Original Article Randomized Study of Asunaprevir Plus Pegylated Interferon-Α and Ribavirin for Previously Untreated Genotype 1 Chronic Hepatitis C

Antiviral Therapy 2013; 18:885–893 (doi: 10.3851/IMP2660)

Original article Randomized study of asunaprevir plus pegylated interferon-α and ribavirin for previously untreated genotype 1 chronic hepatitis C

Jean-Pierre Bronowicki1*, Stanislas Pol2, Paul J Thuluvath3, Dominique Larrey4, Claudia T Martorell5, Vinod K Rustgi6, David W Morris7, Ziad Younes8, Michael W Fried9, Marc Bourlière10, Christophe Hézode11, K Rajender Reddy12, Omar Massoud13, Gary A Abrams14, Vlad Ratziu15, Bing He16, Timothy Eley16, Alaa Ahmad17, David Cohen18, Robert Hindes19, Fiona McPhee18, Bridget Reilly16, Patricia Mendez16, Eric Hughes16

1INSERM 954, Centre Hospitalier Universitaire de Nancy, Université de Lorraine, Vandoeuvre les Nancy, France 2Université Paris Descartes, INSERM U1610 and Liver Unit, Hôpital Cochin, Paris, France 3Mercy Medical Center, Baltimore, MD, USA 4Hôpital Saint Eloi, Service d’Hépato-Gastroentérologie et Transplantation, INSERM 1040-IRB, Montpellier, France 5The Research Institute, Springfield, MA, USA 6Metropolitan Research, Fairfax, VA, USA 7Healthcare Research Consultants, Tulsa, OK, USA 8Gastro One, Germantown, TN, USA 9Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, NC, USA 10Hôpital Saint Joseph, Service d’Hépato-Gastroentérologie, Marseille, France 11CHU Henri Mondor, Service d’Hépato-Gastroentérologie, Créteil, France 12Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA, USA 13Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, USA 14Alabama Liver & Digestive Specialists, Montgomery, AL, USA 15Groupe Hospitalier Pitié Salpêtrière, Service d’Hépato-Gastroentérologie, Paris, France 16Bristol–Myers Squibb, Princeton, NJ, USA 17Hoffmann–La Roche, Nutley, NJ, USA 18Bristol–Myers Squibb, Wallingford, CT, USA 19BeyondWest Pharmaceuticals, Skillman, NJ, USA

*Corresponding author e-mail: [email protected]

Background: Asunaprevir is a selective NS3 protease inhib- twice-daily, 600 mg twice-daily and 600 mg once-daily itor with in vitro activity against HCV genotypes 1 and 4. groups, respectively, versus 0% (0/11) in the placebo

Methods: In this Phase IIa double-blind study, treatment- group. Corresponding SVR24 rates were 83% (10/12), naive HCV genotype-1-infected patients in the United 83% (10/12) and 92% (11/12) in the asunaprevir groups States and France were randomly assigned 1:1:1:1 to pla- and 46% (5/11) in the placebo group. There was no viro- cebo or asunaprevir 200 mg twice daily, 600 mg twice logical breakthrough in any asunaprevir group. Following daily or 600 mg once daily in combination with pegylated the 12-week analysis, the 600 mg doses were reduced interferon (PEG-IFN)-α2a and ribavirin for 48 weeks. The to 200 mg twice daily because of a greater frequency of primary efficacy end point was undetectable HCV RNA transaminase elevations at the 600 mg dose. The most at weeks 4 and 12 (extended rapid virological response common grade 3–4 laboratory abnormalities were con- [eRVR]). Other end points included safety and undetect- sistent with those reported for PEG-IFN and ribavirin. able HCV RNA at 24 weeks post-treatment (24-week sus- Conclusions: Asunaprevir plus PEG-IFN and ribavirin tained virological response [SVR24]). achieved higher response rates than placebo plus PEG- Results: A total of 47 patients were randomized and IFN and ribavirin, with a tolerable adverse event profile at treated. eRVR was achieved by 75% (9/12), 75% (9/12) the 200 mg twice-daily dose. This dose is being evaluated and 92% (11/12) of patients in the asunaprevir 200 mg in the Phase IIb and Phase III studies.

