Prevalence in the USA of rilpivirine resistance-associated mutations in clinical samples and effects on phenotypic susceptibility to rilpivirine and etravirine.

BACKGROUND: The prevalence of rilpivirine resistance-associated mutations (RAMs) in the USA, and their effect on phenotypic susceptibility to rilpivirine and etravirine, was evaluated in clinical samples from HIV-1-infected patients. METHODS: In total, 15,991 samples submitted to Monogram Biosciences (South San Francisco, CA, USA) for routine resistance testing between January 2010 and June 2011 were assessed for the presence of known rilpivirine RAMs K101E/P, E138A/G/K/Q/R, V179L, Y181C/I/V, Y188L, H221Y, F227C and M230I/L; non-nucleoside reverse transcriptase inhibitor (NNRTI) RAMs K103N, L100I and L100I+K103N; and the nucleoside reverse transcriptase inhibitor (NRTI) RAMs M184I/V and their combinations with rilpivirine RAMs. Phenotypic susceptibility (PhenoSenseGT(®) assay; Monogram Biosciences) was evaluated, with reduced susceptibility defined as fold change (FC) in 50% inhibitory concentration (IC50)>2.0 for rilpivirine and FC>2.9 for etravirine. RESULTS: Of the 15,991 samples, 17% harboured ≥1 rilpivirine RAMs. The prevalence of most rilpivirine RAMs and combinations of NNRTI RAMs of interest was low (≤3%), except for Y181C (7%). Rilpivirine RAMs were often associated with reduced rilpivirine phenotypic susceptibility. Median FC values >2.0 were observed for clinical isolates with rilpivirine RAMs K101P, E138Q/R, Y181C/I/V, Y188L or M230L, and for the combination of E138K with M184I/V, and K101E with M184I. Most rilpivirine FC values >2.0 were associated with etravirine FC values >2.9 for individual rilpivirine RAMs and those combined with M184I/V. There was no relationship between the presence of K103N and rilpivirine FC. However, the L100I+K103N combination (without rilpivirine RAMs), at <2% prevalence, was associated with a rilpivirine FC>2.0. CONCLUSIONS: Based on 15,991 US clinical samples from HIV-1-infected patients, the frequency of most known rilpivirine RAMs apart from Y181C was low.

Telaprevir activity in treatment-naive patients infected hepatitis C virus genotype 4: a randomized trial.

BACKGROUND: This partially blinded, randomized, phase 2a C210 study evaluated the antiviral activity of telaprevir-based regimens in treatment-naive patients with chronic hepatitis C virus (HCV) genotype 4 infection. METHODS: Twenty-four patients received telaprevir 750 mg every 8 hours for 15 days (T; n = 8), telaprevir in combination with pegylated interferon alfa-2a and ribavirin (Peg-IFN/RBV) for 15 days (TPR; n = 8), or Peg-IFN/RBV plus placebo for 15 days (PR; n = 8), followed by Peg-IFN/RBV for 46 or 48 weeks. The primary objective was to assess the effect of telaprevir on HCV RNA levels. RESULTS: HCV RNA levels decreased slightly with T and PR; TPR produced substantial, rapid declines. On day 15, median reductions in the HCV RNA load from baseline were -0.77, -4.32, and -1.58 log10 IU/mL for T, TPR, and PR, respectively, and 0 patients in the T group, 1 in the TPR group, and 0 in the PR group had undetectable HCV RNA. Five of 8 patients who received telaprevir monotherapy had viral breakthrough within 15 days of treatment. Adverse event incidence was similar across treatments and comparable with the incidences from previous clinical trials. One patient (in T group) had a serious adverse event (considered unrelated to telaprevir) that led to treatment discontinuation. CONCLUSIONS: Telaprevir with Peg-IFN/RBV had greater activity than Peg-IFN/RBV treatment or telaprevir monotherapy against HCV genotype 4. Telaprevir was generally safe and well tolerated. Further investigation of telaprevir combination therapy in patients with HCV genotype 4 infection is warranted.

