Viral Breakthrough Research Articles

ダクラタスビル/アスナプレビル/ベクラブビルによる再治療中にP495L耐性変異を検出したC型代償性肝硬変のviral breakthrough例

We describe a case with viral breakthrough of hepatitis C virus (HCV) during the treatment of daclatasvir/asunaprevir/beclabuvir (DCV/ASV/BCV). The case is a 63-year-old man with HCV-associated cirrhosis, who failed to respond to previous direct-acting antiviral agent (DAA) regimens including DCV/ASV and ledipasvir/sofosbuvir. Sequence analyses of HCV-NS3, NS5A and NS5B regions revealed that he had acquired an additional substitution of P495L in NS5B region at viral breakthrough, with another substitution as C451Y simultaneously. Although the data from phase III clinical trials in Japanese patients infected with HCV genotype 1 displayed no virological failures, our case indicates that retreatment with DCV/ASV/BCV in failures to prior DAA regimens can result in the emergence of a new NS5B resistance-associated substitution like P495L.

Factors associated with HBV virological breakthrough.

Little is known about non-adherence to HBV therapy. This study aimed to investigate the relationship between self-reported missed days of antiviral therapy and HBV virological breakthrough and factors associated with virological breakthrough. A cross-sectional survey of 211 HBV patients receiving oral antiviral therapies was undertaken at three tertiary hospitals in Sydney, Australia. Associations between 0 to >6 missed days in the last 30 days and virological breakthrough (defined as >10-fold rise in serum HBV DNA above nadir or after achieving virological response in the last 12 months) were examined. Logistic regression analyses determined the number of missed days most strongly associated with virological breakthrough and the associated factors. We report odds ratios (ORs) and relative risks (RRs). Of the 204, 32 participants (15.6%) had quantifiable HBV DNA levels (>20 IU/ml); 15 (46.8%) of them experienced virological breakthrough. Participants reported never missing medication (n=130, 63.7%) or missing 1 day (n=23, 11.3%), >1 day (n=23, 11.3%), 2-6 days (n=15, 7.3%) and >6 days (n=13, 6.4%). The most discriminating definition of non-adherence was missing >1 day of medication (RR=8.3; OR=10.2, 95% CI 3.1, 33.8, receiver operating characteristic curve 0.76). Factors independently associated with virological breakthrough included non-adherence (OR=9.0, 95% CI 2.5, 31.9) diagnosed with HBV ≤14 years (OR=5.3, 95% CI 1.0, 26.2) and age ≤47 years (OR=5.4, 95% CI 1.1, 26.9). Results provide an evidence-based definition of non-adherence to inform clinical practice and provide a basis for key patient education messages. Closer monitoring of groups at risk of viral breakthrough is required.

Efficacy and safety of dual therapy with daclatasvir and asunaprevir in elderly patients.

AIMTo survey the efficacy and safety of dual therapy with daclatasvir and asunaprevir in the elderly hepatitis C virus (HCV) patients multicentricity.METHODSInterferon-ineligible/intolerant patients and non-responders to previous pegylated-interferon/ribavirin therapy with chronic HCV genotype 1b infection were enrolled. Child B, C cirrhotic patients were excluded. Patients received oral direct acting antiviral treatment consisting of 60 mg daclatasvir once daily plus 200 mg asunaprevir twice daily for 24 wk. We divided the patients into two groups of 56 elderly patients (≥ 75 years-old) and 141 non-elderly patients (< 75 years old) and compared the efficacy and safety.RESULTSNinety-one point one percent of elderly patients and 90.1% of non-elderly patients achieved sustained virological response at 24 wk (SVR24). In the former, 1.8% experienced viral breakthrough, as compared with 3.5% in the latter (not significant). Adverse events occurred in 55.4% of the former and 56.0% of the latter. In the former, 7 cases (12.5%) were discontinued due to adverse events, and in the latter 9 cases were discontinued (6.4%, not significant).CONCLUSIONDual therapy with daclatasvir and asunaprevir achieved the same high rates of SVR24 in HCV elderly patients without more adverse events than in the non-elderly patients.

