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Featured researches published by Joji Toyota.


Hepatology | 2014

Daclatasvir Plus Asunaprevir for Chronic HCV Genotype 1b Infection

Yoshiyuki Suzuki; Kenji Ikeda; Joji Toyota; Yoshiyasu Karino; Kazuaki Chayama; Yoshiiku Kawakami; Akio Ido; Kazuhide Yamamoto; Koichi Takaguchi; Namiki Izumi; Kazuhiko Koike; Tetsuo Takehara; Norifumi Kawada; Michio Sata; Hidetaka Miyagoshi; Timothy Eley; Fiona McPhee; Andrew Damokosh; Hiroki Ishikawa; Eric Hughes

All‐oral combinations of direct‐acting antivirals may improve efficacy and safety outcomes for patients with hepatitis C virus (HCV) infection, particularly those who are poor candidates for current interferon/ribavirin‐based regimens. In this open‐label, phase 3 study, 135 interferon‐ineligible/intolerant and 87 nonresponder patients with chronic HCV genotype 1b infection were enrolled at 24 centers in Japan. Patients received daclatasvir 60 mg once daily plus asunaprevir 100 mg twice daily for 24 weeks. The primary endpoint was sustained virologic response 24 weeks after treatment (SVR24). This study is registered with ClinicalTrials.gov (NCT01497834). SVR24 was achieved by 87.4% of interferon‐ineligible/intolerant patients and 80.5% of nonresponder (null and partial) patients; rates were similar in cirrhosis (90.9%) and noncirrhosis (84.0%) patients, and in patients with IL28B CC (84.5%) or non‐CC (84.8%) genotypes. Fourteen patients in each group (12.6%) discontinued dual therapy, mainly due to adverse events or lack of efficacy. Nine nonresponder patients received additional treatment with peginterferon/ribavirin per protocol‐defined criteria. The rate of serious adverse events was low (5.9%) and varied among patients. The most common adverse events were nasopharyngitis, increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST), headache, diarrhea, and pyrexia. Conclusion: Interferon‐free, ribavirin‐free all‐oral therapy with daclatasvir and asunaprevir for 24 weeks is well tolerated and can achieve a high rate of SVR in patients with HCV genotype 1b who were ineligible, intolerant, or had not responded to prior interferon‐based therapy. (Hepatology 2014;59:2083–2091)


Hepatology | 2012

Dual therapy with the nonstructural protein 5A inhibitor, daclatasvir, and the nonstructural protein 3 protease inhibitor, asunaprevir, in hepatitis C virus genotype 1b-infected null responders.

Kazuaki Chayama; Shoichi Takahashi; Joji Toyota; Yoshiyasu Karino; Kenji Ikeda; Hiroki Ishikawa; Hideaki Watanabe; Fiona McPhee; Eric Hughes

Patients with chronic hepatitis C virus (HCV) infection and previous null response to pegylated interferon (Peg‐IFN) and ribavirin (RBV) have limited therapeutic options. HCV genotype 1 is the most common worldwide and the most difficult to treat; genotype 1b is the most common subtype of genotype 1 outside North America. The enhanced antiviral activity achieved by combining two direct‐acting antiviral (DAA) agents may improve clinical outcomes. This open‐label, phase IIa study included 10 patients with chronic HCV genotype 1b infection and previous null response (<2 log10 reduction in HCV RNA after 12 weeks) to Peg‐IFN and RBV. Patients received dual DAA treatment for 24 weeks with the nonstructural protein 5A replication complex inhibitor, daclatasvir (60 mg once‐daily), and the nonstructural protein 3 protease inhibitor, asunaprevir (initially 600 mg twice‐daily, then subsequently reduced to 200 mg twice‐daily). The primary efficacy endpoint was the proportion of patients with sustained virologic response (SVR) at 12 weeks post‐treatment (SVR12). Nine patients completed 24 weeks of treatment; 1 patient discontinued treatment after 2 weeks. In the 9 patients who completed the full course of treatment, HCV RNA was undetectable at week 8 and remained undetectable through the end of treatment; all 9 patients achieved SVR12 and SVR24. HCV RNA also remained undetectable post‐treatment in the patient who discontinued after 2 weeks. There was no viral breakthrough. Diarrhea and headache, generally mild, were the most common adverse events; transaminase elevations were reported in 3 patients, but did not result in discontinuation. Conclusions: Dual therapy with daclatasvir and asunaprevir, without Peg‐IFN and RBV, can achieve high SVR rates in difficult‐to‐treat patients with HCV genotype 1b infection and previous null response to Peg‐IFN and RBV. (HEPATOLOGY 2011)


