studies

1310A AASLD ABSTRACTS HEPATOLOGY, October, 2015
HCV replication and the impact on the response to treatment of
HCV Materials and Methods: The replicon cells Huh7/Ava.5
(genotype 1b), Huh7/J6/JFH (genotype 2a) and Huh7.5/
Con1 (genotype 1b) were obtained and the mirVana let-7g
mimic/inhibitor, miR-122 inhibitor and miRNA mimic/inhibitor
negative control were purchased. The 1.0-kb and 0.5-
kb fragments of the let-7g promoter were amplified by PCR.
Site-directed mutagenesis of the AP-1 binding-site presented in
the let-7g promoter region was carried out. WST-1 assay and
Renilla Luciferase Assay were used. Expression levels of let-7g
in each sample were normalized to the corresponding level of
snU6B. Expression levels of let-7g were determined by using
the Quantitative real-time PCR. Anti-phospho-ERK, p38, JNK,
and total-ERK, p38, JNK antibodies, Anti-GAPDH and α-tubulin
antibodies were used for Immunoblot analysis. Results:
Our results demonstrated that overexpression of let-7g reduces
HCV expression in the cell line. The HCV loads were more
decreased by let-7g mimic than miR-122 inhibitor transfected
cell. High levels of lin28 correlate with low levels of let-7g
in HCV-infected cells and the knockdown of lin28 via siRNA
reduces HCV replication. The treatment with a let-7g mimic
alone was shown to induce IFN-induced genes inclusion MxA
and OAS1. Interferon (IFN)/RBV induces let-7g expression,
and let-7g and IFN/ribavirin also elicited an addictive inhibitory
effect on HCV expression. The anti-viral effects of let-7g
mediated IFN/RBV signaling and the regulation of let-7g by
IFN/RBV occurs through p38/AP1 signaling. Conclusions: We
have indicated an important role of let-7g on the replication of
HCV and on the response of HCV to anti-HCV treatment. The
IFN/ribavirin induces let-7g expression through p38/AP-1 signaling
and the let-7g and IFN/RBV have additively inhibitory
effect on HCV replication. The let-7g may serve as a potential
target for HCV therapy.
Disclosures:
Wan-Long Chuang - Advisory Committees or Review Panels: Gilead, Abbvie;
Speaking and Teaching: BMS, Roche, MSD
Ming-Lung Yu - Advisory Committees or Review Panels: ABBOTT, MSD, ABBVIE,
GILEAD, J&J, ROCHE, BMS; Grant/Research Support: ABBOTT, ROCHE, MSD,
ABBVIE, GILEAD; Speaking and Teaching: ABBOTT, ROCHE, MSD, GILEAD,
BMS, GSK
The following authors have nothing to disclose: Chia-Yen Dai, Wen-Wen Chou,
Yi-Shan Tsai, Shu-Chi Wang, Chung-Feng Huang, Ming-Lun Yeh, Jee-Fu Huang
2265
Drug-Drug Interaction Studies between HCV Antivirals
Sofosbuvir and GS-5816 and HIV Antiretrovirals
Erik Mogalian 1 , Luisa M. Stamm 2 , Anu Osinusi 2 , Gong Shen 4 ,
Karim Sajwani 3 , John McNally 2 , Anita Mathias 1 ; 1 Clinical Pharmacology,
Gilead Sciences, Inc., Foster City, CA; 2 Clinical Research,
Gilead Sciences, Inc., Foster City, CA; 3 Clinical Operations, Gilead
Sciences, Inc., Foster City, CA; 4 Biostatistics, Gilead Sciences,
Inc., Foster City, CA
Introduction A once-daily fixed-dose combination tablet composed
of sofosbuvir (SOF; nucleotide analog NS5B inhibitor)
and GS-5816 (pangenotypic NS5A inhibitor) is in clinical
development for the treatment of chronic HCV infection. Phase
1 studies were conducted in healthy volunteers to evaluate
potential drug-drug interactions (DDIs) between SOF/GS-5816
and HIV antiretroviral (ARV) regimens without a pharmacokinetic
“booster” (ritonavir or cobicistat) to support their use
together in HIV/HCV co-infected patients. Methods These were
multiple-dose, randomized, cross-over DDI studies. Subjects
received SOF/GS-5816 and ARVs (EFV/FTC/TDF [Atripla ® ;
ATR], FTC/RPV/TDF [Complera ® ; CPA], DTG [Tivicay ® ], and
RAL [Isentress®] + FTC/TDF [Truvada®]) alone and in combination.
