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Debio-025 is an oral cyclophilin (Cyp) inhibitor with potent anti-hepatitis C virus activity in vitro. Its effect on viral load as well as its influence on intracellular Cyp levels was investigated in a randomized, double-blind, placebo-controlled study. Mean hepatitis C viral load decreased significantly by 3.6 log 10 after a 14-day oral treatment with 1200 mg twice daily (P < 0.0001) with an effect against the 3 genotypes (1, 3, and 4) represented in the study. In addition, the absence of viral rebound during treatment indicates that Debio-025 has a high barrier for the selection of resistance. In Debio-025-treated patients, cyclophilin B (CypB) levels in peripheral blood mononuclear cells decreased from 67 ؎ 6 (standard error) ng/mg protein (baseline) to 5 ؎ 1 ng/mg protein at day 15 (P < 0.01). Conclusion: Debio-025 induced a strong drop in CypB levels, coinciding with the decrease in hepatitis C viral load. These are the first preliminary human data supporting the hypothesis that CypB may play an important role in hepatitis C virus replication and that Cyp inhibition is a valid target for the development of anti-hepatitis C drugs. (HEPATOLOGY 2008; 47:817-826.)

Inhibition of mitochondrial permeability transition pore (mPTP) opening by cyclosporin A or ischemic postconditioning attenuates lethal reperfusion injury. Its impact on major post-myocardial infarction events, including worsening of left ventricular (LV) function and death, remains unknown. We sought to determine whether pharmacological or postconditioning-induced inhibition of mPTP opening might improve functional recovery and survival following myocardial infarction in mice. Anesthetized mice underwent 25 min of ischemia and 24 h (protocol 1) or 30 days (protocol 2) of reperfusion. At reperfusion, they received no intervention (control), postconditioning (3 cycles of 1 min ischemia-1 min reperfusion), or intravenous injection of the mPTP inhibitor Debio-025 (10 mg/kg). At 24 h of reperfusion, mitochondria were isolated from the region at risk for assessment of the Ca(2+) retention capacity (CRC). Infarct size was measured by triphenyltetrazolium chloride staining. At 30 days of reperfusion, mortality and LV contractile function (echocardiography) were evaluated. Postconditioning and Debio-025 significantly improved Ca(2+) retention capacity (132 +/- 13 and 153 +/- 31 vs. 53 +/- 16 nmol Ca(2+)/mg protein in control) and reduced infarct size to 35 +/- 4 and 32 +/- 7% of area at risk vs. 61 +/- 6% in control (P < 0.05). At 30 days, ejection fraction averaged 74 +/- 6 and 77 +/- 6% in postconditioned and Debio-025 groups, respectively, vs. 62 +/- 12% in the control group (P < 0.05). At 30 days, survival was improved from 58% in the control group to 92 and 89% in postconditioned and Debio-025 groups, respectively. Inhibition of mitochondrial permeability transition at reperfusion improves functional recovery and mortality in mice.

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Hepatitis C virus (HCV) represents a major health burden. An estimated 170 million to 180 million people worldwide are chronically infected with this virus and are at increased risk of developing liver cirrhosis and/or hepatocellular carcinoma (64). The current standard of care for chronic hepatitis C consists of pegylated alpha interferon (IFN) in combination with ribavirin (RBV) (12). This therapy is, however, associated with serious side effects and results in a sustained virological response in only 50 to 60% of patients (depending on the genotype). There is thus an urgent need for more effective and better-tolerated drugs.Selective inhibitors of HCV replication that target the NS3 protease and the NS5B RNA-dependent RNA polymerase (RdRp) in particular have been pursued as potential new therapies (38). BILN 2061 (culprivir), a peptidomimetic inhibitor of the HCV NS3 protease (the first selective inhibitor of HCV to be administered to patients), resulted in a rapid and pronounced decline in the level of viral replication in patients chronically infected with HCV genotype 1. Its clinical development was, however, halted because of cardiotoxicity (22,31). Currently, four NS3 protease inhibitors are in clinical development, i.e., VX-950 (telaprevir), SCH-503034 (boceprevir), and TMC435350 (2,51,56). Telaprevir and boceprevir are at the most advanced stages of development and are being evaluated in combination with the standard therapy in phase III and phase II clinical trials, respectively (3,39,45,50). Several nucleoside polymerase inhibitors (NIs) and nonnucleoside polymerase inhibitors (NNIs) are or have been in development. Nucleoside analogue inhibitors of HCV replication basically act as chain terminators of the polymerization process once they have been phosphorylated to their 5Ј-triphosphate metabolite (13).