Resistencia a los antivirales de acción directa contra el virus de la hepatitis C / Direct acting antivirals resistance to HCV

El virus de la hepatitis C puede causar cirrosis y carcinoma hepatocelular. El tratamiento con interferón pegilado y ribavirina resulta en bajas tasas de respuesta viral sostenida y conlleva serios efectos adversos. Sin embargo, con nuevos y prometedores antivirales de acción directa contra el VHC, algunos aprobados recientemente y otros en desarrollo, las tasas de curación han mejorado significativamente. Los nuevos antivirales de acción directa incluyen inhibidores de la proteasa viral, inhibidores de la polimerasa viral e inhibidores del complejo replicativo NS5A. Una consecuencia asociada al uso de antivirales de acción directa es el desarrollo de resistencia en la mayoría de los pacientes con fallo terapéutico. El desarrollo de resistencia es más frecuente con ciertos mecanismos de acción, aunque las variantes resistentes suelen no ser detectadas en la mayoría de los pacientes tratados con inhibidores de la proteasa 1 a 2 años luego de finalizado el tratamiento. Sin embargo, queda aún por establecer si el desarrollo de resistencia acarrea consecuencias a largo plazo, en particular relacionadas al uso de estrategias de re-tratamiento

HCV can cause cirrhosis and hepatocellular carcinoma. Treatment with pegylatd interferon and ribavarin rsults in low rates of sustained virologic response and is associated with serious adverse events. however, with new promising direct acting antivirals against HCV, some recently approved and others currently in development, cures rates have significantly improved. New direct acting antivirals include protease inhibitors, polymerase inhibitors and inhibitors of the NS5A replictive complex. A consequence of the use of direct acting antivirals is the development of resistance in the majority of patients with therapeutic failure. Although resistance development is usually more frequent with certain mechanisms of action than others, resistant viral variants are usually no longer detected in the majority of patients treated with protease inhibitors 1 to 2 years after end of treatment. however, it stills remains to be determined if resistance development is associated with long term consequences, in particulr with the use retreatment strategies

Resistencia a los antivirales de acción directa contra el virus de la hepatitis C / Direct acting antivirals resistance to HCV

El virus de la hepatitis C puede causar cirrosis y carcinoma hepatocelular. El tratamiento con interferón pegilado y ribavirina resulta en bajas tasas de respuesta viral sostenida y conlleva serios efectos adversos. Sin embargo, con nuevos y prometedores antivirales de acción directa contra el VHC, algunos aprobados recientemente y otros en desarrollo, las tasas de curación han mejorado significativamente. Los nuevos antivirales de acción directa incluyen inhibidores de la proteasa viral, inhibidores de la polimerasa viral e inhibidores del complejo replicativo NS5A. Una consecuencia asociada al uso de antivirales de acción directa es el desarrollo de resistencia en la mayoría de los pacientes con fallo terapéutico. El desarrollo de resistencia es más frecuente con ciertos mecanismos de acción, aunque las variantes resistentes suelen no ser detectadas en la mayoría de los pacientes tratados con inhibidores de la proteasa 1 a 2 años luego de finalizado el tratamiento. Sin embargo, queda aún por establecer si el desarrollo de resistencia acarrea consecuencias a largo plazo, en particular relacionadas al uso de estrategias de re-tratamiento (AU)

HCV can cause cirrhosis and hepatocellular carcinoma. Treatment with pegylatd interferon and ribavarin rsults in low rates of sustained virologic response and is associated with serious adverse events. however, with new promising direct acting antivirals against HCV, some recently approved and others currently in development, cures rates have significantly improved. New direct acting antivirals include protease inhibitors, polymerase inhibitors and inhibitors of the NS5A replictive complex. A consequence of the use of direct acting antivirals is the development of resistance in the majority of patients with therapeutic failure. Although resistance development is usually more frequent with certain mechanisms of action than others, resistant viral variants are usually no longer detected in the majority of patients treated with protease inhibitors 1 to 2 years after end of treatment. however, it stills remains to be determined if resistance development is associated with long term consequences, in particulr with the use retreatment strategies (AU)

Prevalence of hepatitis C virus antibody in newborn infants in southern California in 2003.

