Dennis M. Grasela

Daclatasvir plus Sofosbuvir for Previously Treated or Untreated Chronic HCV Infection

BACKGROUND 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. METHODS 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 of <25 IU per milliliter) at week 12 after the end of therapy. RESULTS 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. CONCLUSIONS 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.).

Chemical genetics strategy identifies an HCV NS5A inhibitor with a potent clinical effect

The worldwide prevalence of chronic hepatitis C virus (HCV) infection is estimated to be approaching 200 million people. Current therapy relies upon a combination of pegylated interferon-α and ribavirin, a poorly tolerated regimen typically associated with less than 50% sustained virological response rate in those infected with genotype 1 virus. The development of direct-acting antiviral agents to treat HCV has focused predominantly on inhibitors of the viral enzymes NS3 protease and the RNA-dependent RNA polymerase NS5B. Here we describe the profile of BMS-790052, a small molecule inhibitor of the HCV NS5A protein that exhibits picomolar half-maximum effective concentrations (EC50) towards replicons expressing a broad range of HCV genotypes and the JFH-1 genotype 2a infectious virus in cell culture. In a phase I clinical trial in patients chronically infected with HCV, administration of a single 100-mg dose of BMS-790052 was associated with a 3.3 log10 reduction in mean viral load measured 24 h post-dose that was sustained for an additional 120 h in two patients infected with genotype 1b virus. Genotypic analysis of samples taken at baseline, 24 and 144 h post-dose revealed that the major HCV variants observed had substitutions at amino-acid positions identified using the in vitro replicon system. These results provide the first clinical validation of an inhibitor of HCV NS5A, a protein with no known enzymatic function, as an approach to the suppression of virus replication that offers potential as part of a therapeutic regimen based on combinations of HCV inhibitors.

Preliminary Study of Two Antiviral Agents for Hepatitis C Genotype 1

BACKGROUND Patients with chronic hepatitis C virus (HCV) infection who have not had a response to therapy with peginterferon and ribavirin may benefit from the addition of multiple direct-acting antiviral agents to their treatment regimen. METHODS This open-label, phase 2a study included an exploratory cohort of 21 patients with chronic HCV genotype 1 infection who had not had a response to previous therapy (i.e., had not had ≥2 log(10) decline in HCV RNA after ≥12 weeks of treatment with peginterferon and ribavirin). We randomly assigned patients to receive the NS5A replication complex inhibitor daclatasvir (60 mg once daily) and the NS3 protease inhibitor asunaprevir (600 mg twice daily) alone (group A, 11 patients) or in combination with peginterferon alfa-2a and ribavirin (group B, 10 patients) for 24 weeks. The primary end point was the percentage of patients with a sustained virologic response 12 weeks after the end of the treatment period. RESULTS A total of 4 patients in group A (36%; 2 of 9 with HCV genotype 1a and 2 of 2 with genotype 1b) had a sustained virologic response at 12 weeks after treatment and also at 24 weeks after treatment.. Six patients (all with HCV genotype 1a) had viral breakthrough while receiving therapy, and resistance mutations to both antiviral agents were found in all cases; 1 patient had a viral response at the end of treatment but had a relapse after the treatment period. All 10 patients in group B had a sustained virologic response at 12 weeks after treatment, and 9 had a sustained virologic response at 24 weeks after treatment. Diarrhea was the most common adverse event in both groups. Six patients had transient elevations of alanine aminotransferase levels to more than 3 times the upper limit of the normal range. CONCLUSIONS This preliminary study involving patients with HCV genotype 1 infection who had not had a response to prior therapy showed that a sustained virologic response can be achieved with two direct-acting antiviral agents only. In addition, a high rate of sustained virologic response was achieved when the two direct-acting antiviral agents were combined with peginterferon alfa-2a and ribavirin. (Funded by Bristol-Myers Squibb; ClinicalTrials.gov number, NCT01012895.).

Pharmacodynamics of fluoroquinolones against Streptococcus pneumoniae in patients with community-acquired respiratory tract infections.

