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The discovery of a pan-genotypic hepatitis C virus (HCV) NS3/4A protease inhibitor based on a P1–P3 macrocyclic tripeptide motif is described. The all-carbon tether linking the P1–P3 subsites of 21...

The risk of hepatitis C virus (HCV) recurrence after direct-acting antiviral (DAA) treatment is &lt, 0.5%. However, the distinction between HCV RNA late relapse and reinfection still represents a challenge in virological diagnostics. The aim of this study was to employ next-generation sequencing (NGS) to investigate HCV RNA recurrence in patients achieving a sustained virologic response (SVR) at least six months post-treatment. NGS was performed on plasma samples from six HCV-positive patients (Pt1–6) treated with DAA. NGS of HCV NS5B was analyzed before treatment (T0), after HCV RNA rebound (T1), and, for Pt3, after a second rebound (T2). Reinfection was confirmed for Pt5, and for the first rebound observed in Pt3. Conversely, viral relapse was observed when comparing T0 and T1 for Pt6 and T1 and T2 for Pt3. Z-scores were calculated and used to predict whether HCV-positive patient samples at different time points belonged to the same quasispecies population. A low Z-score of &lt, 2.58 confirmed that viral quasispecies detected at T0 and T1 were closely related for both Pt1 and Pt2, while the Z-score for Pt4 was suggestive of possible reinfection. NGS data analyses indicate that the Z-score may be a useful parameter for distinguishing late relapse from reinfection.

Torque Teno virus (TTV) is a ubiquitous virus that causes chronic infection in humans with unknown clinical consequences. Here, we investigated the influence of TTV infection on HCV direct-acting antiviral (DAA) efficacy in HIV/HCV coinfected and HCV monoinfected patients as controls. Of 92 study patients, 79.3% were TTV DNA positive, untreated patients exhibited a significantly higher proportion of TTV DNA-positivity vs. sustained virological response (SVR) patients (100.0% vs. 65.2%, p &lt, 0.001), while TTV positivity was not significant in DAA failure patients vs. SVR patients despite HIV/HCV coinfection. TTV DNA viral load was higher among HCV monoinfected patients vs. HIV/HCV coinfected, although marginally significant (p = 0.074) and no significant viral load difference was detected between DAA failures and SVR patients, while untreated vs. SVR patients had a significantly higher viral load (19,884, IQR 5977–333,534, vs. 469, IQR 10–4124, p = 0.004). Alpha-genogroup 3 TTV was the most prevalent genetic group, and no specific strain or genogroup was observed in relapser patients. Among HIV/HCV patients with HCV RNA detectable at end of treatment (EOT), TTV DNA was detected in 9/17 treatment responder patients and 3/5 relapser patients, thus, TTV infection does not appear to influence the control HCV viremia after EOT. Levels of IL-6 IL-4, and CD14 were not significantly different between TTV PCR-positive and -negative patients. These results suggest no association between TTV DNA positivity or viral load and HCV DAA failure whether patients were HIV/HCV coinfected or HCV monoinfected.

Background Optimal treatment for patients with HCV genotype-3 infection and liver cirrhosis remains a medical priority. Daclatasvir+sofosbuvir and ribavirin is a recommended option for such patients, but clinical trial data are lacking for treatment >16 weeks. Methods This was a single-arm, Phase III study of daclatasvir+sofosbuvir+ribavirin for 24 weeks in patients with compensated cirrhosis and HCV genotype-3 infection. The primary end point was sustained virological response at post-treatment week 12 (SVR12); the primary objective was to demonstrate statistical superiority to historical SVR12 data for 12 weeks’ daclatasvir+sofosbuvir without ribavirin in genotype-3-infected patients with cirrhosis (95% CI lower bound >79.0%). Results A total of 78 patients were treated (54 treatment-naive, 24 treatment-experienced including 8 with prior sofosbuvir exposure). SVR12 was achieved by 87% (68/78; 95% CI 77.7, 93.7%) of patients in the primary analysis of central laboratory data. One additional patient achieved SVR12 by local testing resulting in an overall SVR12 rate of 88% (95% CI 79.2, 94.6%) and the lower bound of the 95% CI above the historical threshold. SVR12 rates were 93% (50/54) for treatment-naive and 79% (19/24) for treatment-experienced patients. Of the nine non-SVR12 patients, four were lost to follow-up, two relapsed (both sofosbuvir-experienced), two had end-of-treatment virological failure and one discontinued early. There were no unexpected safety signals; only one patient discontinued for an adverse event. Conclusions Daclatasvir+sofosbuvir+ribavirin for 24 weeks was well tolerated and efficacious in HCV genotype-3-infected patients with compensated cirrhosis, with SVR12 outcomes comparable to previously reported outcomes in patients treated with this regimen for 12–16 weeks.

Claudia Minosse,1,* Marina Selleri,1,* Emanuela Giombini,1 Barbara Bartolini,1 Maria Rosaria Capobianchi,1 Stefano Cerilli,2 Laura Loiacono,2 Chiara Taibi,2 Gianpiero D’Offizi,2 Fiona McPhee,3 AnnaRosa Garbuglia1 1Department of Pre-clinical Research Epidemiology and Advanced Diagnostics, Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani”– IRCCS, Rome, Italy; 2Clinical Department, Infectious Disease-Hepatology Unit, National Institute for Infectious Diseases, “Lazzaro Spallanzani” – IRCCS, Rome, Italy; 3Bristol-Myers Squibb Research and Development, Wallingford, CT, USA *These authors contributed equally to this work Background: The efficacy of direct-acting antivirals (DAAs) depends on the hepatitis C virus (HCV) genotype 4 (GT4) subtype which are used in the treatment of HCV. We aimed to ­retrospectively investigate the baseline prevalence of HCV NS5A and NS5B polymorphisms and their impact on virological outcome in GT4-infected patients treated with various DAA regimens.Patients and methods: Available plasma samples from HCV GT4-infected patients treated with different DAA regimens were analyzed at baseline and after treatment failure, where applicable. Sanger sequencing of patient-derived NS5A and NS5B regions was performed on all available samples, while ultradeep pyrosequencing (UDPS) of NS5A and NS5B regions was performed only on samples from treatment failures at different time points.Results: Sustained virological response (SVR) was achieved by 96% (48/50) of patients. Of 16 patients with baseline NS5A sequence, polymorphisms at amino acid positions associated with drug resistance were detected only at position 58: P58 (69.2%) and T58 (30.8%). Of 21 patients with baseline NS5B sequence, N142S was detected only in the two treatment failures, both with GT4d were treated with sofosbuvir (SOF)-based regimens, suggesting a potential involvement in SOF efficacy. Two patients (patient 1 [Pt1] and patient 2 [Pt2]) relapsed. In Pt1, NS5A-T56I and NS5A-Y93H/S emerged. In Pt2, NS5A-L28F emerged and a novel NS5B resistance-associated substitution (RAS), L204F, representing 1.5% of the viral population at baseline, enriched to 71% and 91.6% during and after treatment failure, respectively. UDPS of NS5B from Pt2 indicated a mixed infection of approximately 1:5, GT1a:GT4d, at baseline and GT4d during failure. Phylogenetic analysis of NS5A sequences indicated no clustering of HCV strains from patients achieving SVR vs patients who relapsed. The mean genetic distance in NS5A sequences was 5.8%, while a lower genetic distance (3.1%) was observed in NS5B sequences.Conclusion: Results from these analyses confirm the importance of UDPS in the analysis of viral quasispecies variability and the identification of novel RASs potentially associated with DAA treatment failure in HCV GT4-infected patients. Keywords: hepatitis C virus genotype 4, virological failure, population sequencing, deep sequencing, resistance-associated substitution, RAS, identification

