Real-World Outcomes of Direct-Acting Antiviral Treatment and Retreatment in United Kingdom-Based Patients Infected With Hepatitis C Virus Genotypes/Subtypes Endemic in Africa

Direct-acting antiviral treatment outcomes in people infected with endemic compared to epidemic hepatitis C virus subtypes in England

BACKGROUND

Current evidence suggests reduced efficacy of direct-acting antiviral (DAA) treatment among people with endemic Hepatitis C virus (HCV) subtypes rare to high-income countries. We aimed to determine real-world DAA treatment outcomes of people with endemic HCV subtypes in England.

METHODS

Data were collected through a national treatment program. People who had their virus subtyped between 2019-2023, were resident in England and had an outcome recorded for their first DAA treatment episode, were included. Subtypes were divided into epidemic and endemic in England; endemic subtypes were confirmed with whole genome sequencing and resistance associated substitutions (RAS) were determined. Logistic regression was used to determine associations between treatment outcome and exposure variables.

RESULTS

In people with an outcome recorded, 93 with an endemic and 8671 with an epidemic HCV subtype were identified, of whom 49.5% (46/93) and 91.8% (7953/8668) achieved a sustained virological response at 12 weeks post end of DAA treatment (SVR12), respectively. In the multivariable model, people with an endemic subtype had 93% (aOR 0.07 95%CI 0.04-0.12, P=<0.001) reduced odds of achieving SVR12. Treatment with sofosbuvir/velpatasvir or glecaprevir/pibrentasvir was successful for genotypes 1, 2, 4 and 5 (SVR12 100%, n=13) but not 3 (27.3%, n=22) endemic subtypes. Sofosbuvir/velpatasvir/voxilaprevir was successful for GT3 endemic subtypes at retreatment (SVR12 11/12, 91.7%). Treatment failures for genotypes 1, 3 and 4 were likely mediated by naturally occurring baseline NS5A RAS (median n=2).

DISCUSSION

This study provides further evidence that endemic HCV subtypes lead to sub-optimal DAA efficacy, which may impact global HCV elimination.

Genotyping and treatment issues with 'unusual' HCV 1 subtypes

Unusual non 1a/1b HCV 1 subtypes are mostly prevalent in Sub-Saharan Africa. These variants harbour resistance associated substitutions as natural polymorphisms in the NS5A region and are difficult to characterize and treat. We report the HCV genome sequences from two African subjects with unusual subtype 1 g and 1e treated with the pangenotypic regimen sofosbuvir/velpatasvir with failure in the latter. Sequence analysis of different regions of the HCV genome in a subtype 1 reference panel and use of multiple subtyping tools showed that the NS5A region is the most suitable to detect these unusual HCV subtypes and assist treatment choices.

Prevalence of Drug Resistance Associated Substitutions in Persons With Chronic Hepatitis C Infection and Virological Failure Following Initial or Re-treatment With Pan-genotypic Direct-Acting Antivirals: A Systematic Review and Meta-analysis

BACKGROUND

The advent of short-course, curative treatment with direct-acting antivirals (DAA) has given promise for the global elimination of hepatitis C virus (HCV) infections by 2030. Virological failure occurs in 2%-12% of persons receiving curative DAA treatment and may be presaged by pre-existing polymorphisms or result from selection of drug resistant variants during therapy.

METHODS

We conducted a systematic review to assess the prevalence of HCV resistance associated substitutions (RAS) among individuals with chronic hepatitis C infection who had virological failure following initial or re-treatment with pan-genotypic DAA regimens. We included 34 and 22 studies assessing RAS in people with virological failure published between January 2014 and July 2023. Pooled RAS prevalence was estimated using random-effects meta-analysis.