ABSTRACT Fluoroquinolone antibiotic agents have demonstrated efficacy in the treatment of respiratory tract infections. This analysis was designed to examine the relationship between drug exposure, as measured by the free-drug area under the concentration-time curve at 24 h (AUC24)/MIC ratio, and clinical and microbiological responses in patients with community-acquired respiratory tract infections involving Streptococcus pneumoniae. The study population included 58 adult patients (34 males, 24 females) who were enrolled in either of two phase III, randomized, multicenter, double-blind studies of levofloxacin versus gatifloxacin for the treatment of community-acquired pneumonia or acute exacerbation of chronic bronchitis. Clearance equations from previously published population pharmacokinetic models were used in conjunction with dose and adjusted for protein binding to estimate individual patient free-drug AUC24s. In vitro susceptibility was determined in a central laboratory by broth microdilution in accordance with NCCLS guidelines. Pharmacodynamic analyses were performed on data from all evaluable patients with documented S. pneumoniaeinfection using univariate and multivariable logistic regression; pharmacodynamic breakpoints were estimated using Classification and Regression Tree analysis. A statistically significant (P = 0.013) relationship between microbiological response and the free-drug AUC24/MIC ratio was detected. At a free-drug AUC24/MIC ratio of <33.7, the probability of a microbiological response was 64%, and at a free-drug AUC24/MIC ratio of >33.7, it was 100% (P < 0.01). These findings may provide a minimum target free-drug AUC24/MIC ratio for the treatment of infections involving S. pneumoniae with fluoroquinolone antibiotics and provide a paradigm for the selection of fluoroquinolones to be brought forward from drug discovery into clinical development and dose selection for clinical trials. Further, when target free-drug AUC24/MIC ratios are used in conjunction with stochastic modeling techniques, these findings may be used to support susceptibility breakpoints for fluoroquinolone antibiotics and S.pneumoniae.

Efficacy of an Interferon- and Ribavirin-Free Regimen of Daclatasvir, Asunaprevir, and BMS-791325 in Treatment-Naive Patients With HCV Genotype 1 Infection

BACKGROUND & AIMS The combination of peginterferon and ribavirin with telaprevir or boceprevir is the standard treatment of hepatitis C virus (HCV) genotype 1 infection. However, these drugs are not well tolerated because of their side effects and suboptimal virologic responses. In a phase 2a, open-label study, we examined the safety and efficacy of an interferon-free, ribavirin-free regimen of direct-acting antivirals, comprising daclatasvir (an NS5A replication complex inhibitor), asunaprevir (an NS3 protease inhibitor), and BMS-791325 (a non-nucleoside NS5B inhibitor), in patients with chronic HCV infection. METHODS We analyzed data from 66 treatment-naive patients with HCV genotype 1 infection without cirrhosis who were assigned randomly to groups given daclatasvir (60 mg, once daily), asunaprevir (200 mg, twice daily), and BMS-791325 (75 or 150 mg, twice daily) for 12 or 24 weeks. The primary end point was an HCV-RNA level less than 25 IU/mL at 12 weeks after treatment (sustained virologic response at 12 weeks [SVR12]). RESULTS In 64 patients, HCV-RNA levels were less than 25 IU/mL by week 4 of treatment (including 48 of 49 patients with HCV genotype 1a infection and 45 of 46 patients with the non-CC interleukin 28B genotype). Sixty-one patients (92%) achieved SVR12, based on a modified intention-to-treat analysis. Virologic responses were similar between 12 and 24 weeks of treatment. During the study, 2 patients experienced viral breakthrough and 1 patient relapsed. There were no grade 3-4 increases in levels of alanine or aspartate aminotransferases or bilirubin; there were no deaths or discontinuations resulting from serious adverse events or adverse events related to the treatment regimen. The most common adverse events were headache, asthenia, and gastrointestinal symptoms. CONCLUSIONS In a phase 2a study, the all-oral, interferon-free, and ribavirin-free regimen of daclatasvir, asunaprevir, and BMS-791325 was well tolerated and achieved high rates of SVR12 in patients with HCV genotype 1 infection. Further studies of this regimen are warranted. ClinicalTrials.gov, number NCT01455090.

The effects of HIV protease inhibitors atazanavir and lopinavir/ritonavir on insulin sensitivity in HIV-seronegative healthy adults