Introduction IU/ml. Patients had no prior treatment with any anti- HCV agent or <4 weeks of total exposure to ribavirin Chronic infection with HCV affects up to 170 million or PEG-IFN-based therapy. Patients had to be non- individuals worldwide, including up to 5.2 million in the cirrhotic, documented by liver biopsy obtained within United States [1–3]. Chronic HCV infection is a common 24 months before randomization. Exclusion criteria cause of chronic liver disease, cirrhosis and hepatocellu- included advanced liver disease, coinfection with HBV lar carcinoma [2,4]. Among the seven main HCV geno- or HIV, hepatocellular carcinoma, and other clinically types, genotype 1 is one of the most difficult to treat and relevant comorbidities. Patients were excluded if they the most prevalent globally [1,5]. The genotype 1a sub- had alanine aminotransferase (ALT)≥5× the upper limit type predominates in the United States whereas subtype of normal (ULN), total bilirubin ≥2 mg/dl, albumin ≤3.5 1b predominates in Europe and Japan [1,5–7]. g/dl, international normalized ratio (INR)≥1.7, platelets Current treatment options for patients with chronic ≤90×109 cells/l, or haemoglobin ≤12 g/dl (women) or HCV genotype 1 infection are evolving and include dual ≤13 g/dl (men). therapy with pegylated interferon (PEG-IFN)-a2a or -2b and ribavirin, and triple-therapy regimens including an Study design HCV protease inhibitor. A 24-week sustained virological This Phase IIa double-blind parallel-group study (clini- response (SVR24; undetectable HCV RNA at 24 weeks caltrials.gov identifier NCT01030432) randomized post-treatment) is achieved in only 40–50% of patients patients 1:1:1:1 to placebo plus PEG-IFN-a2a (Pegasys®, treated with dual therapy and 68–75% of patients Roche, Basel, Switzerland) and ribavirin (Copegus®, treated with triple therapy [8–11]. However, these Roche) or oral asunaprevir 200 mg twice daily, 600 mg regimens are limited by adverse events, difficult dosing twice daily or 600 mg once daily plus PEG-IFN and schedules and the potential for viral resistance. A need ribavirin for 48 weeks. PEG-IFN was administered sub- remains for other direct-acting antivirals with improved cutaneously at 180 mg/week, and ribavirin was admin- tolerability and more convenient dosing schedules. New istered orally twice daily and dosed according to body agents will also likely be used in combination with other weight (1,000 mg/day if <75 kg and 1,200 mg/day if classes of direct-acting antivirals, with or without PEG- ≥75 kg). Patients meeting futility criteria – a decrease IFN or ribavirin, to optimize treatment regimens. from baseline in HCV RNA of <2 logs and HCV RNA Asunaprevir is a selective HCV NS3 protease inhibitor ≥ the lower limit of quantitation (LLOQ; 25 IU/ml) at with activity against HCV genotypes 1 and 4 in vitro [12]. week 12; or HCV RNA detectable at week 12 and >50 In single- and multiple-ascending dose studies in patients IU/ml at week 24; or virological breakthrough (defined with HCV genotype 1 infection, asunaprevir produced below) – were required to discontinue treatment. rapid and substantial declines in HCV RNA, with a toler- The asunaprevir dose range was selected based on the able adverse event profile [13]. In HCV genotype 1a- or results of monotherapy studies [13]. After the week 12 1b-infected null responders, asunaprevir plus the NS5A analysis, the asunaprevir 600 mg once daily and twice inhibitor daclatasvir and PEG-IFN/ribavirin achieved daily doses were changed to 200 mg twice daily due to SVR in ≥90% of patients [14,15]. The all-oral regimen elevations in ALT and aspartate aminotransferase (AST). of asunaprevir plus daclatasvir achieved SVR in 91% of The elevations were greater and more frequent at the genotype-1b-infected null responders, and in 64% of gen- 600 mg than the 200 mg dose, and only patients receiv- otype-1b-infected patients intolerant to, or ineligible for, ing the 600 mg doses discontinued due to transaminase PEG-IFN/ribavirin therapy [16]. abnormalities. The 48-week treatment duration was This study is the first Phase IIa clinical trial conducted based on health authorities’ recommendation to add to evaluate the safety and efficacy profile of asunaprevir asunaprevir to the previous standard-of-care for geno- at different doses in combination with PEG-IFN/ribavi- type 1 HCV, and allowed data collection on the safety of rin in previously untreated patients with HCV genotype extended asunaprevir treatment. Shorter durations will 1 infection. Based on the results of this exploratory study, be explored in the Phase IIb study. an asunaprevir dose was selected for further evaluation Patients were enrolled at 15 sites in the United States in combination with PEG-IFN/ribavirin in an ongoing and France between 9 February and 29 April 2010; Phase IIb study, and in combination with daclatasvir with follow-up was complete on 9 September 2011. Eligi- or without PEG-IFN/ribavirin in large Phase III studies. ble patients were randomly assigned to a treatment by an interactive voice response system using a computer- Methods generated random allocation sequence. Investigators and patients were blinded to treatment assignment Patients throughout the study. The sponsor was blinded to Eligible patients were adults aged 18–70 years with treatment assignment until the primary end point anal- chronic HCV genotype 1 infection and HCV RNA≥105 ysis. Written informed consent was obtained from all

