Sofosbuvir-velpatasvir in adults with hepatitis C virus infection and compensated cirrhosis in Japan.

BACKGROUND & PURPOSE: Protease-free regimens for chronic hepatitis C virus (HCV) infection are safe and effective for persons with either compensated or decompensated cirrhosis. We examined the efficacy and safety of sofosbuvir-velpatasvir in participants with HCV and compensated cirrhosis in Japan. METHODS: This was a Phase 3, multi-center, open-label study. At 20 sites, 37 individuals with chronic HCV infection of any genotype and compensated cirrhosis received sofosbuvir-velpatasvir (400 mg/100 mg) daily for 12 weeks. Participants were treatment-naïve or treatment-experienced with interferon-based treatments with or without HCV NS3/4A protease inhibitors. Prior exposure with HCV NS5A or NS5B inhibitors was prohibited. The primary study endpoint was sustained virologic response 12 weeks after treatment (SVR12). RESULTS: Among participants, 62% had HCV genotype 1 infection, and 38% had HCV genotype 2. More than three quarters (29/37, 78%) were HCV treatment naïve. All participants (37/37, 100%) achieved SVR12. Seventeen participants (46%) and three participants (8%) had pretreatment resistance-associated substitutions to HCV NS5A and NS5B nucleoside inhibitors respectively, yet no on-treatment breakthrough or relapse occurred. Sofosbuvir-velpatasvir for 12 weeks treatment was safe and well tolerated. The most commonly reported adverse events were headache (8%, 3/37) and diarrhea (5%, 2/37). One serious adverse event, patella fracture, occurred and was considered not treatment related. No participants discontinued study treatment due to an adverse event. Three participants (8%) had a Grade 3 laboratory abnormality; all were hyperglycemia. CONCLUSION: Sofosbuvir-velpatasvir resulted in high SVR rates and was well tolerated among Japanese patients with HCV and compensated cirrhosis. This single-tablet regimen offers a highly effective, protease-inhibitor free regimen for treating HCV. CLINICALTRIALS: gov Identifier: NCT04112303.

Structure-activity relationship (SAR) studies on the mutagenic properties of 2,7-diaminofluorene and 2,7-diaminocarbazole derivatives.

We discovered that 2,7-diaminofluorene or 2,7-diaminocarbazole moiety can be employed as a core structure of highly effective NS5A inhibitors that are connected through amide bonds to proline-valine-carbamate motifs. Amide bonds can be easily cleaved via various metabolic pathways upon administration into the body, and metabolites containing 2,7-diaminofluorene and 2,7-diaminocarbazole core structures have been known to be strong mutagens. To avoid the mutagenesis issue of these core structures, we examined various functional groups at the C9 or N9 position of 2,7-diaminofluorene or 2,7-diaminocarbazole, respectively, through the Ames test in TA98 and TA100 mutants of Salmonella typhimurium LT-2. We discovered that, through proper alkyl substitution at the C9 or N9 position, 2,7-diaminofluorene and 2,7-diaminocarbazole moieties can be successfully employed in drug discovery without necessarily causing mutagenicity problems.

Cell Culture Studies of the Efficacy and Barrier to Resistance of Sofosbuvir-Velpatasvir and Glecaprevir-Pibrentasvir against Hepatitis C Virus Genotypes 2a, 2b, and 2c.

The introduction of highly efficient therapies with direct-acting antivirals (DAA) for patients with chronic hepatitis C virus (HCV) infection offers exceptional opportunities to globally control this deadly disease. For achieving this ambitious goal, it is essential to prevent antiviral resistance against the most optimal first-line and retreatment DAA choices. We performed independent comparisons of the efficacy and barrier to resistance of pangenotypic DAA regimens for HCV genotype 2 infections, using previously and newly developed efficient cell culture-adapted strains of subtypes 2a, 2b, and 2c. With the applied experimental cell culture conditions, combination treatment with the sofosbuvir-velpatasvir or glecaprevir-pibrentasvir DAA regimen was efficient in eradicating HCV infections; in contrast, single-drug treatments frequently led to viral escape. Sequence analysis of drug targets from recovered viruses revealed known resistance-associated substitutions (RAS) emerging in the NS3 protease or NS5A after treatment failure. These RAS were genetically stable after viral passage, and viruses with these RAS exhibited significant phenotypic resistance. After sofosbuvir treatment failure, only a genotype 2a virus harbored NS5B RAS S282T and thus had decreased susceptibility to nucleotide analogs (nucs). However, in most cases, viral escape from sofosbuvir led to other NS5B substitutions but drug susceptibility was maintained, and in one case, no changes in NS5B were detected. For a genotype 2b virus, after treatment failure with sofosbuvir-velpatasvir, the efficacy of retreatment with glecaprevir-pibrentasvir was maintained due to the high barrier to resistance and low cross-resistance of pibrentasvir. Our findings suggest the slight superiority of glecaprevir-pibrentasvir against genotype 2b in culture, which could have potential therapeutic interest meriting more definitive investigations in the clinic.

