Efficacy and safety of the novel capsid inhibitor lenacapavir to treat multidrug-resistant HIV: week 52 results of a phase 2/3 trial.

BACKGROUND: Lenacapavir, a first-in-class HIV-1 capsid inhibitor, is in development as a long-acting agent for treating and preventing HIV-1. We aimed to evaluate the efficacy and safety of lenacapavir with an optimised background regimen in adults living with multidrug-resistant HIV-1 up to 52 weeks. METHODS: This ongoing, international, phase 2/3 trial at 42 sites included adults living with multidrug-resistant HIV-1. In cohort 1, 36 participants were randomly assigned (2:1) to add oral lenacapavir (600 mg, days 1 and 2; 300 mg, day 8) or placebo to an existing failing regimen. At day 15, those on oral lenacapavir received subcutaneous lenacapavir 927 mg every 26 weeks; those on placebo started lenacapavir (2-week oral lead-in then subcutaneous). Cohort 1 started an optimised background regimen on day 15. In cohort 2 (non-randomised), 36 participants started an optimised background regimen concurrent with lenacapavir (oral to subcutaneous). Here we report the secondary endpoints of plasma HIV-1 RNA of less than 50 copies per mL or less than 200 copies per mL at week 52 (US Food and Drug Administration snapshot algorithm) in cohort 1 along with results for cohorts 1 and 2 combined. This trial is registered with ClinicalTrials.gov, NCT04150068, and clinicaltrialregister.eu, EudraCT 2019-003814-16 and is ongoing. FINDINGS: Of 72 participants, 46 (64%) had CD4 counts of less than 200 cells per µL and 38 (53%) had no more than one fully active antiretroviral drug at baseline. In cohort 1, 30 of 36 participants (83%, 95% CI 67-94) had less than 50 HIV-1 RNA copies per mL and 31 of 36 participants (86%, 71-95) had less than 200 HIV RNA copies per mL, at week 52. In all, nine participants (four in cohort 1, five in cohort 2) had emergent lenacapavir resistance; four resuppressed (HIV-1 RNA <50 copies per mL) while maintaining lenacapavir use. One participant discontinued study drug owing to injection site reaction. INTERPRETATION: In participants with multidrug-resistant HIV-1, subcutaneous lenacapavir in combination with an optimised background regimen resulted in a high rate of virological suppression up to 52 weeks. FUNDING: Gilead Sciences.

Lenacapavir administered every 26 weeks or daily in combination with oral daily antiretroviral therapy for initial treatment of HIV: a randomised, open-label, active-controlled, phase 2 trial.

BACKGROUND: Antiretroviral agents with novel mechanisms and dosing intervals could expand treatment options for people with HIV. Lenacapavir, an inhibitor of capsid protein that makes use of a unique mechanism, can be administered orally or subcutaneously. We sought to explore the efficacy of lenacapavir in various combination regimens as initial and maintenance therapy for HIV. METHODS: In a phase 2, randomised, open-label, ongoing study at 41 investigational sites in the USA and Dominican Republic, we randomly assigned adults with HIV who had not previously received antiretrovirals to four groups (2:2:2:1). Randomisation was stratified by plasma HIV-1 RNA load (≤100 000 or >100 000 copies per mL) at screening. Groups 1 and 2 both received lenacapavir (927 mg) subcutaneously every 26 weeks (after 2 weeks of oral loading [600 mg on days 1 and 2, followed by 300 mg on day 8]) with oral daily emtricitabine (200 mg) and tenofovir alafenamide (25 mg) for 28 weeks followed by subcutaneous lenacapavir (927 mg) plus oral daily tenofovir alafenamide (25 mg, group 1) or bictegravir (75 mg, group 2). Group 3 received oral daily lenacapavir (600 mg on days 1 and 2, followed by 50 mg daily) with emtricitabine (200 mg) and tenofovir alafenamide (25 mg). Group 4 received oral daily bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg). Participants and investigators were not masked to group assignment. The primary endpoint was the percentage of participants with virological suppression (HIV-1 RNA <50 copies per mL) at week 54, analysed in the full analysis set (all randomly assigned participants who received at least one dose of study drug) using only on-treatment data. The safety outcome measures were incidences of treatment-emergent adverse events and graded laboratory abnormalities, analysed in the full analysis set. This study is registered at ClinicalTrials.gov, NCT04143594. FINDINGS: Between Nov 22, 2019, and Aug 27, 2020, 249 people with HIV were screened, 183 participants were randomly assigned and 182 received a dose of antiretroviral drugs (52 in group 1, 53 in group 2, 52 in group 3, and 25 in group 4). 22 participants did not complete the full study course (five in group 1, 12 in group 2, four in group 3, and one in group 4). At week 54, virological suppression was 90% (47 of 52 patients) for group 1 (difference vs group 4: -2·6%, 95% CI -18·4 to 13·2), 85% (45 of 53) for group 2 (-7·1%, -23·4 to 9·3), 85% (44 of 52) for group 3 (-7·2%, -23·5 to 9·1), and 92% (23 of 25) for group 4. The most frequent non-injection-site adverse events with lenacapavir (subcutaneous or oral) were headache (13%, 21 of 157) and nausea (13%, 21 of 157). The most common lenacapavir-related injection-site reactions were erythema (27%, 28 of 105), swelling (23%, 24 of 105), and pain (19%, 20 of 105), which were generally mild or moderate. No serious adverse event related to study treatment occurred. Three participants discontinued subcutaneous lenacapavir because of grade 1 injection-site reactions (two for induration and one for erythema or swelling). INTERPRETATION: Lenacapavir warrants further investigation as a potential antiretroviral used orally and as injection in combination with other antiretroviral drugs. FUNDING: Gilead Sciences.

