Is resistance to direct-acting antivirals in sub-Saharan Africa a threat to HCV elimination? Recommendations for action

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.

Hepatitis C treatment program in Maputo, Mozambique, the challenge of genotypes and key populations: A 5-year retrospective analysis of routine programmatic data

Background and Aims

Hepatitis C (HCV) programs face challenges, especially linked to key populations to achieve World Health Organization (WHO) goals of eliminating hepatitis. Médecins Sans Frontières and Mozambique's Ministry of Health first implemented HCV treatment in Maputo, in 2016 and harm reduction activities in 2017.

Methods

We retrospectively analyzed routine data of patients enrolled between December 2016 and July 2021. Genotyping was systematically requested up to 2018 and subsequently in cases of treatment failure. Sustainable virological response was assessed 12 weeks after the end of treatment by sofosbuvir-daclatasvir or sofosbuvir-velpatasvir.

Results

Two hundred and two patients were enrolled, with 159 (78.71%) males (median age: 41 years [interquartile range (IQR): 37.10, 47.00]). Risk factors included drug use (142/202; 70.29%). One hundred and eleven genotyping results indicated genotype 1 predominant (87/111; 78.37%). Sixteen patients presented genotype 4, with various subtypes. The people who used drugs and HIV coinfected patients were found more likely to present a genotype 1. Intention-to-treat analysis showed 68.99% (89/129) cure rate among the patients initiated and per-protocol analysis, 88.12% (89/101) cure rate. Nineteen patients received treatment integrated with opioid substitution therapy, with a 100% cure rate versus 59.37% (38/64) for initiated ones without substitution therapy (p < 0.001). Among the resistance testing performed, NS5A resistance-associated substitutions were found in seven patients among the nine tested patients and NS5B ones in one patient.

Conclusion

We found varied genotypes, including some identified as difficult-to-treat subtypes. People who used drugs were more likely to present genotype 1. In addition, opioid substitution therapy was key for these patients to achieve cure. Access to second-generation direct-acting antivirals (DAAs) and integration of HCV care with harm reduction are crucial to program effectiveness.

HCV Diagnosis and Sequencing Using Dried Blood Spots from Patients in Kinshasa (DRC): A Tool to Achieve WHO 2030 Targets

The World Health Organization has established an elimination plan for hepatitis C virus (HCV) by 2030. In Sub-Saharan Africa (SSA) access to diagnostic tools is limited, and a number of genotype 4 subtypes have been shown to be resistant to some direct-acting antivirals (DAAs). This study aims to analyze diagnostic assays for HCV based on dried blood spots (DBS) specimens collected in Kinshasa and to characterize genetic diversity of the virus within a group of mainly HIV positive patients. HCV antibody detection was performed on 107 DBS samples with Vidas® anti-HCV and Elecsys anti-HCV II, and on 31 samples with INNO-LIA HCV. Twenty-six samples were subjected to molecular detection. NS3, NS5A, and NS5B regions from 11 HCV viremic patients were sequenced. HCV seroprevalence was 12.2% (72% with detectable HCV RNA). Both Elecsys Anti-HCV and INNO-LIA HCV were highly sensitive and specific, whereas Vidas® anti-HCV lacked full sensitivity and specificity when DBS sample was used. NS5B/NS5A/NS3 sequencing revealed exclusively GT4 isolates (50% subtype 4r, 30% 4c and 20% 4k). All 4r strains harbored NS5A resistance-associated substitutions (RAS) at positions 28, 30, and 31, but no NS3 RAS was detected. Elecsys Anti-HCV and INNO-LIA HCV are reliable methods to detect HCV antibodies using DBS. HCV subtype 4r was the most prevalent among our patients. RASs found in subtype 4r in NS5A region confer unknown susceptibility to DAA.

Simplification of Care for Chronic Hepatitis C Virus Infection

In 2016, the World Health Organization (WHO) set a target for eliminating viral hepatitis as a major public health threat by 2030. However, while today's highly effective and well-tolerated pangenotypic direct-acting antiviral regimens have maximized simplification of hepatitis C virus (HCV) treatment, there remain a plethora of barriers to HCV screening, diagnosis, and linkage to care. As of 2017, only 19% of the estimated 71 million individuals living with chronic HCV worldwide were diagnosed and in 2015 to 2016, only 21% of diagnosed individuals had accessed treatment. Simplification and decentralization of the HCV care cascade would bolster patient engagement and support the considerable scale-up needed to achieve WHO targets. Recent developments in HCV screening and diagnosis, together with reduced pretreatment assessment and on-treatment monitoring requirements, can further streamline the care continuum, ensuring patients are linked to care quickly and earlier in the disease course, and minimize clinic visits.