Eight weeks of sofosbuvir/velpatasvir for genotype 3 hepatitis C in previously untreated patients with significant (F2/3) fibrosis.

Twelve weeks sofosbuvir/velpatasvir (SOF/VEL) is a highly effective pan-genotypic regimen for hepatitis C. Phase 2 data suggest 8 weeks of treatment may be sufficient for previously untreated noncirrhotic patients with genotype 3 (GT3) infection. To maximize the number of patients potentially cured within a fixed treatment budget, we elected to treat such patients locally eligible for treatment (F2/3), with 8 weeks of SOF/VEL. By local protocol, treatment-naive patients with F2 (LSM > 6.9kPa < 9.5kPa) or F3 fibrosis (≥9.5kPa < 12.5kPa) were eligible for 8-week SOF/VEL treatment. Patients commencing treatment before 1 Oct 2017 were identified from the Scottish HCV database. Baseline and treatment outcome data obtained. Ninety patients were included for analysis (72 (80%) male, mean age 45 (IQR ± 8.4), 28 (31.1%) F3 fibrosis). Opioid agonist therapy (OAT) was prescribed in 82 (91.1%) patients. Of 49 patients attending Glasgow city Alcohol and Drug Services, 27 (55.1%) had evidence of recent drug use (< 3 months) including 8 (16.3%) with self-reported intravenous drug use. On an intention-to-treat basis, SVR rates were 86/90 (95.6%, 95% CI 89.0-98.8). Excluding those who prematurely discontinued treatment (n = 4), died prior to SVR testing (n = 1) or whom experienced reinfection (n = 1), per-protocol SVR rate was 84/84 (100%, 95% CI 95.7-100.0). In conclusion, eight-week SOF/VEL is highly effective in treatment-naive GT3 patients with significant fibrosis. This offers a non-protease inhibitor-based 8-week regimen which may be useful for complex drug interactions or where time-limited opportunity for treatment. In limited resource settings, reduction in drug acquisition costs may help achieve progress towards the goal of HCV elimination.

Real-world safety and effectiveness of retreatment of Egyptian chronic hepatitis C patients not responding to NS5A inhibitor-based therapies.

The aim of this study was to assess the efficacy and safety of two protocols for retreatment of a cohort of Egyptian patients with chronic hepatitis C (CHC) who relapsed after NS5A inhibitor-based therapy. We conducted a prospective cohort study to assess the safety and efficacy of 12 weeks' retreatment with either combination of sofosbuvir/daclatasvir/simeprevir plus ribavirin (SOF/DCV/SMV/RBV, n = 45) or sofosbuvir/ombitasvir/paritaprevir/ritonavir plus ribavirin (SOF/OBV/PTV/r/RBV, n = 163) in patients who had previously failed NS5A inhibitors-based regimens. The primary end point was SVR 12 weeks after the end of treatment (SVR12). Safety follow-up data were recorded for 60 weeks after the end of treatment. Two hundred-eight patients were included in the study. Of them, 53.4% of patients were females and 40.4% had liver cirrhosis. The most common prior drug combinations were sofosbuvir/daclatasvir (n = 94) and sofosbuvir/daclatasvir plus ribavirin (n = 109). The overall SVR12 rates were 98.1%. In SOF/DCV/SMV/RBV group, 95.6% achieved SVR12, while in SOF/OBV/PTV/r/RBV group, the SVR12 rates were 98.8%. SVR12 was higher in cirrhotic patients (84/84) than noncirrhotic (120/124), P value = .0149. Regarding the safety outcomes, anaemia and fatigue were significantly higher in SOF/OBV/PTV/r/RBV group. Hepatocellular carcinoma (HCC) was reported in eight (3.8%) patients (four in each group). Of them, death was confirmed in four patients. Retreatment of Egyptian CHC relapsed patients with either sofosbuvir/daclatasvir/simeprevir plus ribavirin or sofosbuvir/ombitasvir/paritaprevir/ritonavir plus ribavirin is highly effective and well-tolerated for both noncirrhotic and compensated cirrhotic patients. Incidental de novo HCC and hepatic decompensation are comparable in the two groups.

Development and validation of a LC-MS/MS method for simultaneous determination of TQ-A3326 and its major metabolites in human plasma, urine and feces: application to pharmacokinetic assay.