Genotype 3 (GT3) is responsible for most European autochthonous hepatitis E virus (HEV) infections. This study analyzed circulating genotypes and GT3 subtypes in the Lazio region, Italy, between 2011 and 2019, as well as their pathogenic characteristics. Of the 64 evaluable HEV GT3 patient-derived sequences, identified subtypes included GT3f (n = 36), GT3e (n = 15), GT3c (n = 9), GT3a (n = 1) and three unsubtyped GT3 sequences. GT3c strains were similar to Dutch sequences (96.8&ndash, 98.1% identity), GT3e strains showed high similarity (96.8%) with a United Kingdom sequence, while the most related sequences to GT3f Italian strains were isolated in France, Belgium and Japan. One sequence was closely related to another Italian strain isolated in raw sewage in 2016. The liver functioning test median values for 56 evaluable GT3 patients were: alanine aminotransferase (ALT), 461 (range 52&ndash, 4835 U/L), aspartate aminotransferase (AST), 659 (range 64&ndash, 6588 U/L), and total bilirubin, 3.49 (range 0.4&ndash, 33 mg/dL). The median HEV RNA viral load for 26 evaluable GT3 patients was 42,240 IU/mL (range 5680&ndash, 895,490 IU/mL). Of the 37 GT3 patients with available clinical information, no correlation was observed between HEV clinical manifestations and GT3 subtype. HEV symptoms were comparable among GT3c/e/f patients across most analyzed categories except for epigastric pain, which occurred more frequently in patients with HEV GT3e (75%) than in patients with GT3c (50%) or GT3f (19%) (p = 0.01). Additionally, patients with HEV GT3c exhibited significantly higher median international normalized ratio (INR) than patients with GT3e and GT3f (p = 0.033). The severity of GT3 acute hepatitis E was not linked to HEV RNA viral load or to the GT3 subtype.

Entecavir (ETV) is a first‐line therapy for chronic hepatitis B virus (HBV), demonstrating potent suppression of HBV DNA and a high barrier to viral resistance. Previous studies revealed that ETV‐resistant (ETVr) HBV DNA resulted from substitutions in the HBV reverse transcriptase (RT) at positions rtT184, rtS202, or rtM250 in combination with lamivudine resistance (LVDr) substitutions rtM204I/V±rtL180M. In vitro, viral variants exhibit varying degrees of ETV susceptibility and replication capacity depending on specific resistance substitutions. To explore the potential for additional pathways to ETVr, HBV RT sequences from 982 evaluable patients enrolled in 17 ETV clinical studies were analyzed. Thirty novel emergent substitutions at amino acid positions not previously associated with HBV nucleos(t)ide drug resistance were observed in at least 2 patients and were identified in patient‐derived HBV with a wild‐type, LVDr, or ETVr RT sequence. Phenotypic analysis of these substitutions indicated that they had no effect on ETV susceptibility. Phenotypic analysis was also performed on patient‐derived HBV RT sequences from 10 LVD‐naive and 13 LVD‐experienced patients with virologic breakthrough and emergent novel substitutions while on ETV treatment. One LVD‐experienced patient‐derived HBV RT harboring LVDr substitutions rtL180M+rtM204V with rtA181C displayed reduced ETV susceptibility (122‐fold greater than wild‐type HBV) and remained susceptible to adefovir and tenofovir. HBV harboring the rtA181C substitution without LVDr substitutions rtL180M+rtM204V remained susceptible to inhibition by ETV, adefovir, and tenofovir, although cross‐resistance to LVD and telbivudine was observed. Conclusion: An integrated genotypic analysis of HBV RT sequences from patients with chronic HBV treated with ETV led to the discovery of the novel ETVr substitution rtA181C. This substitution was always detected in combination with LVDr substitutions rtL180M+rtM204V in ETV‐treated patients.

In the UNITY-3 study, 96% sustained virologic response (SVR12) rate was observed in Japanese patients with hepatitis C virus (HCV) genotype (GT)-1 infection treated for 12 weeks with fixed-dose daclatasvir, asunaprevir, and beclabuvir (DCV-TRIO). As HCV clearance may improve liver outcomes, we assessed hepatic fibrosis and alpha-fetoprotein (AFP), a hepatocellular carcinoma risk marker, pre- and post-treatment in UNITY-3. Treatment-naive or interferon-experienced UNITY-3 patients with HCV GT-1 who received twice-daily DCV-TRIO were assessed for fibrosis [FibroTest; FibroScan; fibrosis-4 index (FIB-4), aspartate-aminotransferase-to-platelet-ratio index] and AFP at baseline and Weeks 4 (FIB-4 only), 12 or 24 post-treatment. Of 217 patients, 99% had GT-1b infection, 46% were aged > 65 years, 21% had compensated cirrhosis, and 26% baseline HCV-RNA > 107 IU/mL. All GT-1b patients treated ≥ 4 weeks achieved SVR12 with (n = 54) or without (n = 144) baseline NS5A polymorphisms associated with DCV resistance (positions 28/30/31/93). Statistically significant post-treatment reductions from baseline were observed for all fibrosis measures and AFP, with numerically greater reductions in cirrhotic patients. FibroTest category improved in 44%, remained stable in 50%, and worsened in 6% of patients; 98% with baseline AFP

Naphthalene-linked P2-P4 macrocycles within a tri-peptide-based acyl sulfonamide chemotype have been synthesized and found to inhibit HCV NS3 proteases representing genotypes 1a and 1b with single digit nanomolar potency. The pharmacokinetic profile of compounds in this series was optimized through structural modifications along the macrocycle tether as well as the P1 subsite. Ultimately a compound with oral bioavailability of 100% in rat, and a long half-life in plasma was obtained. However, compounds in this macrocyclic series exhibited cardiac effects in an isolated rabbit heart model and for this reason further optimization efforts were discontinued.