Journal of Hepatology | 2012

Telaprevir with peginterferon and ribavirin for treatment-naive patients chronically infected with HCV of genotype 1 in Japan

Joji Toyota; Takeshi Okanoue; Kazuaki Chayama; Hirohito Tsubouchi; Norio Hayashi

BACKGROUND & AIMS To evaluate the efficacy and safety of telaprevir in combination with peginterferon-α2b (PEG-IFN) and ribavirin (RBV) in patients with chronic hepatitis C. METHODS In a multi-center randomized clinical trial in Japan, on patients infected with HCV of genotype 1, 126 patients were assigned to telaprevir for 12 weeks along with PEG-IFN and RBV for 24 weeks (Group A), while 63 to PEG-IFN and RBV for 48 weeks (Group B). RESULTS HCV RNA disappeared more swiftly in patients in Group A than B, and the frequency of patients without detectable HCV RNA at week 4 (rapid virological response (RVR)) was higher in Group A than B (84.0% vs. 4.8%, p <0.0001). Grade 3 and 4 skin disorders, including Stevens-Johnson syndrome and drug rashes with eosinophilia and systemic symptoms, as well as Grade 3 anemia (<8.0 g/dl), occurred more frequently in Group A than B (skin disorders, 11.9% vs. 4.8%; anemia, 11.1% vs. 0.0%). The total RBV dose was smaller in Group A than B (47.0% vs. 77.7% of the target, p <0.0001). Despite these drawbacks, sustained virological response (SVR) was achieved more frequently in Group A than B (73.0% vs. 49.2%, p=0.0020). CONCLUSIONS Although the triple therapy with telaprevir-based regimen for 24 weeks resulted in more adverse events and less total RBV dose than PEG-IFN and RBV for 48 weeks, it was able to achieve higher SVR within shorter duration by carefully monitoring adverse events and modifying the RBV dose as required.


Oncogene | 2000

Frequent hypermethylation of CpG islands and loss of expression of the 14-3-3 σ gene in human hepatocellular carcinoma

Norikazu Iwata; Hiroyuki Yamamoto; Shigeru Sasaki; Fumio Itoh; Hiromu Suzuki; Takefumi Kikuchi; Hiroyuki Kaneto; Shouhei Iku; Itaru Ozeki; Yoshiyasu Karino; Toshihiro Satoh; Joji Toyota; Masaaki Satoh; Takao Endo; Kohzoh Imai

The 14-3-3 σ gene has been implicated in G2/M cell cycle arrest by p53. Frequent inactivation of the 14-3-3 σ gene by hypermethylation of CpG islands has recently been reported in human breast carcinoma. The aim of this study was to examine the methylation status of CpG islands of the 14-3-3 σ gene in hepatocellular carcinoma (HCC). The methylation status of the 14-3-3 σ gene was evaluated in four normal liver tissues and 19 paired specimens of carcinoma and adjacent non-tumorous liver tissues using bisulfite-single strand conformation polymorphism (bisulfite-SSCP), a combination of sodium bisulfite modification and fluorescence-based polymerase chain reaction (PCR)-SSCP. The 14-3-3 σ protein expression was examined by immunohistochemical staining. Hypermethylation of CpG islands of the 14-3-3 σ gene was detected in 89% (17/19) of the HCC tissues but not in any of the four normal liver tissues. All of the 14 methylation-positive HCC samples analysed by immunohistochemistry showed loss of 14-3-3 σ expression, while both of the methylation-negative HCC samples retained the expression, and a significant correlation was found between methylation and loss of expression. Lower levels of methylation were detected in adjacent non-tumorous liver tissues (6/16 in cirrhotic tissues and 1/3 in chronic hepatitis tissues), but the 14-3-3 σ expression was retained in all of these tissues. In a methylation-positive HCC cell line, HLE, 5-aza-2′-deoxycytidine (5-aza-dC)-induced demethylation of CpG islands led to reactivation of gene expression, indicating that hypermethylation plays a causal role in inactivation of the 14-3-3 σ gene in HCC. Hypermethylation and the resulting loss of expression of the 14-3-3 σ gene corresponds to one of the most common abnormalities reported to date in HCC, suggesting their crucial role in the development and/or progression of HCC.