TQ-A3326 has been developed as a new drug by modifying the structure of daclatasvir with deuterium. The pharmacokinetics (PK) of TQ-A3326 in human remains unclear. The aim of the present study was to establish a LC-MS/MS method to investigate preliminarily the PK characteristics of TQ-A3326 and its major metabolites in healthy Chinese volunteers. All volunteers were administrated TQ-A3326 (60 mg). Plasma, feces and urine samples were extracted through protein precipitation. A rapid and sensitive LC-MS/MS method was successfully developed and applied to assess the PK properties of TQ-A3326. The AUC0-t and Cmax were 39516.3 ± 10778.5, 1034.6 ± 452.9 and 71.0 ± 49.5 ng·h·mL-1, and 1411.2 ± 325.4, 52.9 ± 16.4 and 1.8 ± 0.5 ng·mL-1, respectively, for TQ-A3326, M2-D and M4-D. Feces were the predominant route of elimination of TQ-A3326. M2-D was an abundant metabolite in feces and urine, representing 23.72% and 0.24% of the dose, respectively. The measurements of TQ-A3326 and its active metabolites would help to better understand the predominant route of elimination of the prototype drug, and provide meaningful information for further investigation of the bioactive mechanism of TQ-A3326 and its clinical applications.

Efficacy of glecaprevir and pibrentasvir treatment for genotype 1b hepatitis C virus drug resistance-associated variants in humanized mice.

Combination therapy with glecaprevir (GLE) and pibrentasvir (PIB) has high efficacy for pan-genotypic hepatitis C virus (HCV)-infected patients. However, the efficacy for patients who acquired potent NS5A inhibitor resistance-associated variants (RAVs) as a result of failure to respond to previous direct-acting antiviral (DAA) therapies is unclear. We investigated the efficacy of GLE/PIB treatment for genotype 1b HCV strains containing RAVs using subgenomic replicon systems and human hepatocyte transplanted mice. Mice were injected with serum samples obtained from a DAA-naïve patient or daclatasvir plus asunaprevir (DCV/ASV) treatment failures including NS5A-L31M/Y93H, -P58S/A92K or -P32 deletion (P32del) RAVs, then treated with GLE/PIB. HCV was eliminated by GLE/PIB treatment in mice with wild-type and NS5A-L31M/Y93H but relapsed in mice with NS5A-P58S/A92K, followed by emergence of additional NS5A mutations after cessation of the treatment. In NS5A-P32del-infected mice, serum HCV RNA remained positive during the GLE/PIB treatment. NS5A-P58S/A92K showed 1.5-fold resistance to PIB relative to wild-type based on analysis using HCV subgenomic replicon systems. When mice were administered various proportions of HCV wild-type and P32del strains and treated with GLE/PIB, serum HCV RNA remained positive in mice with high frequencies of P32del. In these mice, the P32del was undetectable by deep sequencing before GLE/PIB treatment, but P32del strains relapsed after cessation of the GLE/PIB treatment. GLE/PIB is effective for wild-type and NS5A-L31M/Y93H HCV strains, but the effect seems to be low for P58S/A92K and NS5A-P32del RAVs. Although NS5A-P32del was not detected, the mutation may be present at low frequency in DCV/ASV treatment failures.

In vitro resistance profile of hepatitis C virus NS5A inhibitor velpatasvir in genotypes 1 to 6.

Velpatasvir is a pan-genotypic hepatitis C virus (HCV) NS5A inhibitor, which is used with sofosbuvir for treatment of infection with HCV genotypes 1-6. In vitro resistance studies were performed to characterize NS5A changes that might confer reduced velpatasvir susceptibility in vivo. Resistance selection studies using HCV replicon cells for subtypes 1a, 1b, 2a, 2b, 3a, 4a, 5a and 6a identified NS5A resistance-associated substitutions (RASs) at nine positions, most often 28M/S/T, 31F/I/M/P/V and 93D/H/N/S. In subtype 1a, RASs were selected at positions 31 and/or 93, while in subtype 1b, replicons with two or more RASs at positions 31, 54 or 93 were selected. Y93H was selected in subtypes 1a, 1b, 2a, 3a and 4a. In subtype 5a or 6a, L31P or P32L/Q was selected, respectively. Velpatasvir susceptibility of 358 replicons from genotypes 1 to 6 containing one or more NS5A RASs was also evaluated. The majority (63%) of subtypes 1a and 1b single RAS-containing replicons retained susceptibility to velpatasvir (<2.5-fold change in EC50 ). High levels of resistance to velpatasvir were observed for six single mutants in subtype 1a, including M28G, A92K, Y93H/N/R/W and for one mutant, A92K, in subtype 1b. Most single mutants in subtypes 2a, 2b, 3a, 4a and 5a displayed low levels of reduced velpatasvir susceptibility. High-level resistance was observed for C92T and Y93H/N in subtype 2b, Y93H/S in 3a, and L31V and P32A/L/Q/R in 6a, and several double mutants in these subtypes. Overall, velpatasvir maintained activity against most common RASs that are known to confer resistance to first-generation NS5A inhibitors.