Background and Aim This multinational (Taiwan, South Korea, Russia) phase 3 study evaluated the all-oral, ribavirin-free, fixed-dose combination (DCV-TRIO) of daclatasvir (NS5A inhibitor) 30 mg, asunaprevir (NS3 inhibitor) 200 mg, and beclabuvir (NS5B inhibitor) 75 mg, in patients with chronic hepatitis C virus genotype-1 infection, with or without compensated cirrhosis. Methods UNITY-4 (NCT02170727) was an open-label, two-cohort study in which 169 patients, treatment-naive (n = 138) or treatment-experienced (n = 31), received twice-daily DCV-TRIO for 12 weeks with 24 weeks of post-treatment follow-up. The primary efficacy end point was sustained virologic response at post-treatment week 12 (SVR12) in treatment-naive patients. Results Eighty-eight (52%) patients were men, 81 (48%) Taiwanese, 78 (46%) Korean, and 10 (6%) Russian; 23 (14%) had compensated cirrhosis, and 52 (31%) were IL28B (rs1297860) non-CC genotype. Baseline resistance-associated NS5A polymorphisms (L31 and/or Y93) were detected in 25/165 (15%) patients with available genotype-1 sequencing data. SVR12 was achieved by 98.6% (136/138; 95% confidence interval: 94.9–99.8%) of treatment-naive and 100% (31/31; 95% confidence interval: 88.8–100%) of treatment-experienced patients. Both virologic failures were found to be infected with hepatitis C virus genotype-6g; 100% SVR12 was observed for genotype-1a (n = 8) and genotype-1b (n = 157). Two patients experienced serious adverse events. Eight (5%) patients experienced reversible grade 3/4 alanine aminotransferase or aspartate aminotransferase elevations, leading to discontinuation in four (2%); all achieved SVR12. There were no grade 3/4 total bilirubin increases and no deaths. Conclusions Twelve weeks of DCV-TRIO was well tolerated and provided 100% SVR12 in treatment-naive and treatment-experienced patients with genotype-1 infection, with or without cirrhosis, including those with baseline NS5A-L31 or NS5A-Y93 resistance-associated substitutions.

Daclatasvir (DCV) is a potent, pangenotypic, hepatitis C virus (HCV) non-structural protein 5A inhibitor with low potential for drug interactions with antiretroviral therapy (ART). We evaluated the safety and efficacy of DCV plus peginterferon alfa-2a/ribavirin (PegIFN/RBV) in HIV-1/HCV genotype-1-coinfected patients. AI444043 (NCT01471574), an open-label, Phase III, single-arm, response-guided treatment (RGT) study included 301 patients. They received DCV doses of 30, 60 or 90 mg once daily (depending on concomitant ART), plus weight-based RBV (

Daclatasvir plus asunaprevir has demonstrated efficacy and safety in patients with chronic hepatitis C virus genotype 1b infection. This study focused on evaluating daclatasvir plus asunaprevir in interferon (±ribavirin)-ineligible or -intolerant Asian patients with genotype 1b infection from mainland China, Korea, and Taiwan. Interferon (±ribavirin)-ineligible and -intolerant patients with genotype 1b infection received daclatasvir 60 mg tablets once-daily plus asunaprevir 100 mg soft capsules twice-daily for 24 weeks. The primary endpoint was sustained virologic response at post-treatment Week 24 (SVR24). Of the 159 patients treated, 89.3% were Chinese, 65.4% were female, and 73.6% were interferon-intolerant. Cirrhosis was present in 32.7% of patients and 40.3% had IL28B non-CC genotypes. SVR24 was achieved by 145/159 (91.2%) patients (100% concordance with SVR12) and was similarly high in cirrhotic patients (47/52, 90.4%). SVR24 was higher in patients without baseline NS5A (L31M or Y93H) resistance-associated variants (RAVs) (137/139, 98.6%), including those with cirrhosis (43/44, 97.7%). Prevalence of baseline NS5A RAVs was low (19/159, 11.9%), particularly in mainland China (10/127, 7.9%). One death (0.6%), five serious adverse events (3.1%), and three grade 4 laboratory abnormalities (1.9%) occurred on-treatment; none were considered related to study drugs. Two patients (1.3%) discontinued due to adverse events. Treatment was generally well-tolerated regardless of cirrhosis status. Daclatasvir plus asunaprevir achieved a SVR24 rate of 91.2%, rising to 98.6% in patients without baseline NS5A RAVs, and was generally well tolerated in interferon (±ribavirin)-ineligible or -intolerant patients with genotype 1b infection from mainland China, Korea, and Taiwan. This article is protected by copyright. All rights reserved.

Introduction: Unlike other hepatitis C virus (HCV) genotypes (GTs), patients infected with GT3 are associated with an increased risk of accelerated liver disease progression. Although early immuno-...

HCV genotype 6 (GT-6) is found predominantly in East and Southeast Asia. Clinical studies have focused on patients infected with hepatitis C virus (HCV) GT-6a, where high sustained virologic response (SVR) rates to direct-acting antivirals (DAAs) have been achieved. However, GT-6 is highly diverse, with 29 reported subtypes. We explored the diversity of GT-6 polymorphisms at residues associated with DAA resistance, their impact on DAA in vitro potency when evaluated in a GT-6a consensus replicon, and their association with specific GT-6 subtypes. GT-6 sequences from 25 patient-derived samples and 105 sequences from the U.S. HCV database were compared, and substitutions at resistance-associated residue positions were phenotyped against different DAAs. Preexisting resistance-associated substitutions (RASs) to NS3 protease (A156V and D168E) and NS5B nucleotide (L159F and S282C) inhibitors were rare (5,000 nM) and were detected in evaluated GT-6b and -6f sequences. NS5A-L28A-R30A, observed in GT-6r, did not replicate. In conclusion, HCV GT-6b, GT-6f, and GT-6r sequences harbored highly resistant RASs to all evaluated NS5A drugs. Therefore, monitoring SVR in patients infected with these GT-6 subtypes treated with NS5A drug-containing regimens is suggested to confirm any association between noted NS5A polymorphisms and treatment failure.