The prevalence of hepatitis C virus (HCV) antibody in newborn infants in 3 counties in southern California in 2003 was found to be 2.5 per 1000 live births using dried blood spot testing. With advances in HCV antiviral therapy providing decreasing morbidity from chronic HCV infection, prenatal HCV screening to identify both mothers and at-risk infants should be reconsidered.

Viral resistance to specifically targeted antiviral therapies for hepatitis C (STAT-Cs).

Promising results have been observed with an investigational drug class for hepatitis C (HCV), the specifically targeted antiviral therapies for hepatitis C (STAT-Cs), when combined with peginterferon plus ribavirin (Peg-IFN/RBV). This class has the potential to increase sustained virological response (SVR) rates and reduce therapy duration in genotype 1 chronic HCV patients compared with Peg-IFN/RBV alone. However, because of the remarkable sequence variation in HCV (resulting from the high viral replication rate and intrinsically error-prone nature of HCV polymerase), variants with reduced susceptibility to STAT-Cs can occur naturally before treatment, usually at low levels, and can be selected in patients not responding to potent STAT-C treatment. This review first describes how resistance to a STAT-C can develop and then provides an overview of mutations that confer varying levels of resistance to STAT-Cs, which have been identified and characterized using both genotypic and phenotypic tools. We will discuss why an understanding of the selection of variants with reduced susceptibility to a treatment regimen may be important in optimizing the use of this new class of HCV therapy. Strategies for optimizing treatment regimens to increase response rates, and thereby minimize resistance, will be discussed. Finally, although resistance can be a consequence of not achieving an SVR on an initial regimen, there may be alternative treatment options for patients to achieve an SVR in the future. Future potential therapeutic strategies to address patients who do develop resistance to STAT-Cs are discussed, including combination therapy with multiple STAT-Cs with non-overlapping resistance profiles.

High prevalence of infection with a single hepatitis C virus genotype in a small rural community of Argentina.

BACKGROUND: During the years preceding this study, we noticed a relatively unusual high number of individuals with elevated alanine aminotransferase (ALT) levels in O'Brien, a small rural town in Argentina. Moreover, four individuals from this town underwent liver transplantation owing to hepatitis C virus (HCV)-induced liver cirrhosis. These findings prompted us to conduct a large population-based survey to evaluate the prevalence of HCV in this community. METHODS AND RESULTS: A total of 1637 individuals were studied. The overall HCV-seroprevalence was 5.7% (93/1637), being slightly higher in men (45/769; 5.9%) than in women (48/868; 5.5%). HCV seroprevalence increased with age, reaching a peak rate of 23.9% among individuals between 61 and 70 years of age. HCV RNA was present in 82.7% of all HCV seropositive individuals identified and 100% of them were infected with genotype 1b. ALT elevations were detected in 44% of HCV+ patients and were only observed among viremic individuals. Hepatitis B virus infection was also prevalent (52%) among HCV-seropositive patients. The most common risk factor associated with HCV transmission identified was the apparent use of inadequately sterilized glass syringes by a health care provider serving the community; however, other risk factors may have also played a role in the dissemination of HCV. CONCLUSIONS: Our findings provide an explanation for the relative high number of individuals with elevated ALT levels observed in this community and form the basis of future prospective studies on the natural history of genotype 1b infection.

Two mechanisms for human immunodeficiency virus type 1 inhibition by N-terminal modifications of RANTES.