Resistance Analyses in Highly Treatment-Experienced People With Human Immunodeficiency Virus (HIV) Treated With the Novel Capsid HIV Inhibitor Lenacapavir.

BACKGROUND: Lenacapavir (LEN) is a first-in-class inhibitor of human immunodeficiency virus type 1 (HIV-1) capsid function in clinical development for the treatment of heavily treatment-experienced (HTE) people with HIV (PWH) harboring multidrug resistance (MDR) in combination with an optimized background regimen (OBR). Here we describe resistance analyses conducted in the pivotal phase 2/3 CAPELLA study. METHODS: CAPELLA enrolled viremic HTE PWH with resistance to ≥3 of 4 of the main antiretroviral (ARV) classes and resistance to ≥2 ARV drugs per class. Baseline resistance analyses used commercial assays (HIV-1 protease, reverse transcriptase, integrase genotypic/phenotypic tests). Postbaseline resistance was evaluated in participants experiencing virologic failure. RESULTS: At baseline, 46% of participants had resistance to the 4 main ARV drug classes, with one-third of participants having exhausted all drugs from ≥3 of the 4 main ARV classes. Treatment with LEN + OBR for 26 weeks led to viral suppression in 81% of participants. Postbaseline resistance mutations to lenacapavir occurred in 8 participants (6 with M66I, 1 with K70H, 1 with Q67H + K70R) who were receiving unintended functional LEN monotherapy at the time of resistance selection. CONCLUSIONS: LEN added to OBR led to high efficacy in this HTE patient population with MDR but could select for resistance when used unintentionally as functional monotherapy.

Capsid Inhibition with Lenacapavir in Multidrug-Resistant HIV-1 Infection.