Journal of Hepatology | 2013

Dual oral therapy with daclatasvir and asunaprevir for patients with HCV genotype 1b infection and limited treatment options

Yoshiyuki Suzuki; Kenji Ikeda; Fumitaka Suzuki; Joji Toyota; Yoshiyasu Karino; Kazuaki Chayama; Yoshiiku Kawakami; Hiroki Ishikawa; Hideaki Watanabe; Wenhua Hu; Timothy Eley; Fiona McPhee; Eric Hughes

BACKGROUND & AIMS Improved therapeutic options for chronic hepatitis C virus (HCV) infection are needed for patients who are poor candidates for treatment with current regimens due to anticipated intolerability or low likelihood of response. METHODS In this open-label, phase 2a study of Japanese patients with chronic HCV genotype 1b infection, 21 null responders (<2 log₁₀ HCV RNA reduction after 12 weeks of peginterferon/ribavirin) and 22 patients intolerant to or medically ineligible for peginterferon/ribavirin therapy received dual oral treatment for 24 weeks with the NS5A replication complex inhibitor daclatasvir (DCV) and the NS3 protease inhibitor asunaprevir (ASV). The primary efficacy end point was sustained virologic response at 12 weeks post-treatment (SVR₁₂). RESULTS Thirty-six of 43 enrolled patients completed 24 weeks of therapy. Serum HCV RNA levels declined rapidly, becoming undetectable in all patients on therapy by week 8. Overall, 76.7% of patients achieved SVR₁₂ and SVR₂₄, including 90.5% of null responders and 63.6% of ineligible/intolerant patients. There were no virologic failures among null responders. Three ineligible/intolerant patients experienced viral breakthrough and four relapsed post-treatment. Diarrhea, nasopharyngitis, headache, and ALT/AST increases, generally mild, were the most common adverse events; three discontinuations before week 24 were due to adverse events that included hyperbilirubinemia and transaminase elevations (two patients). CONCLUSIONS Dual therapy with daclatasvir and asunaprevir, without peginterferon/ribavirin, was well tolerated and achieved high SVR rates in two groups of difficult-to-treat patients with hepatitis C virus genotype 1b infection.


Journal of Hepatology | 2013

Characterization of virologic escape in hepatitis C virus genotype 1b patients treated with the direct-acting antivirals daclatasvir and asunaprevir.

Yoshiyasu Karino; Joji Toyota; Kenji Ikeda; Fumitaka Suzuki; Kazuaki Chayama; Yoshiiku Kawakami; Hiroki Ishikawa; Hideaki Watanabe; Dennis Hernandez; Fei Yu; Fiona McPhee

BACKGROUND & AIMS Daclatasvir and asunaprevir are NS5A and NS3 protease-targeted antivirals currently under development for treatment of chronic hepatitis C virus infection. Clinical data on baseline and on-treatment correlates of drug resistance and response to these agents are currently limited. METHODS Hepatitis C virus genotype 1b Japanese patients (prior null responders to PegIFN-α/RBV [n=21] or PegIFN-α/RBV ineligible or intolerant [n=22]) were administered daclatasvir/asunaprevir for 24 weeks during a phase 2a open-label study. Genotypic and phenotypic analyses of NS3 and NS5A substitutions were performed at baseline, after virologic failure, and post-treatment through follow-up week 36. RESULTS There were three viral breakthroughs and four relapsers. Baseline NS3 polymorphisms (T54S, Q80L, V170M) at amino acid positions previously associated with low-level resistance (<9-fold) to select NS3 protease inhibitors were detected in four null responders and three ineligibles, but were not associated with virologic failure. Baseline NS5A polymorphisms (L28M, L31M, Y93H) associated with daclatasvir resistance (<25-fold) were detected in five null responders and six ineligibles. All three viral breakthroughs and 2/4 relapsers carried a baseline NS5A-Y93H polymorphism. NS3 and NS5A resistance-associated variants were detected together (NS3-D168A/V, NS5A-L31M/V-Y93H) after virologic failure. Generally, daclatasvir-resistant substitutions persisted through 48weeks post-treatment, whereas asunaprevir-resistant substitutions were no longer detectable. Overall, 5/10 patients with baseline NS5A-Y93H experienced virologic failure, while 5/10 achieved a sustained virologic response. CONCLUSIONS The potential association of a pre-existing NS5A-Y93H polymorphism with virologic failure on daclatasvir/asunaprevir combination treatment will be examined in larger studies. The persistence of treatment-emergent daclatasvir- and asunaprevir-resistant substitutions will require assessment in longer-term follow-up studies.