Background: Therapy with some HIV protease inhibitors (PI) contributes to insulin resistance and type 2 diabetes mellitus, by inhibition of insulin-sensitive glucose transporters. Atazanavir (ATV) is a new PI with substantially less in vitro effect on glucose transport than observed with other PI, including lopinavir (LPV) or ritonavir (RTV). Methods: Randomized, double-blind, crossover study of the effect of 5 days of administering ATV, lopinavir/ritonavir (LPV/r) or placebo on insulin-stimulated glucose disposal in 30 healthy HIV-negative subjects. Each subject was studied on two of three possible treatments with a wash-out period between treatments. Results: The mean insulin-stimulated glucose disposal (mg/min per kg body weight) per unit insulin (μU/ml) (M/I) was 9.88, 9.80 and 7.52 for placebo, ATV and LPV/r, respectively (SEM, 0.84 for all). There was no significant difference between ATV and placebo. The M/I for LPV/r was 23% lower than that for ATV (P = 0.010) and 24% lower than that for placebo (P = 0.008). The mean glycogen storage rates were 3.85, 4.00 and 2.54 mg/min per kg for placebo, ATV and LPV/r, respectively (SEM, 0.39 for all). There was no significant difference between ATV and placebo. The glycogen storage rate for LPV/r was 36% lower than ATV (P = 0.003) and 34% lower than placebo (P = 0.006). Conclusions: ATV given to healthy subjects for 5 days did not affect insulin sensitivity, while LPV/r induced insulin resistance. This observation is consistent with differential in vitro effects of these PI on glucose transport. Further data are needed to assess clinical implications for body composition.

Multiple ascending dose study of BMS‐790052, a nonstructural protein 5A replication complex inhibitor, in patients infected with hepatitis C virus genotype 1

The antiviral activity, resistance profile, pharmacokinetics (PK), safety, and tolerability of BMS‐790052, a nonstructural protein 5A (NS5A) replication complex inhibitor, were evaluated in a double‐blind, placebo‐controlled, sequential panel, multiple ascending dose study. Thirty patients with chronic hepatitis C virus (HCV) genotype 1 infection were randomized to receive a 14‐day course of BMS‐790052 (1, 10, 30, 60, or 100 mg once daily or 30 mg twice daily) or placebo in a ratio of 4:1. The mean maximum decline from baseline in HCV RNA ranged from 2.8 to 4.1 log10 IU/mL; the placebo group showed no evidence of antiviral activity. Most patients experienced viral rebound on or before day 7 of treatment with BMS‐790052 monotherapy; viral rebound was associated with viral variants that had been previously implicated in resistance development in the in vitro replicon system. The PK profile was supportive of once‐daily dosing with median peak plasma concentrations at 1‐2 hours postdose and mean terminal half‐life of 12‐15 hours. Steady state was achieved following 3‐4 days of daily dosing. BMS‐790052 was well tolerated in all dose groups, with adverse events occurring with a similar frequency in BMS‐790052‐ and placebo‐treated groups. There were no clinically relevant changes in vital signs, laboratory, or electrocardiogram parameters. Conclusion: BMS‐7590052 is the first NS5A replication complex inhibitor with multiple dose proof‐of‐concept in clinic. At doses of 1‐100 mg daily, BMS‐790052 was well tolerated, had a PK profile supportive of once‐daily dosing, and produced a rapid and substantial decrease in HCV‐RNA levels in patients chronically infected with HCV genotype 1. (HEPATOLOGY 2011

Randomized trial of daclatasvir and asunaprevir with or without PegIFN/RBV for hepatitis C virus genotype 1 null responders

BACKGROUND & AIMS Patients with chronic hepatitis C virus (HCV) infection and prior null response (<2 log HCV RNA decline after ⩾ 12 weeks of PegIFN/RBV) have limited options. We evaluated daclatasvir plus once- or twice-daily asunaprevir in non-cirrhotic genotype 1 null responders. METHODS In this randomized, phase 2a, open-label, 24-week treatment study, 101 patients received daclatasvir (60 mg) once-daily. In addition, 38 genotype 1b patients received asunaprevir (200mg) twice- (DUAL A1) or once-daily (DUAL A2); 36 genotype 1a and 5 genotype 1b patients received asunaprevir twice- (QUAD B1) or once-daily (QUAD B2) plus PegIFN/RBV; and 18 genotype 1a and 4 genotype 1b patients received asunaprevir twice-daily plus ribavirin (TRIPLE B3). The primary endpoint was undetectable HCV RNA 12 weeks post-treatment (sustained virologic response, SVR12). RESULTS Across all groups, mean HCV RNA was ⩾ 6 log IU/ml, and 99% of patients had a non-CC IL28B genotype. SVR12 rates were 78% (A1), 65% (A2), 95% (B1), and 95% (B2). In B3, most genotype 1a patients experienced virologic breakthrough. The most common adverse events were headache, diarrhea, and asthenia. Grade 3-4 aminotransferase elevations were infrequent and not treatment-limiting. CONCLUSIONS In genotype 1 null responders, daclatasvir plus twice-daily asunaprevir DUAL therapy is effective for most genotype 1b patients, and daclatasvir, asunaprevir, and PegIFN/RBV QUAD therapy is effective for nearly all genotype 1a and 1b patients; but neither DUAL nor TRIPLE therapy is effective for genotype 1a patients. Interferon-free regimens including daclatasvir and twice-daily asunaprevir for genotype 1 null responders should be tailored to subtype.

