Prevalence of hepatitis C virus infection and the IL28B genotype polymorphism among blood donors and high-risk populations

Real-world impact of a subsidy decision of sofosbuvir-velpatasvir for treatment of chronic hepatitis C on clinical practice and patient outcomes

Background and Aim

Sofosbuvir-velpatasvir was recommended for subsidy to treat chronic hepatitis C in Singapore in 2018. We measured the impact of the subsidy decision on clinical practice and patient outcomes. Specifically, we looked at pre- and post-subsidy changes in the utilization and prescribing pattern of chronic hepatitis C treatment and the real-world clinical effectiveness.

Method

Utilization trends and prescribing patterns were assessed using aggregated drug utilization data from public hospitals' dispensing systems and clinical data from the national electronic health record database, respectively. An audit was conducted to evaluate sustained virological response rate 12 weeks post treatment (SVR12).

Results

Use of sofosbuvir-velpatasvir increased sharply since its subsidy listing and dropped subsequently, whereas the utilization of comparator drugs remained low. Prescribing rate of sofosbuvir-velpatasvir increased from 13.7% in the pre-subsidy period to 90.2% in the post-subsidy period; 39.1% of patients previously on pegylated interferon and ribavirin switched to sofosbuvir-velpatasvir following its subsidy listing. In the audit, 365 out of 375 patients (97.3% [95% confidence interval: 95.1-98.6%]) achieved SVR12.

Conclusion

The subsidy decision led to increased accessibility to patients and intended changes in clinical practice. Sofosbuvir-velpatasvir was also clinically effective in the real world. These findings augur well for the continued eradication of chronic hepatitis C infection in Singapore.

Failure of sterilization in a dental outpatient facility: Investigation, risk assessment, and management

In 2017, an incident of failed sterilization of dental instruments occurred at a large dental outpatient facility in Singapore. We aim to describe findings of the investigation of the sterilization breach incident, factors related to risk of viral transmission to the potentially affected patients, and the contact tracing process, patient management, and blood test results at a 6-month follow-up. A full assessment of the incident was immediately carried out. The factors related to risk of viral transmission due to affected instruments were analyzed using 3 keys points: breached step(s) and scale of the incident, prevalence of underlying bloodborne diseases and immunity in the Singapore population, health status of potential source patients, and type of dental procedure performed, and health status of affected patients and type of dental procedure received. Up to 72 affected instrument sets were used in 714 potentially affected patients who underwent noninvasive dental procedures. The investigation revealed that there was a lapse in the final step of steam sterilization, resulting in the use of incompletely sterilized items. The assessment determined that there was an extremely low risk of bloodborne virus transmission of diseases to the patients. At the 6-month follow-up, there were no infected/colonized cases found related to the incident. Lapses in the sterilization process for medical and dental instruments can happen, but a risk assessment approach is useful to manage similar incidents. Quick response and proper documentation of the sterilization process can prevent similar incidents.

Systematic Review of Hepatitis C Virus Prevalence in the WHO Western Pacific Region

BACKGROUND

This review aimed to identify hepatitis C virus (HCV) prevalence estimates among the general population and six key populations (people who inject drugs, men who have sex with men, sex workers, prisoners/detainees, Indigenous people, and migrants) in the World Health Organization Western Pacific Region (WHO WPR).

METHODS

Original research articles published between 2016 and 2020 were identified from bibliographic databases. Publications were retrieved, replicas removed, and abstracts screened. Retained full texts were assessed and excluded if inclusion criteria were not met. Methodological quality was assessed using the Johanna Briggs Institute critical appraisal checklist for prevalence data. Data on HCV exposure and active infection were extracted and aggregated and forest plots generated for each population by country.

RESULTS

There were no HCV prevalence estimates in any population for more than half of WPR countries and territories. Among the 76 estimates, 97% presented prevalence of exposure and 33% prevalence of active infection. General population viraemic prevalence was 1% or less, except in Mongolia. Results confirm the endemic nature of HCV among people who inject drugs, with estimates of exposure ranging from 30% in Cambodia to 76% in Hong Kong.