BACKGROUND: Patients with multidrug-resistant human immunodeficiency virus type 1 (HIV-1) infection have limited treatment options. Lenacapavir is a first-in-class capsid inhibitor that showed substantial antiviral activity in a phase 1b study. METHODS: In this phase 3 trial, we enrolled patients with multidrug-resistant HIV-1 infection in two cohorts, according to the change in the plasma HIV-1 RNA level between the screening and cohort-selection visits. In cohort 1, patients were first randomly assigned in a 2:1 ratio to receive oral lenacapavir or placebo in addition to their failing therapy for 14 days; during the maintenance period, starting on day 15, patients in the lenacapavir group received subcutaneous lenacapavir once every 6 months, and those in the placebo group received oral lenacapavir, followed by subcutaneous lenacapavir; both groups also received optimized background therapy. In cohort 2, all the patients received open-label oral lenacapavir with optimized background therapy on days 1 through 14; subcutaneous lenacapavir was then administered once every 6 months starting on day 15. The primary end point was the percentage of patients in cohort 1 who had a decrease of at least 0.5 log10 copies per milliliter in the viral load by day 15; a key secondary end point was a viral load of less than 50 copies per milliliter at week 26. RESULTS: A total of 72 patients were enrolled, with 36 in each cohort. In cohort 1, a decrease of at least 0.5 log10 copies per milliliter in the viral load by day 15 was observed in 21 of 24 patients (88%) in the lenacapavir group and in 2 of 12 patients (17%) in the placebo group (absolute difference, 71 percentage points; 95% confidence interval, 35 to 90). At week 26, a viral load of less than 50 copies per milliliter was reported in 81% of the patients in cohort 1 and in 83% in cohort 2, with a least-squares mean increase in the CD4+ count of 75 and 104 cells per cubic millimeter, respectively. No serious adverse events related to lenacapavir were identified. In both cohorts, lenacapavir-related capsid substitutions that were associated with decreased susceptibility developed in 8 patients during the maintenance period (6 with M66I substitutions). CONCLUSIONS: In patients with multidrug-resistant HIV-1 infection, those who received lenacapavir had a greater reduction from baseline in viral load than those who received placebo. (Funded by Gilead Sciences; CAPELLA ClinicalTrials.gov number, NCT04150068.).

Lenacapavir: a first-in-class HIV-1 capsid inhibitor.

PURPOSE OF REVIEW: This review summarizes available data for lenacapavir, an investigational first-in-class agent that disrupts functioning of HIV capsid protein across multiple steps in the viral life cycle. RECENT FINDINGS: Lenacapavir demonstrated picomolar potency in vitro with no cross resistance to existing antiretroviral classes and potent antiviral activity in persons with HIV-1. In persons with HIV-1, there was no preexisting resistance to lenacapavir regardless of treatment history. Lenacapavir can be administered orally either daily or weekly and subcutaneously up to every 6 months. In heavily treatment-experienced persons with multidrug-resistant HIV-1 and in treatment-naive persons with HIV-1, lenacapavir in combination with other antiretroviral agents led to high rates of virologic suppression and was well tolerated. SUMMARY: Ongoing studies are evaluating long-acting dosing of lenacapavir for treating HIV-1 in combination with other antiretrovirals and preventing HIV-1 as a single agent.

Ledipasvir/Sofosbuvir for 8, 12, or 24 Weeks in Hepatitis C Patients Undergoing Dialysis for End-Stage Renal Disease.

INTRODUCTION: We evaluated 8, 12, or 24 weeks of ledipasvir/sofosbuvir in patients with hepatitis C virus and end-stage renal disease undergoing dialysis. METHODS: Primary efficacy end point was sustained virologic response 12 weeks after treatment. Primary safety end point was treatment discontinuation because of adverse events (AEs). RESULTS: Ninety-four percent (89/95) achieved sustained virologic response 12 weeks after treatment. Six patients died during treatment (n = 4) or before study completion (n = 2); no deaths were related to treatment. No patients discontinued treatment because of AEs. Thirteen percent had serious AEs; none were related to treatment. DISCUSSION: Treatment with ledipasvir/sofosbuvir was safe and effective in patients with end-stage renal disease undergoing dialysis.

Twelve weeks of ledipasvir/sofosbuvir all-oral regimen for patients with chronic hepatitis C genotype 2 infection: Integrated analysis of three clinical trials.

AIM: The combination of ledipasvir and sofosbuvir (LDV/SOF) has been approved for the treatment of various hepatitis C virus (HCV) genotypes across many countries. This article presents an integrated analysis of three prospective phase II/III trials in the Asia-Pacific region to evaluate the efficacy and safety of 12 weeks of LDV/SOF in HCV genotype 2 patients without cirrhosis or with compensated cirrhosis. METHODS: A total of 200 patients were included in the integrated analysis. The primary end-point was the rate of sustained virologic response for 12 weeks after the end of therapy (SVR12), analyzed by fibrosis stage, treatment history, HCV genotype subtype, and presence of baseline resistance-associated substitutions (RAS). Safety was evaluated by adverse events and laboratory abnormalities. RESULTS: Twelve weeks of treatment with LDV/SOF was associated with high SVR12 rates (overall 98%) in patients with genotype 2 HCV, irrespective of fibrosis stage, treatment history, genotype 2 subtype, and presence of baseline non-structural protein 5A resistance-associated substitution (NS5A RAS), and LDV/SOF was well tolerated. CONCLUSIONS: Twelve weeks of treatment with LDV/SOF provides a highly effective and safe treatment for patients with genotype 2 HCV, including those with advanced fibrosis. As a ribavirin-free and protease inhibitor-free regimen with minimal on-treatment monitoring requirements, LDV/SOF can potentially play a crucial role in achieving the WHO's goal of HCV elimination.