patients. The study was approved by the institutional a validated pharmacokinetic programme (Kinetica®; review board at each participating site and was con- Letchworth, UK) and included observed maximum ducted in compliance with the Declaration of Helsinki, (Cmax) and minimum (Cmin) plasma concentrations and Good Clinical Practice guidelines, and local regulatory area under the concentration–time curve in one dosing requirements. interval (AUCTAU).

End points Statistical analyses The primary efficacy end point was the proportion of It was determined that a target sample size of 12 patients with undetectable HCV RNA at weeks 4 and patients per arm would detect, with 80% probability, a 12 (extended rapid virological response [eRVR]). Safety safety event occurring at an incident rate of 13%. The was also a primary end point, assessed by frequencies target size of 12 patients would also provide the fol- of adverse events and discontinuations due to adverse lowing 80% exact binomial CIs for eRVR rates: 92% events. Secondary efficacy end points included undetect- (11/12; CI 71%, 99%), 75% (9/12; CI 52%, 90%), able HCV RNA at week 4 (rapid virological response; 58% (7/12; CI 36%, 78%), 50% (6/12; CI 29%, 71%),

RVR), at the end of treatment, and at 12 (SVR12) and 17% (2/12; CI 5%, 39%) and 8% (1/12; CI 1%, 29%).

24 (SVR24) weeks post-treatment. Virological break- For the antiviral activity end points, analyses included through on-treatment was defined as a confirmed >1 log all patients who received ≥1 dose of study medication increase in HCV RNA from nadir or confirmed HCV (modified intention-to-treat analysis). Pharmacokinetic RNA≥LLOQ after undetectable HCV RNA. Virologi- parameters are summarized by treatment regimen with cal relapse was defined as detectable HCV RNA during descriptive statistics. Probability distributions of the follow-up after undetectable HCV RNA at the end of maximum observed area under the plasma concen- treatment. Drug-resistant variants were characterized tration-time curve at 24 h (AUC24 h) at different doses by population sequencing. An exploratory analysis were generated based on observed data and variability examined the relationship between safety end points assuming a log normal distribution for AUC24 h. and asunaprevir exposure. Results Assessments HCV RNA levels were measured with the Roche Patient disposition and baseline characteristics COBAS® TaqMan® HCV version 2.0 assay (LLOQ 25 Of 77 patients enrolled, 48 were randomized: 12 to IU/ml; assay limit of detection ≈10 IU/ml; Roche Diag- each asunaprevir arm and 12 to the placebo arm (Addi- nostics, Indianapolis, IN, USA) at screening, baseline tional file 1). Of the 29 enrolled patients who were not and weeks 2, 4, 6, 8 and 12; every 4 weeks through randomized, 20 no longer met study entry criteria, 5 week 48 or the end of treatment; and at 4, 12 and 24 withdrew consent, 1 was non-compliant and 3 with- weeks post-treatment. Physical examination, vital signs drew for other reasons. One patient assigned to placebo and laboratory tests were performed at baseline, and was not treated due to pregnancy. A total of 35 patients throughout the study up to post-treatment week 4. All completed 48 weeks of treatment and 12 discontin- baseline samples were analysed for resistance by popu- ued therapy before 48 weeks for lack of efficacy (n=2), lation sequencing. Samples from the on-treatment and adverse events (n=4), withdrawal of consent (n=3), loss post-treatment periods were analysed by population to follow-up (n=2) and non-adherence (n=1). A total of sequencing in patients with virological failure and in 42 patients completed follow-up and 47 were included patients who discontinued if HCV RNA was ≥1,000 IU/ in the analyses. ml at the end of treatment. The IL28B rs12979860 sin- Demographic and baseline disease characteristics gle nucleotide polymorphism (SNP) genotype assay was were generally balanced across arms (Table 1). Most developed by the sponsor; FAM and VIC probes were patients were male (75%) and White (81%), and most obtained from Applied Biosystems (Carlsbad, CA, USA) (79%) were infected with HCV genotype 1a. Mean and forward and reverse primers were obtained from baseline HCV RNA ranged from 6.4 to 6.8 log10 IU/ml. Sigma–Aldrich (St Louis, MO, USA). There was an imbalance in IL28B genotype distribu- Intensive pharmacokinetic sampling was performed tion, with fewer patients carrying the CC genotype in on day 1 and at week 12. On day 1, asunaprevir samples the asunaprevir 600 mg twice daily and placebo arms were obtained pre-dose and at 1, 2, 3, 4 and 6 h post- (Table 1). dose. At the week 12 visit, asunaprevir sampling took place pre-dose and at 1, 2, 4, 8 and 12 h post-dose. Asu- Virological response naprevir trough samples were collected pre-dose at day At week 2, the mean reduction in HCV RNA was

