Purpose A Phase l trial of intravesical recombinant adenovirus-mediated interferon-α2b gene therapy (rAd-IFNα) formulated with the excipient SCH Syn3 was conducted in patients with non-muscle invasive bladder cancer (NMIBC) who recurred after Bacillus Calmette-Guerin (BCG). The primary objective was to determine the safety of rAd-IFNα/Syn3; secondary endpoints were to demonstrate effective rAd-IFNα gene expression and preliminary evidence of clinical activity at three months. Patients and Methods Seventeen patients with recurrent NMIBC after BCG were enrolled. A single treatment of rAd-IFNα (3×109 to 3×1011 particles/mL) formulated with the excipient Syn3 was administered. Patient safety was evaluated for ≥12 weeks. Efficacy of gene transfer was determined by urine IFNα protein concentrations. Preliminary drug efficacy was determined at 3 months. Results Intravesical rAd-IFNα/Syn3 was well tolerated as no dose limiting toxicity (DLT) was encountered. Urgency was the most common adverse event and all were grade 1 or 2. rAd-IFNα DNA was not detected in the blood, however, transient low serum IFNα and Syn3 levels were measured. High and prolonged dose-related urine IFNα levels were achieved with the initial treatment. Of the 14 patients treated at doses ≥ 1010 particles/mL with detectable urine IFNα, 6 (43%) experienced a complete response at 3 months and 2 remained disease free at 29.0 and 39.2 months respectively. Conclusion Intravesical rAd-IFNα/Syn3 was well tolerated with no DLT encountered. Dose dependent urinary IFNα concentrations confirmed efficient gene transfer and expression. Intravesical rAd-IFNα/Syn3 demonstrated promising clinical activity in NMIBC recurring after BCG.

ABSTRACT:Boceprevir (SCH 503034), a protease inhibitor, is under clinical development for the treatment of human hepatitis C virus infections. In human liver microsomes, formation of oxidative metabolites after incubations with [ 14 C]boceprevir was catalyzed by CYP3A4 and CYP3A5. In addition, the highest turnover was observed in recombinant CYP3A4 and CYP3A5. After a single radiolabeled dose to human, boceprevir was subjected to two distinct pathways, namely cytochrome P450-mediated oxidation and ketone reduction. Therefore, attempts were made to identify the enzymes responsible for the formation of carbonyl-reduced metabolites. Human liver S9 and cytosol converted ϳ28 and ϳ68% of boceprevir to M28, respectively, in the presence of an NADPHgenerating system. Screening of boceprevir with recombinant human aldo-keto reductases (AKRs) revealed that AKR1C2 and AKR1C3 exhibited catalytic activity with respect to the formation of M؉2 metabolites (M28 and M31). The formation of M28 was inhibited by 100

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ABSTRACT:Vorapaxar (SCH 530348), a potent oral thrombin protease-activated receptor 1 antagonist, is being developed as an antiplatelet agent for patients with established vascular disease. The objective of this study was to identify the human liver cytochrome P450 (P450) enzyme(s) responsible for the metabolism of SCH 530348. Human liver microsomes metabolized SCH 530348 to M19, an amine metabolite formed via carbamate cleavage, and M20 (monohydroxy-SCH 530348). Recombinant human CYP3A4 exhibited the most activity (11.5% profiled radioactivity) for the formation of M19, followed by markedly less substrate conversion with CYP1A1 and CYP2C19. Trace levels of M19, a major excreted human metabolite, were detected with CYP1A2, CYP3A5, and CYP4F3A. Formation of M19 by human liver microsomes was inhibited 89% by ketoconazole (IC 50 , 0.73 M), 34% by tranylcypromine, and 89% by anti-CYP3A4 monoclonal antibody. There was a significant correlation between the rate of M19 formation and midazolam 1-hydroxylation (r ‫؍‬ 0.75) or M19 formation and testosterone 6␤-hydroxylation (r ‫؍‬ 0.92). The results of screening, inhibition, and correlation studies confirmed that CYP3A4 is the major P450 enzyme responsible for M19 formation from SCH 530348. In contrast, formation of M20, a major circulating human metabolite at steady state, was primarily catalyzed by CYP3A4 and CYP2J2. M20 is pharmacologically equipotent to SCH 530348, whereas M19 is an inactive metabolite. Formation of M20 by human liver microsomes was inhibited 89% by ketoconazole, 75% by astemizole (a CYP2J2 inhibitor), and 43% by CYP3A4 monoclonal antibody. These results suggest that CYP3A4 and CYP2J2 are both involved in the formation of M20 metabolite.

Immune clearance of Hepatitis B virus (HBV) is characterized by broad and robust antiviral T cell responses, while virus-specific T cells in chronic hepatitis B (CHB) are rare and exhibit immune exhaustion that includes programmed-death-1 (PD-1) expression on virus-specific T cells. Thus, an immunotherapy able to expand and activate virus-specific T cells may have therapeutic benefit for CHB patients. Like HBV-infected patients, woodchucks infected with woodchuck hepatitis virus (WHV) can have increased hepatic expression of PD-1-ligand-1 (PD-L1), increased PD-1 on CD8+ T cells, and a limited number of virus-specific T cells with substantial individual variation in these parameters. We used woodchucks infected with WHV to assess the safety and efficacy of anti-PD-L1 monoclonal antibody therapy (αPD-L1) in a variety of WHV infection states. Experimentally-infected animals lacked PD-1 or PD-L1 upregulation compared to uninfected controls, and accordingly, αPD-L1 treatment in lab-infected animals had limited antiviral effects. In contrast, animals with naturally acquired WHV infections displayed elevated PD-1 and PD-L1. In these same animals, combination therapy with αPD-L1 and entecavir (ETV) improved control of viremia and antigenemia compared to ETV treatment alone, but with efficacy restricted to a minority of animals. Pre-treatment WHV surface antigen (sAg) level was identified as a statistically significant predictor of treatment response, while PD-1 expression on peripheral CD8+ T cells, T cell production of interferon gamma (IFN-γ) upon in vitro antigen stimulation (WHV ELISPOT), and circulating levels of liver enzymes were not. To further assess the safety of this strategy, αPD-L1 was tested in acute WHV infection to model the risk of liver damage when the extent of hepatic infection and antiviral immune responses were expected to be the greatest. No significant increase in serum markers of hepatic injury was observed over those in infected, untreated control animals. These data support a positive benefit/risk assessment for blockade of the PD-1:PD-L1 pathway in CHB patients and may help to identify patient groups most likely to benefit from treatment. Furthermore, the efficacy of αPD-L1 in only a minority of animals, as observed here, suggests that additional agents may be needed to achieve a more robust and consistent response leading to full sAg loss and durable responses through anti-sAg antibody seroconversion.