Real-World Effectiveness of Simeprevir-containing Regimens Among Patients With Chronic Hepatitis C Virus: The SONET Study.

BackgroundThe Simeprevir ObservatioNal Effectiveness across practice seTtings (SONET) study evaluated the real-world effectiveness of simeprevir-based treatment for hepatitis C virus (HCV) infection.MethodsThe SONET study was a phase 4, prospective, observational, United States–based study enrolling patients ≥18 years of age with chronic genotype 1 HCV infection. The primary endpoint was the proportion of patients who achieved sustained virologic response 12 weeks after the end of treatment (SVR12), defined as HCV ribonucleic acid undetectable ≥12 weeks after the end of all HCV treatments.ResultsOf 315 patients (intent-to-treat [ITT] population), 275 (87.3%) completed the study. Overall, 291 were treated with simeprevir + sofosbuvir, 17 with simeprevir + sofosbuvir + ribavirin, and 7 with simeprevir + peginterferon + ribavirin. The majority of patients were male (63.2%) and white (60.6%); median age was 58 years, 71.7% had genotype/subtype 1a, and 39.4% had cirrhosis. The SVR12 was achieved by 81.2% (255 of 314) of ITT patients (analysis excluded 1 patient who completed the study but was missing SVR12 data); 2 had viral breakthrough and 18 had viral relapse. The SVR12 was achieved by 92.4% (255 of 276) of patients in the modified ITT (mITT) population, which excluded patients who discontinued treatment for nonvirologic reasons before the SVR12 time point or were missing SVR12 assessment data. Among mITT patients, higher SVR12 rates were associated with factors including age ≥65 years, non-Hispanic/Latino ethnicity, and employment status, but not genotype/subtype nor presence of cirrhosis. Simeprevir-based treatment was well tolerated; no serious adverse events were considered related to simeprevir.ConclusionsIn the real-world setting, simeprevir + sofosbuvir treatment was common and 92% of mITT patients achieved SVR12. Simeprevir-based treatment was effective and well tolerated in this cohort, including patients with cirrhosis.

Management of direct antiviral agent failures.

The current standard of care for patients with chronic hepatitis C virus (HCV) infection is a combination of direct-acting antiviral agents (DAAs). Most HCV patients treated with these drugs achieve viral elimination, but 1% to 15% fail to attain this objective. Treatment failures are usually related to relapse, and less often to on-treatment viral breakthrough. HCV drug resistant associated substitutions are detected in most patients who do not eliminate the virus. The risk of developing these variants depends on host- and virus-related factors, the properties of the drugs used, and the treatment strategies applied. Patients who carry Resistant Associated Substitutions (RASs) may not obtain benefits from treatment, and are at a risk of disease progression. Whether HCV RASs persist depends on their type: NS3-4A variants often disappear gradually after DAA therapy is stopped, whereas NS5A variants tend to persist for more than 2 years. The best way to prevent emergence of resistant variants is to eliminate the virus at the first treatment using highly potent DAAs with genetic barriers to resistance. For those who fail an NS5A inhibitor, deferral of treatment is recommended pending the availability of additional data if they do not have cirrhosis or reasons for urgent re-treatment. If re-treatment is needed, the most commonly used strategy is sofosbuvir as backbone therapy plus a drug from a class other than that previously used, for 24 weeks. Unless it is contraindicated, weight-based ribavirin should also be added. If available, nucleotide-based (eg, sofosbuvir) triple or quadruple DAA regimens may be considered. The optimal treatment for patients who fail an NS5A inhibitor and those with multidrug-resistant variants remains to be defined, and research efforts should continue to focus on treatment for these patients.