1 and weeks 4, 8, 12 and 24. Pharmacokinetic param- >5.0 log10 IU/ml in all asunaprevir-containing arms, eters were derived by non-compartmental methods using compared with 1.8 log10 IU/ml in the placebo plus

Antiviral Therapy 18.7 887 J-P Bronowicki et al.

Table 1. Baseline demographics and disease characteristics

Treatment combined with PEG-IFN-a2a plus RBV ASV 200 mg twice ASV 600 mg twice ASV 600 mg once Placebo Variable daily (n=12) daily (n=12) daily (n=12) (n=11)

Median age, years 46.5 49.0 51.5 47.0 Male, n (%) 8 (67) 8 (67) 10 (83) 9 (82) Race White, n (%) 11 (92) 8 (67) 9 (75) 10 (91) Black/African American, n (%) 1 (8) 4 (33) 2 (17) 1 (9) American Indian/Alaska Native, n (%) 0 0 1 (8) 0 HCV genotype 1a, n (%) 9 (75) 10 (83) 9 (75) 9 (82) 1b, n (%) 3 (25) 2 (17) 3 (25) 2 (18) sd Mean HCV RNA, log10 IU/ml ( ) 6.7 (0.69) 6.4 (0.73) 6.8 (0.43) 6.4 (0.62) IL28B genotype CC, n 5 1 5 2 CT, n 6 8 4 6 TT, n 1 3 3 3

ASV, asunaprevir; PEG-IFN, pegylated interferon; RBV, ribavirin.

PEG-IFN/ribavirin arm. High proportions of asu- Virological failure naprevir-treated patients achieved RVR, compared No virological breakthrough occurred in any treat- with none in the placebo arm (Figure 1A). eRVR was ment arm. Three (27%) patients in the placebo arm achieved by 75% (9/12; 80% CI 52%, 90%), 75% had detectable HCV RNA at the end of treatment, and (9/12; 80% CI 52%, 90%) and 92% (11/12; 80% one (9%) experienced viral relapse. In the asunaprevir CI 71%, 99%) of patients in the asunaprevir 200 mg 200 mg arm, one (8%) patient had HCV RNA detect- twice-daily, 600 mg twice-daily and 600 mg once- able but

SVR24 by the protocol definition, one (200 mg twice have been associated with resistance to other NS3 pro- daily) had HCV RNA detectable but

In this small study, rates of eRVR and SVR24 were high skin, myalgia and depression occurred more frequently among asunaprevir-treated patients across CC and in the asunaprevir arms. Rates of serious adverse events non-CC genotypes (Figure 1B). In the placebo arm, were comparable across asunaprevir doses (Table 2). In

