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Significant scientific advances have enabled the development of new classes of antivirals for the treatment of HCV. Protease inhibitors were the first approved, achieving substantially higher response rates, with shorter treatment durations, in the majority of genotype 1 infected patients. However, in patients who fail treatment, drug resistant variants frequently emerge. The pattern of resistant variants observed is a result of the specific inhibitor, viral subtype, and level of drug selective pressure. Data suggest the replacement of these variants over time; however, retreatment of these patients is an area of needed investigation. As multiple drug classes progress in development, combinations of agents improve treatment success, increase the genetic barrier to resistance, and provide shorter treatment durations for diverse patient populations., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background/aims: This study assessed the safety and antiviral effects of telaprevir (VX-950) in combination with peginterferon alfa-2a and ribavirin., Methods: Twelve treatment-naïve patients with chronic genotype 1 hepatitis C virus infection received telaprevir (750 mg q8h), peginterferon alfa-2a (180 microg/week), and ribavirin (1000 or 1200 mg/day) for 28 days. Patients could then start off-study treatment with peginterferon alfa-2a and ribavirin for up to 44 weeks, at the discretion of the investigator and patient., Results: The combination of telaprevir, peginterferon alfa-2a, and ribavirin was well tolerated, with no serious adverse events or treatment discontinuations. Rash or pruritus occurred in 5 of the 12 patients; all cases resolved either during or after the end of telaprevir treatment. All 12 patients had undetectable HCV RNA levels by day 28 (rapid viral response, RVR). Eight patients completed 44 weeks of off-study peginterferon alfa-2a and ribavirin treatment. Eight patients achieved a sustained viral response (SVR), including one patient who received only 22 weeks of treatment., Conclusions: The combination of telaprevir, peginterferon alfa-2a, and ribavirin was generally well tolerated. Events of pruritus and rash resolved during or after end of telaprevir dosing. All 12 patients achieved an RVR.

To further understand the role of LPS in the pathogenesis of Francisella infection, we characterized murine infection with F. novicida, and compared immunobiological activities of F. novicida LPS and the LPS from F. tularensis live vaccine strain (LVS). F. novicida had a lower intradermal LD(50) in BALB/cByJ mice than F. tularensis LVS, and mice given a lethal F. novicida dose intraperitoneally died faster than those given the same lethal F. tularensis LVS dose. However, the pattern of in vivo dissemination was similar, and in vitro growth of both bacteria in bone marrow-derived macrophages was comparable. F. novicida LPS stimulated very modest in vitro proliferation of mouse splenocytes at high doses, but F. tularensis LVS LPS did not. Murine bone marrow macrophages treated in vitro with F. novicida LPS produced IL12 and TNF-alpha, but did not produce detectable interferon-gamma, IL10, or nitric oxide; in contrast, murine macrophages treated with F. tularensis LVS LPS produced none of these mediators. In contrast to clear differences in stimulation of proliferation and especially cytokines, both types of purified LPS stimulated early protection against lethal challenge of mice with F. tularensis LVS, but not against lethal challenge with F. novicida. Thus, although LPS recognition may not be a major factor in engendering protection, the ability of F. novicida LPS to stimulate the production of proinflammatory cytokines including TNF-alpha likely contributes to the increased virulence for mice of F. novicida compared to F. tularensis LVS.