Sofosbuvir susceptibility of genotype 1 to 6 HCV from DAA-naïve subjects.

High sequence diversity of HCV may lead to variation in susceptibility to antiviral agents amongst different genotypes and subtypes of the virus. We assessed the susceptibility to sofosbuvir of chimeric replicons carrying the full length NS5B coding region from 479 HCV infected, treatment-naïve patients, including 15 subtypes in 6 genotypes. NS5B replicon vectors with subtype 1b, subtype 4a and subtype 6a backbone were modified to support testing of patient samples. We also evaluated sofosbuvir susceptibility in a panel of 331 replicons containing engineered NS5B inhibitor resistance-associated substitutions. The mean 50% effective sofosbuvir concentration (EC50) amongst different genotypes ranged from 32 (subtype 2a) to 130 nM (genotype 4); while some variation in susceptibility amongst patient isolates was observed, the 95th percentile for any genotype did not exceed 189 nM. Levels of resistance to sofosbuvir in replicons containing S282T were between 2.4 and 18 fold-change in EC50; no other single NS5B resistance-associated substitution demonstrated reduced sofosbuvir susceptibility. These data suggest that S282T is the only known substitution that confers detectable resistance to sofosbuvir in vitro. Sofosbuvir displayed potent antiviral activity across a diverse range of NS5B mutants and HCV clinical isolates in multiple subtypes of genotypes 1 to 6.

Sofosbuvir/velpatasvir for 12 weeks in hepatitis C virus-infected patients with end-stage renal disease undergoing dialysis.

BACKGROUND & AIMS: Although off-label use of sofosbuvir-containing regimens occurs regularly in patients with hepatitis C virus (HCV) infection undergoing dialysis for severe renal impairment or end-stage renal disease (ESRD), these regimens are not licensed for this indication, and there is an absence of dosing recommendations in this population. This study evaluated the safety and efficacy of sofosbuvir/velpatasvir in patients with HCV infection with ESRD undergoing dialysis. METHODS: In this phase II, single-arm study, 59 patients with genotype 1-6 HCV infection with ESRD undergoing hemodialysis or peritoneal dialysis received open-label sofosbuvir/velpatasvir (400 mg/100 mg) once daily for 12 weeks. Patients were HCV treatment naive or treatment experienced without cirrhosis or with compensated cirrhosis. Patients previously treated with any HCV NS5A inhibitor were not eligible. The primary efficacy endpoint was the proportion of patients achieving sustained virologic response (SVR) 12 weeks after discontinuation of treatment (SVR12). The primary safety endpoint was the proportion of patients who discontinued study drug due to adverse events. RESULTS: Overall, 56 of 59 patients achieved SVR12 (95%; 95% CI 86-99%). Of the 3 patients who did not achieve SVR12, 2 patients had virologic relapse determined at post-treatment Week 4 (including 1 who prematurely discontinued study treatment), and 1 patient died from suicide after achieving SVR through post-treatment Week 4. The most common adverse events were headache (17%), fatigue (14%), nausea (14%), and vomiting (14%). Serious adverse events were reported for 11 patients (19%), and all were deemed to be unrelated to sofosbuvir/velpatasvir. CONCLUSIONS: Treatment with sofosbuvir/velpatasvir for 12 weeks was safe and effective in patients with ESRD undergoing dialysis. LAY SUMMARY: Sofosbuvir/velpatasvir is a combination direct-acting antiviral that is approved for treatment of patients with hepatitis C virus (HCV) infection. Despite the lack of dosing recommendations, sofosbuvir-containing regimens (including sofosbuvir/velpatasvir) are frequently used for HCV-infected patients undergoing dialysis. This study evaluated the safety and efficacy of sofosbuvir/velpatasvir for 12 weeks in patients with HCV infection who were undergoing dialysis. Treatment with sofosbuvir/velpatasvir was safe and well tolerated, resulting in a cure rate of 95% in patients with HCV infection and end-stage renal disease. Clinical Trial Number: NCT03036852.