SVR24 was achieved by both patients (100%, 2/2) with the 200 mg arm, serious adverse events included abdom- a CC genotype compared to 33% (3/9) of those with a inal pain (n=1) and lung neoplasm (n=1); neither was non-CC genotype. judged as related to therapy. One patient in the 600 mg

Figure 1. Virological response during and after treatment: modified intention-to-treat

A ASV 200 mg ASV 600 mg ASV 600 mg Placebo + twice daily + twice daily + once daily + PEG-IFN/RBV PEG-IFN/RBV PEG-IFN/RBV PEG-IFN/RBV (n=12) (n=11)a (n=12) (n=12) 100 100 92 92 92a 90 83 83 83 83 83 83 80 75 75

70 11/12 10/12 60 11/12 12/12 10/12 11/12 10/12 10/12 0/11 10/12 50 10/12 46 46 9/12 9/12 0/11 40 5/11 30 5/11

20 Patients achieving end point, % 10 00 0

eRVR RVR SVR12 SVR24 (primary end point) LOD≈10 IU/ml

B ASV 200 mg ASV 600 mg ASV 600 mg Placebo + twice daily + twice daily + once daily + PEG-IFN/RBV PEG-IFN/RBV PEG-IFN/RBV PEG-IFN/RBV

100 100 100 100 100 100 100 86 86 86 82 5/5 80 80 1/1 5/5 73 1/1 5/5 2/2 6/7 57 6/7 60 9/11 6/7 4/5 8/11 40 4/7 33

Patients achieving end point, % 3/9 0/2 0/9 0 CC CT/TT CC CT/TT

eRVR SVR24

a Response rates are shown (A) among all treated patients and (B) by host IL28B genotype. One patient with 12-week sustained virological response (SVR12) had missing data at post-treatment week 24 (classified as a failure for 24-week sustained virological response [SVR24]). No viral breakthrough occurred in any asunaprevir (ASV)- treated patient. Among ASV-treated patients not achieving SVR24, one (200 mg) had HCV RNA detectable but less than the lower limit of quantification (LLOQ) at post-treatment week 24, one (200 mg) had HCV RNA detectable but less than the LLOQ at the end of treatment and undetectable HCV RNA at post-treatment week 4 and was subsequently lost to follow-up, two (600 mg twice daily) discontinued prior to post-treatment week 24, and one (600 mg once daily) was missing an HCV RNA measurement at post-treatment week 24. eRVR, extended rapid virological response; LOD, limit of detection; PEG-IFN, pegylated interferon-α2a; RBV, ribavirin; RVR, rapid virological response.

Antiviral Therapy 18.7 889 J-P Bronowicki et al.

Table 2. Cumulative safety on treatment

Treatment combined with PEG-IFN-α2a plus RBV ASV 200 mg twice ASV 600 mg twice ASV 600 mg once Placebo (n=11) Variable daily (n=12) daily (n=12) daily (n=12)