OBJECTIVE Daclatasvir (DCV) is a pan-genotypic non-structural protein 5A (NS5A) inhibitor that is approved for treatment of hepatitis C virus (HCV) genotype (GT)1 and GT3 in the USA and GT1, GT3 and GT4 in Europe. We set out to examine the impact of daclatasvir-based regimens on the sustained virologic response (SVR) in patients with GT2 infection with respect to GT2 subtype and NS5A polymorphisms at amino acid positions associated with daclatasvir resistance. METHODS Analyses were performed on 283 GT2 NS5A sequences from five daclatasvir regimen-based clinical trials (ClinicalTrials.gov: NCT-01257204, NCT-01359644, NCT-02032875, NCT-02032888 and NCT-01616524) and 143 NS5A sequences from the Los Alamos HCV database. Susceptibility analyses of substitutions at amino acid positions associated with daclatasvir resistance and patient-derived NS5A sequences were performed using an in vitro HCV replication assay. RESULTS Of 13 GT2 subtypes identified from 426 NS5A sequences, the most prevalent were GT2a (32%), GT2b (48%) and GT2c (10%). The most prevalent NS5A polymorphism was L31M (GT2a = 88%; GT2b = 59%; GT2c = 10%). Substitutions identified in 96% of GT2 NS5A sequences exhibited daclatasvir EC50 values ranging from 0.005 to 20 nM when tested in vitro. A similar range in daclatasvir EC50 values was observed for 16 diverse GT2 patient-derived NS5A sequences (EC50 = 0.005-60 nM). Depending on the daclatasvir-based regimen studied (daclatasvir/interferon-based or daclatasvir/sofosbuvir-based), SVR rates ranged from 90% to 100% in GT2 patients with the most prevalent baseline NS5A-L31M polymorphism, compared with from 96% to 100% without this polymorphism. CONCLUSIONS High SVR rates were achieved in patients infected with GT2 treated with daclatasvir-based regimens irrespective of GT2 subtype or baseline NS5A polymorphisms.

DCV-TRIO, a fixed-dose combination of daclatasvir (pangenotypic NS5A inhibitor), asunaprevir (NS3/4A protease inhibitor), and beclabuvir (non-nucleoside NS5B inhibitor), has achieved high rates of sustained virologic response at post-treatment Week 12 (SVR12) in phase 3 studies.In this phase 3 study, DCV-TRIO for 12 weeks and daclatasvir plus asunaprevir (DUAL) for 24 weeks were studied in Japanese patients infected with HCV genotype 1 (99 % genotype 1b).SVR12 rates ≥95 % were achieved in both treatment-naive (N = 152) and interferon-experienced (N = 65) cohorts treated with DCV-TRIO for 12 weeks and were comparable across patient subgroups, including patients aged ≥65 years and those with cirrhosis. DUAL recipients (N = 75) had an SVR12 rate of 87 %. In the absence of baseline resistance-associated polymorphisms at positions NS5A-Y93H or -L31, SVR12 rates were 98 % with DCV-TRIO or DUAL. Among genotype 1b-infected patients with baseline Y93H or L31 polymorphisms, 35/38 (92 %) DCV-TRIO recipients, and 7/16 (44 %) DUAL recipients achieved SVR12. Adverse events, mostly liver related, led to treatment discontinuation in 10 % of DCV-TRIO recipients. In this group, SVR12 was achieved by 3/9 patients who discontinued before Week 4 and by 12/12 patients who completed ≥4 weeks of DCV-TRIO. Treatment-related serious adverse events occurred in 4 and 3 % of DCV-TRIO and DUAL recipients, respectively. Seven patients (9 %) discontinued DUAL due to adverse events. No deaths occurred.SVR12 was achieved by 96 % of Japanese patients with HCV genotype 1 infection after 12 weeks of treatment with the DCV-TRIO regimen. DCV-TRIO and DUAL exhibited comparable safety profiles.

Key Clinical Message There is currently minimal clinical experience regarding retreatment options for patients failing direct‐acting antiviral combination regimens. Here, we report the outcomes of a HCV genotype 1b‐infected patient with virologic failure following treatment with daclatasvir and asunaprevir, who was successfully retreated with sofosbuvir plus simeprevir.

Chronic hepatitis C virus (HCV) infection with advanced cirrhosis or post‐liver transplantation recurrence represents a high unmet medical need with no approved therapies effective across all HCV genotypes. The open‐label ALLY‐1 study assessed the safety and efficacy of a 60‐mg once‐daily dosage of daclatasvir (pan‐genotypic NS5A inhibitor) in combination with sofosbuvir at 400 mg once daily (NS5B inhibitor) and ribavirin at 600 mg/day for 12 weeks with a 24‐week follow‐up in two cohorts of patients with chronic HCV infection of any genotype and either compensated/decompensated cirrhosis or posttransplantation recurrence. Patients with on‐treatment transplantation were eligible to receive 12 additional weeks of treatment immediately after transplantation. The primary efficacy measure was sustained virologic response at posttreatment week 12 (SVR12) in patients with a genotype 1 infection in each cohort. Sixty patients with advanced cirrhosis and 53 with posttransplantation recurrence were enrolled; HCV genotypes 1 (76%), 2, 3, 4, and 6 were represented. Child‐Pugh classifications in the advanced cirrhosis cohort were 20% A, 53% B, and 27% C. In patients with cirrhosis, 82% (95% confidence interval [CI], 67.9%‐92.0%) with genotype 1 infection achieved SVR12, whereas the corresponding rates in those with genotypes 2, 3, and 4 were 80%, 83%, and 100%, respectively; SVR12 rates were higher in patients with Child‐Pugh class A or B, 93%, versus class C, 56%. In transplant recipients, SVR12 was achieved by 95% (95% CI, 83.5%‐99.4%) and 91% of patients with genotype 1 and 3 infection, respectively. Three patients received peritransplantation treatment with minimal dose interruption and achieved SVR12. There were no treatment‐related serious adverse events. Conclusion: The pan‐genotypic combination of daclatasvir, sofosbuvir, and ribavirin was safe and well tolerated. High SVR rates across multiple HCV genotypes were achieved by patients with post‐liver transplantation recurrence or advanced cirrhosis. (Hepatology 2016;63:1493‐1505)

Background and Aims This phase-2b study examined the safety and efficacy of an all-oral, interferon-free combination of the NS5A replication complex inhibitor daclatasvir (DCV), the NS3 protease inhibitor asunaprevir (ASV), and the nonnucleoside NS5B polymerase inhibitor beclabuvir (BCV) with or without ribavirin in patients with HCV genotype (GT) 1 infection. Methods A total of 187 patients received 12 weeks of DCV 30 mg BID plus ASV 200 mg BID and BCV 150 mg BID (n = 86) or 75 mg BID with (n = 21) or without (n = 80) weight-based ribavirin BID. The primary endpoint was HCV RNA

The design and synthesis of potent, tripeptidic acylsulfonamide inhibitors of HCV NS3 protease that contain a difluoromethyl cyclopropyl amino acid at P1 are described. A cocrystal structure of 18 with a NS3/4A protease complex suggests the presence of a H-bond between the polarized C–H of the CHF2 moiety and the backbone carbonyl of Leu135 of the enzyme. Structure–activity relationship studies indicate that this H-bond enhances enzyme inhibitory potency by 13- and 17-fold compared to the CH3 and CF3 analogues, respectively, providing insight into the deployment of this unique amino acid.