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.

In Vitro Susceptibility of Hepatitis C Virus Genotype 1 through 6 Clinical Isolates to the Pangenotypic NS3/4A Inhibitor Voxilaprevir.

Voxilaprevir is a direct-acting antiviral agent (DAA) that targets the NS3/4A protease of hepatitis C virus (HCV). High sequence diversity of HCV and inadequate drug exposure during unsuccessful treatment may lead to the accumulation of variants with reduced susceptibility to DAAs, including NS3/4A protease inhibitors such as voxilaprevir. The voxilaprevir susceptibility of clinical and laboratory strains of HCV was assessed. The NS3 protease regions of viruses belonging to 6 genotypes and 29 subtypes from 345 DAA-naive or -experienced (including protease inhibitor) patients and 344 genotype 1 to 6 replicons bearing engineered NS3 resistance-associated substitutions (RASs) were tested in transient-transfection assays. The median voxilaprevir 50% effective concentration against NS3 from protease inhibitor-naive patient samples ranged from 0.38 nM for genotype 1 to 5.8 nM for genotype 3. Voxilaprevir susceptibilities of HCV replicons with NS3 RASs were dependent on subtype background and the type and number of substitutions introduced. The majority of RASs known to confer resistance to other protease inhibitors had little to no impact on voxilaprevir susceptibility, except A156L, T, or V in genotype 1 to 4 which conferred >100-fold reductions but exhibited low replication capacity in most genotypes. These data support the use of voxilaprevir in combination with other DAAs in DAA-naive and DAA-experienced patients infected with any subtype of HCV.

Sofosbuvir/Velpatasvir/Voxilaprevir for patients with HCV who previously received a Sofosbuvir/Velpatasvir-containing regimen: Results from a retreatment study.

This study evaluated 12-week retreatment with sofosbuvir/velpatasvir/voxilaprevir in patients with chronic hepatitis C virus (HCV) infection who did not achieve sustained virologic response after previous treatment with a sofosbuvir- and velpatasvir-containing regimen. All 31 patients maintained a sustained virologic response 12 weeks after the last sofosbuvir/velpatasvir/voxilaprevir dose.

Efficacy and safety of sofosbuvir-velpatasvir with or without ribavirin in HCV-infected Japanese patients with decompensated cirrhosis: an open-label phase 3 trial.

BACKGROUND: In Japan, hepatitis C virus (HCV)-infected patients with decompensated cirrhosis currently have no treatment options. In this Phase 3 study, we evaluated sofosbuvir-velpatasvir with or without ribavirin for 12 weeks in patients with any HCV genotype and decompensated cirrhosis [Child-Pugh-Turcotte (CPT) class B or C] in Japan. METHODS: Patients were randomized 1:1 to receive sofosbuvir-velpatasvir with or without ribavirin for 12 weeks. Randomization was stratified by CPT class and genotype. Sustained virologic response 12 weeks following completion of treatment (SVR12) was the primary efficacy endpoint. RESULTS: Of the 102 patients enrolled, 57% were treatment naive, 78% and 20% had genotype 1 and 2 HCV infection, respectively, and 77% and 20% had CPT class B and C cirrhosis, respectively, at baseline. Overall, 61% of patients were female and the mean age was 66 years (range 41-83). SVR12 rates were 92% (47/51) in each group. Among patients who achieved SVR12, 26% had improved CPT class from baseline to posttreatment week 12. Most adverse events (AEs) were consistent with clinical sequelae of advanced liver disease or known toxicities of ribavirin. Four patients (8%) who received sofosbuvir-velpatasvir and seven (14%) who received sofosbuvir-velpatasvir plus ribavirin experienced a serious AE. The 3 deaths (bacterial sepsis, gastric varices hemorrhage, hepatocellular carcinoma) were attributed to liver disease progression. CONCLUSION: Sofosbuvir-velpatasvir for 12 weeks provides a highly effective and well-tolerated therapy for Japanese patients with HCV and decompensated cirrhosis. Ribavirin did not improve efficacy but increased toxicity.