Deferred treatment with a fixed-dose combination of sofosbuvir-velpatasvir for chronic hepatitis C virus genotype 1, 2, 4 and 6 infection.

Sofosbuvir-velpatasvir is approved for the treatment of chronic hepatitis C virus (HCV) infection. In this single-arm, open-label, phase 3, deferred treatment study, we investigated the efficacy and safety of sofosbuvir-velpatasvir among patients randomized to the placebo group in the ASTRAL-1 study. Patients received sofosbuvir-velpatasvir (400/100 mg) once daily for 12 weeks. The primary efficacy endpoint was the proportion of patients with sustained virologic response 12 weeks after the end of therapy (SVR12). The primary safety endpoint was any adverse events (AEs) leading to the permanent discontinuation of study drug. Overall, 108/111 (97%, 95% confidence interval [CI], 92%-99%) achieved SVR12, and only one patient had virological failure. SVR12 was achieved by 61/63 (97%, 95%CI, 89%-100%) genotype 1 patients, 20/20 (100%; 95%CI, 83%-100%) with genotype 2, 19/19 (100%; 95%CI, 82%-100%) with genotype 4 and 8/9 (89%; 95% CI, 52%-100%) with genotype 6. All (19/19; 95%CI, 82-100) patients with cirrhosis and all (31/31, 95%CI, 89-100) with prior treatment experience achieved SVR12. The safety profile during treatment was similar to that observed in patients receiving placebo treatment. The most common AEs were headache, fatigue and nausea. One patient (1%) discontinued treatment due to an AE of gallbladder carcinoma, which was not considered related to treatment. Of five reported serious AEs, none were considered related to study drug. Sofosbuvir-velpatasvir for 12 weeks was effective and well tolerated among untreated and previously treated patients with HCV genotype 1, 2, 4 or 6 infection, including those with compensated cirrhosis (ClinicalTrials.gov NCT02346721).

Favorable efficacy of glecaprevir plus pibrentasvir as salvage therapy for HCV failures to prior direct-acting antivirals regimens.

In real-world settings, not much information is probably available on the treatment efficacy of the combination of glecaprevir and pibrentasvir (G/P) as a salvage therapy in failures of prior direct-acting antiviral (DAA) regimens. Especially, the evolution of NS5A resistance-associated variants (RAVs) and treatment efficacy in patients who received G/P for failures of prior treatment more than once is unknown. Twenty patients, who were exposed to glecaprevir 300 mg/d and pibrentasvir 120 mg/d for 12 weeks in failures of prior DAAs regimens were evaluated for sustained virological response at 12 weeks after the end of treatment (SVR12). The overall rate of SVR12 was 100%, based on intention-to-treat analysis. Five patients infected with genotype 1b, who received G/P for failures of prior treatment more than once, were analyzed for the evolution of RAVs in NS5A region. All of the five patients exhibited SVR12, regardless of the numbers of times of prior treatment (more than once), prior treatment response (nonresponse), and fibrosis stage (FIB-4 index ≥ 3.25). At the commencement of G/P, all five patients were detected with NS5A RAVs at the position of aa 93. Four patients, except for one, were detected with RAVs at both positions of aa 31 and aa 93 (double mutation). All patients could achieve SVR12 with G/P, regardless of the emergence of NS5A RAVs, accompanied by failure to prior NS5A regimens more than once. In conclusion, our study indicated that G/P was a potentially useful salvage treatment for patients who failed prior DAAs regimens more than once.

Discovery of novel pan-genotypic HCV NS5A inhibitors containing a novel tetracyclic core.

A series of novel tetracyclic core-containing HCV NS5A inhibitors has been discovered. Incorporation of tetrahydropyran-substituted amino acid moiety improved their potency and yielded HCV NS5A inhibitors with a minimum potency shift from the GT1a strain compared to other genotypes and mutants. Compounds 53 and 54 showed the best potency profile and had reasonable half-times in rat PK studies. However, further optimization of their oral bioavailability is still needed in order to advance them for further development. [BMCL ABSTRACT] ©2000 Elsevier Science Ltd. All rights reserved.

Sofosbuvir/velpatasvir for 12 weeks in genotype 1-4 HCV-infected liver transplant recipients.

