Efficacy and safety of telaprevir with pegylated interferon α-2a and ribavirin in Japanese patients.

AIM: To assess the efficacy and safety of telaprevir (TVR) in combination with pegylated interferon α-2a (PEG-IFNα-2a) and ribavirin (RBV) for treatment-naïve patients and relapsed patients compared to previous TVR-based triple therapy in Japan. METHODS: The study group included 35 treatment-naïve (median age, 55 years) and 19 relapsed (median age, 55 years) patients with genotype 1 hepatitis C virus infection. Patients received TVR (750 mg every 8 h) for 12 weeks, in combination with PEG-IFNα-2a and RBV. RESULTS: The sustained virological response (SVR24 ) rates for naïve and relapsed patients were 85.7% (30/35) and 94.7% (18/19), respectively. The discontinuation rate of all study drugs due to adverse events was 5.6% (3/54). Among the 54 patients, grade 3 skin disorders and grade 3 anemia (<8.0 g/dL) were reported in 2 (3.7%) and 6 patients (11.1%), respectively. Although the overall safety profiles were similar for the TVR/PEG-IFNα-2a/RBV and TVR/PEG-IFNα-2b/RBV regimens (previous study), the proportion of patients discontinuing all study drugs due to adverse events was lower in the patients treated with the TVR/PEG-IFNα-2a/RBV regimen (3/54, 5.6%) than TVR/PEG-IFNα-2b/RBV regimen (44/267, 16.5%). CONCLUSION: Telaprevir in combination with PEG-IFNα-2a/RBV provided a high sustained virological response rate for the treatment of genotype 1 hepatitis C virus in both treatment-naïve and relapsed patients in Japan. Telaprevir-based therapy may provide a useful treatment option for patients who are difficult to treat due to NS5A (Y93, L31) and NS3/4A (D168) variants.

Plasma pharmacokinetics and synovial concentrations of S-flurbiprofen plaster in humans.

PURPOSE: The purpose of this study is to investigate the pharmacokinetics and deep tissue penetration capability of the newly developed S-flurbiprofen plaster (SFPP) in humans. METHODS: Study 1: SFPP tape-type patch (2-60 mg) was applied to the lower back for 24 h in healthy adult volunteers. S-flurbiprofen (SFP) plasma concentration was measured over time to examine SFP pharmacokinetics. Study 2: SFPP (20 mg) was applied for 12 h to the affected knee of osteoarthritis (OA) patients who were scheduled for total knee arthroplasty. Deep tissues (synovial tissue and synovial fluid) were collected during surgery to compare SFP concentrations after application of SFPP or a commercially available flurbiprofen (FP) gel-type patch. RESULTS: Study 1: The plasma concentration of SFP was sustained during 24-h topical application of the SFPP, showing a high percutaneous absorption ratio of 51.4-72.2 %. Cmax and AUC0-∞ were dose-proportional. Study 2: After application of the SFPP for 12 h, SFP concentrations in the synovial tissue and synovial fluid were 14.8-fold (p = 0.002) and 32.7-fold (p < 0.001) higher, respectively, than those achieved by the FP patch. CONCLUSIONS: Sustained plasma concentration of SFP and high percutaneous absorption ratio was observed after 24-h topical application of the SFPP. Compared to the FP patch, the SFPP showed superior percutaneous absorption and greater tissue penetration of SFP into the synovial tissue. Greater tissue penetration of the SFPP seemed to be primarily due to its formulation. Thus, SFPP is expected to show higher efficacy for the treatment of knee OA.

Efficacy of telaprevir-based therapy for difficult-to-treat patients with genotype 2 chronic hepatitis C in Japan.

AIM: This study assessed the efficacy and safety of telaprevir in combination with peginterferon-α-2b (PEG IFN) and ribavirin (RBV), for Japanese difficult-to-treat patients with hepatitis C virus (HCV) genotype 2 who had not achieved sustained virological response (SVR) during prior treatment. METHODS: In total, 108 relapsed (median age, 59.0 years) and 10 non-responding (median age, 59.0 years) patients with genotype 2 HCV participated. Patients received telaprevir (750 mg, every 8 h) for 12 weeks and PEG IFN/RBV for 24 weeks. RESULTS: The SVR rates for relapsers and non-responders were 88.0% (95/108) and 50.0% (5/10), respectively. The SVR rates did not differ significantly between patients with rs8099917 TT and non-TT. The SVR rates for relapsers and non-responders with extended rapid viral response (eRVR) were 97.6% (82/84) and 100% (5/5), respectively. On the other hand, the SVR rates for relapsers and non-responders completing the treatment protocol were 98.4% (61/62) and 100% (5/5), respectively. The overall safety profiles of telaprevir-based regimens were similar for Japanese patients with genotype 1 and 2 HCV infection who experienced treatment failure. CONCLUSION: Telaprevir, in combination with PEG IFN/RBV, provided a high SVR rate for genotype 2 HCV, difficult-to-treat patients who had not achieved SVR during prior IFN-based treatment. The eRVR had a strong influence on the cure rate of telaprevir-based therapy. In addition, the continuation of telaprevir-based treatment for up to 24 weeks was a significant predictor of SVR.