Background & aims Daclatasvir has achieved high sustained virologic response (SVR) rates in diverse hepatitis C virus (HCV) populations. This study evaluated the long-term efficacy and safety of daclatasvir-based regimens administered during clinical studies. Methods Patients enrolled within 6 months of parent study completion or protocol availability at the study sites. The primary objective was durability of SVR at follow-up Week 12 (SVR12). Secondary objectives included analyzing HCV sequences in non-responders or responders who relapsed, and characterization of liver disease progression. Results Between 24-February-2012 and 17-July-2015, this study enrolled and began following 1503 recipients of daclatasvir-based regimens (follow-up cut-off, 13-October-2015); 60% were male, 18% aged ≥65 years, 87% had genotype-1a (42%) or -1b (45%) infection, and 18% had cirrhosis. Median follow-up from parent study follow-up Week 12 was 111 (range, 11-246) weeks. 1329/1489 evaluable patients were SVR12 responders; 1316/1329 maintained SVR until their latest visit. Twelve responders relapsed by (n=9) or after (n=3) parent study follow-up Week 24; one was reinfected. Relapse occurred in 3/842 (0.4%) and 9/487 (2%) responders treated with interferon-free or interferon-containing regimens, respectively. Hepatic disease progression and new hepatocellular carcinoma were diagnosed in 15 and 23 patients, respectively. Among non-responders, emergent non-structural protein-5A (NS5A) and -3 (NS3) substitutions were replaced by wild-type sequences in 27/157 (17%) and 35/47 (74%) patients, respectively. Conclusions SVR12 was durable in 99% of recipients of daclatasvir-based regimens. Hepatic disease progression and new hepatocellular carcinoma were infrequent. Emergent NS5A substitutions persisted longer than NS3 substitutions among non-responders. This article is protected by copyright. All rights reserved.

AIM To assess daclatasvir plus asunaprevir (DUAL) in treatment-naïve patients from mainland China, Russia and South Korea with hepatitis C virus (HCV) genotype 1b infection. METHODS Patients were randomly assigned (3:1) to receive 24 wk of treatment with DUAL (daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period (immediate treatment arm) or following 12 wk of matching placebo (placebo-deferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12 (SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin (70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in DUAL-treated patients compared with placebo patients during the first 12 wk (double-blind phase), and during 24 wk of DUAL in both arms combined. RESULTS In total, 207 patients were randomly assigned to immediate (n = 155) or placebo-deferred (n = 52) treatment. Most patients were Asian (86%), female (59%) and aged < 65 years (90%). Among them, 13% had cirrhosis, 32% had IL28B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/mL. Among patients in the immediate treatment arm, SVR12 was achieved by 92% (95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate (70%). SVR12 was largely unaffected by cirrhosis (89%), age ≥ 65 years (92%), male sex (90%), baseline HCV RNA ≥ 6 million (89%) or IL28B non-CC genotypes (96%), although SVR12 was higher among patients without (96%) than among those with (53%) baseline NS5A resistance-associated polymorphisms (at L31 or Y93H). During the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving DUAL. During 24 wk of DUAL therapy (combined arms), the most common adverse events (≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities (alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued DUAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths. CONCLUSION DUAL was well-tolerated during this phase 3 study, and SVR12 with DUAL treatment (92%) exceeded the historical SVR rate for peg-interferon plus ribavirin of 70%.

BACKGROUND The combination of daclatasvir, a hepatitis C virus (HCV) NS5A inhibitor, and the NS5B inhibitor sofosbuvir has shown efficacy in patients with HCV monoinfection. Data are lacking on the efficacy and safety of this combination in patients coinfected with human immunodeficiency virus type 1 (HIV-1). METHODS This was an open-label study involving 151 patients who had not received HCV treatment and 52 previously treated patients, all of whom were coinfected with HIV-1. Previously untreated patients were randomly assigned in a 2:1 ratio to receive either 12 weeks or 8 weeks of daclatasvir at a standard dose of 60 mg daily (with dose adjustment for concomitant antiretroviral medications) plus 400 mg of sofosbuvir daily. Previously treated patients were assigned to undergo 12 weeks of therapy at the same doses. The primary end point was a sustained virologic response at week 12 after the end of therapy among previously untreated patients with HCV genotype 1 who were treated for 12 weeks. RESULTS Patients had HCV genotypes 1 through 4 (83% with genotype 1), and 14% had compensated cirrhosis; 98% were receiving antiretroviral therapy. Among patients with genotype 1, a sustained virologic response was reported in 96.4% (95% confidence interval [CI], 89.8 to 99.2) who were treated for 12 weeks and in 75.6% (95% CI, 59.7 to 87.6) who were treated for 8 weeks among previously untreated patients and in 97.7% (95% CI, 88.0 to 99.9) who were treated for 12 weeks among previously treated patients. Rates of sustained virologic response across all genotypes were 97.0% (95% CI, 91.6 to 99.4), 76.0% (95% CI, 61.8 to 86.9), and 98.1% (95% CI, 89.7 to 100), respectively. The most common adverse events were fatigue, nausea, and headache. There were no study-drug discontinuations because of adverse events. HIV-1 suppression was not compromised. CONCLUSIONS Among previously untreated HIV–HCV coinfected patients receiving daclatasvir plus sofosbuvir for HCV infection, the rate of sustained virologic response across all genotypes was 97.0% after 12 weeks of treatment and 76.0% after 8 weeks. (Funded by Bristol-Myers Squibb; ALLY-2 ClinicalTrials.gov number, NCT02032888.)

Hepatitis C virus (HCV) drug development has resulted in treatment regimens composed of interferon-free, all-oral combinations of direct-acting antivirals. While the new regimens are potent and highly efficacious, the full clinical impact of HCV drug resistance, its implications for retreatment, and the potential role of baseline resistance testing remain critical research and clinical questions. In this report, we discuss the viral proteins targeted by HCV direct-acting antivirals and summarize clinically relevant resistance data for compounds that have been approved or are currently in phase 3 clinical trials. Conclusion: This report provides a comprehensive, systematic review of all resistance information available from sponsors’ trials as a tool to inform the HCV drug development field. (Hepatology 2015;62:1623–1632)

Background. Daclatasvir is an NS5A inhibitor approved for treatment of infection due to hepatitis C virus (HCV) genotypes (GTs) 1–4. To support daclatasvir use in HCV genotype 4 infection, we examined a diverse genotype 4–infected population for HCV genotype 4 subtype prevalence, NS5A polymorphisms at residues associated with daclatasvir resistance (positions 28, 30, 31, or 93), and their effects on daclatasvir activity in vitro and clinically. Methods. We performed phylogenetic analysis of genotype 4 NS5A sequences from 186 clinical trial patients and 43 sequences from the European HCV database, and susceptibility analyses of NS5A polymorphisms and patient-derived NS5A sequences by using genotype 4 NS5A hybrid genotype 2a replicons. Results. The clinical trial patients represented 14 genotype 4 subtypes; most prevalent were genotype 4a (55%) and genotype 4d (27%). Daclatasvir 50% effective concentrations for 10 patient-derived NS5A sequences representing diverse phylogenetic clusters were ≤0.080 nM. Most baseline sequences had ≥1 NS5A polymorphism at residues associated with daclatasvir resistance; however, only 3 patients (1.6%) had polymorphisms conferring ≥1000-fold daclatasvir resistance in vitro. Among 46 patients enrolled in daclatasvir trials, all 20 with baseline resistance polymorphisms achieved a sustained virologic response. Conclusions. Circulating genotype 4 subtypes are genetically diverse. Polymorphisms conferring high-level daclatasvir resistance in vitro are uncommon before therapy, and clinical data suggest that genotype 4 subtype and baseline polymorphisms have minimal impact on responses to daclatasvir-containing regimens.