Sofosbuvir-velpatasvir for treatment of chronic hepatitis C virus infection in Asia: a single-arm, open-label, phase 3 trial.

BACKGROUND: Treatment with combined sofosbuvir and velpatasvir has resulted in high sustained virological response rates in patients chronically infected with hepatitis C virus (HCV) with genotypes 1-6 in clinical trials and real-world settings, but its efficacy and safety has not been assessed in Asia, a region with diverse HCV genotypes. METHODS: In this single-arm, open-label, phase 3 trial, we recruited patients from 38 sites across China, Thailand, Vietnam, Singapore, and Malaysia, who were chronically infected with HCV genotypes 1-6, and were HCV treatment-naive or treatment-experienced, either without cirrhosis or with compensated cirrhosis. Patients self-administered a combined sofosbuvir (400 mg) and velpatasvir (100 mg) tablet once daily for 12 weeks. The primary efficacy endpoint was sustained virological response, defined as HCV RNA less than 15 IU/mL at 12 weeks after completion of treatment (SVR12), assessed in all patients who received at least one dose of study drug. The primary safety endpoint was the proportion of adverse events leading to premature discontinuation of study drug. This trial is registered with ClinicalTrials.gov, number NCT02671500, and is completed. FINDINGS: Between April 14, 2016, and June 30, 2017, 375 patients were enrolled in the study, of whom 374 completed the full treatment course and one discontinued treatment. Overall, 362 (97% [95% CI 94-98]) of 375 patients achieved SVR12. Among 42 patients with HCV genotype 3b, all of whom had baseline resistance-associated substitutions in NS5A, 25 (89% [95% CI 72-98]) of 28 patients without cirrhosis and seven (50% [23-77]) of 14 patients with cirrhosis achieved SVR12. The most common adverse events were upper respiratory tract infection (36 [10%] patients) and headache (18 [5%] patients). There were no discontinuations due to adverse events. Serious adverse events were reported in three (1%) patients, none of which was judged to be related to sofosbuvir-velpatasvir treatment. INTERPRETATION: Consistent with data from other phase 3 studies, single-tablet sofosbuvir-velpatasvir for 12 weeks is an efficacious and safe treatment for Asian patients with chronic HCV infection, but might have lower efficacy in those infected with HCV genotype 3b and with cirrhosis. FUNDING: Gilead Sciences.

No impact of resistance-associated substitutions on the efficacy of sofosbuvir, velpatasvir, and voxilaprevir for 12 weeks in HCV DAA-experienced patients.

BACKGROUND & AIMS: In phase III studies, the fixed dose combination of sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) administered for 12 weeks led to a sustained virologic response at 12 weeks (SVR12) in 96% of NS5A inhibitor-experienced patients, and an SVR12 rate of 98% in DAA-experienced patients who had not previously received an NS5A inhibitor. Herein, we evaluate the relationship between the presence of detectable resistance-associated substitutions (RASs) at baseline and treatment outcome, and whether RASs were selected for in cases of virologic failure. METHODS: NS3, NS5A, and NS5B deep sequencing analyses were performed at baseline for all patients and at the time of virologic failure. Results are reported using a 15% cut-off. RESULTS: A total of 82.7% of NS5A inhibitor-experienced patients (205/248) had baseline NS3 and/or NS5A RASs; 79% had baseline NS5A RASs. SVR12 rates were similar in patients with or without NS3 and/or NS5A RASs, and with or without VOX- or VEL-specific RASs. RASs at NS5A position Y93 were present in 37.3% of patients and 95% achieved SVR12. All patients with ≥2 NS5A RASs achieved SVR12. Baseline NS3 and/or NS5A RASs were present in 46.6% (83/178) of non-NS5A inhibitor DAA-experienced patients, all of whom achieved SVR12. All patients with baseline NS5B nucleoside inhibitor RASs, including two patients with S282T, achieved SVR12. Treatment-selected resistance was seen in one of seven patients who relapsed. CONCLUSIONS: Baseline RASs had no impact on virologic response in DAA-experienced patients following treatment with SOF/VEL/VOX for 12 weeks. Selection of viral resistance with virologic relapse was uncommon. LAY SUMMARY: In phase III studies, 12 weeks of treatment with the combination of sofosbuvir, velpatasvir and voxilaprevir (SOF/VEL/VOX) cured 97% of patients with hepatitis C virus who failed prior treatment with direct-acting antiviral drugs. Herein, we show that the presence of pretreatment drug resistance did not affect treatment outcome in these patients who had previously received direct-acting antivirals. We also showed that new drug resistance was rare in patients who failed treatment with SOF/VEL/VOX for 12 weeks. This has important implications for the selection of best retreatment strategies for these patients.