RESULTS

The pooled prevalence of RAS in people with virological failure following initial DAA treatment was 78.0% (95% confidence interval [CI]: 62.0-92.0) for sofosbuvir/velpatasvir, 81.0% (95% CI: 67.0-93.0) for sofosbuvir/daclatasvir, and 79.0% (95% CI: 70.0-87.0) for glecaprevir/pibrentasvir, with a high prevalence of resistance to the NS5A inhibitors. Among those with virological failure following re-treatment regimens, RAS were present in 93.0% (95% CI: 83.0-99.0) for sofosbuvir/velpatasvir/voxilepravir and in 100% (95% CI: 92.0-100) for glecaprevir/pibrentasvir, with resistance driven by RAS to NS5A inhibitors.

DISCUSSION

At least 1 RAS is present in a high proportion of the few individuals with virological failure following initial or re-treatment with pan-genotypic DAA regimens. There is a need for ongoing surveillance for DAA-associated resistance, to assess risk factors for their development and clinical impact to inform best practice strategies for re-treatment.

'Unusual' HCV genotype subtypes: origin, distribution, sensitivity to direct-acting antiviral drugs and behaviour on antiviral treatment and retreatment

The high genetic diversity of hepatitis C virus (HCV) has led to the emergence of eight genotypes and a large number of subtypes in limited geographical areas. Currently approved pangenotypic DAA regimens have been designed and developed to be effective against the most common subtypes (1a, 1b, 2a, 2b, 2c, 3a, 4a, 5a and 6a). However, large populations living in Africa and Asia, or who have migrated from these regions to industrialised countries, are infected with 'unusual', non-epidemic HCV subtypes, including some that are inherently resistant to currently available direct-acting antiviral (DAA) drugs due to the presence of natural polymorphisms at resistance-associated substitution positions. In this review article, we describe the origin and subsequent global spread of HCV genotypes and subtypes, the current global distribution of common and unusual HCV subtypes, the polymorphisms naturally present in the genome sequences of unusual HCV subtypes that may confer inherently reduced susceptibility to DAA drugs and the available data on the response of unusual HCV subtypes to first-line HCV therapy and retreatment. We conclude that the problem of unusual HCV subtypes that are inherently resistant to DAAs and its threat to the global efforts to eliminate viral hepatitis are largely underestimated and warrant vigorous action.

Feasibility, safety, efficacy and potential scaling-up of sofosbuvir-based HCV treatment in Central and West Africa: (TAC ANRS 12311 trial)

Access to Hepatis C treatment in Sub-Saharan Africa is a clinical, public health and ethical concern. The multi-country open-label trial TAC ANRS 12311 allowed assessing the feasibility, safety, efficacy of a specific care model of HCV treatment and retreatment in patients with hepatitis C in Sub Saharan Africa. Between November 2015 and March 2017, with follow-up until mid 2019, treatment-naïve patients with HCV without decompensated cirrhosis or liver cancer were recruited to receive 12 week-treatment with either sofosbuvir + ribavirin (HCV genotype 2) or sofosbuvir + ledipasvir (genotype 1 or 4) and retreatment with sofosbuvir + velpatasvir + voxilaprevir in case of virological failure. The primary outcome was sustained virological response at 12 weeks after end of treatment (SVR12). Secondary outcomes included treatment adherence, safety and SVR12 in patients who were retreated due to non-response to first-line treatment. The model of care relied on both viral load assessment and educational sessions to increase patient awareness, adherence and health literacy. The study recruited 120 participants, 36 HIV-co-infected, and 14 cirrhotic. Only one patient discontinued treatment because of return to home country. Neither death nor severe adverse event occurred. SVR12 was reached in 107 patients (89%): (90%) in genotype 1 or 2, and 88% in GT-4. All retreated patients (n = 13) reached SVR12. HCV treatment is highly acceptable, safe and effective under this model of care. Implementation research is now needed to scale up point-of-care HCV testing and SVR assessment, along with community involvement in patient education, to achieve HCV elimination in Sub-Saharan Africa.