Background & Aims Improved therapies for peginterferon/ribavirin null or partial responders are needed. This study evaluated daclatasvir (NS5A inhibitor) and asunaprevir (NS3 protease inhibitor) plus peginterferon alfa-2a and ribavirin in this patient population. Methods This open-label, phase 3 study (HALLMARK-QUAD; NCT01573351) treated patients with chronic hepatitis C virus (HCV) genotype 1 (n=354) or 4 (n=44) infection who had a prior null or partial response to peginterferon/ribavirin. Patients received daclatasvir 60mg once-daily plus asunaprevir 100mg twice-daily, with weekly peginterferon alfa-2a and weight-based ribavirin for 24weeks. The primary endpoint was sustained virological response at post-treatment week 12 (SVR12) among genotype 1-infected patients. Results Daclatasvir plus asunaprevir and peginterferon/ribavirin demonstrated SVR12 rates of 93% (95% CI 90–96) in prior non-responders infected with HCV genotype 1. SVR12 rates among genotype 4-infected patients were 98% (95% CI 93–100); one patient had a missing post-treatment week-12 HCV-RNA measurement, but achieved an SVR at post-treatment week 24, yielding a 100% SVR rate in genotype 4 patients. Prior peginterferon/ribavirin response, sex, age, IL28B genotype, or cirrhosis status did not influence SVR12 rates. Serious adverse events occurred in 6% of patients; 5% discontinued treatment due to an adverse event. Grade 3/4 laboratory abnormalities included neutropenia (22%), lymphopenia (16%), anemia (6%), thrombocytopenia (4%), and ALT/AST elevations (3% each). Conclusions Daclatasvir plus asunaprevir and peginterferon/ribavirin demonstrated high rates of SVR12 in genotype 1- or 4-infected prior null or partial responders. The combination was well tolerated and no additional safety and tolerability concerns were observed compared with peginterferon/ribavirin regimens.

Background Daclatasvir (DCV) is an approved NS5A inhibitor with potent anti-HCV activity and broad genotype coverage. DCV resistance-associated variants (RAVs) have been described for patients infected with genotype (GT) 1, but increased GT4 prevalence in European countries as a result of immigration has boosted interest in this genotype. Objectives Establishment of NS5A variability in treatment-naive patients with HCV genotype 4 infection and a case study of the dynamics of resistance-associated variants in a virologic failure receiving pIFN/RBV + DCV, as assessed by ultra-deep sequencing. Study design Five treatment-naive GT4 patients (GT4a [n = 1], GT4d [n = 3], GT4o [n = 1]) were evaluated for inclusion in the COMMAND-4 study and treatment with pIFN/RBV ± DCV. Results Patient (Pt) 1 received pIFN/RBV; Pts2–4 received pIFN/RBV + DCV; Pt5 was a screening failure. Pt1 relapsed; Pt2 experienced breakthrough at Wk4; Pts3 and 4 achieved a sustained virologic response. No substitutions associated with DCV-resistance were detected at baseline. In terms of viremic time points for Pts1 and 2, the extent of NS5A diversity pre-treatment was not significantly related to viral load (r = −0568; p = 0.035). In Pt2, multiple substitutions associated with DCV-resistance were observed after breakthrough at NS5A amino acid positions 28, 31 and 93. These substitutions were frequently observed on the same haplotype (L28S + M31I = 55.52, 82.50, and 99.36% at Wk4, 8 and 9; L28S + M31I + Y93H = 11.77, 5.01 and Conclusions This is the first report to describe DCV-resistance in patients infected with GT4d, supporting a possible role for a recently described RAV (L28S), and presenting the dynamics of HCV quasispecies during therapy failure, with indications of changes of diversity and association of mutations.

Chronic infection with hepatitis C virus (HCV) genotype 3 is common throughout the world and remains a significant disease burden for many patients.1,2 Infection with HCV genotype 3 has been associated with an increased risk of progression to cirrhosis, as well as development of steatosis or hepatocellular carcinoma (HCC), compared with other HCV genotypes.3–5 In an observational cohort study, analysis of real-world data from the Veterans Affairs HCV clinical registry found that the risks of cirrhosis, HCC, liver-related hospitalization, and death were significantly higher in genotype 3–infected patients, compared with genotype 1–infected patients,6 underscoring the medical need for safe, effective treatment options for patients with genotype 3 infection. Recent advances have led to the approval of interferon (IFN)-free and/or ribavirin (RBV)-free therapies for chronic infection with HCV genotypes 1, 2, 3, and 4. However, for both treatment-naive and treatment-experienced patients with genotype 3 infection, IFN- and RBV-free therapy options are currently limited. Therapies approved in the United States and Europe for treatment of genotype 3 infection include a 24-week, all-oral regimen of sofosbuvir (SOF; a pangenotypic nonstructural protein [NS]5B inhibitor) in combination with RBV7,8 and a 24-week regimen of pegylated IFN (Peg-IFN) plus RBV.9,10 In addition, a 12-week, IFN-based regimen of SOF plus Peg-IFN and RBV8 is approved in Europe for treating genotype 3 infection, as are all-oral, 24-week regimens of daclatasvir (DCV; a potent, pangenotypic NS5A inhibitor) plus SOF with RBV11 and ledipasvir (LDV; an NS5A inhibitor) plus SOF with RBV12 for patients with compensated cirrhosis and/or previous treatment experience. The all-oral combination of SOF plus RBV requires 24 weeks of treatment because 12- and 16-week treatment durations were associated with lower response rates (30%-61% and 62%, respectively) in genotype 3–infected patients.7,13,14 With 24-week treatment, lower response rates were observed in genotype 3–infected patients who were treatment experienced (77%), particularly those with cirrhosis (60%), compared with those who were treatment naive (93%).7,15 In addition, there was an increased incidence of anemia, which is consistent with the hemolytic anemia known to occur with RBV treatment.15,16 Thus, patients with genotype 3 infection have a need for improved treatment options, preferably with therapies of shorter duration and without the addition of Peg-IFN or RBV. DCV was evaluated in combination with SOF in a phase II study.17 Treatment for 24 weeks with DCV plus SOF, with or without the addition of RBV, resulted in an 89% rate of sustained virological response (SVR) at post-treatment week 12 (SVR12) among 18 treatment-naive patients with genotype 3 infection.11,17 Of 5 genotype 3–infected patients who had ≥F3 fibrosis (based on FibroTest scores), all 5 achieved SVR12.11 In this phase III study, the efficacy and safety of 12-week, RBV-free treatment with DCV plus SOF were evaluated in treatment-naive and treatment-experienced patients chronically infected with HCV genotype 3.