Deferred treatment with sofosbuvir-velpatasvir-voxilaprevir for patients with chronic hepatitis C virus who were previously treated with an NS5A inhibitor: an open-label substudy of POLARIS-1.

BACKGROUND: Direct-acting antiviral regimens containing NS5A inhibitors are highly effective treatments for chronic hepatitis C virus (HCV) infection, but are not always successful. In the POLARIS-1 phase 3 study, sofosbuvir-velpatasvir-voxilaprevir for 12 weeks was highly effective in the treatment of chronic HCV infection in patients previously treated with a direct-acting antiviral regimen containing an NS5A inhibitor. We aimed to assess the efficacy and safety of sofosbuvir-velpatasvir-voxilaprevir in patients from the deferred treatment group of POLARIS-1, who were initially assigned to masked placebo treatment. METHODS: This open-label, deferred treatment substudy was done at 73 clinical sites (hospitals and clinics) in the USA, France, Canada, the UK, Germany, Australia, and New Zealand. Patients who received placebo in the primary study and who did not have a new clinically significant illness at the post-treatment week 4 assessment were eligible to enter this substudy. Participants received a combination tablet of sofosbuvir (400 mg), velpatasvir (100 mg), and voxilaprevir (100 mg) once daily for 12 weeks. The primary efficacy outcome was achievement of sustained virological response (defined as HCV RNA concentration below the lower limit of quantification) 12 weeks after the end of treatment (SVR12). The primary safety outcome was the proportion of patients who discontinued treatment due to adverse events. This study is registered with ClinicalTrials.gov, number NCT02607735, and the EU Clinical Trials Register, number 2015-003455-21. FINDINGS: 152 patients received placebo in the primary study and were potentially eligible for participation in the open-label substudy, of whom 147 were enrolled from March 30, 2016, to Oct 12, 2016. All 147 patients completed treatment, and 143 (97%; 95% CI 93-99) achieved SVR12. Four (3%) patients had virological relapse; all had HCV genotype 1a infection and one also had compensated cirrhosis. The most common adverse events were fatigue (31 [21%]), headache (29 [20%]), diarrhoea (28 [19%]), and nausea (21 [14%]). No deaths, treatment discontinuations, or treatment-related serious adverse events occurred. INTERPRETATION: Supporting the results from the blinded portion of the phase 3 primary study, the single-tablet regimen of sofosbuvir-velpatasvir-voxilaprevir for 12 weeks was safe, well tolerated, and highly effective in patients with chronic HCV infection who had previous treatment failure with NS5A inhibitor-containing regimens. A salvage regimen for this population represents an important advance for patients with limited retreatment options. FUNDING: Gilead Sciences.

Ledipasvir-sofosbuvir for treating Japanese patients with chronic hepatitis C virus genotype 2 infection.