Detection of a genetic footprint of the sofosbuvir resistance-associated substitution S282T after HCV treatment failure

The major resistance-associated substitution for sofosbuvir (S282T) in HCV NS5B causes severe viral fitness costs and rapidly reverts back to prototype in the absence of selection pressure. Accordingly, resistance against sofosbuvir is rarely detected even in patients after treatment failure. We report a case of a GT3a infected patient with viral breakthrough under SOF/DCV therapy. At the time of breakthrough the RAS S282T was predominant in NS5B and then rapidly disappeared during follow-up by week 12 after treatment. Interestingly, despite only serine was encoded in position 282 during follow-up, two distinct genetic pathways for reversion were detectable. In 31% of the quasispecies the original codon for serine was present whereas in the majority of the quasispecies an alternative codon was selected. This alternative codon usage was unique for all GT3a isolates from the HCV database and remained detectable as a genetic footprint for prior resistance selection at the RNA level for at least 6 months. Comparative analyses of viral sequences at the codon level before and after DAA treatment may help to elucidate the patient’s history of resistance selection, which is particularly valuable for highly unfit substitutions that are detectable only for a short period of time. If such codon changes increase the risk of re-selection of resistance upon a second exposure to SOF remains to be addressed.

The practical management of chronic hepatitis C infection in Japan - dual therapy of daclatasvir + asunaprevir

ABSTRACTIntroduction: Without treatment, many of the 200 million people worldwide with chronic hepatitis C virus (HCV) infection will develop cirrhosis or liver cancer. Japan was the first nation to approve an interferon-free therapy for HCV, and sustained viral response (SVR) rates >90% have been achieved with asunaprevir, a protease inhibitor, plus daclatasvir, an inhibitor of the non-structural 5A (NS5A) protein.Areas covered: This review provides an overview of the results from both clinical trials and real world experience with asunaprevir and daclatasvir therapy focused primarily on Japan. A literature search using the keywords ‘asunaprevir,’ ‘daclatasvir,’ ‘interferon-free therapy,’ and ‘direct-acting antiviral drugs’ was initially used to select relevant literature for inclusion in the review.Expert commentary: While not approved in the United States, dual therapy with asunaprevir plus daclatasvir has already been successfully used in Japan and throughout East Asia to treat many thousands of patients. Pre-existing or treatment-emergent NS5A-Y93 or -L31 resistance-associated variants (RAVs) may lead to viral breakthrough, and alternative therapies should be considered for these patients, but patients who harbor NS5A RAVs only at low frequency are likely to achieve SVR. The therapy has also been shown to be safe and effective with renal dysfunction or liver cirrhosis.

Efficacy and Safety of Tenofovir and Entecavir in Patients with Chronic Hepatitis B - Comparative Cohort Study

Background: Hepatitis B virus (HBV) infection is a global problem and >350 million HBV carriers in the world. HBV infection causes chronic hepatitis and can lead to liver cirrhosis and hepatocellular carcinoma (HCC). Aim: To evaluate safety and efficacy of Tenofovir and Entecavir medications in liver disease course in HBVdecompensated cirrhosis patients Patients & Methods: The study was carried out in hepatology Out-Patient Clinic, Amiri hospital, Kuwait. Forty six HBV decompensated cirrhosis patients were classified into 2 groups; Tenofovir group (n=23) and Entecavir group (n=23). All patients underwent clinical examination, laboratory data (liver profile, HBV DNA, eGFR, Phosphate) and Assessment of Child-Pugh (CP) score, Model for end stage liver disease (M ELD) score before and after treatment. Results: Baseline HBV DNA and liver enzymes of both groups showed no significant difference before treatment. 21 (91.3%) of patients of in each group had undetectable HBV DNA at 12 months. CP and MELD scores among the 2 groups showed improvement in both scores after treatment with similar changes in both scores between the 2 medications at any time. Comparison of eGFR among the 2groups showed no changes at any time in eGFR at each group and in between the 2 groups. Conclusion: Both antivirals (Tenofovir and Entecavir) were well tolerated; none of the patients discontinued therapy, while eGFRs were not different between Tenofovir and Entecavir groups during the follow up period, the patients had excellent virological response without viral breakthrough and with improvement in severity of liver disease.

Prevention of allograft HCV recurrence with peri-transplant human monoclonal antibody MBL-HCV1 combined with a single oral direct-acting antiviral: A proof-of-concept study.