With increasing interest in alternative options to interferon-alpha-based treatments, IFN-λ has shown therapeutic promise in a variety of diseases. Although the antiviral activity of IFN-λ has been extensively studied, there is limited knowledge regarding the immunological functions of IFN-λ and how these differ from those of other classes of IFNs. In this study, we investigated the effects of IFN-λ on primary human NK cells, both in a direct and indirect capacity. We demonstrate that in contrast to interferon-alpha, IFN-λ is unable to directly stimulate NK cells, due to the absence of IFN-λ receptor chain 1 (IFN-λR1) on NK cells. However, IFN-λ, in combination with TLR4 challenge, is able to induce the production of select members of the IL-12 family of cytokines in monocyte-derived macrophages. We further show that through macrophage-mediated IL-12 production, IFN-λ is able to indirectly affect NK cells and ultimately induce IFN-γ production.

Hepatitis C virus (HCV) genotype (GT)3 is associated with increased risk of steatosis, development of cirrhosis and hepatocellular carcinoma. Limited data are available regarding genetic variability and use of direct-acting antiviral agents in these patients. non-structural protein 5A (NS5A) and non-structural protein 5B (NS5B) sequencing was performed on 45 HCV GT3-infected Italian patients subsequently treated with sofosbuvir ± daclatasvir (SOF ± DCV). Novel GT3a polymorphisms were observed by Sanger sequencing in three NS5A (T79S, T107K, and T107S) and three NS5B (G166R, Q180K, and C274W) baseline sequences in patients who achieved sustained virological response (SVR). Baseline NS5A resistance-associated substitutions (RASs) A30K and Y93H were detected in 9.5% of patients; one patient with A30K did not achieve SVR. Phylogenetic analyses of sequences showed no distinct clustering. Genetic heterogeneity of NS5A and NS5B was evaluated using ultra-deep pyrosequencing (UDPS) in samples longitudinally collected in patients not achieving SVR. Some novel NS5A and NS5B polymorphisms detected at baseline may not impact treatment outcome, as they were not enriched in post-failure samples. In contrast, the clinically novel GT3 NS5A-L31F RAS emerged in one treatment failure, and I184T, G188D and N310S, located on the same NS5B haplotype, became predominant after failure. These findings suggest a potential impact of these novel substitutions on the treatment outcome; however, their significance requires further investigation.

Background Daclatasvir (DCV; non-structural [NS]5A inhibitor) plus asunaprevir (ASV; NS3 inhibitor) plus beclabuvir (BCV; non-nucleoside NS5B inhibitor) is an approved regimen for hepatitis C virus (HCV) genotype (GT)-1 treatment in Japan. A comprehensive analysis of pre-treatment and treatment-emergent HCV resistance to this regimen ± ribavirin (RBV) was performed. Methods Data were pooled from five Phase 2/3 studies of DCV+ASV+BCV±RBV given for 12 weeks to GT-1a- or GT-1b-infected patients. The prevalence and impact of pre-treatment resistance-associated substitutions (RAS) in NS5A, NS3, and NS5B on sustained virological response (SVR) was assessed, as were emergent RAS and their post-treatment persistence. Results Baseline NS5A RAS (GT-1a: M28T, Q30H/L/R/S, L31M, Y93C/H; GT-1b: L31I/M, Y93C/H) were present in 5% (26/561) of GT-1a and 16% (85/537) of GT-1b sequences. SVR12 for GT-1b without RBV was 100% (82/82) with RAS and >99% (427/428) without RAS. For GT-1a, SVR12 without RAS was 97% (85/88) with RBV and 92% (410/447) without RBV; SVR12 with RAS was 100% (2/2) with RBV and 54% (13/24) without RBV. Baseline NS3 (at R155 or D168) and NS5B (at P495) RAS were rare (≤1%). Treatment-emergent NS5A RAS (mostly Q30E/H/K/R+Y93H/N) in GT-1a persisted 60 weeks post-treatment, while NS3 RAS (mostly R155K) and NS5B-P495L/S were no longer detected after 48 or 24 weeks, respectively. Conclusions DCV+ASV+BCV+RBV was highly efficacious in HCV GT-1 infection, including HCV GT-1b with NS5A RAS. The fitness of treatment-emergent RAS post-treatment was NS5A > NS3 > NS5B; NS3 and NS5B RAS were generally replaced by wild-type sequence within 48 weeks.

This multinational (Taiwan, South Korea, Russia) phase 3 study evaluated the all-oral, ribavirin-free, fixed-dose combination (DCV-TRIO) of daclatasvir (NS5A inhibitor) 30 mg, asunaprevir (NS3 inhibitor) 200 mg, and beclabuvir (NS5B inhibitor) 75 mg, in patients with chronic hepatitis C virus genotype-1 infection, with or without compensated cirrhosis.UNITY-4 (NCT02170727) was an open-label, two-cohort study in which 169 patients, treatment-naive (n = 138) or treatment-experienced (n = 31), received twice-daily DCV-TRIO for 12 weeks with 24 weeks of post-treatment follow-up. The primary efficacy end point was sustained virologic response at post-treatment week 12 (SVR12) in treatment-naive patients.Eighty-eight (52%) patients were men, 81 (48%) Taiwanese, 78 (46%) Korean, and 10 (6%) Russian; 23 (14%) had compensated cirrhosis, and 52 (31%) were IL28B (rs1297860) non-CC genotype. Baseline resistance-associated NS5A polymorphisms (L31 and/or Y93) were detected in 25/165 (15%) patients with available genotype-1 sequencing data. SVR12 was achieved by 98.6% (136/138; 95% confidence interval: 94.9-99.8%) of treatment-naive and 100% (31/31; 95% confidence interval: 88.8-100%) of treatment-experienced patients. Both virologic failures were found to be infected with hepatitis C virus genotype-6g; 100% SVR12 was observed for genotype-1a (n = 8) and genotype-1b (n = 157). Two patients experienced serious adverse events. Eight (5%) patients experienced reversible grade 3/4 alanine aminotransferase or aspartate aminotransferase elevations, leading to discontinuation in four (2%); all achieved SVR12. There were no grade 3/4 total bilirubin increases and no deaths.Twelve weeks of DCV-TRIO was well tolerated and provided 100% SVR12 in treatment-naive and treatment-experienced patients with genotype-1 infection, with or without cirrhosis, including those with baseline NS5A-L31 or NS5A-Y93 resistance-associated substitutions.