Gut | 2001

Detection of hypermethylation of the p16 INK4A gene promoter in chronic hepatitis and cirrhosis associated with hepatitis B or C virus

Hiroyuki Kaneto; Shigeru Sasaki; Hiroyuki Yamamoto; Fumio Itoh; Minoru Toyota; Hiromu Suzuki; Itaru Ozeki; N Iwata; T Ohmura; T Satoh; Y Karino; Joji Toyota; Masaaki Satoh; Takao Endo; M Omata; Kohzoh Imai

BACKGROUND/AIM Inactivation of the p16 INK4A(p16) tumour suppressor gene by promoter region hypermethylation has been demonstrated not only in many types of tumours, including hepatocellular carcinoma (HCC), but also in early preneoplastic lesions in the lung, colon, oesophagus, and pancreas. The aim of this study was to examine the methylation status of thep16 promoter in pre- and/or non-neoplastic liver diseases. PATIENTS/SUBJECTS/METHODS The methylation status of p16 was evaluated in 22 HCC, 17 cirrhosis, 17 chronic hepatitis, nine primary biliary cirrhosis (PBC), eight autoimmune hepatitis, seven drug induced liver disease, six fatty liver, and three normal liver tissues using methylation specific polymerase chain reaction (MSP). p16 protein expression was also examined by immunohistochemical staining. RESULTS Methylation of the p16 promoter was detected in HCC (72.7%, 16/22) and also in cirrhosis (29.4%, 5/17) and chronic hepatitis (23.5%, 4/17), all of which were positive for hepatitis B or C virus infections. Methylation was not detected in any of the other samples. All methylation positive HCC, cirrhosis, and chronic hepatitis samples showed loss of p16 expression, and a significant correlation was found between methylation and loss of expression. Analysis of serial samples from individual patients with methylation positive HCC revealed that loss of p16 expression with promoter methylation occurred in 18 of 20 patients at the stage of chronic hepatitis without clinically detectable carcinoma. CONCLUSIONS Our results suggest that methylation of the p16promoter and the resulting loss of p16 protein expression are early events in a subset of hepatocarcinogenesis and that their detection is useful in the follow up of patients with a high risk of developing HCC, such as those with hepatitis B or C viral infections.


The Journal of Infectious Diseases | 2011

IL28B But Not ITPA Polymorphism Is Predictive of Response to Pegylated Interferon, Ribavirin, and Telaprevir Triple Therapy in Patients With Genotype 1 Hepatitis C

Kazuaki Chayama; C. Nelson Hayes; Hiromi Abe; Daiki Miki; Hidenori Ochi; Yoshiyasu Karino; Joji Toyota; Yusuke Nakamura; Naoyuki Kamatani; Hitomi Sezaki; Mariko Kobayashi; Norio Akuta; Fumitaka Suzuki