CONCLUSIONS

Countries require detailed knowledge of HCV prevalence in diverse populations to evaluate the impact of efforts to support WHO HCV elimination goals. Results provide baseline estimates from which to monitor and evaluate progress and by which to benchmark future elimination efforts.

Prevalence of HCV genotypes and subtypes in Southeast Asia: A systematic review and meta-analysis

Known for its high genetic diversity and variation in genotypic presence in different regions of the world, hepatitis C virus (HCV) is estimated to infect about 71 million people globally. Selection of an appropriate therapeutic regimen largely depends on the identification of the genotype responsible for the infection. This systematic review and meta-analysis was conducted to provide a comprehensive view of HCV genotype and subtype distribution in Southeast Asia (SEA). The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). We searched five databases without year and language restrictions. Data from 90 eligible studies involving 15,089 genotypes and 9,646 subtypes representing 10 SEA countries were analyzed. The pooled estimates showed that genotype 1 (46.8%) [95% CI, 43.2–50.4; I² = 92.77%; p < 0.001] was the most dominant HCV genotype in the region, followed by genotype 3 (23.1%) [95% CI, 19.4–27.2; I² = 93.03%; p < 0.001], genotype 6 (16.5%) [95% CI, 13.8–19.6], genotype 2 (4.6%) [95% CI, 3.5–5.9], genotype 4 (1.1%) [95% CI, 0.7–1.5] and genotype 5 (0.8%) [95% CI, 0.4–1.3]. Philippines had the highest prevalence of genotypes 1 and 2. Genotype 6 became more prevalent after year 2000. Over 40 different subtypes were identified, with subtypes 1b (26.3%), 1a (21.3%), and 3a (14.3%) being the most prevalent of all the reported subtypes. Although on a global scale, genotype 6 is considered highly prevalent in SEA, evidence from this study reveals that it is the third most prevalent genotype within the region.

What is required for achieving hepatitis C virus elimination in Singapore? A modeling study

BACKGROUND AND AIM

The vast majority of hepatitis C virus (HCV) infection in Singapore is among those with a history of injecting drug use (IDU), yet harm reduction is not available and what is required to achieve the World Health Organization (WHO) HCV elimination targets (80% incidence reduction and 65% mortality reduction by 2030) is unknown. We model the intervention scale-up required to achieve WHO targets in Singapore.

METHODS

A dynamic model of HCV transmission and progression among those with a history of IDU was calibrated to Singapore, a setting with declining IDU and no harm reduction (~11 000 people with IDU history in 2017 and 45% HCV seropositive). We projected HCV treatment scale-up from 2019 required to achieve WHO targets with varying prioritization scenarios, with/without opiate substitution therapy scale-up (to 40% among people who inject drugs [PWID]).

RESULTS

We estimated 3855 (95% confidence interval: 2635-5446) chronically HCV-infected individuals with a history of IDU and 148 (87-284) incident HCV cases in Singapore in 2019. Reaching the HCV incidence target requires 272 (187-384) treatments in 2019, totaling 2444 (1683-3452) across 2019-2030. By prioritizing PWID or PWID and cirrhotics, 60% or 30% fewer treatments are required, respectively, whereas the target cannot be achieved with cirrhosis prioritization. Opiate substitution therapy scale-up reduces treatments required by 21-24%. Achieving both WHO targets requires treating 631 (359-1047) in 2019, totaling 3816 (2664-5423) across 2019-2030.

CONCLUSIONS

Hepatitis C virus elimination is achievable in Singapore but even with declining IDU requires immediate treatment scale-up among PWID. Harm reduction provision reduces treatments required and provides additional benefits.

Hepatitis C virus infection in HIV-infected men in Singapore, 2006-2018: incidence and associated factors

Background The epidemiology of hepatitis C virus (HCV) infection in people living with HIV has been evolving, with increasing evidence of permucosal (sexual) transmission identified predominantly in HIV-positive men who have sex with men (MSM). The aim of this study was to estimate the incidence rate and elucidate epidemiological factors associated with HCV infection among HIV-infected men in Singapore from 2006 to 2018.