Any AE 12 (100) 12 (100) 12 (100) 11 (100) Serious AEs 2 (16.7) 1 (8.3) 2 (16.7) 0 Discontinued due to AEs 0 1 (8.3) 2 (16.7) 1 (9.1) Death 0 0 0 0 Grade 3–4 AEs 1 (8.3) 2 (16.7) 4 (33.3) 3 (27.3) Grade 3–4 laboratory abnormalitiesa Haemoglobinb 0; 0 0; 0 2 (16.7); 0 1 (9.1); 0 Plateletsc 0; 0 0; 0 0; 1 (8.3) 0; 0 Neutrophils plus bandsd 3 (25.0); 0 2 (16.7); 2 (16.7) 4 (33.3); 0 2 (18.2); 0 Lymphocytese 1 (8.3); 0 1 (8.3); 0 3 (25.0); 0 0; 0 WBC 0; 0 2 (16.7); 0 3 (25.0); 0 1 (9.1); 0 ALTf 0; 0 1 (8.3); 0 0; 2 (16.7) 0; 0 AST 0; 0 1 (8.3); 0 1 (8.3); 1 (8.3) 0; 0 Total bilirubing 1 (8.3); 0 1 (8.3); 0 0; 1 (8.3) 0; 0 Lipase 0; 0 1 (8.3); 0 0; 0 0; 0 Adverse events of all grades occurring in ≥15% patientsh Fatigue 6 (50.0) 5 (41.7) 10 (83.3) 5 (45.5) Diarrhoea 6 (50.0) 6 (50.0) 6 (50.0) 1 (9.1) Influenza-like illness 4 (33.3) 3 (25.0) 7 (58.3) 5 (45.5) Nausea 3 (25.0) 6 (50.0) 4 (33.3) 2 (18.2) Headache 5 (41.7) 3 (25.0) 5 (41.7) 6 (54.5) Asthenia 5 (41.7) 4 (33.3) 1 (8.3) 4 (36.4) Asthenia grade 3–4 0 0 0 1 (9.1) Irritability 4 (33.3) 1 (8.3) 2 (16.7) 4 (36.4) Rash 3 (25.0) 3 (25.0) 0 3 (27.3) Pruritus 4 (33.3) 3 (25.0) 3 (25.0) 2 (18.2) Decreased appetite 4 (33.3) 4 (33.3) 4 (33.3) 3 (27.3) Dry skin 4 (33.3) 2 (16.7) 5 (41.7) 1 (9.1) Myalgia 4 (33.3) 3 (25.0) 2 (16.7) 1 (9.1) Depression 4 (33.3) 3 (25.0) 2 (16.7) 1 (9.1) Insomnia 7 (58.3) 2 (16.7) 1 (8.3) 1 (9.1) Arthralgia 2 (16.7) 1 (8.3) 1 (8.3) 4 (36.4) Cough 2 (16.7) 1 (8.3) 4 (33.3) 3 (27.3) Dyspnea 4 (33.3) 1 (8.3) 5 (41.7) 3 (27.3) Alopecia 5 (41.7) 2 (16.7) 0 3 (27.3)

Data are n (%) unless indicated otherwise. aData are presented as n (%) abnormalities for grade 3; grade 4. bGrade 3, 7–8.9 g/dl; grade 4, <7.0 g/dl. cGrade 3, 25,000– 49,999 cells/mm3; grade 4, <25,000 cells/mm3. dGrade 3, 500–749 cells/mm3; grade 4, <500 cells/mm3. eGrade 3, 350–499 cells/mm3; grade 4, <350 cells/mm3. fGrade 3, 5.1–10× the upper limit of normal (ULN); grade 4, >10×ULN. gGrade 3, 2.6–5×ULN; grade 4, >5×ULN. hAll events were grade 1 or 2, except where specified. AE, adverse event; ALT, alanine aminotransferase; AST, aspartate aminotransferase; ASV, asunaprevir; PEG-IFN, pegylated interferon; RBV, ribavirin; WBC, white blood cell.

once-daily arm experienced cytolytic hepatitis (potential lymphocytes these abnormalities also occurred in the drug-induced liver injury [19]) at week 6: ALT increased PEG-IFN/ribavirin control arm (Table 2). to 535 U/l and total bilirubin increased to 3.5 mg/dl; the Elevations in ALT, AST and total bilirubin were patient had jaundice, but INR and albumin remained greater and more frequent in the asunaprevir 600 mg within normal limits. The patient discontinued asunap- arms than in the 200 mg and placebo arms. ALT lev- revir, but continued PEG-IFN/ribavirin, and the event els in individual patients over time are shown in Figure resolved at week 11. Rates of discontinuation of all study 2. Grade 3–4 ALT elevations occurred only in patients therapy due to adverse events varied (Table 2). The most receiving the 600 mg doses, and grade 3–4 elevations common grade 3–4 laboratory abnormalities in asunap- in total bilirubin occurred in one patient in each asu- revir-treated patients included decreases in haemoglobin, naprevir arm (Table 2 and Figure 2). Grade 3–4 ALT absolute lymphocytes, absolute neutrophils, and leuko- elevations normalized among patients who had their cytes, and, with the exception of grade 3 decreases in asunaprevir dose reduced (Figure 2).