Patients with active hepatitis C virus (HCV) infection at transplantation experience rapid allograft infection, increased risk of graft failure and accelerated fibrosis. MBL-HCV1, a neutralizing human monoclonal antibody (mAb) targeting the HCV envelope, was combined with a licensed oral direct-acting antiviral (DAA) to prevent HCV recurrence post-transplant in an open-label exploratory efficacy trial. Eight subjects received MBL-HCV1 beginning on the day of transplant with telaprevir initiated between days 3 and 7 post-transplantation. Following FDA approval of sofosbuvir, two subjects received MBL-HCV1 starting on the day of transplant with sofosbuvir initiated on day 3. Combination treatment was administered for 8-12weeks or until the stopping rule for viral rebound was met. The primary endpoint was undetectable HCV RNA at day 56 with exploratory endpoints of sustained virologic response (SVR) at 12 and 24weeks post-treatment. Both subjects receiving mAb and sofosbuvir achieved SVR24. Four of eight subjects in the mAb and telaprevir group met the primary endpoint; one subject achieved SVR24 and three subjects relapsed 2-12weeks post-treatment. The other four subjects experienced viral breakthrough. There were no serious adverse events related to study treatment. This proof-of-concept study demonstrates that peri-transplant immunoprophylaxis combined with a single oral direct-acting antiviral in the immediate post-transplant period can prevent HCV recurrence.

Management of Direct-Acting Antiviral Failures in Chronic Hepatitis C Infection

Direct-acting antiviral agents have revolutionized the treatment for chronic hepatitis C infection with very high cure rates. Treatment failures are commonly due to non-adherence and relapse but less often to viral breakthrough while on therapy. Resistance-associated variants have also emerged to be a culprit for treatment failures. Optimal retreatment regimens in patients who fail direct-acting antiviral agents have been unclear due to limited data. In vitro and in vivo studies have suggested that hepatitis C drug-resistant variants undermine direct-acting antiviral-based therapy in patients who do not achieve viral eradication. The risk of developing these variants depends on host- and virus-related factors, the properties of the drugs used, and the treatment strategies applied. The most effective methods in preventing the development of resistant variants include using potent antiviral combinations with high barriers to resistance and reinforcing patient compliance with treatment. Despite the effectiveness of direct-acting antiviral agents, patients may fail to attain sustained virologic response and salvage therapy may need to be considered. Therapeutic options are limited and more research needs to be directed towards this select group of patients.

Future Therapy for Hepatitis B Virus and Hepatitis D Virus

Chronic delta hepatitis (CDH) represents the least encountered but the most severe form of chronic viral hepatitis. Whereas in other forms of chronic viral hepatitis breakthrough advances has occurred in the last two decades, this did not happen in CDH. The only effective treatment in CDH consists of the use of pegylated interferons. Interferon therapy has to be given at high doses, and the optimal duration is unknown although there is data to suggest that treatment has to be individualized and prolonged treatment duration beyond 1 year is necessary. Effective treatment of chronic hepatitis B (CHB) could be of value in CDH as long as it significantly decreases hepatitis B surface antigen (HBsAg) levels. However, nucleos(t)ide analogs currently in use for the treatment of CHB do not affect HBsAg levels and are not beneficial in CDH. New treatment approaches for CHB aiming for functional or complete cure in CHB are attractive but most are in the preclinical stage of drug development and are not expected to be in use in the very near future. Hence, treatment development targeting different steps of the hepatitis delta virus is rationale. These include hepatocyte entry inhibitors, nucleic acid polymers, and prenylation inhibitors. The former two approaches may also be considered for CHB mono-infection. Studies on these three approaches have reached phase 2 studies in humans. The use of the hepatocyte entry inhibitor myrcludex B, several nucleic acid polymers, and the prenylation inhibitor lonafarnib in clinical trials have displayed some promising results and further data need to be generated but there is now, after decades of silence in terms of translational activity, for the first time a hope for effective new treatments in CDH.

Efficacy of long-term tenofovir-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs.

