Clinical, immunological and virological aspects of short duration treatment for chronic hepatitis C

Lone Wulff Madsen

Research output: ThesisPh.D. thesis

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The introduction of direct-acting antivirals (DAA) has led to a paradigm shift in the treatment for chronichepatitis C with cure rates above 95% after 8-12 weeks treatment with DAA. The high cure rate has led tothe speculation if treatment duration could be shorten.The World Health Organization (WHO) has highlighted that defining the target population for reducedtreatment duration as an important area for further research. Certain clinical factors have previously beendefined as predictors for achieving sustained virological response at week 12 (SVR12) and increasing evidencehave showed that the immune response also plays an important role in determine the response to DAAtherapy. Knowledge about the host immunity role during short-term treatment is still limited. A majorconcern in relation to short-term treatment is the development of treatment-related resistance-associatedsubstitutions (RAS) and their possible impact of retreatment.If a well-defined patient group could be treated with DAA and still achieve cure rates above 90%, highertreatment coverage could be reached within the same health budget. This achievement would be animportant improvement in the effort to achieve the 2030 elimination targets and reduce the overallmorbidity and mortality caused by hepatitis C virus (HCV).

Aims and methods
All studies in this PhD are based on the 4RIBC study. The 4RIBC study was an investigator initiated, randomized, open label clinical trial and was designed in two phases. The overall aim was to investigate clinical, virological and immunological parameters in four weeks treatment with glecaprevir/pibrentasvir (GLE/PIB) with or without ribavirin. The first phase (study I), a pilot phase, aimed to include 40 patients and the second larger phase (study II) aimed to include 195 patients. Blood samples were taken at each study visit in the pilot phase and these samples were used in study III+IV. Patients included in the trial were treatment naive patients age 18-49 with chronic hepatitis C and absence of liver fibrosis (liver stiffness measurement 8<kPa). 

Study I aimed to investigate if four weeks treatment with (GLE/PIB) without ribavirin would be feasible.Furthermore we investigated RAS at baseline and for patients with treatment failure at the time of virologicalrelapse and determined the outcome of 12 weeks retreatment.

Study II aimed to compare the percentage of subjects achieving SVR12 after four weeks treatment withGLE/PIB + ribavirin compared to eight weeks of treatment with GLE/PIB for patients with recent drug use.Furthermore we estimated predictors to achieve cure after ultra-short treatment for hepatitis C includingpatients treated with GLE/PIB + ribavirin for four weeks in the pilot phase. 

The objective for Study III was to analyze whether distinct soluble inflammatory mediators differ betweenpatients who achieve SVR12 with patients with treatment failure after four weeks treatment. Solubleinflammatory mediators (SIMs) were measured at baseline and by end of treatment. A pre-defined panelsimultaneously measuring 92 inflammation- related proteins in plasma was used. 

Study IV investigated simplified immune subsets with antiviral potential in patients who received four weekstreatment. Blood samples by baseline and by end of treatment were processed for flow cytometry analysisin order to measure the expression of the inhibitory receptors PD-1, 2B4, BY55, CTLA-4, TIM-3 and LAG-3 on12 distinct T cell subsets. 

We included 32 patients in the pilot phase of the 4RIBC study. SVR12 after four weeks treatment was 59%(10/17) for GLE/PIB and 73% (11/15) for GLE/PIB + ribavirin. Baseline RASs were detected for 23% (5/21) ofpatients with SVR12 and 54.5% (6/11) of patients with virological relapse. Development of RAS did occur butdid not impede retreatment with 12 weeks sofosbuvir containing regimens and all retreated patients (n=10)achieved SVR12.We started inclusion for the second phase of the 4RIBC study in marts 2019. Recruitment to the study wasinitially hampered by the inclusion criteria of intravenous drug use during the last year which was added afterthe pilot phase. An amendment change this in January 2020. The consequences of the COVID-19 pandemicaffected the study and we were forced to close the study prematurely. Overall 24 patients were included tothe study of which 21 started treatment. In the modified intention to treat group 100 % (7/7) achieved cureafter eight weeks and for patients treated for four weeks the SVR12 was 58.3% (7/12). By including the datafrom the pilot phase the total SVR12 was 66.7% (18/27) for patients who were treated with GLE/PIB +ribavirin for four weeks.In the analysis for predictors to achieve cure after ultra-short treatment we found that low baseline viral load(p=0.0045) and genotype 3 (p=0.042) were significant predictors for achieving cure. Virological relapse werenot observed in patients with baseline viral load < 1,000,000 IU/ml and among patients with a baseline viralload < 2,000,000 IU/ml, 93.3% (14/15) of the patients achieved SVR12. 
Study IIIshowed that after four weeks of therapy eight markers (MMP-10, CCL20, CXCL11, FGF-23, TNF, MCP2, IL-18R1 and CXCL10) were identified that could distinguish patients with SVR12 from the patients withvirological relapse. Pretreatment SIM profiles did not differ between the group who achieved SVR12 andvirological relapse. However, study IV identified a measurable immunological phenotype for SVR12 patientscompared to non SVR12 patients at baseline. In general SVR12 patients had lower frequency of theexpression of the six measured inhibitory receptor and furthermore we observed a significant positivecorrelation between baseline viral load and the expression of PD-1 on the total CD8+cells and effectormemory T-cells CD4+ and CD8+for patients with virological relapse. 

The 4RIBC study is one of the largest four week treatment trials investigating second-generationpangenotypic DAA without a sofosbuvir containing regimen. We found that a majority of patients withfavorable baseline characteristics can be treated with shorter treatment duration than is currentlyrecommended by international guidelines. However the cure rate is still disappointing in the DAA era. Ourresults suggest that baseline viral load is an important factor in the effort to shorten treatment duration andbaseline RAS can probably be important for the outcome of ultra-short treatment for chronic hepatitis C.Nonetheless, testing for baseline RAS will not be a realistic option in a clinical setting. Instead it is importantto highlight that even though that RAS development do occur during short treatment this does not impederetreatment. This is also an important issue in treatment of vulnerable patient groups were treatment maybe interrupted early. The 4RIBC study showed that distinct inflammatory proteins can distinguish patientswho achieve cure after four weeks treatment. This supports the theory that a certain immune activation isneeded to obtain SVR12 with short treatment. This is also supported by that patients who achieved SVR12had an overall lower expression of inhibitory receptors and could indicate that these patients had a lessexhausted phenotype at baseline compared to the relapse group. Furthermore, PD-1 correlated to viral loadshowed that the amount of antigen is associated with increased expression of PD-1 on distinct type of T-cells.Future studies have to clarify whether this could be a useful predictive biomarker for shortening treatment. 
Original languageEnglish
Awarding Institution
  • University of Southern Denmark
  • Christensen, Peer Brehm, Principal supervisor
  • Øvrehus, Anne Lindebo Holm, Supervisor
  • Gerstoft, Jan, Supervisor, External person
  • Lillevang, Søren Thue, Supervisor
Date of defence30. Sep 2022
Publication statusPublished - 16. Sep 2022

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