Figure 2. Alanine aminotransferase trend over time by dose group

A B 500 Grade 4 500 Grade 4 450 450 400 400 350 350 300 300 b 250 Grade 3 250 Grade 3 ALT, U/l

ALT, U/l 200 200 a 150 Grade 2 150 Grade 2 100 100 Grade 1 Grade 1 50 50 0 0 04812162024283236404448525660 04812162024283236404448525660 Weeks Weeks CDc 500 Grade 4 500 Grade 4 450 450 400 400 350 350 300 300 250 Grade 3 250 Grade 3 ALT, U/l

ALT, U/l 200 200 150 Grade 2 150 Grade 2 100 100 Grade 1 Grade 1 50 50 0 0 04812162024283236404448525660 04812162024283236404448525660 Weeks ALT>500 U/l Weeks

(A) Asunaprevir (ASV) 200 mg twice daily plus pegylated interferon-α2a (PEG-IFN)/ribavirin (RBV; n=12). (B) ASV 600 mg twice daily plus PEG-IFN/RBV (n=12). (C) ASV 600 mg once daily plus PEG-IFN/RBV (n=12). (D) Placebo plus PEG-IFN/RBV (n=11). Arrows indicate ASV dose change to 200 mg twice daily. Dotted lines indicate off-treatment follow-up. aDiscontinued ASV at week 7, continued PEG-IFN/RBV. bDiscontinued ASV at week 12, continued PEG-IFN/RBV. cDiscontinued ASV at week 10, continued PEG-IFN/RBV. ALT, alanine aminotransferase.

Pharmacokinetics transaminase elevations (Figure 3). The simulations Pharmacokinetic analyses explored the relationship predicted grade 3–4 ALT or AST elevations in <10% between asunaprevir exposure and ALT elevations of patients receiving this dose. (Additional file 1). Grade 3–4 ALT elevations occurred in three patients; two discontinued asunaprevir but Discussion continued PEG-IFN/ribavirin, and one discontinued all medications. Analyses showed that patients in the 600 This study assessed the safety and antiviral activity of mg asunaprevir arms with elevated transaminases who asunaprevir plus PEG-IFN/ribavirin compared with discontinued had Cmax and AUCTAU values that were placebo plus PEG-IFN/ribavirin in genotype 1 treat- much higher than the maximum values observed in ment-naive patients. The results complement the SVR the 200 mg twice-daily arm. The maximum observed data reported for asunaprevir plus the NS5A inhibitor

AUC24 h for the 200 mg twice-daily arm was 12,600 daclatasvir in genotype 1 prior null responders [14,20]. ng•h/ml, while the minimum AUC24 h of patients dis- In the current study, SVR24 was achieved by 83%, 83% continuing due to elevated transaminases was 18,300 and 92% of patients in the asunaprevir 200 mg twice- ng•h/ml. Simulations exploring the probability distri- daily, 600 mg twice-daily and 600 mg once-daily arms, bution of AUC24 h by dose level indicated a low prob- respectively, compared with 46% (5/11) in the placebo ability of patients receiving the 200 mg twice-daily arm. There was no viral breakthrough among patients dose achieving exposures associated with grade 3–4 receiving asunaprevir regimens. Virological failure was

Antiviral Therapy 18.7 891 J-P Bronowicki et al.

Figure 3. Simulated probability distribution of 24 h area under An aim of this Phase IIa dose-ranging study was to the curve by dose level select an asunaprevir dose for the Phase IIb study and for future combination studies in Phase III. All doses of Total daily dose asunaprevir were efficacious, meeting the criteria for 0.00015 600 mg dose selection, and achieved high SVR24 rates. A trend 1,200 mg of transaminase elevations and treatment discontinu-

24 h 400 mg 0.00010 ations was observed with the 600 mg once-daily and twice-daily doses; similar observations were reported in previous studies that included this dose of asunaprevir, 0.00005 with or without PEG-IFN and ribavirin [14]. In this a given AUC study, no patient in the 200 mg twice-daily group had

Probability of observing 0.0 0 grade 3–4 transaminase elevations, and none discon- ,000 ,000 ,000 ,000 10 20 30 40 50,000 60,000 tinued due to hepatic adverse events. Pharmacokinetic analyses showed that patients with elevated transami- AUC24 h, ng●h/ml nases who discontinued treatment had asunaprevir exposures higher than the maximum exposure values