Evaluation of the potency of telaprevir and its metabolites as inhibitors of renal organic cation transporters, a potential mechanism for the elevation of serum creatinine.

Telaprevir-based triple therapy is a highly effective treatment for chronic hepatitis C. However, adverse reactions include reversible and dose-dependent elevation of serum creatinine levels. We speculated that this effect reflects inhibition of the renal organic cation transporters hOCT2, hMATE1, and hMATE2-K by telaprevir or its metabolites (VRT-127394 and VRT-0922061). Telaprevir, VRT-127394, and VRT-0922061 showed negligible or weak effects on hOCT2 at concentrations of ≥20 µM, but inhibited hMATE1 by 35, 38, and 53% and hMATE2-K by 47, 45, and 61% at 100 µM, respectively. Telaprevir or its metabolites (10 µM) did not affect basal-to-apical transport of MPP(+) across monolayers of hOCT2-hMATE1 double-transfected MDCKII cells, whereas pyrimethamine, a potent inhibitor of hMATE1, markedly inhibited MPP(+) transport. Taken together, inhibition of hOCT2, hMATE1, and hMATE2-K is unlikely to be clinically relevant because unbound plasma concentrations of telaprevir and its metabolites reach only 2 µM following oral administration of a dose of 750 mg telaprevir. Hence, elevated serum creatinine during telaprevir therapy may not be related to direct inhibition of renal organic cation transporters.

Dermatological side-effects of telaprevir-based triple therapy for chronic hepatitis C in phase III trials in Japan.

Telaprevir-based triple therapy is highly effective for chronic hepatitis C. However, concern has been expressed over the high frequency and severity of its dermatological side-effects compared with those associated with peginterferon (PEG-IFN) and ribavirin (RBV) therapy. Thus, here, we evaluated the dermatological adverse reactions of telaprevir-based triple therapy in Japanese multicenter phase III clinical trials in an attempt to characterize the dermatological side-effects and establish appropriate management plans. In these trials, 126 treatment-naïve patients and 141 treatment-failure patients were administrated telaprevir, PEG-IFN-α-2b and RBV for 12 weeks followed by PEG-IFN-α-2b and RBV for another 12 weeks (T12/PR24 group), and 63 treatment-naïve patients were administrated PEG-IFN-α-2b and RBV for 48 weeks (PR48 group). Dermatological adverse reactions developed in over 80% patients in both groups, and most of them were grade 1 or 2. In the T12/PR24 group, there were more grade 2 or grade 3 events, and the time to onset was earlier than that in the PR48 group. Most reactions could be managed with topical corticosteroids and oral antihistamines, and the rates of discontinuation due to dermatological reactions were not high even in the T12/PR24 group. In the T12/PR24 group, however, two cases of Stevens-Johnson syndrome and one case of drug rash with eosinophilia and systemic symptoms, which corresponds to drug-induced hypersensitivity syndrome in Japan, were reported. For appropriate treatments of individual dermatological adverse reactions, the judgment of discontinuation of antiviral drugs and treatment based on the severity are extremely important in this triple therapy.

Exploratory study on telaprevir given every 8 h at 500 mg or 750 mg with peginterferon-alpha-2b and ribavirin in hepatitis C patients.

AIM: The aims of this study are to assess the antiviral effects, safety and telaprevir (TVR) pharmacokinetics in two cohorts given TVR every 8 h (q8h) at doses of 500 mg and 750 mg with peginterferon-α-2b and ribavirin in chronic hepatitis C patients. METHODS: Twenty chronic hepatitis C (HCV) patients with genotype 1b in high viral loads were randomly assigned to two TVR-based regimens of 750 mg q8h (group A) and 500 mg q8h (group B) in combination with peginterferon-α-2b and ribavirin for 12 weeks. RESULTS: Although the difference was not statistically significant other than trough concentration (Ctrough ) at week 4, the parameters of maximum concentration (Cmax ), the area under the concentration time curve (AUC0-∞ ) and Ctrough tended to be higher in group A than those in group B. The antiviral effects were similar in the two groups (sustained virological response rates [SVR], 40% in group A, 50% in group B). The discontinuation rates by anemia were 30% in group A and 20% in group B. Serum creatinine concentrations were lower in group B than those in group A. CONCLUSION: Although the exposure to TVR tended to be lower in 500 mg q8h than that in 750 mg q8h, the SVR rates in both groups were similar. The result suggests that the 500 mg q8h dose may be one option for treatment. In addition, the present findings indicate that the development of adverse events which increase with a TVR-based regimen, specifically anemia and creatinine, could be avoided by dose adjustment of TVR.