BACKGROUND Pegylated interferon, ribavirin, and telaprevir triple therapy is a new strategy expected to eradicate the hepatitis C virus (HCV) even in patients infected with difficult-to-treat genotype 1 strains, although adverse effects, such as anemia and rash, are frequent. METHODS We assessed efficacy and predictive factors for sustained virological response (SVR) for triple therapy in 94 Japanese patients with HCV genotype 1. We included recently identified predictive factors, such as IL28B and ITPA polymorphism, and substitutions in the HCV core and NS5A proteins. RESULTS Patients treated with triple therapy achieved comparatively high SVR rates (73%), especially among treatment-naive patients (80%). Of note, however, patients who experienced relapse during prior pegylated interferon plus ribavirin combination therapy were highly likely to achieve SVR while receiving triple therapy (93%); conversely, prior nonresponders were much less likely to respond to triple therapy (32%). In addition to prior treatment response, IL28B SNP genotype and rapid viral response were significant independent predictors for SVR. Patients with the anemia-susceptible ITPA SNP rs1127354 genotype typically required ribavirin dose reduction earlier than did patients with other genotypes. CONCLUSIONS Analysis of predictive factors identified IL28B SNP, rapid viral response, and transient response to previous therapy as significant independent predictors of SVR after triple therapy.


Journal of Viral Hepatitis | 2012

Efficacy and safety of telaprevir, a new protease inhibitor, for difficult-to-treat patients with genotype 1 chronic hepatitis C.

Nana Hayashi; Takeshi Okanoue; Hirohito Tsubouchi; Joji Toyota; Kazuaki Chayama

Summary.  The aims of this phase III study were to assess the efficacy and safety of telaprevir in combination with peginterferon alfa‐2b (PEG‐IFN) and ribavirin (RBV) for difficult‐to‐treat patients who had not achieved sustained virological response (SVR) to prior regimens in Japan. The subjects were 109 relapsers (median age of 57.0 years) and 32 nonresponders (median age of 57.5 years) with hepatitis C virus genotype 1. Patients received telaprevir (750 mg every 8 h) for 12 weeks and PEG‐IFN/RBV for 24 weeks. The SVR rates for relapsers and nonresponders were 88.1% (96/109) and 34.4% (11/32), respectively. Specified dose modifications of RBV that differed from that for the standard of care were introduced to alleviate anaemia. RBV dose reductions were used for 139 of the 141 patients. The SVR rates for relapsers did not depend on RBV dose reduction for 20–100% of the planned dose (SVR rates 87.5–100%, P < 0.05). Skin disorders were observed in 82.3% (116/141). Most of the skin disorders were controllable by anti‐histamine and/or steroid ointments. The ratios of discontinuation of telaprevir only or of all the study drugs because of adverse events were 21.3% (30/141) and 16.3% (23/141), respectively. A frequent adverse event leading to discontinuation was anaemia. Telaprevir in combination with PEG‐IFN/RBV led to a high SVR rate for relapsers and may offer a potential new therapy for nonresponders even with a shorter treatment period.


Nature Genetics | 2011

Variation in the DEPDC5 locus is associated with progression to hepatocellular carcinoma in chronic hepatitis C virus carriers

Daiki Miki; Hidenori Ochi; C. Nelson Hayes; Hiromi Abe; Tadahiko Yoshima; Kenji Ikeda; Joji Toyota; Takashi Morizono; Tatsuhiko Tsunoda; Michiaki Kubo; Yusuke Nakamura; Naoyuki Kamatani; Kazuaki Chayama

Chronic viral hepatitis is the most important risk factor for progression to hepatocellular carcinoma (HCC). To identify genetic risk factors for progression to HCC in individuals with chronic hepatitis C virus (HCV), we analyzed 467,538 SNPs in 212 Japanese individuals with chronic HCV with HCC and 765 individuals with chronic HCV without HCC. We identified one intronic SNP in the DEPDC5 locus on chromosome 22 associated with HCC risk and confirmed the association using an independent case-control population (710 cases and 1,625 controls). The association was highly significant when we analyzed the stages separately as well as together (rs1012068, Pcombined = 1.27 × 10−13, odds ratio = 1.75). The significance level of the association further increased after adjustment for gender, age and platelet count (P = 1.35 × 10−14, odds ratio = 1.96). Our findings suggest that common variants within the DEPDC5 locus affect susceptibility to HCC in Japanese individuals with chronic HCV infection.

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Namiki Izumi

Tokyo Medical and Dental University

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Itaru Ozeki

Sapporo Medical University

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Kenji Ikeda

University of Tokushima

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