Hepatitis C reinfection following successful direct-acting antiviral therapy among patients attending a multidisciplinary treatment centre for people who use drugs in Zurich, Switzerland

Personalized care approaches to hepatitis C therapy: recent advances and future directions

INTRODUCTION

The introduction of direct-acting antivirals (DAAs) has significantly transformed the therapeutic landscape for chronic C hepatitis virus (HCV) infection. However, there is still room for further improvement in optimizing therapy efficacy and minimizing adverse effects.

AREAS COVERED

This review is devoted to the rationale for adopting a personalized approach to HCV therapy. Specifically, we explore the role of host-related factors, such as sex or the presence of comorbidities. We thoroughly examine the implications of commonly encountered comorbidities, including HIV infection, chronic renal disease, liver cirrhosis, and other chronic viral hepatitis infections. Additionally, we discuss the prevalent drug-to-drug interactions between DAAs and other medications, while providing guidance on their management. Finally, we investigate viral-related issues that can influence treatment outcomes, such as viral genotype, quasi-species, and the presence of resistance-associated mutations.

EXPERT OPINION

Despite pivotal trials demonstrating efficacy rates exceeding 90% for currently available DAA regimens, there are still opportunities to optimize therapy outcomes and tailor treatment to each patient. This can be achieved through a meticulous evaluation of the patient's specific clinical conditions and comorbidities, a vigilant approach to manage potential drug interactions, and diligent patient follow-up.

The rate of hepatitis C reinfection in Canadians coinfected with HIV and its implications for national elimination

BACKGROUND

The World Health Organisation (WHO) has set targets for the rate of new infections as a way to measure progress towards the elimination of hepatitis C virus (HCV) as a public health threat. As more people are successfully treated for HCV, a higher proportion of new infections will be reinfections. We consider whether the reinfection rate has changed since the interferon era and what we can infer about national elimination efforts from the current reinfection rate.

METHODS

The Canadian Coinfection Cohort is representative of HIV HCV coinfected people in clinical care. We selected cohort participants successfully treated for a primary HCV infection either in the interferon era or in the era of direct acting antivirals (DAAs). Selected participants were followed from 12 weeks after completing a successful treatment until the end of 2019 or until their last measured HCV RNA. We estimated the reinfection rate in each treatment era, overall and in participant subgroups, using proportional hazard models appropriate for interval censored data.

RESULTS

Among 814 successfully treated participants with additional HCV RNA measurements, there were 62 reinfections. The overall reinfection rate was 2.6 (95% confidence interval, CI, 1.2-4.1) /100 person years (PY) in the interferon era and 3.4 (95% CI 2.5-4.4) /100 PY in the DAA era. The rate in those reporting injection drug use (IDU) was much higher: 4.7 (95% CI 1.4-7.9) /100 PY and 7.6 (95% CI 5.3-10) /100 PY in the interferon and DAA eras respectively.

CONCLUSION

The overall reinfection rate in our cohort is now above the WHO target set for new infections in people who inject drugs. The reinfection rate in those reporting IDU has increased since the interferon era. This suggests Canada is not on track to achieve HCV elimination by 2030.

HCV elimination in a Swiss opioid agonist therapy programme - a cohort study

BACKGROUND

In opioid agonist therapy (OAT) programmes, chronic hepatitis C is highly prevalent and directly observed therapy guarantees optimal adherence. Since 2017, all patients with chronic hepatitis C in Switzerland can be treated with pangenotypic direct-acting antivirals irrespective of liver fibrosis stage. Until the end of 2021, however, prescription was restricted to infectious disease specialists, gastroenterologists and certain addiction specialists. Difficult venous access after long-term intravenous drug use and, in the case of referral to a specialist, difficulties keeping appointments are barriers to HCV diagnosis and treatment.

AIMS

To assess whether minimally invasive point-of-care tests and a "test-and-treat / vaccinate on-site" approach can improve human immunodeficiency virus (HIV) / hepatitis C virus (HCV) screening, HCV treatment uptake and immunity against hepatitis A/B.

METHODS

Since September 2018, an infectious disease specialist and a study nurse performed 4-weekly visits in the OAT programme "HAG" (heroin dispensation of the canton Aargau), offering HIV/HCV antibody rapid testing (20 min) and HCV RNA quantification (GeneXpert®, 60 min) from capillary blood, noninvasive liver fibrosis assessment (Fibroscan®, 5-10 min) and HCV treatment prescription on-site. Recommended venous blood draws for HAV/HBV serology and HAV/HBV vaccinations were performed by the staff of the "HAG". Project performance was assessed by annual cross-sectional chart review.

RESULTS

Of the 128 patients registered in April 2018, 79 (62%) were still present in May 2021. With 72 newly registered, a total of 200 patients could be assessed, of whom 129 (65%) were still present in May 2021. Between April 2018 and May 2021, the proportion ever tested for HIV antibodies increased from 79% (101/128) to 91% (117/129), the proportion ever tested for HCV antibodies from 83% (106/128) to 93% (120/129) and the proportion of those HCV antibody positive ever tested for HCV RNA tested from 89% (47/53) to 98% (56/57). The proportion with adequate HCV management (last HCV antibody test ≤1 year ago, if HCV antibody negative or last HCV RNA test ≤1 year ago, if HCV antibody-positive and RNA-negative) improved from 23% ([15 + 15]/128) to 80% ([55 + 48]/129). Overall, HCV treatment uptake increased from 60% (21/35) to 92% (55/60) and HCV RNA prevalence among the HCV antibody positives decreased from 38% (18/47) to 7% (6/84). Between 2018 and 2021, 19 non-cirrhotic chronic hepatitis C patients were successfully treated on-site (18 sustained virological responses [SVR] 12, 1 SVR4), with excellent adherence (≥93%) and, so far, no reinfection. The proportion with known HAV/HBV serostatus increased from 38%/51% to 64%/76%. Immunity against HAV/HBV improved from 19%/23% to 50%/57%.

CONCLUSION

Capillary blood point-of-care tests and a "test-and-treat / vaccinate on-site" approach remove crucial barriers to diagnosis and treatment, making hepatitis elimination in OAT programmes achievable. A high fluctuation rate requires HIV/HCV/HAV/HBV testing at admission, but also allows more patients to be screened.