Rapid emergence of telaprevir resistant hepatitis C virus strain from wildtype clone in vivo.

UNLABELLED: Telaprevir is a potent inhibitor of hepatitis C virus (HCV) NS3-4A protease. However, the emergence of drug-resistant strains during therapy is a serious problem, and the susceptibility of resistant strains to interferon (IFN), as well as the details of the emergence of mutant strains in vivo, is not known. We previously established an infectious model of HCV using human hepatocyte chimeric mice. Using this system we investigated the biological properties and mode of emergence of mutants by ultra-deep sequencing technology. Chimeric mice were injected with serum samples obtained from a patient who had developed viral breakthrough during telaprevir monotherapy with strong selection for resistance mutations (A156F [92.6%]). Mice infected with the resistant strain (A156F [99.9%]) developed only low-level viremia and the virus was successfully eliminated with interferon therapy. As observed in patients, telaprevir monotherapy in viremic mice resulted in breakthrough, with selection for mutations that confer resistance to telaprevir (e.g., a high frequency of V36A [52.2%]). Mice were injected intrahepatically with HCV genotype 1b clone KT-9 with or without an introduced resistance mutation, A156S, in the NS3 region, and treated with telaprevir. Mice infected with the A156S strain developed lower-level viremia compared to the wildtype strain but showed strong resistance to telaprevir treatment. Although mice injected with wildtype HCV showed a rapid decline in viremia at the beginning of therapy, a high frequency (11%) of telaprevir-resistant NS3 V36A variants emerged 2 weeks after the start of treatment. CONCLUSION: Using deep sequencing technology and a genetically engineered HCV infection system, we showed that the rapid emergence of telaprevir-resistant HCV was induced by mutation from the wildtype strain of HCV in vivo.

Antiviral effects of peginterferon alpha-2b and ribavirin following 24-week monotherapy of telaprevir in Japanese hepatitis C patients.

BACKGROUND/AIMS: Anemia is commonly observed as a side effect in a treatment with protease inhibitors combined with peginterferon alpha and ribavirin for hepatitis C virus infection. This study assessed the safety, tolerability, viral kinetics, and selection of variants in telaprevir monotherapy for 24 weeks, and outcomes of the off-study treatment with peginterferon alpha-2b and ribavirin among Japanese female patients at a median age of 54 years who were difficult to treat with the standard therapy (peginterferon alpha-2b and ribavirin) alone in Japan. METHODS: Four treatment-naïve patients with chronic hepatitis C virus subtype 1b infection received telaprevir (750 mg every 8 h) alone for 24 weeks. All patients then started the off-study treatment with peginterferon alpha-2b and ribavirin. Safety, tolerability, hepatitis C virus RNA levels, and emergence of telaprevir-resistant variants were monitored. RESULTS: During the 24 weeks of telaprevir monotherapy, there was no discontinuation due to adverse events, but 2 patients stopped the intake at weeks 6 and 15 because of viral breakthrough. Emergence of telaprevir-resistant variants was observed in 3 patients who showed viral breakthrough. These variants were eliminated by the off-study treatment, and sustained virological response was achieved in all patients. CONCLUSIONS: Anemia was manageable by carefully adjusting the ribavirin dosage in the standard therapy that followed telaprevir monotherapy. This sequential regimen seems to be safer and more tolerable than the triple combination of telaprevir, peginterferon alpha, and ribavirin, especially among elderly females with low baseline hemoglobin.

Elimination of hepatitis C virus by short term NS3-4A and NS5B inhibitor combination therapy in human hepatocyte chimeric mice.