BACKGROUND & AIMS: Japanese patients with chronic hepatitis C virus (HCV) genotype 2 infection have high rates of sustained virological response (SVR) following 12 weeks of treatment with the nucleotide polymerase inhibitor sofosbuvir in combination with ribavirin, which was the standard of care at the time this study was undertaken. We assessed the efficacy of 12 weeks of treatment with a ribavirin-free regimen of ledipasvir-sofosbuvir. METHODS: In an open-label, Phase 3 trial we enrolled Japanese patients with chronic HCV genotype 2 infection, with or without compensated cirrhosis. In Cohort 1, participants were randomized 1:1 to receive ledipasvir-sofosbuvir (n = 106) or sofosbuvir + ribavirin (n = 108) for 12 weeks. In Cohort 2, 25 ribavirin-intolerant or -ineligible patients received ledipasvir-sofosbuvir for 12 weeks. The primary endpoint was SVR 12 weeks after therapy (SVR12). In Cohort 1 non-inferiority was assessed with a prespecified margin of 10%. RESULTS: One-third (33%) of patients were treatment experienced, and 14% had cirrhosis. In Cohort 1, SVR12 rates were 96% (95% CI, 91% to 99%) with ledipasvir-sofosbuvir and 95% (95% CI, 90% to 98%) with sofosbuvir plus ribavirin, thus achieving non-inferiority. Among ribavirin-intolerant/ineligible patients in Cohort 2, SVR12 was 96% (95% CI, 80% to 100%) with ledipasvir-sofosbuvir. Overall, the most common adverse events were nasopharyngitis, anaemia, and headache; anaemia was only observed in patients receiving ribavirin. The percentage of patients who discontinued treatment because of an adverse event was low (1%). CONCLUSIONS: Among Japanese patients with HCV genotype 2, 12 weeks of treatment with ledipasvir-sofosbuvir resulted in high rates of SVR12 that were non-inferior to sofosbuvir + ribavirin.

Establishment of robust HCV genotype 4d, 5a, and 6a replicon systems.

Hepatitis C Virus (HCV) is a diverse human pathogen which displays ~15% divergence at the subtype level. To facilitate development of antivirals with pan-genotype activity, we developed the first genotype 4d subgenomic replicon, as well as new replicons for genotypes 5a, and 6a. Adaptive mutations developed in these replicons differ greatly across genotypes. Their impacts on the replication capacity were tested using site-directed mutants. In the genotype 4d replicon, single mutations have moderate effect, but the double mutation NS4A-Q34R+NS5A-S232G increased the replication capacity by 161-fold. These new stable replicon cell lines were used to determine the antiviral activity of HCV inhibitors. The NS3 protease inhibitor voxilaprevir, NS5A second generation inhibitor velpatasvir, and NS5B nucleoside analog inhibitor sofosbuvir, had similar antiviral activities across the different genotypes/subtypes tested, while the NS5A first generation inhibitor, ledipasvir, had very good antiviral activity against GT1, 4, 5, and 6 in vitro.

Characterization of HCV resistance from a 3-day monotherapy study of voxilaprevir, a novel pangenotypic NS3/4A protease inhibitor.

BACKGROUND: Voxilaprevir (VOX; GS-9857) is a pangenotypic HCV NS3/4A protease inhibitor (PI) with potent antiviral activity against HCV genotypes (GTs) 1-6 and improved coverage of GT1 NS3 resistance-associated substitutions (RAS) associated with other HCV PIs. In a 3-day Phase Ib monotherapy study in patients infected with HCV GT1a, 1b, 2, 3 and 4, VOX was well-tolerated and resulted in maximal mean viral load reduction >3 log10 IU/ml at the 100 mg dose across all genotypes evaluated. This report characterizes the HCV NS3 RAS in the study. METHODS: The NS3 gene was amplified and successfully deep sequenced using MiSeq for 66 patients at baseline and 61 patients post-baseline using 15% and 1% assay cutoffs. RESULTS: With a 15% assay cutoff, pretreatment HCV NS3 RAS were present in the HCV of 38% (9/24) of patients with GT1a and 5% (1/19) with GT3a; there were no pretreatment NS3 RAS present in patients with GT1b (n=6), GT2 (n=7) or GT4 (n=4). In patients with and without pretreatment NS3 RAS, ≥3.4 log10 mean maximal viral load reductions over 3 days of VOX administration were observed. The majority of patients did not have detectable treatment-emergent NS3 RAS and only 12% (7/53) and 26% (14/53) had emergent NS3 RAS using 15% and 1% cutoffs, respectively. No NS3 RAS were detected in patients with GT2 or GT4. A156T or A156V were the most prevalent emergent NS3 RAS in patients with GT1a or GT1b infection, but were not observed in patients with GT3 infection. CONCLUSIONS: The lack of selection of NS3 RAS in the majority of patients demonstrates a high resistance barrier for VOX. ClinicalTrails.gov identifier NCT02185794.