Preliminary data based on 2,000 simulated subjects. AUC24 h, area under the observed among patients who received the 200 mg concentration–time curve at 24 h. twice-daily dose. A projected distribution of the AUC for the three asunaprevir doses studied suggested that patients receiving the 200 mg twice daily dose have more frequent in the PEG-IFN/ribavirin control arm a low probability of achieving exposure levels associ- than in the asunaprevir arms; virological failure as ated with the transaminase elevations observed at the defined by the protocol occurred in only two asunap- higher doses. The model predicts grade 3 or 4 ALT or revir-treated patients and involved HCV RNA that was AST elevations in <10% of patients receiving this dose. detectable but

PEG-IFN and ribavirin alone – and most were also for 48 weeks results in high rates of SVR24 in genotype observed in the PEG-IFN/ribavirin control arm [8]. 1 patients. The 200 mg twice-daily dose demonstrated Elevations in ALT, AST and bilirubin were observed similar virological efficacy to the 600 mg twice-daily and in some patients in all asunaprevir dose groups. How- once-daily doses, with a more tolerable adverse event pro- ever, these elevations were greater and more frequent file. The 200 mg asunaprevir dose is being studied in com- in the asunaprevir 600 mg groups than in the 200 mg bination with PEG-IFN and ribavirin in a Phase IIb trial group (Figure 2 and Table 2). Grade 3–4 transami- in treatment-naive patients, and is also being evaluated nase elevations were only associated with the 600 in Phase III studies of combination direct-acting antiviral mg doses of asunaprevir, which were changed to 200 regimens, with and without PEG-IFN and ribavirin, in mg twice daily after the week 12 analysis. Following difficult-to-treat patients including prior null responders. the dose change, hepatic enzyme levels normalized in those patients who had elevations, and no further Acknowledgements grade 3–4 transaminase elevations occurred. Patients who discontinued treatment for transaminase and bil- The authors thank Cyril Llamoso for his contribution irubin elevations also experienced their normalization to the conduct of this study. This study was funded after discontinuation. by Bristol–Myers Squibb. Assistance with manuscript

9. Fried MW, Shiffman ML, Reddy KR, et al. Peginterferon preparation was provided by Jennifer Tobin (Articulate alfa-2a plus ribavirin for chronic hepatitis C virus infection. Science, Hamilton, NJ, USA), with funding provided by N Engl J Med 2002; 347:975–982. Bristol–Myers Squibb. 10. Poordad F, McCone J, Jr., Bacon BR, et al. Boceprevir for untreated chronic HCV genotype 1 infection. N Engl J Med 2011; 364:1195–1206. Disclosure statement 11. Jacobson IM, McHutchison JG, Dusheiko G, et al. Telaprevir for previously untreated chronic hepatitis C virus J-PB, SP, DL and CTM have received consulting fees infection. N Engl J Med 2011; 364:2405–2416. 12. McPhee F, Sheaffer AK, Friborg J, et al. Preclinical profile or honoraria from Bristol–Myers Squibb. PJT, SP, DL, and characterization of the hepatitis C virus NS3 protease CTM and VKR have received research grants from inhibitor asunaprevir (BMS-650032). Antimicrob Agents Bristol–Myers Squibb. KRR has served as an ad hoc Chemother 2012; 56:5387–5396. 13. Pasquinelli C, McPhee F, Eley T, et al. Single and multiple advisor to Bristol–Myers Squibb, and is an investigator ascending dose studies of the NS3 protease inhibitor for Bristol–Myers Squibb. BH, TE, DC, FM, BR, PM asunaprevir in subjects with or without chronic hepatitis C. and EH are employees of Bristol–Myers Squibb. RH Antimicrob Agents Chemother 2012; 56:1838–1844. 14. Lok AS, Gardiner DF, Lawitz E, et al. Preliminary study of and AA are former employees of Bristol–Myers Squibb. two antiviral agents for hepatitis C genotype 1. N Engl J Med 2012; 366:216–224. 15. Lok AS, Gardiner D, Hezode C, et al. 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Accepted 8 May 2013; published online 26 June 2013

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