Few studies have investigated the efficacy of long-term tenofovir disoproxil fumarate (TDF)-based rescue therapy in patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs. We retrospectively analyzed 40 Japanese patients with chronic hepatitis B refractory to nucleoside/nucleotide analogs who received TDF-based rescue therapy [TDF monotherapy, TDF plus lamivudine (LAM) combination therapy, or TDF plus entecavir (ETV) combination therapy] followed up for a median of 45 months (range 14-99months). Viral response, changes in hepatitis B surface antigen levels from the baseline, and viral breakthrough during therapy were analyzed. The proportion of patients with undetectable serum hepatitis B virus (HBV) DNA levels (less than 2.1 log copies per milliliter) (viral response) during TDF-based rescue therapy was 68, 78, 85, 88, 83, 81, 88, and 100% at 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4years respectively. There were no differences in the viral response rate between the TDF plus LAM group and the TDF plus ETV group. The mean reduction from the baseline in hepatitis B surface antigen levels in patients with LAM-resistant HBV was greater than the reductions in patients with adefovir dipivoxil (ADV)-resistant or ETV-resistant HBV at 2 and 3years (P=0.024, and P=0.025 respectively). However, two patients with ADV- or ETV-resistant HBV at the baseline developed viral breakthrough during TDF-based rescue therapy. Long-term therapy with a TDF-based rescue regimen demonstrated high viral suppression in patients in whom LAM plus ADV combination therapy, ETV plus ADV combination therapy, or ETV monotherapy had failed. However, patients with ADV- or ETV-resistant HBV at the baseline may develop viral breakthrough and resistance, and careful follow-up is advised.

Intermittent Pattern of Detection of Hepatitis B Viral DNA After Achieving Undetectable Viral Levels

Introduction: Intermittent detection of hepatitis B viral DNA after suppression to undetectable viral level raises concerns about inadequate viral suppression, viral breakthrough, resistance, or noncompliance. This retrospective review was conducted in order to characterize the frequency and clinical significance of this laboratory finding, which will be referred to as intermittency pattern (IP). Methods: Patients with hepatitis B seen in an outpatient hepatology practice from April 2015 to 2016 who had been treated or were undergoing treatment with oral nucleos(t)ides were included for review. Patients who did not attain viral suppression < 20 IU/ml by PCR amplification for quantitative HBV DNA were excluded. Results: A total of 61 patients with HBV were identified. 10 did not require treatment, another 10 did not achieve viral suppression to < 20 IU/ml. The final study included 41 patients, ranging in age from 33 to 96 years (median 53), 51% female, and HBeAg positive in 27% at time of initiation of therapy. Thirtyeight (93%) were treated with a regimen that included either tenofovir (N=29) or entecavir (N=8) or both (N=1), the remainder were treated with lamivudine or adefovir (N=3). 83% (N=34) reached undetectable viral load, while the remainder had detectable HBV DNA but < 20 IU/ ml at nadir. Of these 34 patients, 50% (N=17) demonstrated IP, with median of 2 occasions of detectable DNA after reaching undetectable level. In all of these cases, viral load was < 20 IU/ml but detectable on PCR. None had concurrent elevation in ALT or symptoms at times of viral detectability. In those with IP, median age was 55 years, 58% were female, HBeAg was present in 23%, 6% had cirrhosis, and median time to reach viral suppression < 20 IU/ml was 2 years. In those without IP (N=17) median age was 52 years, 41% were female, HBeAg was present in 29%, and 17% had cirrhosis. Conclusion: 50% of patients with long term viral suppression demonstrated IP by PCR. There was a slight female predominance and fewer patients with cirrhosis in patients with IP compared to those without. Possible explanations for the IP phenomenon include low level of viral replication fluctuating around the level of detectability in patients whose virus is adequately suppressed by treatment, incomplete medication compliance, and false positivity of the assay. Given that IP was not associated with concurrent elevation of ALT, symptoms, or quantifiable viral level, IP appears to have little clinical significance.

Antiviral Activity of Bictegravir (GS-9883), a Novel Potent HIV-1 Integrase Strand Transfer Inhibitor with an Improved Resistance Profile.