METHODS

A retrospective cohort study was conducted using a clinical database maintained by the Clinical HIV Program at the National Centre for Infectious Diseases, Singapore. Factors associated with incident HCV infections were identified using Cox proportional hazards regression analyses.

RESULTS

Among 1348 HIV-infected male patients who were HCV seronegative at baseline, 64 (4.7%) subsequently tested positive for HCV, giving an incidence of 0.88 per 100 person-years of follow-up (PYFU) (95% confidence interval (CI) 0.69-1.13). The incidence rate of HCV seroconversion increased from 0.33 (95% CI 0.12-0.71) per 100 PYFU in 2010-2012 to 1.93 (95% CI 1.36-2.67) in 2016-2018. Independent factors associated with incident HCV infection were younger age groups at HIV diagnosis versus ≥45 years, HIV acquisition via MSM or via both sexual contact and intravenous drug use versus heterosexual transmission, HIV diagnosis in later periods versus 2006-2009, and recent syphilis acquisition.

CONCLUSIONS

An increasing trend of incident HCV infection was seen in HIV-infected men, particularly for MSM. Preventive and behavioural interventions should be targeted at HIV-infected individuals engaged in high-risk sexual behaviour.

Glecaprevir-pibrentasvir to treat chronic hepatitis C virus infection in Asia: two multicentre, phase 3 studies- a randomised, double-blind study (VOYAGE-1) and an open-label, single-arm study (VOYAGE-2)

BACKGROUND

Glecaprevir-pibrentasvir results in high rates of sustained virological response in patients with chronic hepatitis C virus (HCV) genotype 1-6 infection. Data for glecaprevir-pibrentasvir in non-Japanese Asian patients have been minimal. The aim of these studies was to assess the efficacy and safety of glecaprevir-pibrentasvir in treatment-naive and treatment-experienced Asian patients with chronic HCV genotype 1-6 infection without cirrhosis (VOYAGE-1) and with compensated cirrhosis (VOYAGE-2).

METHODS

We did two phase 3 studies in treatment-naive and treatment-experienced patients with chronic HCV genotype 1-6 infection. VOYAGE-1 was a randomised, double-blind, placebo-controlled study that recruited patients without cirrhosis at 47 sites across China, South Korea, and Singapore. Randomisation was 2:1 with a fixed block size of three and stratified by geographical region and HCV genotype. Investigators, study site personnel, the study sponsor, and patients were masked to treatment allocation. VOYAGE-2 was a single-arm, open-label study that recruited patients with compensated cirrhosis at 34 sites across China and South Korea. Glecaprevir (300 mg) and pibrentasvir (120 mg) or placebo (VOYAGE-1, 2:1 ratio), administered as three tablets daily, was given for 8 weeks in patients without cirrhosis and for 12 weeks in those with cirrhosis (and for 16 weeks in treatment-experienced patients with genotype 3). The primary efficacy endpoint was the proportion of patients with a sustained virological response, defined as HCV RNA below the lower limit of quantification 12 weeks after the last dose of glecaprevir-pibrentasvir. We analysed efficacy and safety in all patients who received at least one dose of the study drug. These trials are registered with ClinicalTrials.gov, NCT03222583 (VOYAGE-1) and NCT03235349 (VOYAGE-2); both trials have been completed. This Article reports the results of the primary analysis for each study, undertaken when all patients who received glecaprevir-pibrentasvir (during the double-blind period in VOYAGE-1) had been followed up for 12 weeks following their last dose of study drug. Data from the double-blind period for placebo patients in VOYAGE-1 are also summarised.