Steady-state plasma concentrations of SOF, its predominant
circulating nucleoside metabolite GS-331007, GS-5816,
and ARVs were analyzed on the last day of dosing for each
treatment and PK parameters were calculated. Geometric leastsquares
means ratios and 90% confidence intervals (combination
vs. alone) for SOF, GS-331007, GS-5816, and ARV
AUC tau
, C max
and C tau
were estimated and compared against
pre-specified lack of PK alteration boundaries of 70-143% for
all analytes except RAL (50-200%). Safety assessments were
conducted throughout the study. Results Twenty-nine of 30 subjects
in Group 1 and all subjects in Groups 2-4 (N=78 total)
completed the study. The majority of adverse events (AEs) were
Grade 1 and there were no serious AEs. The most frequent AEs
were headache (12%) and constipation (10%). One subject in
Group 1 discontinued due to an AE (Grade 1 urticaria). SOF/
GS-5816 PK was unaffected by RPV, DTG, and RAL regimens.
A decrease (~53%) in GS-5816 exposure with no impact on
overall SOF or GS-331007 exposure was observed following
administration with ATR. No clinically significant changes
in the PK of DTG, EFV, FTC, RAL, and RPV were observed
when administered with SOF/GS-5816. Increased TFV exposure
(ATR: ~1.8-2.2-fold; CPA: ~1.4-1.8-fold; FTC/TDF+RAL:
~1.4-1.7-fold) was observed with SOF/GS-5816; overall,
absolute TFV AUC in the test (combination) treatments were
similar to those achieved when FTC/TDF is administered with
ritonavir-boosted PIs, which do not warrant dose adjustment.
Conclusion Study treatments were generally well tolerated.
Results from this study demonstrate that SOF/GS-5816 may be
administered safely with CPA, RAL and DTG with a backbone
of FTC/TDF. Additional data from SOF/GS-5816 Phase 3 PK/
PD will guide the recommendation for use with ATR.
Disclosures:
Erik Mogalian - Employment: Gilead Sciences, Inc; Stock Shareholder: Gilead
Sciences, Inc
Luisa M. Stamm - Employment: Gilead Sciences
Anu Osinusi - Employment: Gilead Sciences
Karim Sajwani - Employment: Gilead Sciences, Inc.
John McNally - Employment: Gilead Sciences, Inc; Stock Shareholder: Gilead
Sciences, Inc
Anita Mathias - Employment: Gilead Sciences Inc.,
The following authors have nothing to disclose: Gong Shen
2266
Discovery of AT-337 and AT-339, Two Highly Potent
and Selective Nucleotide Prodrug Inhibitors of HCV
Polymerase
Steven S. Good 1 , Adel Moussa 1 , Jean-Christophe Meillon 2 , Jean-
Pierre Sommadossi 1 ; 1 Atea Pharmaceuticals Inc., Boston, MA;
2 Oxeltis, Montpellier, France
Background: Nucleotide analogs are preferred candidates for
treatment of HCV infection since they are potent, pan-genotypic
inhibitors of NS5B polymerase with a high barrier to
drug resistance. Here we report novel nucleotide prodrugs with
both base and sugar modifications that are selective for and
highly active against in vitro HCV replication. Methods: Novel
nucleotide prodrugs were synthesized and tested in Huh-7 cells
bearing an HCV genotype 1b replicon and evaluated for activity
against other viruses. Selectivity was assessed in 14-day
exposure with human BFU-E and CFU-GM cells and in 3-day
exposure with human iPS cell-derived cardiomyocytes. Selected
nucleoside-5’-triphosphate analogs were evaluated against the
NS5B polymerase and human DNA polymerases α, β and
γ. Results: The two most potent nucleotide prodrugs, AT-337
and AT-339, inhibited HCV replication, with EC 50
values as
low as 0.005 mM. Intra-assay comparisons demonstrated that
AT-337 and AT-339 were at least 10-fold more potent than