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Future treatment of HCV with Host Targeting Antivirals. Francesco Negro University Hospitals, Geneva, Switzerland. Host-Targeting Antivirals (HTA) vs. Direct Acting Antivirals (DAA). PRO’s. CON’s. Risk of toxicity due to interference with cellular functions.
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Future treatment of HCVwith Host Targeting Antivirals Francesco Negro University Hospitals, Geneva, Switzerland
Host-Targeting Antivirals (HTA)vs. Direct Acting Antivirals (DAA) PRO’s CON’s • Risk of toxicity due to interference with cellular functions • Less or no risk of selecting drug resistance • Pan-genotypic activity
Host factors as target for anti-HCV therapy Adapted from VON HAHN et al, 2011; HERKER et al, 2010; SAINZ et al, 2012 TROTARD et al, 2009; LUPBERGER et al, 2011
Alisporivir (DEBIO-025), a cyclophilin inhibitor without immunosuppressive effects DEBIO-025 CsA Cyclophilin binding domain Calcineurin binding domain
Alisporivir binds to cyclophilin but not to calcineurin Alisporivir-Cyp complexdoes NOT bind to CN leaving immune response intact CyP Cyclosporin A-cyclophilin complex binds calcineurin CyP alisporivir CsA CN CN CN NF-ATc dephosphorylation is blocked P P Activation of immune response NF-ATc NF-ATc NF-ATc
CYCLOPHILINS ARE CHAPERONES PENG et al, 2005; RYFFEL et al, 1991; COLGAN, et al. 2004 • Cyclophilins have diverse cellular functions • Ubiquitous proteins • Expressed in various tissues(liver, muscle, CNS) • >7 subtypes reported in humans • Detected in cytosol, nucleus, ER, mitochondria (depending on subtype) • Peptidyl prolyl isomerase (PPIase) activity • Catalyzes isomerization of peptidic bonds from trans to cis to facilitate the de novo protein unfolding • HCV exploits the PPIase activity ofCypA for its own replication
Cyclophilin A (CyPA) is the main cyclophilin involved in HCV replication Yang F, et al. J Virol 2008;82:5269–5278; Chatterji U, et al. J Biol Chem 2009;284:16998–17005 Kaul A, et al. PLoS Pathog 2009;5:e1000546
Additional effects of cyclophilin inhibition in HCV infection • Restoration of mitochondrial function QUARATO et al, Hepatology 2011 • Reduction of autophagy, thus limiting the inhibitory effect of autophagy on innate immune response CARREIRA et al, Autophagy 2010
Alisporivir FLISIAK et al, Hepatology 2009; FERNANDEZ et al. Hepatology 2007; GOTTO et al, Cancer Sci 2009 CRABBE et al Expert Opin Investig Drugs 2009; WIEDERMANN et al, Antimicrob Agents Chemother 2010 FLISIAK et al, EASL 2011; CHATTERJI et al, J Hepatol 2010; COLMONT et al, PLoS One 2010 Pan-genotype antiviral activity • As a monotherapy or added to SOC, G1-4 High resistance barrier • Mutations associated with resistance to Cyp inhibitors can be selected in vitro within NS5A (a substrate of PPIase activity of CypA) but appear very slowly (28 passages, 4-6 months) • The D320E (domain III of NS5A) mutation is associated with resistance to alisporivir (cross-resistance to CsA and alisporivir) but is not sufficient to lead to breakthrough in patients • Resistance is low-level (<5-fold) and involves reduced binding to CyPA
Alisporivir monotherapy or in combination with SOC[4 weeks, treatment-naive, HCV genotypes 1 and 4] FLISIAK et al, Hepatology 2009;49:1460–1468
Alisporivir monotherapy or in combination with SOC[4 weeks, treatment-naive, HCV genotypes 2 and 3] FLISIAK et al, Hepatology 2009;49:1460–1468
The ESSENTIAL Study (205 Study)Multicenter (EU), 48 weeks, treatment-naive, HCV-1, phase IIb RCTITT population (n=288) PEG-IFN-a/RBV (n=73) Placebo + PEG-IFN-a /RBV 48 weeks FU 600 mg BID first week then 600mg QD Alisporivir48 (n=72) Alisporivir + PEG-IFN-a /RBV 48 weeks FU RVR Alisporivir-RGT (n=71) Alisporivir + PEG-IFN-a /RBV 24-48 weeks FU non-RVR Alisporivir24 (n=72) Alisporivir + PEG-IFN-a /RBV 24 weeks FU 0 24 48 72 FLISIAK et al, EASL 2011
The ESSENTIAL Study – SVRITT population (n=288) P=0.008 39/73 49/71 34/72 54/72 FLISIAK et al, EASL 2011
Alisporivir + PEG-IFN-a/RBV is superior to PEG-IFN-a/RBV: RVR was ~3-fold higher in all alisporivir-containing arms SVR increased from 55% to 76% in the 48-week triple regimen Improvement of SVR was independent of IL28B genotype Triple regimen was well tolerated (transient, reversible hyperbilirubinemia in ~1/3 of patients, without cholestasis or hepatotoxicity) The ESSENTIAL Study (205 Study)ITT population (n=288) FLISIAK et al, EASL 2011
Alisporivir disposal and risk of DDIs DEB025 is mainly metabolised through cytochrome P450 3A4 DEB025 is an inhibitor of P-gp, BSEP, MRP2 (leading to hyperbilirubinemia), NTCP, OATP1B1 and OATP1B3
miRNA-122 is essential to HCV replication Miravirsen (Santaris) is a small LNA modified phosphorothioate anti-sense oligonucleotide targeting (and blocking) miR-122 JOPLIN et al, Science 2005; JANSSEN et al, AASLD 2011
Preclinical and phase 1 data on Miravirsen • Miravirsen inhibits HCV in vitro (EC50 0.67 mm) • No resistance-conferring mutations in the miR-122 seed regions (conserved among HCV genotypes) • In healthy volunteers, safe and well tolerated, with no dose limiting toxicity LANFORD et al, Science 2010; ELMEN et al, Nature 2008
Proof-of-concept study of Miravirsen (oligonucleotide targeting miR-122) in treatment-naïve HCV-1 JANSSEN et al, AASLD 2011
Mean HCV RNA Log changes during Miravirsen Prolonged dose-dependent antiviral activity well beyond the end of therapy, consistent with 30 day terminal half-life No evidence of drug resistance JANSSEN et al, AASLD 2011