BACKGROUND & AIMS: Sofosbuvir, an NS5B inhibitor, combined with velpatasvir, an NS5A inhibitor (SOF/VEL), produces high sustained virologic response rates 12 weeks after treatment (SVR12) in patients with genotype 1-6 HCV infection, and has no anticipated clinically relevant drug-drug interactions with immunosuppressants. This study evaluated the safety and efficacy of SOF/VEL in adults with recurrent chronic genotype 1-4 HCV infection after liver transplant. METHODS: Patients received SOF/VEL 400/100 mg daily for 12 weeks. Patients could be treatment experienced or treatment naïve with no cirrhosis or with compensated cirrhosis. The primary endpoints were SVR12 and discontinuations due to adverse events. RESULTS: A total of 79 patients were enrolled and treated in this study (37 [47%] had genotype 1, 3 [4%] genotype 2, 35 [44%] genotype 3, and 4 [5%] genotype 4 HCV). Of these, 81% were male, 82% were white, 18% had compensated cirrhosis, and 59% were treatment experienced. The most commonly used immunosuppressants were tacrolimus (71%), mycophenolic acid (24%), cyclosporine (14%), and azathioprine (11%). Median (range) time from liver transplantation was 7.5 (0.3, 23.9) years. The SVR12 rate was 96%. By genotype, SVR12 rates were 95% (genotype 1), 100% (genotype 2), 97% (genotype 3), and 100% (genotype 4). Two patients experienced virologic relapse: one with genotype 1a infection was non-cirrhotic and treatment naïve, and one with genotype 3 infection was non-cirrhotic and treatment experienced. One patient discontinued SOF/VEL due to hyperglycemia. No serious or severe adverse events were deemed SOF/VEL-related by the investigator, and no liver transplant rejection episodes or deaths occurred during the study period. CONCLUSIONS: Treatment with SOF/VEL for 12 weeks was highly effective and well tolerated in genotype 1-4 HCV-infected liver transplant recipients with and without cirrhosis. LAY SUMMARY: Sofosbuvir/velpatasvir is a combination of two drugs in one tablet that is approved for the treatment of patients with chronic hepatitis C virus (HCV) infection. When patients with chronic HCV infection receive a liver transplant, the HCV infection usually recurs, and damages the transplanted liver. This study tested the effects of 12 weeks of sofosbuvir/velpatasvir treatment in patients who had HCV recurrence after a liver transplant. Three months following the end of treatment, 96% of patients were cured of HCV infection. Clinical trial number: NCT02781571.

Integrated Resistance Analysis of CERTAIN-1 and CERTAIN-2 Studies in Hepatitis C Virus-Infected Patients Receiving Glecaprevir and Pibrentasvir in Japan.

Glecaprevir and pibrentasvir are hepatitis C virus (HCV) pangenotypic inhibitors targeting NS3/4A protease and NS5A, respectively. This once-daily, fixed-dose combination regimen demonstrated high sustained virologic response 12 weeks postdosing (SVR12) rates in CERTAIN-1 and CERTAIN-2 studies in Japanese HCV-infected patients, with a low virologic failure rate (1.2%). There were no virologic failures among direct-acting antiviral (DAA)-treatment-naive genotype 1a (GT1a) (n = 4)-, GT1b (n = 128)-, and GT2 (n = 97)-infected noncirrhotic patients treated for 8 weeks or among GT1b (n = 38)- or GT2 (n = 20)-infected patients with compensated cirrhosis treated for 12 weeks. Two of 33 DAA-experienced and 2 of 12 GT3-infected patients treated for 12 weeks experienced virologic failure. Pooled resistance analysis, grouped by HCV subtype, treatment duration, prior treatment experience, and cirrhosis status, was conducted. Among DAA-naive GT1b-infected patients, the baseline prevalence of NS3-D168E was 1.2%, that of NS5A-L31M was 3.6%, and that of NS5A-Y93H was 17.6%. Baseline polymorphisms in NS3 or NS5A were less prevalent in GT2, with the exception of the common L/M31 polymorphism in NS5A. Among DAA-experienced GT1b-infected patients (30/32 daclatasvir plus asunaprevir-experienced patients), the baseline prevalence of NS3-D168E/T/V was 48.4%, that of NS5A-L31F/I/M/V was 81.3%, that of the NS5A P32deletion was 6.3%, and that of NS5A-Y93H was 59.4%. Common baseline polymorphisms in NS3 and/or NS5A had no impact on treatment outcomes in GT1- and GT2-infected patients; the impact on GT3-infected patients could not be assessed due to the enrollment of patients infected with diverse subtypes and the limited number of patients. The glecaprevir-pibrentasvir combination regimen allows a simplified treatment option without the need for HCV subtyping or baseline resistance testing for DAA-naive GT1- or GT2-infected patients. (The CERTAIN-1 and CERTAIN-2 studies have been registered at ClinicalTrials.gov under identifiers NCT02707952 and NCT02723084, respectively.).

