Richard Njouom Chef du Service de Virologie Centre Pasteur du Cameroun ANRS

Transcription

1 Projet Validation d un test moléculaire automatisé de faible coût pour le suivi de l infection par le virus de l hépatite B en Afrique et en Asie du Sud-Est Richard Njouom Chef du Service de Virologie Centre Pasteur du Cameroun

2 Principal Objectifs de l étude Valider un test moléculaire pour la quantification de l ADN VHB sur des échantillons sanguins provenant de sujets vivant en Afrique de l Ouest et Centrale, en Asie du Sud-Est et en France. Spécifiques Evaluer un test générique de quantification de l ADN VHB par PCR utilisant une plateforme d'extraction/amplification ouverte par comparaison avec les méthodes commerciales de référence (Roche ou Abbott). Analyser les performances du test moléculaire générique en fonction des génotypes VHB (A, B, C, D, E) circulants en Afrique de l Ouest, en Afrique Centrale, en Asie du Sud Est et en France. 2

3 Etat d avancement Obtention des autorisations éthiques et administratives dans les différents pays participants Signature de convention pour virement des fonds Début effectif prévu courant

4 Projet Évaluation de la performance de l antigène core du VHC comme marqueur diagnostique et de suivi sous traitement par antiviraux directs de l hépatite C chronique en Afrique Sub-saharienne : un nouvel outil de Point Of Care Richard Njouom Chef du Service de Virologie Centre Pasteur du Cameroun

5 Continuum of biological follow-up in chronic hepatitis C 5

6 Continuum of biological follow-up in chronic hepatitis C Challenge: change from a multi-step procedure to a two-step procedure 3

7 Techniques in development Point of care (POC) platform for HCV-RNA assays HCV RNA quantitative assay - Alere Q (Alere Inc.) - EOSCAPE-HCV rapid RNA assay (Wave 80 Biosciences) - Truelab Uno real time Micro PCR system (Molbio Diagnostics Pvt Ltd) - GeneXpert (Cepheid) - RT CPA HCV Viral Load Test (Ustar Biotechnologies) HCV RNA qualitative assays - Gendrive (Epistem) - PanNAT (Micronics Inc.) Source: UNITAID report April

8 Techniques in development HCV antigen core (AgC) quantification - To date, only one marketed test: Abbott ARCHITECT platform - One POC platform in development: DAKTARI 8

9 12336 Study: Assessment of the performance of the HCV core antigen as a diagnostic tool for chronic hepatitis C in Africa Richard Njouom Centre Pasteur du Cameroun Léa Duchesne, Karine Lacombe Inserm Unit UMR-S 1136, Team 2 Pierre Louis Institute of Epidemiology and Public Health 9

10 Objectives Principal objective: Assessment of the performance of HCV core antigen quantification as a diagnostic tool for chronic hepatitis C in Africa Secondary objectives: To assess the impact of the following covariables on the AgC diagnostic performance: Demographic variables (age, gender) HCV genotype HIV infection HBV infection 10

11 Methods AgC quantification: Abbott ARCHITECT HCV Ag Assay - < 3 fmol/l : negative - 10 fmol/l: positive - 3 [AgC] < 10 fmol/l: «grey zone» retested twice HCV RNA quantification by quantitative rt-pcr : gold standard Anti-HCV Ab Anti-HHs Ab ELISA serologies Ag HBs 11

12 Population 1037 serum samples from the Pasteur Center of Cameroon in Yaounde Inclusion criteria HCV+: - HCV antibody (HCV Ab) positive serology - Quantifiable HCV RNA HCV-: - HCV Ab negative serology - OR undetectable HCV RNA HIV status known HBV status known Exclusion criteria 11 Tri-infection (HCV/HIV/HBV) 7 Infection status unknown 10 Retest unavailable Included samples: n= HCV- 544 HCV+ 12

13 Socio-demographic and virologic caracteristics of the sera 13

14 Ag core HCV (fmol/l) Ag core HCV (fmol/l) Ag core HCV (fmol/l) Results: correlation between AgC and HCV RNA, by infection group Correlation between AgC quantification and HCV RNA in HCV mono-infected Correlation between AgC quantification and HCV RNA in HIV-HCV co-infected sera Correlation between AgC quantification and HCV RNA in HBV-HCV co-infected sera spearman r=0,75 (p<0,00001) n=489 spearman r=0,84 (p<0,00001) n=27 Spearman r=0,58 (p<0,001)) n= e e e e+07 HCV RNA (IU/mL) 0 5.0e e e e+07 HCV RNA (IU/mL) 0 5.0e e e e+07 HCV RNA (IU/mL) 14

15 Sensitivity Results: AgC overall performance ROC curves of the performance of AgC quantification for the diagnostic of chronic hepatitis C in HCV mono-infected and HCV uninfected, HIV-infected and HBV-infected patients p= Specificity Mono-HCV ROC area:0.99 [0.98;1.0] HIV-HVC ROC area:0.99 [0.97;1.0] HBV-HCV ROC area:0.98 [0.95;1.0] Reference 15

16 Results: AgC overall performance Performance of the AgC quantification by infection group n Se [CI97.5%] Spe [CI97.5%] VPP* VPN* AUC [CI95%] LR+ LR- Mono [93.2 ; 97.5] 99.7 [98.1 ; 100] [ ] HIV [85.0 ; 100] 88.2 [74.3 ; 96.2] [ ] HBV [79.2 ; 99.9] 96.2 [88.1 ; 99.4] [ ] Performance of the AgC quantification by genotype among the mono-infected and not infected sera group n Se [CI 97.5%] Spe [CI 97.5%] VPP* VPN* AUC [CI95%] LR+ LR- Genotype [ ] 99.7[ ] [ ] Genotype [ ] 99.7 [ ] [ ] 318 0,051 Genotype [ ] 99.7 [ ] [ ] *Estimated HCV prevalence in Cameroon: 13,8% 16

17 Conclusion High performance No influence of genotype No influence of HBV and HIV infection on the overall performance Lower specificity in HIV-infected patients Reliable diagnostic tool Limits: not a study in real world setting => feasibility? Perspective: assessment of the performance of AgC quantification as a monitoring tool of HCV antiviral therapy =>2 nd part of the study 17

18 Perspective: Which role for AgC in hepatitis C diagnosis and screening? Unique diagnosis test or confirmatory test? Test available only on a specific Abbott platform Need for a POC test Alternative solution: use of DBS technique + laboratory test => BUT lower AgC quantification performance 1 Need for screening strategy evaluation 1 Chevaliez, J Infect Dis.,

19 Thank you for your attention 19