Besides type I interferons (IFNs), type III IFNs, including IFNλ1 (interleukin-29 [IL-29]), possess potent antiviral activity. In patients infected with the hepatitis C virus (HCV), it has been demonstrated that viral clearance is associated with genetic variation near the IFNλ3 (IL-28B) gene. The rapid influx of research being conducted on this family of cytokines has led to several inconsistencies and controversies, including the possible correlation of serum cytokine levels with disease in chronic viral hepatitis patients. In a detailed study, well-characterized cohorts of patients with HBV and HCV were evaluated with 3 different immunoassays, and no differences in the levels of serum IFNλ were observed between patient groups, disease stages, or clinical parameters.

Direct-acting antivirals (DAAs) are either part of the current standard of care or are in advanced clinical development for the treatment of patients chronically infected with hepatitis C virus (HCV) genotype 1, but concern exists with respect to the patients who fail these regimens with emergent drug-resistant variants. In the present study, ultradeep sequencing was performed to analyze resistance to daclatasvir (DCV), which is a highly selective nonstructural protein 5A (NS5A) inhibitor. Eight patients with HCV genotype 1b, who were either treatment naive or prior nonresponders to pegylated interferon plus ribavirin (Rebetol; Schering-Plough) (PEG-IFN/RBV) therapy, were treated with DCV combined with PEG-IFN alpha-2b (Pegintron; Schering-Plough, Kenilworth, NJ) and RBV. To identify the cause of viral breakthrough, the preexistence and emergence of DCV-resistant variants at NS5A amino acids were analyzed by ultradeep sequencing. Sustained virological response (SVR) was achieved in 6 of 8 patients (75%), with viral breakthrough occurring in the other 2 patients (25%). DCV-resistant variant Y93H preexisted as a minor population at higher frequencies (0.1% to 0.5%) in patients who achieved SVR. In patients with viral breakthrough, DCV-resistant variant mixtures emerged at NS5A-31 over time that persisted posttreatment with Y93H. Although enrichment of DCV-resistant variants was detected, the preexistence of a minor population of the variant did not appear to be associated with virologic response in patients treated with DCV/PEG-IFN/RBV. Ultradeep sequencing results shed light on the complexity of DCV-resistant quasispecies emerging over time, suggesting that multiple resistance pathways are possible within a patient who does not rapidly respond to a DCV-containing regimen. (This study has been registered at ClinicalTrials.gov under registration no. {"type":"clinical-trial","attrs":{"text":"NCT01016912","term_id":"NCT01016912"}}NCT01016912.)

The discovery of asunaprevir (BMS-650032, 24) is described. This tripeptidic acylsulfonamide inhibitor of the NS3/4A enzyme is currently in phase III clinical trials for the treatment of hepatitis C virus infection. The discovery of 24 was enabled by employing an isolated rabbit heart model to screen for the cardiovascular (CV) liabilities (changes to HR and SNRT) that were responsible for the discontinuation of an earlier lead from this chemical series, BMS-605339 (1), from clinical trials. The structure-activity relationships (SARs) developed with respect to CV effects established that small structural changes to the P2* subsite of the molecule had a significant impact on the CV profile of a given compound. The antiviral activity, preclincial PK profile, and toxicology studies in rat and dog supported clinical development of BMS-650032 (24).

The discovery of BMS-605339 (35), a tripeptidic inhibitor of the NS3/4A enzyme, is described. This compound incorporates a cyclopropylacylsulfonamide moiety that was designed to improve the potency of carboxylic acid prototypes through the introduction of favorable nonbonding interactions within the S1' site of the protease. The identification of 35 was enabled through the optimization and balance of critical properties including potency and pharmacokinetics (PK). This was achieved through modulation of the P2* subsite of the inhibitor which identified the isoquinoline ring system as a key template for improving PK properties with further optimization achieved through functionalization. A methoxy moiety at the C6 position of this isoquinoline ring system proved to be optimal with respect to potency and PK, thus providing the clinical compound 35 which demonstrated antiviral activity in HCV-infected patients.

All-oral combination therapy is desirable for patients with chronic hepatitis C virus (HCV) infection. We evaluated daclatasvir (an HCV NS5A replication complex inhibitor) plus sofosbuvir (a nucleotide analogue HCV NS5B polymerase inhibitor) in patients infected with HCV genotype 1, 2, or 3.In this open-label study, we initially randomly assigned 44 previously untreated patients with HCV genotype 1 infection and 44 patients infected with HCV genotype 2 or 3 to daclatasvir at a dose of 60 mg orally once daily plus sofosbuvir at a dose of 400 mg orally once daily, with or without ribavirin, for 24 weeks. The study was expanded to include 123 additional patients with genotype 1 infection who were randomly assigned to daclatasvir plus sofosbuvir, with or without ribavirin, for 12 weeks (82 previously untreated patients) or 24 weeks (41 patients who had previous virologic failure with telaprevir or boceprevir plus peginterferon alfa-ribavirin). The primary end point was a sustained virologic response (an HCV RNA level of25 IU per milliliter) at week 12 after the end of therapy.Overall, 211 patients received treatment. Among patients with genotype 1 infection, 98% of 126 previously untreated patients and 98% of 41 patients who did not have a sustained virologic response with HCV protease inhibitors had a sustained virologic response at week 12 after the end of therapy. A total of 92% of 26 patients with genotype 2 infection and 89% of 18 patients with genotype 3 infection had a sustained virologic response at week 12. High rates of sustained virologic response at week 12 were observed among patients with HCV subtypes 1a and 1b (98% and 100%, respectively) and those with CC and non-CC IL28B genotypes (93% and 98%, respectively), as well as among patients who received ribavirin and those who did not (94% and 98%, respectively). The most common adverse events were fatigue, headache, and nausea.Once-daily oral daclatasvir plus sofosbuvir was associated with high rates of sustained virologic response among patients infected with HCV genotype 1, 2, or 3, including patients with no response to prior therapy with telaprevir or boceprevir. (Funded by Bristol-Myers Squibb and Pharmasset (Gilead); A1444040 ClinicalTrials.gov number, NCT01359644.).

Please cite this article as: Hassanein, T., Sims, K.D., Bennett, M., Gitlin, N., Lawitz, E., Nguyen, T., Webster, L., Younossi, Z., Schwartz, H., Thuluvath, P.J., Zhou, H., Rege, B., McPhee, F., Zhou, N., Wind-Rotolo, M., Chung, E., Griffies, A., Grasela, D.M., Gardiner, D.F., A Randomized Trial of Daclatasvir in Combination With Asunaprevir and Beclabuvir in Patients With Chronic Hepatitis C Virus Genotype 4 Infection, Journal of Hepatology (2015), doi: http://dx.doi.org/10.1016/j.jhep.2014.12.025