FINDINGS

Between Oct 4, 2017, and April 20, 2018, 546 patients with chronic HCV without cirrhosis were randomly assigned to treatment (363 to glecaprevir-pibrentasvir, 183 to placebo) in VOYAGE-1. One patient withdrew consent and did not receive treatment with glecaprevir-pibrentasvir. 352 of 362 patients who received glecaprevir-pibrentasvir achieved SVR12 (97·2% [95% CI 95·5-98·9]). Of 160 patients with compensated cirrhosis who were enrolled in VOYAGE-2 between Sept 29, 2017, and June 14, 2018, 159 of 160 achieved SVR12 (99·4%, 95% CI 98·2-100·0). 20 patients with HCV genotype 3b across both trials received glecaprevir-pibrentasvir; six of these patients were among the 11 patients who did not achieve SVR12. Upper respiratory tract infection was the most common adverse event (35 [10%] of 362 receiving glecaprevir-pibrentasvir and 18 [10%] of 183 receiving placebo in VOYAGE-1; 19 [12%] of 160 in VOYAGE-2). For patients receiving glecaprevir-pibrentasvir, serious adverse events occurred in three (<1%) of 362 patients in VOYAGE-1 and five (3%) of 160 patients in VOYAGE-2. Grade 3-4 adverse events in patients receiving glecaprevir-pibrentasvir occurred in five (1%) of 362 patients in VOYAGE-1 and six (4%) of 160 patients in VOYAGE-2; each type of event was experienced by at most one patient within a study. One patient with cirrhosis discontinued study drug because of an adverse event.

INTERPRETATION

Glecaprevir-pibrentasvir showed high efficacy and an acceptable safety profile in these studies although responses were less common in the few patients with HCV genotype 3b. The results support the use of glecaprevir-pibrentasvir in these Asian populations.

FUNDING

AbbVie.

Factors Associated with Hepatitis B and C Co-Infection among HIV-Infected Patients in Singapore, 2006-2017

Co-infection of hepatitis B virus (HBV) and hepatitis C virus (HCV) with human immunodeficiency virus (HIV) is associated with increased risk of hepatic complications and mortality. A retrospective study to estimate the proportion of HBV and HCV co-infections in Singapore was conducted using a clinical database. We included 3065 patients who were seen under the Clinical HIV Programme at the largest referral centre for HIV care between 2006 and 2017 and were tested for both HBV and HCV. Factors associated with HIV-HBV and HIV-HCV co-infections were determined using logistic regressions. The majority (86.3%) of HIV-infected patients were mono-infected, while 7.2% were co-infected with HBV, 6.0% with HCV, and 0.5% were co-infected with both HBV and HCV. The most common HCV genotype was GT1 (63%). Factors significantly associated with HBV co-infection in the multivariable model were: Aged 30–49 years and 50–69 years at HIV diagnosis, male gender, and HIV transmission through intravenous drug use (IDU). Independent factors associated with HCV co-infection were: Malay ethnicity, HIV transmission through IDU, and HIV diagnosis between 2006 and 2008. Behavioural risk factors such as IDU, as well as epidemiologic differences associated with co-infection, should inform further studies and interventions aimed at reducing viral hepatitis infection among HIV-infected individuals.

A proof-of-concept study in HCV-infected Huh7.5 cells for shortening the duration of DAA-based triple treatment regimens

With the development of more effective direct-acting antivirals (DAAs), dual- or triple-therapy regimens represent the major strategy used to cure chronic hepatitis C virus (HCV) infection. Thus, shorter treatment duration regimens with low burden, few adverse effects and good patient adherence are urgently needed. This study theoretically demonstrates a proof-of-concept approach for shortening therapy duration by examining HCV-infected Huh7.5 cells after treatment with a high or low fixed dose of three DAAs (simeprevir + daclatasvir + sofosbuvir) for 6-15 days. The results demonstrated that HCV-infected Huh7.5 cells achieved an ultrarapid virologic response with undetectable HCV RNA and protein and were cured after treatment with the triple-therapy regimen for 15 days. When the treatment duration was shortened, virologic relapse might occur after treatment with a low fixed dose of the three DAAs for 9 days and did occur after treatment with a low fixed dose for 6 days, although HCV was below detectable levels at the end of treatment. However, virologic relapse could be avoided with treatment of a high fixed dose of the three DAAs for 9 or 6 days. Although a virologic breakthrough occurred after an intermittent treatment regimen at the low fixed dose, the high fixed dose cured HCV-positive Huh7.5 cells with intermittent treatment. In conclusion, HCV is persistently present below detectable levels in HCV-infected Huh7.5 cells for a long time after treatment, and a shortened therapy duration is associated with an increased risk of virologic relapse, but virologic relapse or breakthrough might be avoided by treatment with a combination of more highly effective DAAs.