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Oral antiretroviral agents provide life-saving treatments for millions of people living with HIV, and can prevent new infections via pre-exposure prophylaxis1–5. However, some people living with HIV who are heavily treatment-experienced have limited or no treatment options, owing to multidrug resistance6. In addition, suboptimal adherence to oral daily regimens can negatively affect the outcome of treatment—which contributes to virologic failure, resistance generation and viral transmission—as well as of pre-exposure prophylaxis, leading to new infections1,2,4,7–9. Long-acting agents from new antiretroviral classes can provide much-needed treatment options for people living with HIV who are heavily treatment-experienced, and additionally can improve adherence10. Here we describe GS-6207, a small molecule that disrupts the functions of HIV capsid protein and is amenable to long-acting therapy owing to its high potency, low in vivo systemic clearance and slow release kinetics from the subcutaneous injection site. Drawing on X-ray crystallographic information, we designed GS-6207 to bind tightly at a conserved interface between capsid protein monomers, where it interferes with capsid-protein-mediated interactions between proteins that are essential for multiple phases of the viral replication cycle. GS-6207 exhibits antiviral activity at picomolar concentrations against all subtypes of HIV-1 that we tested, and shows high synergy and no cross-resistance with approved antiretroviral drugs. In phase-1 clinical studies, monotherapy with a single subcutaneous dose of GS-6207 (450 mg) resulted in a mean log10-transformed reduction of plasma viral load of 2.2 after 9 days, and showed sustained plasma exposure at antivirally active concentrations for more than 6 months. These results provide clinical validation for therapies that target the functions of HIV capsid protein, and demonstrate the potential of GS-6207 as a long-acting agent to treat or prevent infection with HIV. The small molecule GS-6207, which disrupts the function of the HIV capsid protein, shows potential as a long-acting therapeutic agent for the treatment and prevention of HIV infection.

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. Electronic supplementary material The online version of this article (10.1007/s00535-018-1503-x) contains supplementary material, which is available to authorized users.

Background/purpose In Japan, there is a growing population of patients with chronic hepatitis C virus (HCV) infection who failed a direct-acting antiviral (DAA)-based regimen. In this Phase 3 study, we evaluated sofosbuvir–velpatasvir plus ribavirin in Japanese patients with genotype 1 or 2 HCV infection who previously received DAAs. Methods Patients were randomized 1:1 to receive sofosbuvir–velpatasvir plus ribavirin for 12 or 24 weeks. Randomization was stratified by HCV genotype and presence of cirrhosis. The primary endpoint was sustained virologic response 12-week post-treatment (SVR12). Results Of 117 participants, 81% had HCV genotype 1 infection, 33% had cirrhosis, and 95% had NS5A resistance-associated substitutions (RAS) at baseline. Overall, SVR12 rates were 97% (58/60; 95% CI 88–100%) with 24 weeks of treatment and 82% (47/57; 95% CI 70–91%) with 12 weeks. For HCV genotype 1 and 2 infected patients, the SVR12 rates with 24 weeks of treatment were 98% and 92%, respectively. In both treatment groups, SVR12 rates in HCV genotype 1 patients were statistically superior to a historical control rate of 50% (p

Ledipasvir/sofosbuvir (Harvoni®), a fixed-dose combination tablet of an NS5A inhibitor ledipasvir and an NS5B polymerase inhibitor sofosbuvir, is approved for the treatment of chronic hepatitis C virus infection. Ledipasvir/sofosbuvir exhibits a favorable drug-drug interaction profile and can be administered with various medications that may be used by hepatitis C virus-infected patients, including patients with comorbidities, such as co-infection with human immunodeficiency virus or immunosuppression following liver transplantation. Ledipasvir/sofosbuvir is not expected to act as a victim or perpetrator of cytochrome P450- or UDP-glucuronosyltransferase 1A1-mediated drug-drug interactions. With the exception of strong inducers of P-glycoprotein, such as rifampin, ledipasvir/sofosbuvir is not expected to act as a victim of clinically relevant drug-drug interactions. As a perpetrator of pharmacokinetic drug-drug interactions via P-glycoprotein/BCRP, ledipasvir/sofosbuvir should not be used with rosuvastatin and elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate, whereas its co-administration with amiodarone is not recommended because of a pharmacodynamic interaction. This review summarizes a number of drug interaction studies conducted in support of the clinical development of ledipasvir/sofosbuvir.

