCs were recruited and interviewed to complete a 27-item questionnaire in a private setting, and adherence was measured using the Morisky Medication Adherence Scale (MMAS-8).

Results: Among 369 participants, only 16.5% had high adherence (score of 8), 32.2% had medium adherence (score of 6 to <8), and 51.2% were measured with low adherence (score of <6). A logistic regression model was used to determine the factors associated with medication adherence. Significant predictors of high adherence consisted of urban residency, non-cirrhotic status, not using prescribed pills other than HBV medications, and reminders from family members. The five most common reasons for skipping NUCs were that medication(s) are expensive (48.7%), forgetfulness (45.1%), have experienced or worry about potential side effects (19.8%), do not want others to know about my medication(s) usage (18.5%), and ran out of pills and do not have time to refill (15.9%).

Conclusions: This study revealed that adherence rates to oral antiviral therapy were far from optimal. This finding should generate public attention, and it would be beneficial for interventional programs to target Chinese patients from rural regions, as well as patients with low socioeconomic status, cirrhosis, and taking multiple medications.

Pharmacokinetic Analysis of Propofol Target-Controlled Infusion Models in Chinese Patients with Hepatic Insufficiency

Background

Effects of liver dysfunction on target-controlled infusion (TCI) with Marsh parameters of propofol remain poorly documented. The purpose of this study was to evaluate the performance of propofol TCI in a cohort of Chinese patients with severe hepatic insufficiency.

Material/Methods

We assigned 32 patients who underwent liver transplantation to 3 groups according to Child-Turcotte-Pugh (CTP) score. Anesthesia, preceding liver transplantation, was induced and maintained with TCI of 3 μg/mL propofol. Plasma propofol concentration was assessed. Propofol TCI system performance was analyzed in terms of error size, bias, and divergence. Data on plasma propofol concentrations were analyzed, and population pharmacokinetic parameters of propofol were fitted by NONMEM software.

Results

In the CTP C group, measured concentrations of propofol were much higher than those of predictive concentrations, with significantly higher overshoots compared to CTP A patients. Overall, TCI system performance was significantly lower in CTP C patients. Linear regression equations of Cm vs. Cp and a regression model of pharmacokinetics were obtained.

Conclusions

Propofol TCI device performance with Marsh parameters was clinically acceptable in CTP A patients but may not be suitable for patients with severe hepatic impairment.

A new scheme with infusion of hepatitis B immunoglobulin combined with entecavir for prophylaxis of hepatitis B virus recurrence among liver transplant recipients

OBJECTIVE

Liver transplantation significantly increases recurrence of hepatitis B virus (HBV) among high-risk patients. Hepatitis B immunoglobulin (HBIG) and antiviral nucleotide analogues are effective prophylaxis reagents in preventing HBV recurrence. However, HBV recurrence still occurs with these treatments.

METHODS

To explore a more cost-effective prophylaxis protocol in patients after liver transplantation, we treated patients with an initial high dose of 10 000 IU HBIG during the anhepatic phase and a second high dose of HBIG at an optimal time point during surgery. The patients were treated with the traditional European protocol as a control, in which one dose of 10 000 IU HBIG was infused during the anhepatic phase and multiple doses of 10 000 IU HBIG were administered daily for 1 week after liver transplantation.

RESULTS

There were two mortalities among 50 patients treated with the new protocol and nine mortalities among 52 patients treated with the European protocol within 3 years after liver transplantation. The new prophylaxis method markedly improved the 3-year survival without HBV recurrence in 50 treated patients. However, there were five recurrences in 52 patients treated with the European protocol. High-risk factors such as HBV DNA+, positive hepatitis B e antigen, and hepatocellular carcinoma were all detected among five patients with HBV recurrence. The suppressed HBV recurrence was associated with significantly lower serum alanine aminotransferase and aspartate aminotransferase in the new protocol-treated patients tested at 1 month and 1 week after liver surgery compared with those treated with the European protocol.