C-C chemokine receptor 5 (CCR5) is the primary coreceptor for human immunodeficiency virus type 1 (HIV-1) infection. Native chemokines that bind to CCR5 inhibit HIV-1 infection, albeit weakly, but chemically modified chemokines inhibit infection more efficiently. We have investigated the inhibitory mechanism of three N-terminally modified RANTES variants (AOP-, NNY-, and PSC-RANTES) with the MT-2 human T-cell line stably expressing either native or mutated CCR5. The RANTES analogues showed the same rank order (PSC > NNY > AOP) in their capacity to induce prolonged CCR5 internalization, inhibit surface reexpression, and prevent HIV-1 infection on MT-2 cells expressing wild-type CCR5 or CCR5 with four C-terminal serine phosphorylation sites mutated to alanine. None of the RANTES analogues caused internalization of a C-terminal cytoplasmic domain deletion mutant of CCR5, and each derivative had equal potency in inhibiting HIV-1 infection of MT-2 cells expressing this mutant. We conclude that the C-terminal cytoplasmic residues of CCR5 are necessary for receptor sequestration by RANTES analogues but that the process and the relative activity of each derivative are not dependent upon phosphorylation of the C-terminal serine residues. Two mechanisms of antiviral activity are demonstrated: receptor blockade and receptor sequestration. Potency correlates with the ability to induce CCR5 sequestration but not with receptor binding, suggesting that sequestration may make the greater contribution to antiviral activity.

Establishment of B-cell lymphoma cell lines persistently infected with hepatitis C virus in vivo and in vitro: the apoptotic effects of virus infection.

Hepatitis C virus (HCV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Studies of HCV replication and pathogenesis have so far been hampered by the lack of an efficient tissue culture system for propagating HCV in vitro. Although HCV is primarily a hepatotropic virus, an increasing body of evidence suggests that HCV also replicates in extrahepatic tissues in natural infection. In this study, we established a B-cell line (SB) from an HCV-infected non-Hodgkin's B-cell lymphoma. HCV RNA and proteins were detectable by RNase protection assay and immunoblotting. The cell line continuously produces infectious HCV virions in culture. The virus particles produced from the culture had a buoyant density of 1.13 to 1.15 g/ml in sucrose and could infect primary human hepatocytes, peripheral blood mononuclear cells (PBMCs), and an established B-cell line (Raji cells) in vitro. The virus from SB cells belongs to genotype 2b. Single-stranded conformational polymorphism and sequence analysis of the viral RNA quasispecies indicated that the virus present in SB cells most likely originated from the patient's spleen and had an HCV RNA quasispecies pattern distinct from that in the serum. The virus production from the infected primary hepatocytes showed cyclic variations. In addition, we have succeeded in establishing several Epstein-Barr virus-immortalized B-cell lines from PBMCs of HCV-positive patients. Two of these cell lines are positive for HCV RNA as detected by reverse transcriptase PCR and for the nonstructural protein NS3 by immunofluorescence staining. These observations unequivocally establish that HCV infects B cells in vivo and in vitro. HCV-infected cell lines show significantly enhanced apoptosis. These B-cell lines provide a reproducible cell culture system for studying the complete replication cycle and biology of HCV infections.

Decreased recovery of replication-competent HIV-1 from peripheral blood mononuclear cell-derived monocyte/macrophages of HIV-positive patients after 3 years on highly active antiretroviral therapy.

We studied the release of p24 antigen from peripheral blood mononuclear cell-derived monocyte/macrophages obtained from 13 HIV-positive patients receiving highly active antiretroviral therapy (HAART). Although HIV-infected monocyte/macrophages were detected in 80% of patients after 36 months of continuous treatment, additional exposure to HAART reduced the chance of detecting HIV-releasing monocyte/macrophages. Therefore, after more than 3 years of HAART, recently infected monocytes may play a less important role as a source of emerging HIV-1 upon HAART interruption.