Neuropsychiatric disorders in chronic hepatitis C patients after receiving interferon or direct-acting antivirals: a nationwide cohort study

Background: Data on the neuropsychological outcomes after receiving direct-acting antivirals (DAAs) among chronic hepatitis C (CHC) patients have not been well-documented. Aim: This study aimed to evaluate the difference in incidence of neuropsychological disorders (NPDs) after treatment completion between CHC patients receiving interferon (IFN) therapy and DAA therapy. Methods: A nationwide retrospective cohort study was performed using Taiwan's National Health Insurance Research Database (NHIRD) between 2010 and 2018. CHC patients without pre-existing mental disorders were included and divided into the treatment (Tx)-naïve DAA group, retreatment (re-Tx) DAA group, and Tx-naïve IFN group based on their HCV therapy. Propensity score matching was used to balance baseline differences between groups. The primary outcome was the incidence of NPDs during 6 months after completion of therapy. Results: After one-to-one matching, there were 6,461 pairs of patients selected from the Tx-naïve DAA group and Tx-naïve IFN group and 3,792 pairs from the re-Tx DAA group and Tx-naïve IFN group. A lower incidence of NPDs was observed in the Tx-naïve DAA group than in the Tx-naïve IFN group (HR = 0.72, 95% CI = 0.55-0.94, and p = 0.017). The risk of NPDs did not differ between the re-Tx DAA group and the Tx-naïve IFN group (HR = 0.74, 95% CI: 0.52-1.05, and p = 0.092). Conclusion: DAA therapy was associated with lower risk of NPDs when compared with IFN therapy among Tx-naïve CHC patients in a 6-month period after treatment completion, especially among the patients less than 65 years, male gender, and cirrhosis.

Hepatitis C: recent advances and practical management

Hepatitis B virus and hepatitis C virus (HCV) remain leading causes of disability and premature death worldwide. In May 2016, the UK, as a member of the World Health Assembly, adopted the Global Health Sector Strategy and its targets to eliminate viral hepatitis as a public health threat by 2030. In pursuit of this goal, there have been a number of recent advances in viral hepatitis care. Perhaps most notable is the availability of short courses of all-oral curative direct acting antivirals for hepatitis C. However, while access to treatment has been scaled up across the UK, an estimated 93 000 people were still living with HCV at the end of 2021 of which three-quarters remained unaware of their infection. This review article will summarise key advances in hepatitis C treatment and prevention and provide a practical approach to the management of individuals living with hepatitis C infection.

Hepatitis C subtyping assay failure in UK patients born in sub-Saharan Africa: Implications for global treatment and elimination

BACKGROUND AND AIMS: The newly developed direct-acting antivirals have revolutionized the treatment of chronic hepatitis C virus (HCV), with cure rates as high as 98% in some cohorts. Although genome sequencing has demonstrated that some subtypes of HCV naturally harbor drug resistance associated substitutions (RAS), these are often overlooked as "rarities." Furthermore, commercial subtyping assays and associated epidemiological findings are skewed towards Western cohorts and whole-genome sequencing can be problematic to deploy without significant infrastructure and training support. We thus aimed to develop a simple, robust and accurate HCV subtyping pipeline, to optimize and streamline molecular detection and sequence-based typing of diverse RAS-containing subtypes.

METHODS

HCV serum derived from 146 individuals, whose likely source of infection was from sub-Saharan Africa (SSA) was investigated with a novel panel of single round polymerase chain reaction (PCR) assays targeting NS5B and NS5A genomic regions. Virus subtype assignments were determined by pairwise-distance analysis and compared to both diagnostic laboratory assignments and free-to-use online typing tools.

RESULTS

Partial NS5A and NS5B sequences were respectively obtained from 131 to 135 HCV-positive patients born in 19 different countries from SSA but attending clinics in the UK. We determined that routine clinical diagnostic methods incorrectly subtyped 59.0% of samples, with a further 6.8% incorrectly genotyped. Of five commonly used online tools, Geno2Pheno performed most effectively in determining a subtype in agreement with pairwise distance analysis.

CONCLUSION

This study provides a simple low-cost pathway to accurately subtype in SSA, guide regional therapeutic choice and assist global surveillance and elimination initiatives.