Pooled Resistance Analysis in Patients with Hepatitis C Virus Genotype 1 to 6 Infection Treated with Glecaprevir-Pibrentasvir in Phase 2 and 3 Clinical Trials.

Over 2,200 patients infected with hepatitis C virus (HCV) genotypes (GT) 1 to 6, with or without cirrhosis, who were treatment naive or experienced to interferon, ribavirin, and/or sofosbuvir were treated with glecaprevir/pibrentasvir for 8, 12, or 16 weeks in eight registrational phase 2 and 3 clinical studies. High rates of sustained virologic response at 12 weeks postdosing (SVR12) were achieved with a <1% virologic failure (VF) rate. The prevalence of baseline polymorphisms (BPs) in NS3 at amino acid position 155 or 168 was low (<3%) in patients infected with GT1, GT2, GT3, GT4, and GT6, while 41.9% of the GT5-infected patients had NS3-D168E; BPs were not detected at position 156 in NS3. The prevalence of NS5A-BPs was high across genotypes, driven by common polymorphisms at amino acid position 30 or 31 in GT2, 58 in GT4, and 28 in GT6. The prevalence of NS5A T/Y93 polymorphisms was 5.5% in GT1, 4.9% in GT3, and 12.5% in GT6. Consistent with the activity of glecaprevir and pibrentasvir against most amino acid polymorphisms in vitro, BPs in NS3 and/or NS5A did not have an impact on treatment outcome for patients infected with GT1 to GT6, with the exception of treatment-experienced GT3-infected patients treated for 12 weeks, for whom a 16-week regimen of glecaprevir/pibrentasvir was required to achieve SVR12 rates of ≥95%. Among the 22 patients experiencing VF, treatment-emergent substitutions were detected in NS3 in 50% of patients and in NS5A in 82% of patients, frequently as a combination of substitutions that conferred resistance to glecaprevir and/or pibrentasvir. The glecaprevir/pibrentasvir regimen, when the recommended durations are used, allows for a pan-genotypic treatment option without the need for baseline resistance testing.

Efficacy of Ledipasvir Plus Sofosbuvir for 8 or 12 Weeks in Patients With Hepatitis C Virus Genotype 2 Infection.

BACKGROUND & AIMS: Patients with chronic hepatitis C virus (HCV) genotype 2 have high rates of response to treatment with sofosbuvir and ribavirin. However, ribavirin is associated with hemolytic events and is poorly tolerated by some patients. We evaluated the effectiveness of sofosbuvir and ledipasvir in treatment-naïve and treatment-experienced patients with HCV genotype 2, comparing 12 versus 8 weeks of treatment. METHODS: This Phase 2, open-label study included 2 cohorts in New Zealand. The first received a fixed-dose combination tablet of ledipasvir-sofosbuvir (90/400 mg) once daily for 12 weeks. If this cohort had a 90% rate of sustained virologic response (SVR) 4 weeks after treatment, a second cohort receiving 8 weeks of ledipasvir-sofosbuvir was to be enrolled. The primary endpoint in both cohorts was the percentage of patients with HCV RNA <15 IU/mL 12 weeks after therapy (SVR12). RESULTS: SVR12 rates were 96% (25/26; 95% CI, 80%-100%) for 12 weeks and 74% (20/27; 95% CI, 54%-89%) for 8 weeks of ledipasvir-sofosbuvir. The single patient receiving 12 weeks of ledipasvir-sofosbuvir who did not reach SVR12 did not complete treatment because of withdrawing consent after receiving 1 dose of study drug. Six of the 7 patients who did not reach SVR12 after 8 weeks of treatment experienced virologic relapse after stopping therapy. The most common adverse events were headache (26% of patients), fatigue (21%), and nausea (17%). No patients discontinued treatment because of an adverse event. CONCLUSIONS: For treatment-naïve and -experienced patients, ledipasvir-sofosbuvir for 12 weeks is highly effective for the treatment of HCV genotype 2 (ClinicalTrials.gov: NCT02202980).

Prevalence of NS5A resistance associated variants in NS5A inhibitor treatment failures and an effective treatment for NS5A-P32 deleted hepatitis C virus in humanized mice.