The pharmacokinetics and safety of velpatasvir, a potent pangenotypic hepatitis C virus NS5A inhibitor, were evaluated in two hepatic impairment studies: a phase I study in hepatitis C virus-uninfected subjects and a phase III study (ASTRAL-4) in hepatitis C virus-infected patients. In the phase I study, subjects with moderate or severe hepatic impairment (Child-Pugh-Turcotte Class B or C), and demographically matched subjects with normal hepatic function received a single dose of velpatasvir 100 mg. Pharmacokinetics and safety assessments were performed, and pharmacokinetic parameters were calculated using non-compartmental methods and summarized using descriptive statistics and compared statistically by geometric least-squares mean ratios and 90% confidence intervals. In ASTRAL-4, subjects with decompensated cirrhosis (Child-Pugh-Turcotte Class B) were randomized to receive treatment with either sofosbuvir/velpatasvir ± ribavirin for 12 weeks or sofosbuvir/velpatasvir for 24 weeks. Pharmacokinetic and safety assessments were performed and pharmacokinetic parameters were calculated using a non-compartmental analysis and summarized using descriptive statistics and were compared to pharmacokinetics from ASTRAL-1 [subjects without cirrhosis or with compensated (Child-Pugh-Turcotte Class A) cirrhosis]. In the phase I study, plasma exposures (area under the concentration–time curve) were similar in subjects with Child-Pugh-Turcotte Class B (n = 10) or Child-Pugh-Turcotte Class C hepatic impairment (n = 10) compared with normal hepatic function (n = 13). Percent free velpatasvir was similar in subjects without or with any degree of hepatic impairment. In the phase III study, velpatasvir overall exposure (area under the concentration–time curve over the 24-h dosing interval; AUCtau) was similar and sofosbuvir exposures were higher (~ 100%) for patients with Child-Pugh-Turcotte Class B hepatic impairment compared with the ASTRAL-1 population, which was not considered clinically relevant. No sofosbuvir/velpatasvir dose modification is warranted for patients with any degree of hepatic impairment.

Ledipasvir/sofosbuvir (Harvoni®), a fixed-dose combination tablet of an NS5A inhibitor ledipasvir and an NS5B polymerase inhibitor sofosbuvir, is approved in the US, European Union, Canada, and other regions for the treatment of chronic hepatitis C virus infection in adults. Following absorption, ledipasvir reaches maximum plasma concentrations (T max) 4–4.5 h post-dose and is eliminated with a terminal half-life (t 1/2) of 47 h. Sofosbuvir undergoes intracellular activation to an active triphosphate GS-461203 (not detected in plasma) and ultimately to GS-331007, a predominant circulating metabolite, which is the primary analyte of interest in clinical pharmacology studies. Sofosbuvir is rapidly absorbed and eliminated from plasma (T max: 0.8–1 h; t 1/2: 0.5 h). The peak plasma concentrations for GS-331007 are achieved between 3.5 and 4 h post-dose; the elimination t 1/2 for GS-331007 is 27 h. Ledipasvir/sofosbuvir exhibits a favorable clinical pharmacology profile; it can be administered once daily without regard to food and does not require dose modification in hepatitis C virus-infected patients with any degree of hepatic impairment or mild to moderate renal impairment. The pharmacokinetic profiles of ledipasvir, sofosbuvir, and GS-331007 (predominant circulating metabolite of sofosbuvir) are not significantly affected by demographic variables; pharmacokinetic/pharmacodynamic analyses reveal no exposure-response relationships for efficacy or safety. The review summarizes the clinical pharmacokinetics, pharmacodynamics, and pharmacokinetic/pharmacodynamic analyses for ledipasvir/sofosbuvir.