BACKGROUND & AIMS: The current treatment regimen for chronic hepatitis C virus (HCV) infection is peg-interferon plus ribavirin combination therapy. The majority of developing therapeutic strategies also contain peg-interferon with or without ribavirin. However, interferon is expensive and sometimes intolerable for some patients because of severe side effects. METHODS: Using human hepatocyte chimeric mice, we examined whether a short term combination therapy with the HCV NS3-4A protease inhibitor telaprevir and the RNA polymerase inhibitor MK-0608 with or without interferon eradicates the HCV from infected mice. The effect of telaprevir and MK-0608 combination therapy was examined using subgenomic HCV replicon cells. RESULTS: Combination therapy with the two drugs enhanced inhibition of HCV replication compared with either drug alone. In in vivo experiments, early emergence of drug resistance was seen in mice treated with either telaprevir or MK-0608 alone. However, emergence was prevented by the combination of these drugs. Mice treated with a triple combination therapy of telaprevir, MK-0608, and interferon became negative for HCV RNA soon after commencement of the therapy, and HCV RNA was not detected in serum of these mice 12 weeks after cessation of the therapy. Furthermore, all mice treated with a high dose telaprevir and MK-0608 combination therapy for 4 weeks became negative for HCV RNA 1 week after the beginning of the therapy and remained negative after 18 weeks. CONCLUSIONS: Eradication of HCV from mice with only 4 weeks of therapy without interferon points the way to future combination therapies for chronic hepatitis C patients.

Carrier-mediated hepatic uptake of a novel nonrenal excretion type uric acid generation inhibitor, Y-700.

Y-700, a novel xanthine oxidase inhibitor, was recently developed for the treatment of hyperuricemia and gout. Since the major elimination route of this compound is hepatic metabolism and excretion, the aim of the present study was to characterize the uptake mechanism of Y-700 in the liver, which is also the pharmacological target of Y-700. Efficient uptake of Y-700 was observed both in the liver in vivo and in isolated rat hepatocytes. The uptake was Na(+)-dependent, saturable and inhibited both by ATP-depressants and various organic anions. Indomethacin competitively inhibited Y-700 uptake, whereas the inhibitory effect of organic cations and nucleosides was not so remarkable. Saturable and Na(+)-dependent uptake of Y-700 was also observed in freshly isolated human hepatocytes. Uptake of Y-700 by sinusoidal membrane transporters, such as organic anion transporter (Oat) 2 and organic anion transporting polypeptide (OATP)-B, OATP-C, OATP-8, and Oatp1, could not be detected although uptake of Y-700 in the oocytes expressing sodium/taurocholate cotransporting polypeptide (NTCP) was slightly observed. In conclusion, active transport system(s), which specifically recognize certain types of anionic compounds, are involved in the hepatic uptake of Y-700 and, at least partially, relevant to its elimination from the circulation as well as delivery to pharmacological target.

Y-700, a novel inhibitor of xanthine oxidase, suppresses the development of colon aberrant crypt foci and cell proliferation in 1,2-dimethylhydrazine-treated mice.

Y-700, 1-[3-cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic acid, is a newly synthesized inhibitor of xanthine oxidase. This study found that feeding of Y-700 suppressed the development of colonic aberrant crypt foci, precursor lesions of colon cancer, and cell proliferation in 1,2-dimethylhydrazine-treated mice, accompanied by reduced serum urate. These results suggest that Y-700 is a useful agent for the prevention of colon tumorigenesis and that xanthine oxidase plays an important role in the development of colon cancer.

Y-700 [1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic acid]: a potent xanthine oxidoreductase inhibitor with hepatic excretion.

Y-700 (1-[3-Cyano-4-(2,2-dimethylpropoxy)phenyl]-1H-pyrazole-4-carboxylic acid) is a newly synthesized inhibitor of xanthine oxidoreductase (XOR). Steady-state kinetics with the bovine milk enzyme indicated a mixed type inhibition with K(i) and K(i) ' values of 0.6 and 3.2 nM, respectively. Titration experiments showed that Y-700 bound tightly both to the active sulfo-form and to the inactive desulfo-form of the enzyme with K(d) values of 0.9 and 2.8 nM, respectively. X-ray crystallographic analysis of the enzyme-inhibitor complex revealed that Y-700 closely interacts with the channel leading to the molybdenum-pterin active site but does not directly coordinate to the molybdenum ion. In oxonate-treated rats, orally administered Y-700 (1-10 mg/kg) dose dependently lowered plasma urate levels. At a dose of 10 mg/kg, the hypouricemic action of Y-700 was more potent and of longer duration than that of 4-hydroxypyrazolo(3,4-d)pyrimidine, whereas its action was approximately equivalent to that of 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazolecarboxylic acid, a nonpurine inhibitor of XOR. In normal rats, orally administered Y-700 (0.3-3 mg/kg) dose dependently reduced the urinary excretion of urate and allantoin, accompanied by an increase in the excretion of hypoxanthine and xanthine. Y-700 (1 mg/kg) was absorbed rapidly by the oral route with high bioavailability (84.1%). Y-700 was hardly excreted via the kidneys but was mainly cleared via the liver. These results suggest that Y-700 will be a promising candidate for the treatment of hyperuricemia and other diseases in which XOR may be involved.