Historia natural de la hepatitis C: experiencia multidisciplinaria en Argentina / Natural history of the hepatitis C: multidisciplinary experience in Argentina

O’Brien es un pueblo rural de la Prov. de Buenos Aires con 2300 habitantes. Durante la última década, los profesionales de O’Brien notaron una inusual frecuencia de elevación de transaminasas en análisis obtenidos por rutina y un número creciente de pacientes con diagnóstico de hepatitis C, incluyendo 4 casos que requirieron trasplante hepático por cirrosis avanzada. El objetivo de este trabajo fue investigar la prevalencia de infección y hepatitis por HCV en O’Brien. En 1832 de los 2300 habitantes (80 por ciento) se investigó la presencia de anti-HCV por un EIE de 3ª generación. La prevalencia de infección por HCV en O’Brien fue de 5.6 por ciento (102/1832), 0.56 por ciento en los individuos 40 años (p<0.001) con un pico máximo de 23.4 por ciento entre la 6ª y 7ª década. La edad mediana de los 102 pacientes infectados (52 mujeres y 50 hombres) fue de 60 años con un rango de 7 a 81 años. El 89 por ciento de los sueros reactivos por EIE fueron confirmados por RIBA-3. Once pacientes fueron RIBA-indeterminados y ninguno RIBA-negativo. El internvalo estimado entre la infección y el diagnóstico fue de 36ñ8 años. A pesar de la prolongada duración de la infección, el 81 por ciento de los pacientes (83/102) presentaron HCV RNA detectable en suero por PCR y el 59 por ciento (60/102) elevación de transaminasas. La presencia de viremia se asoció significativamente con la positividad del RIBA (99 por ciento, p<0.001) y con la elevación de AST/ALT (72 por ciento, p<0.001). El genotipo de HCV, determinado por la técnica de RFLP, fue 1b en el 100 por ciento de los pacientes virémicos, hallazgo que diferencia a este estudio de todas las series publicadas... (TRUNCADO)

Historia natural de la hepatitis C: experiencia multidisciplinaria en Argentina / Natural history of the hepatitis C: multidisciplinary experience in Argentina

OBrien es un pueblo rural de la Prov. de Buenos Aires con 2300 habitantes. Durante la última década, los profesionales de OBrien notaron una inusual frecuencia de elevación de transaminasas en análisis obtenidos por rutina y un número creciente de pacientes con diagnóstico de hepatitis C, incluyendo 4 casos que requirieron trasplante hepático por cirrosis avanzada. El objetivo de este trabajo fue investigar la prevalencia de infección y hepatitis por HCV en OBrien. En 1832 de los 2300 habitantes (80 por ciento) se investigó la presencia de anti-HCV por un EIE de 3ª generación. La prevalencia de infección por HCV en OBrien fue de 5.6 por ciento (102/1832), 0.56 por ciento en los individuos <40 años y 12.6 por ciento en aquellos >40 años (p<0.001) con un pico máximo de 23.4 por ciento entre la 6ª y 7ª década. La edad mediana de los 102 pacientes infectados (52 mujeres y 50 hombres) fue de 60 años con un rango de 7 a 81 años. El 89 por ciento de los sueros reactivos por EIE fueron confirmados por RIBA-3. Once pacientes fueron RIBA-indeterminados y ninguno RIBA-negativo. El internvalo estimado entre la infección y el diagnóstico fue de 36ñ8 años. A pesar de la prolongada duración de la infección, el 81 por ciento de los pacientes (83/102) presentaron HCV RNA detectable en suero por PCR y el 59 por ciento (60/102) elevación de transaminasas. La presencia de viremia se asoció significativamente con la positividad del RIBA (99 por ciento, p<0.001) y con la elevación de AST/ALT (72 por ciento, p<0.001). El genotipo de HCV, determinado por la técnica de RFLP, fue 1b en el 100 por ciento de los pacientes virémicos, hallazgo que diferencia a este estudio de todas las series publicadas... (TRUNCADO)(AU)