Bictegravir (BIC; GS-9883), a novel, potent, once-daily, unboosted inhibitor of HIV-1 integrase (IN), specifically targets IN strand transfer activity (50% inhibitory concentration [IC50] of 7.5 ± 0.3 nM) and HIV-1 integration in cells. BIC exhibits potent and selective in vitro antiretroviral activity in both T-cell lines and primary human T lymphocytes, with 50% effective concentrations ranging from 1.5 to 2.4 nM and selectivity indices up to 8,700 relative to cytotoxicity. BIC exhibits synergistic in vitro antiviral effects in pairwise combinations with tenofovir alafenamide, emtricitabine, or darunavir and maintains potent antiviral activity against HIV-1 variants resistant to other classes of antiretrovirals. BIC displayed an in vitro resistance profile that was markedly improved compared to the integrase strand transfer inhibitors (INSTIs) raltegravir (RAL) and elvitegravir (EVG), and comparable to that of dolutegravir (DTG), against nine INSTI-resistant site-directed HIV-1 mutants. BIC displayed statistically improved antiviral activity relative to EVG, RAL, and DTG against a panel of 47 patient-derived HIV-1 isolates with high-level INSTI resistance; 13 of 47 tested isolates exhibited >2-fold lower resistance to BIC than DTG. In dose-escalation experiments conducted in vitro, BIC and DTG exhibited higher barriers to resistance than EVG, selecting for HIV-1 variants with reduced phenotypic susceptibility at days 71, 87, and 20, respectively. A recombinant virus with the BIC-selected M50I/R263K dual mutations in IN exhibited only 2.8-fold reduced susceptibility to BIC compared to wild-type virus. All BIC-selected variants exhibited low to intermediate levels of cross-resistance to RAL, DTG, and EVG (<8-fold) but remained susceptible to other classes of antiretrovirals. A high barrier to in vitro resistance emergence for both BIC and DTG was also observed in viral breakthrough studies in the presence of constant clinically relevant drug concentrations. The overall virologic profile of BIC supports its ongoing clinical investigation in combination with other antiretroviral agents for both treatment-naive and -experienced HIV-infected patients.

High rate of hepatitis B viral breakthrough in elderly non-Hodgkin lymphomas patients treated with Rituximab based chemotherapy

BackgroundRituximab-containing chemotherapies are offered to elderlies for treatment of non-Hodgkin lymphomas (NHL). From 0.7 to 27% of patients with “resolved” HBV infection develop HBV reactivation and related hepatitis during Rituximab-containing chemotherapies. Currently, several antiviral drugs are available for the prophylaxis of patients at risk for HBV reactivation, which include lamivudine, tenofovir, entecavir, and adefovir. Viral breakthrough may occur during therapy, which is defined as an abrupt increase in serum HBV DNA levels after a period of persistent suppression. Viral breakthrough occurs with non-compliance to therapy and, also, when drug-resistant mutants emerge. The risk might be higher in fragile patients as elderlies. AimsSince no study addressed this question, we determined the rate of HBV-RS in patients >65years undergoing Rituximab-containing chemotherapies for NHLs. MethodsWe evaluated 85 newly diagnosed NHL patients with resolved HBV infection, receiving Rituximab-containing chemotherapies. All received lamivudine. HBV DNA was checked at baseline, every 4 weeks, for 1year after completion of Rituximab cointaining regimens. ResultsNine patients (10%) had HBV reactivation and HBV related hepatitis. All received entecavir and recovered without consequences. HBV reactivation was more likely to occur after an average of five R-CHOP cycles or during Fludarabine. ConclusionsThe rate of viral breakthrough (VBK), in our study population, is high considering that the patients were HBV DNA negative at baseline and suggest that Lamivudine prevention may not be sufficient in this population.

Prevalence and risk factors for viral blipping in chronic hepatitis B patients treated with nucleos (t) ide analogues.