Patients with chronic hepatitis C virus (HCV) infection who have failed to respond to direct-acting antiviral (DAA) treatment often acquire drug resistance-associated variants (RAVs). The NS5A-P32 deletion (P32del) RAV confers potent resistance to NS5A inhibitors; therefore, patients who acquire this deletion are likely to fail to respond to DAA re-treatment. We investigated the prevalence of N55A-P32del in patients who failed to respond to prior NS5A inhibitor treatment using direct sequencing and analyzed the efficacy of DAA combination treatment in the presence of NS5A-P32del RAVs using human hepatocyte transplanted mice. NS5A-P32del was detected in one of 23 (4.3%) patients who had failed to respond to prior NS5A inhibitor treatment. Although four weeks of NS3/4A protease inhibitor glecaprevir plus NS5A inhibitor pibrentasvir treatment effectively suppressed HCV replication in wild-type HCV-infected mice, serum HCV RNA never became negative in P32del HCV-infected mice. When P32del HCV-infected mice were treated with four weeks of glecaprevir plus pibrentasvir combined with the NS5B polymerase inhibitor sofosbuvir, serum HCV RNA became negative, and the virus was eliminated from the liver in three out of four mice. We conclude that the combination of sofosbuvir and glecaprevir plus pibrentasvir may be an effective new treatment option for patients with NS5A-P32del.

Sofosbuvir/velpatasvir in patients with hepatitis C virus genotypes 1-6 and compensated cirrhosis or advanced fibrosis.

BACKGROUND & AIMS: Patients with chronic hepatitis C virus infection and advanced fibrosis (Metavir F3) or cirrhosis (Metavir F4) have been identified as a priority group for immediate treatment. We evaluated the safety and efficacy of sofosbuvir-velpatasvir in patients with hepatitis C virus genotype 1-6 infection and compensated cirrhosis or advanced fibrosis. METHODS: This retrospective analysis included 501 patients with compensated cirrhosis or advanced fibrosis (F3/F4), as defined by >0.59 on Fibrotest, >9.5 kPa on Fibroscan, or F3/F4 (Metavir) or F4 (Ishak) on liver biopsy. Patients received sofosbuvir-velpatasvir for 12 weeks. Sustained virological response 12 weeks after treatment was determined. RESULTS: Forty-four per cent of patients had cirrhosis. Sustained virological response 12 weeks after treatment was achieved by 98% of patients (490/501; 95% confidence interval, 96-99). Sustained virological response 12 weeks after treatment rates were 100% for hepatitis C virus genotypes 2 (85/85), 4 (60/60), 5 (13/13), and 6 (20/20). Sustained virological response 12 weeks after treatment rates were 98% (167/170) in hepatitis C virus genotype 1 patients and 95% (145/153) in hepatitis C virus genotype 3 patients. Among patients with cirrhosis 96% (212/220) achieved sustained virological response 12 weeks after treatment, vs 99% (278/281) for those with advanced fibrosis. Sustained virological response 12 weeks after treatment was 98% (306/311) for treatment-naïve patients and 97% (184/190) for treatment-experienced patients. No patients discontinued treatment due to adverse events. Eight patients reported nine serious adverse events; none was considered related to study procedures or drugs. CONCLUSIONS: Sofosbuvir plus velpatasvir is highly effective and safe for treating patients with hepatitis C virus genotypes 1, 2, 3, 4, 5 or 6 and advanced fibrosis or compensated cirrhosis.

Preclinical Pharmacokinetics and First-in-Human Pharmacokinetics, Safety, and Tolerability of Velpatasvir, a Pangenotypic Hepatitis C Virus NS5A Inhibitor, in Healthy Subjects.

Preclinical characterization of velpatasvir (VEL; GS-5816), an inhibitor of the hepatitis C virus (HCV) NS5A protein, demonstrated that it has favorable in vitro and in vivo properties, including potent antiviral activity against hepatitis C virus genotype 1 to 6 replicons, good metabolic stability, low systemic clearance, and adequate bioavailability and physicochemical properties, to warrant clinical evaluation. The phase 1 (first-in-human) study evaluated the safety, tolerability, and pharmacokinetics of VEL in healthy human subjects following administration of single and multiple (n = 7) once-daily ascending doses and of VEL in the presence and absence of food. Following administration of single and multiple doses, VEL was safe and well tolerated when administered at up to 450 mg and when administered with food. The pharmacokinetic behavior of VEL observed in humans was generally in agreement with that seen during preclinical characterization. Following administration of multiple doses, VEL trough concentrations were significantly greater than the protein-adjusted half-maximal (50%) effective concentration of VEL against HCV genotype 1 to 6 replicons at all evaluated doses greater than 5 mg. The pharmacokinetics of VEL were not significantly affected by administration with food. Collectively, the results of this study support the further clinical investigation of VEL administered once daily as part of a regimen with other pangenotypic direct-acting antivirals for the treatment of HCV infection.

