Study to Investigate the Efficacy and Safety of Sofosbuvir/Velpatasvir (SOF/VEL) Fixed-Dose Combination (FDC) and Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX ) FDC for 12 Weeks in Adults With Chronic Hepatitis C Virus (HCV) Infection

Study Overview
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Brief Summary
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The primary objectives of this study are to evaluate the antiviral efficacy, safety, and tolerability of therapy with Sofosbuvir/Velpatasvir (SOF/VEL) Fixed-Dose Combination (FDC) and Sofosbuvir/Velpatasvir/Voxilaprevir (SOF/VEL/VOX ) FDC in participants with chronic HCV infection.

Official Title
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A Phase 3b Multicenter, Open-Label Study to Investigate the Efficacy and Safety of Sofosbuvir/Velpatasvir Fixed-Dose Combination and Sofosbuvir/Velpatasvir/Voxilaprevir Fixed-Dose Combination for 12 Weeks in Subjects With Chronic HCV Infection

Conditions
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Hepatitis C Virus Infection

Intervention / Treatment
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* Drug: SOF/VEL
* Drug: SOF/VEL/VOX


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Chronic HCV infected males and non-pregnant/non-lactating females Treatment-naive or treatment-experienced individuals Non-cirrhosis or compensated cirrhosis at screening Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SOF/VEL<br>Participants with chronic HCV infection (genotype 1 or 2), who are treatment-naive or treatment-experienced with interferon (IFN)-based treatments will receive SOF/VEL for 12 weeks. | Drug: SOF/VEL<br>* 400/100 mg FDC tablet orally once daily.<br>* Other names: GS-7977/GS-5816;|
| Experimental: SOF/VEL/VOX<br>Participants with chronic HCV infection (genotype 1), who are treatment-experienced with nonstructural protein 5A (NS5A) direct-acting antiviral (DAA)-based treatments of at least 4 weeks duration will receive SOF/VEL/VOX for 12 weeks. | Drug: SOF/VEL/VOX<br>* 400/100/100 mg FDC tablet orally once daily.<br>* Other names: GS-7977/GS-5816/GS-9857;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Sustained Virologic Response (SVR) < Lower Limit of Quantification (LLOQ) 12 Weeks After Discontinuation of Study Treatment | SVR12 was defined as HCV RNA < LLOQ (i.e., 15 IU/mL) at 12 weeks after stopping study treatment. | Posttreatment Week 12 | 
| Percentage of Participants Who Permanently Discontinued the Study Drug Due to an Adverse Event |  | First dose date up to 12 weeks plus 30 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With SVR < LLOQ 4 Weeks After Discontinuation of Study Treatment | SVR4 was defined as HCV RNA < LLOQ (i.e.15 IU/mL) 4 weeks after stopping study treatment. | Posttreatment Week 4 | 
| Percentage of Participants With Virologic Failure | Virologic failure was defined as: On-treatment virologic failure: Breakthrough (HCV RNA ≥ LLOQ after having previously had HCV RNA < LLOQ, while on treatment, confirmed with 2 consecutive values), or Rebound (confirmed > 1 log10 IU/mL increase in HCV RNA from nadir while on treatment), or Non-response (HCV RNA persistently ≥ LLOQ through 8 weeks of treatment ) Virologic relapse: • Confirmed HCV RNA ≥ LLOQ during the posttreatment period having achieved HCV RNA < LLOQ at last on-treatment visit | Baseline up to Posttreatment Week 12 | 
| Percentage of Participants With HCV RNA < LLOQ on Treatment | LLOQ was 15 IU/mL. | Week 2, Week 4, Week 8, Week 12 | 
| Change From Baseline in HCV RNA |  | Baseline, Week 2, Week 4, Week 8, Week 12 | 
| Number of Participants With Alanine Aminotransferase (ALT) Normalization | Number of participants with ALT normalization, defined as ALT > upper limit of normal (ULN) (ULN = 43 U/L) at baseline and ALT ≤ ULN, at each visit was presented. | Baseline, Week 2, Week 4, Week 8, Week 12 |