The clinical relevance of viral blipping during nucleos (t) ide analogue (NA) treatment is unclear in chronic hepatitis B (CHB). We investigated the prevalence, risk factors and clinical outcomes for those with viral blipping during NA treatment. A retrospective cohort study investigated consecutively treated CHB patients from May 2008 to February 2015 on the NAs such as entecavir (ETV), tenofovir (TDF) and lamivudine (LAM). Included patients were previously treatment naive. Viral blipping was defined as serum HBV DNA >20IU/mL on one occasion, and not >200IU/mL, with subsequent measurement returning to undetectable levels, that is <20IU/mL. A total of 242 treatment-compliant CHB patients were included with 44 (18.2%) experiencing viral blipping. In multivariable Cox regression, Asian race (HR=7.40, 95% CI 1.01-54.29, P<.049), LAM therapy (vs ETV/TDF, HR=2.53, 95% CI 1.29-4.95, P<.007), higher creatinine (per SD, HR=1.47, 95% CI 1.21-1.79, P<.001), HBeAg positivity (HR=2.68, 95% CI 1.39-5.03, P<.003) and longer time to achieve undetectable HBV DNA (per month, HR=1.05, 95% CI 1.02-1.08, P=.001) were associated with an increased risk of viral blipping. Viral blipping did not show any significant association with viral breakthrough, HBsAg loss, ALT flares or disease progression. Viral blipping is a frequent event during NA therapy; however, it did not lead to any clinically significant outcomes. Thus, it may not require more frequent blood work and patient visits in clinical practice.

Retrospective analysis of the associations and effectiveness of performing therapeutic drug monitoring in pregnant HIV-positive women in two large centres in Manchester.

There is no proven benefit for the routine use of therapeutic drug monitoring in HIV-positive pregnant women either for improving viral control or preventing mother-to-child transmission. This analysis reviewed a cohort of 171 HIV-positive pregnant women delivering between 1 January 2008 and 28 May 2013 to first establish which baseline characteristics are associated with having therapeutic drug monitoring performed, and whether therapeutic drug monitoring was associated with improved HIV control during pregnancy or mother-to-child transmission. Therapeutic drug monitoring was performed in 39% ( n = 66) of patients; it was associated with baseline characteristics of poor adherence to therapy (therapeutic drug monitoring 23% versus non-therapeutic drug monitoring 10%, p = 0.025) and the use of protease inhibitors (therapeutic drug monitoring 94% versus non-therapeutic drug monitoring 77%, p = 0.005). By multivariate analysis therapeutic drug monitoring was associated with medication alterations during pregnancy (therapeutic drug monitoring 68% versus non-therapeutic drug monitoring 12%, p = < 0.001), but not associated with any difference in viral load breakthrough during pregnancy (therapeutic drug monitoring 12% versus non-therapeutic drug monitoring 7%, p = 0.456) and viral load detectable at birth (therapeutic drug monitoring 14% versus non-therapeutic drug monitoring 9%, p = 0.503). There were no instances of mother-to-child transmission. Therapeutic drug monitoring's association with medication changes is postulated as partially causal in this cohort. There was no evidence of any association with improved control or reduced transmission of HIV to advocate routine therapeutic drug monitoring use.

Protease Inhibitors Drug Resistance Mutations in Turkish Patients with Chronic Hepatitis C.

Drug resistance development is an expected problem during treatment with protease inhibitors (PIs), this is largely due to the fact that Pls are low-genetic barrier drugs. Resistance-associated variants (RAVs) however may also occur naturally, and prior to treatment with Pls, the clinical impact of this basal resistance remains unknown. In Turkey, there is yet to be an investigation into the hepatitis C (HCV) drug associated resistance to oral antivirals. 178 antiviral-naïve patients infected with HCV genotype 1 were selected from 27 clinical centers of various geographical regions in Turkey and included in the current study. The basal NS3 Pls resistance mutations of these patients were analyzed. In 33 (18.5%) of the patients included in the study, at least one mutation pattern that can cause drug resistance was identified. The most frequently detected mutation pattern was T54S while R109K was the second most frequently detected. Following a more general examination of the patients studied, telaprevir (TVR) resistance in 27 patients (15.2%), boceprevir (BOC) resistance in 26 (14.6%) patients, simeprevir (SMV) resistance in 11 (6.2%) patients and faldaprevir resistance in 13 (7.3%) patients were detected. Our investigation also revealed that rebound developed in the presence of a Q80K mutation and amongst two V55A mutations following treatment with TVR, while no response to treatment was detected in a patient with a R55K mutation. We are of the opinion that drug resistance analyses can be beneficial and necessary in revealing which variants are responsible for pre-treatment natural resistance and which mutations are responsible for the viral breakthrough that may develop during the treatment.