CONCLUSION

Infusion of two high doses of HBIG during surgery in combination with entecavir significantly prevented HBV recurrence and improved the 3-year survival after liver transplantation.

Long-term antiviral efficacy of entecavir and liver histology improvement in Chinese patients with hepatitis B virus-related cirrhosis

AIM

To evaluate the clinical outcomes of 240-wk treatment with entecavir (0.5 mg) in Chinese nucleoside-naive patients with cirrhosis.

METHODS

A total of 204 nucleoside-naive patients with compensated (n = 96) or decompensated (n = 108) hepatitis B virus (HBV)-induced cirrhosis at the Department of Gastroenterology of the China-Japan Union Hospital (Jilin University, Changchun, China) who were treated with entecavir (0.5 mg) for 240 wk were enrolled in this study. Liver biopsy samples obtained from 38 patients prior to treatment (baseline) and at week 240 were evaluated by different independent histopathologists. Efficacy assessments included the proportions of patients who achieved an HBV DNA level < 500 copies/mL, the association of interleukin-28B genetic variation with antivirus therapy, clinical outcomes, and histologic improvement. Changes in liver disease severity were analyzed, and liver histologic evaluation was performed in 38 patients with paired biopsies. Student t tests were used to compare the means of continuous variables between the groups, and the proportions of patients who achieved the endpoints were compared using the χ(2) test.

RESULTS

At week 240, 87.5% of the patients with compensated cirrhosis and 92.6% of the patients with decompensated cirrhosis achieved a HBV DNA level < 500 copies/mL. Three patients had genotypic entecavir resistance within the 240-wk period. No significant association was observed between virologic response and interleukin-28 genotype (CT, 88.2% vs CC, 90.6%). The proportion of patients with Child-Pugh class A disease was significantly increased at week 240 (68%) from the baseline (47%; P < 0.01). The proportion of patients with Child-Pugh class B disease was significantly decreased at week 240 (25%) from the baseline (39%; P = 0.02). In the patients with paired liver biopsies, the mean reduction in the Knodell necroinflammatory score from the baseline was 3.58 ± 1.03 points (7.11 ± 1.80 vs 3.53 ± 1.35, P < 0.01). The mean reduction in Ishak fibrosis score from the baseline was 1.26 ± 0.64 points (5.58 ± 0.50 vs 4.32 ± 0.81, P < 0.01).

CONCLUSION

Entecavir is an effective treatment option for patients with HBV-related compensated or decompensated cirrhosis that can result in sustained virologic suppression and histologic improvement.

Cost-effectiveness analysis of lamivudine, telbivudine, and entecavir in treatment of chronic hepatitis B with adefovir dipivoxil resistance

The purpose of this study was to analyze the cost-effectiveness of lamivudine (LMV), telbivudine (LdT), and entecavir (ETV) in treatment of chronic hepatitis B with adefovir dipivoxil (ADV) resistance. Two hundred and fifty-two patients were recruited and screened for resistance to ADV and randomly assigned into three groups: LMV + ADV, LdT + ADV, and ETV + ADV. The ratio of biochemical response, virological response, seroconversion of hepatitis Be antigen (HBeAg)/hepatitis Be antibody (HBeAb), viral breakthrough, and the cost and effectiveness of treatments were analyzed. A comparison of the results of the ratio of biochemical response, virological response and seroconversion of HBeAg/HBeAb, showed no statistical difference between the three groups, with the economic cost of LMV + ADV the lowest, LdT + ADV the middle, and ETV + ADV the highest. The side effects of the three plans are all rare and tolerable. LMV + ADV is the optimal rescue strategy, and LdT + ADV the alternative selection in the economically less developed regions, while ETV + ADV was used in the economically developed regions.