A Randomized, Double-Blind, Placebo-Controlled Assessment of BMS-936558, a Fully Human Monoclonal Antibody to Programmed Death-1 (PD-1), in Patients with Chronic Hepatitis C Virus Infection

Expression of the programmed death 1 (PD-1) receptor and its ligands are implicated in the T cell exhaustion phenotype which contributes to the persistence of several chronic viral infections, including human hepatitis C virus (HCV). The antiviral potential of BMS-936558 (MDX-1106) – a fully human anti-PD-1 monoclonal immunoglobulin-G4 that blocks ligand binding – was explored in a proof-of-concept, placebo-controlled single-ascending-dose study in patients (N = 54) with chronic HCV infection. Interferon-alfa treatment-experienced patients (n = 42) were randomized 5∶1 to receive a single infusion of BMS-936558 (0.03, 0.1, 0.3, 1.0, 3.0 mg/kg [n = 5 each] or 10 mg/kg [n = 10]) or of placebo (n = 7). An additional 12 HCV treatment-naïve patients were randomized to receive 10 mg/kg BMS-936558 (n = 10) or placebo (n = 2). Patients were followed for 85 days post-dose. Five patients who received BMS-936558 (0.1 [n = 1] or 10 mg/kg) and one placebo patient achieved the primary study endpoint of a reduction in HCV RNA ≥0.5 log10 IU/mL on at least 2 consecutive visits; 3 (10 mg/kg) achieved a >4 log10 reduction. Two patients (10 mg/kg) achieved HCV RNA below the lower limit of quantitation (25 IU/mL), one of whom (a prior null-responder) remained RNA-undetectable 1 year post-study. Transient reductions in CD4+, CD8+ and CD19+ cells, including both naïve and memory CD4+ and CD8+ subsets, were observed at Day 2 without evidence of immune deficit. No clinically relevant changes in immunoglobulin subsets or treatment-related trends in circulating cytokines were noted. BMS-936558 exhibited dose-related exposure increases, with a half-life of 20–24 days. BMS-936558 was mostly well tolerated. One patient (10 mg/kg) experienced an asymptomatic grade 4 ALT elevation coincident with the onset of a 4-log viral load reduction. Six patients exhibited immune-related adverse events of mild-to-moderate intensity, including two cases of hyperthyroidism consistent with autoimmune thyroiditis. Further investigation of PD-1 pathway blockade in chronic viral disease is warranted. Trial Registration ClinicalTrials.gov NCT00703469 NCT00703469

The use of Monte Carlo simulation to examine pharmacodynamic variance of drugs: fluoroquinolone pharmacodynamics against Streptococcus pneumoniae

BACKGROUND For fluoroquinolones, AUC:MIC ratios correlate with maximal bacterial eradication in in vitro models of infection and favorable cure rates in humans with respiratory tract infection. Inter-subject pharmacokinetic and MIC variability may impact the probability of attaining optimal AUC:MIC ratios and hence favorable clinical outcome. METHODS Monte Carlo simulation was utilized to estimate the probability of attaining AUC:MIC ratios of 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 using AUC values from patients treated with either gatifloxacin or levofloxacin and microbiologic activity against S. pneumoniae observed in 1997 SENTRY Antimicrobial Surveillance Program. RESULTS The probability curves for 5000 patient simulations were plotted. The median AUC:MIC ratios were 120 for gatifloxacin and 50.5 for levofloxacin. The probability of attaining AUC:MIC ratios of 30, 50, 70 and 100 for gatifloxacin were 94%, 86%, 78% and 62%, and for levofloxacin were 80%, 51%, 31% and 17%, respectively. CONCLUSION Gatifloxacin has a higher probability of achieving target AUC:MIC ratios than levofloxacin. Monte Carlo simulation, using patient-based AUC and MIC distributions, may have implications for selection of optimal antibiotics for the empiric treatment of infections. Moreover, Monte Carlo simulation may have utility in the determination of MIC breakpoints.