Rapid In Vitro Evaluation of Antiretroviral Barrier to Resistance at Therapeutic Drug Levels.

Failure of combination antiretroviral (ARV) therapy in HIV-infected patients is often associated with the emergence of drug resistance-associated mutations (RAMs). To facilitate analysis of the barrier to resistance at therapeutically relevant ARV concentrations, we performed fixed-dose in vitro HIV-1 drug resistance selection assays using the immortalized MT-2 T-cell line and primary human CD4+ T cells with a panel of FDA-approved ARVs, each at their respective cell culture equivalent clinical trough concentration (CCE Cmin). At high multiples of its CCE Cmin, emtricitabine (FTC) selected for the rapid emergence of M184I/V, a result consistent with resistance emergence in vivo. While the rate of viral breakthrough in the presence of rilpivirine or efavirenz was delayed relative to FTC, both inhibitors selected for virus with known clinically relevant RAMs. No viral breakthrough was observed for the protease inhibitor atazanavir even at subtherapeutic drug concentrations, which is consistent with its previously characterized high in vivo barrier to resistance. Depending on assay conditions, treatment with integrase inhibitors elvitegravir and raltegravir resulted in breakthrough of both resistant and wild-type virus. The RAMs observed in drug selections were not detected above a 2% threshold by deep sequencing in the in vitro virus inoculum, and only rarely in isolates from treatment-naive HIV+ patients. These new viral breakthrough assays facilitate the analysis of multiple experimental replicates and conditions in parallel and provide a rapid quantitative means to evaluate drug resistance emergence at therapeutically relevant drug concentrations, which should facilitate the identification of new ARVs with a high barrier to resistance.

Drug-Based Lead Discovery: The Novel Ablative Antiretroviral Profile of Deferiprone in HIV-1-Infected Cells and in HIV-Infected Treatment-Naive Subjects of a Double-Blind, Placebo-Controlled, Randomized Exploratory Trial.

Antiretrovirals suppress HIV-1 production yet spare the sites of HIV-1 production, the HIV-1 DNA-harboring cells that evade immune detection and enable viral resistance on-drug and viral rebound off-drug. Therapeutic ablation of pathogenic cells markedly improves the outcome of many diseases. We extend this strategy to HIV-1 infection. Using drug-based lead discovery, we report the concentration threshold-dependent antiretroviral action of the medicinal chelator deferiprone and validate preclinical findings by a proof-of-concept double-blind trial. In isolate-infected primary cultures, supra-threshold concentrations during deferiprone monotherapy caused decline of HIV-1 RNA and HIV-1 DNA; did not allow viral breakthrough for up to 35 days on-drug, indicating resiliency against viral resistance; and prevented, for at least 87 days off-drug, viral rebound. Displaying a steep dose-effect curve, deferiprone produced infection-independent deficiency of hydroxylated hypusyl-eIF5A. However, unhydroxylated deoxyhypusyl-eIF5A accumulated particularly in HIV-infected cells; they preferentially underwent apoptotic DNA fragmentation. Since the threshold, ascertained at about 150 μM, is achievable in deferiprone-treated patients, we proceeded from cell culture directly to an exploratory trial. HIV-1 RNA was measured after 7 days on-drug and after 28 and 56 days off-drug. Subjects who attained supra-threshold concentrations in serum and completed the protocol of 17 oral doses, experienced a zidovudine-like decline of HIV-1 RNA on-drug that was maintained off-drug without statistically significant rebound for 8 weeks, over 670 times the drug’s half-life and thus clearance from circulation. The uniform deferiprone threshold is in agreement with mapping of, and crystallographic 3D-data on, the active site of deoxyhypusyl hydroxylase (DOHH), the eIF5A-hydroxylating enzyme. We propose that deficiency of hypusine-containing eIF5A impedes the translation of mRNAs encoding proline cluster (‘polyproline’)-containing proteins, exemplified by Gag/p24, and facilitated by the excess of deoxyhypusine-containing eIF5A, releases the innate apoptotic defense of HIV-infected cells from viral blockade, thus depleting the cellular reservoir of HIV-1 DNA that drives breakthrough and rebound.Trial Registration: ClinicalTrial.gov NCT02191657