Analysis of minimum target prices for production of entecavir to treat hepatitis B in high- and low-income countries

BACKGROUND

In 2013, an estimated 686,000 people died from hepatitis B virus (HBV) infection worldwide. Mass treatment programmes for hepatitis B will require very low drug costs. International treatment guidelines recommend first-line monotherapy with either entecavir or tenofovir disoproxil fumarate (TDF). While the basic patent on TDF expires in 2017/8, entecavir is already generic in several countries, including the US. The chemical structure of entecavir is related to abacavir, which costs <$200 per person-year in low-income countries.

METHODS

The clinical efficacy, chemical structures, daily doses, routes of chemical synthesis, costs of raw materials and patent expiry dates were analysed for entecavir and TDF. Costs of sustainable, generic production were calculated for entecavir, and compared with published originator and generic prices in high- and low-income countries.

RESULTS

With a daily dose of 0.5 mg, one year's supply of entecavir treatment requires <0.2 g of active pharmaceutical ingredient (API) per person, estimated to cost $4/year, based on quotations of API production from generic suppliers. With an additional $20 per year for formulation/packaging and a 50% profit margin, entecavir was estimated to cost a minimum of $36/person-year, substantially lower than current originator and generic prices. Entecavir is no longer under patent protection in the USA, China, Brazil and South Africa, with European expiry in 2017. Given differences in daily dosing, production volumes for entecavir would be 600 times lower than TDF (300 mg once daily) for treating the same numbers of patients.

CONCLUSIONS

Mass treatment for hepatitis B with generic entecavir could be achieved at very low cost in all countries, provided that important projections can be met in terms of pricing for the API and finished dosage form.

Parallel transjugular intrahepatic portosystemic shunt for controlling portal hypertension complications in cirrhotic patients

AIM: To evaluate the feasibility of a second parallel transjugular intrahepatic portosystemic shunt (TIPS) to reduce portal venous pressure and control complications of portal hypertension.

METHODS: From January 2011 to December 2012, 10 cirrhotic patients were treated for complications of portal hypertension. The demographic data, operative data, postoperative recovery data, hemodynamic data, and complications were analyzed.

RESULTS: Ten patients underwent a primary and parallel TIPS. Technical success rate was 100% with no technical complications. The mean duration of the first operation was 89.20 ± 29.46 min and the second operation was 57.0 ± 12.99 min. The mean portal system pressure decreased from 54.80 ± 4.16 mmHg to 39.0 ± 3.20 mmHg after the primary TIPS and from 44.40 ± 3.95 mmHg to 26.10 ± 4.07 mmHg after the parallel TIPS creation. The mean portosystemic pressure gradient decreased from 43.80 ± 6.18 mmHg to 31.90 ± 2.85 mmHg after the primary TIPS and from 35.60 ± 2.72 mmHg to 15.30 ± 3.27 mmHg after the parallel TIPS creation. Clinical improvement was seen in all patients after the parallel TIPS creation. One patient suffered from transient grade I hepatic encephalopathy (HE) after the primary TIPS and four patients experienced transient grade I-II after the parallel TIPS procedure. Mean hospital stay after the first and second operations were 15.0 ± 3.71 d and 16.90 ± 5.11 d (P = 0.014), respectively. After a mean 14.0 ± 3.13 mo follow-up, ascites and bleeding were well controlled and no stenosis of the stents was found.

CONCLUSION: Parallel TIPS is an effective approach for controlling portal hypertension complications.

Comprehensive treatment of acute-on-chronic liver failure in a patient with hepatitis B: a case report

The clinical data of a patient with acute-on-chronic liver failure were analyzed retrospectively. The patient has suffered from hepatitis B for 30 years. His liver function deteriorated, yielding Child-Pugh grade C and reaching a model for end-stage liver disease score of 33 points within a short period; this condition was complicated with highly active variceal bleeding and coagulation system failure (PT > 100 s). The patient also presented hepatocellular carcinoma. Comprehensive treatments included effective inhibition of hepatitis B virus replication and intensive care support. Piggyback orthotopic liver transplantation was performed as the final treatment. The patient recovered uneventfully and was discharged after surgery.