In Vitro Antiviral Activity and Resistance Profile of the Next-Generation Hepatitis C Virus NS5A Inhibitor Pibrentasvir.

Pibrentasvir (ABT-530) is a novel and pan-genotypic hepatitis C virus (HCV) NS5A inhibitor with 50% effective concentration (EC50) values ranging from 1.4 to 5.0 pM against HCV replicons containing NS5A from genotypes 1 to 6. Pibrentasvir demonstrated similar activity against a panel of chimeric replicons containing HCV NS5A of genotypes 1 to 6 from clinical samples. Resistance selection studies were conducted using HCV replicon cells with NS5A from genotype 1a, 1b, 2a, 2b, 3a, 4a, 5a, or 6a at a concentration of pibrentasvir that was 10- or 100-fold over its EC50 for the respective replicon. With pibrentasvir at 10-fold over the respective EC50, only a small number of colonies (0.00015 to 0.0065% of input cells) with resistance-associated amino acid substitutions were selected in replicons containing genotype 1a, 2a, or 3a NS5A, and no viable colonies were selected in replicons containing NS5A from other genotypes. With pibrentasvir at 100-fold over the respective EC50, very few colonies (0.0002% of input cells) were selected by pibrentasvir in genotype 1a replicon cells while no colonies were selected in other replicons. Pibrentasvir is active against common resistance-conferring substitutions in HCV genotypes 1 to 6 that were identified for other NS5A inhibitors, including those at key amino acid positions 28, 30, 31, or 93. The combination of pibrentasvir with HCV inhibitors of other classes produced synergistic inhibition of HCV replication. In summary, pibrentasvir is a next-generation HCV NS5A inhibitor with potent and pan-genotypic activity, and it maintains activity against common amino acid substitutions of HCV genotypes 1 to 6 that are known to confer resistance to currently approved NS5A inhibitors.

Effectiveness of Ledipasvir-Sofosbuvir Combination in Patients With Hepatitis C Virus Infection and Factors Associated With Sustained Virologic Response.

BACKGROUND & AIMS: The combination of ledipasvir and sofosbuvir has been approved for treatment of genotype 1 hepatitis C virus (HCV) infection, including an 8-week regimen for treatment-naïve patients without cirrhosis and a baseline level of HCV RNA <6 million IU/mL. We analyzed data from a multicenter, prospective, observational study to determine real-world sustained virologic responses 12 weeks after treatment (SVR12) with regimens containing ledipasvir and sofosbuvir and identify factors associated with treatment failure. METHODS: We collected data from 2099 participants in the HCV-TARGET study with complete virologic data (per-protocol population). We analyzed data from 1788 patients receiving ledipasvir-sofosbuvir (282 for 8 weeks, 910 for 12 weeks, 510 for 24 weeks, and 86 for a different duration) and 311 receiving ledipasvir-sofosbuvir plus ribavirin (212 for 12 weeks and 81 for 24 weeks, 18 for other duration) to estimate SVR12 (with 95% confidence interval [CI]), and logistic regression methods to identify factors that predicted an SVR12. RESULTS: The overall study population was 25% black, 66% with HCV genotype 1A infection, 41% with cirrhosis, 50% treatment-experienced, and 30% receiving proton pump inhibitors at start of treatment. In the per-protocol population, SVR12s were achieved by 96% of patients receiving ledipasvir-sofosbuvir for 8 weeks (95% CI, 93%-98%), 97% receiving the drugs for 12 weeks (95% CI, 96%-98%), and 95% receiving the drugs for 24 weeks (95% CI, 93%-97%). Among patients also receiving ribavirin, SVR12 was achieved by 97% of the patients receiving the drugs for 12 weeks (95% CI, 94%-99%) and 95% receiving the drugs for 24 weeks (95% CI, 88%-99%). Of the 586 patients who qualified for 8 weeks of treatment, only 255 (44%) received the drugs for 8 weeks. The rate of SVR12 among those who qualified for and received 8 weeks of therapy was similar in those who qualified for 8 weeks but received 12 weeks therapy (96%; 95% CI, 92%-99% vs 98%; 95% CI, 95%-99%). Factors that predicted SVR12 were higher albumin (≥3.5 g/dL), lower total bilirubin (≤1.2 g/dL), absence of cirrhosis, and absence of proton pump inhibitor use. CONCLUSIONS: Regimens containing ledipasvir and sofosbuvir are highly effective for a broad spectrum of patients with HCV genotype 1 infection treated in different clinical practice settings. Expanded use of 8-week treatment regimens for eligible patients is supported by these real-world results. Modification of proton pump inhibitor use may increase rates of SVR. ClinicalTrials.gov no. NCT01474811.