Sila Akhan

Monitoring of hepatitis B virus surface antigen escape mutations and concomitantly nucleos(t)ide analog resistance mutations in Turkish patients with chronic hepatitis B

BACKGROUND The hepatitis B virus (HBV) polymerase gene completely overlaps with the envelope gene. In the present study we aimed to monitor the prevalence and pattern of the typical mutations for hepatitis B surface antigen (HBsAg) escape, and concomitantly nucleos(t)ide analog (NUC) resistance mutations, in Turkish patients undergoing different antiviral therapies and in treatment-naïve patients with chronic hepatitis B (CHB). METHODS The investigation was undertaken between March 2007 and August 2009 and involved a total of 142 patients under NUC therapy (88 males; mean age 42 years (range 13-68); hepatitis B e antigen (HBeAg) negativity in 94 patients; HBV DNA median log 4.3 log(10) IU/ml (range 2.0->6.0); alanine aminotransferase (ALT) median level 76.1 IU/ml (range 12-1082)) and 185 treatment-naïve CHB patients (120 males; mean age 39 years (range 1-76 years); HBeAg negativity in 132 patients; HBV DNA median log 3.5 log(10) IU/ml (range 2.0-6.0); ALT median level 60.7 IU/l (range 8-874)). RESULTS The overall prevalence of typical HBsAg escape mutations found in the CHB patients was 8.3% (27/327). In the NUC therapy group the prevalence was 8.5% (12/142), with the following patterns: sY100C+sI110V, sL109I, sP120T, sP127T, sG130R+sG145X, sS132A+sY134N, sY134N+sG145R, sC137G, sD144E, sG145R. In the treatment-naïve group the prevalence was 8.1% (15/185), with the following patterns: sL109I, sI110V, sS117INST, sP120T, sP127T, sM133I, sC137L+sG145R, sS143L. However, NUC resistance mutations were found in 7.7% (11/142) of the patients on NUC therapy and 3.8% (7/185) of the treatment-naïve group patients. Interestingly, the treatment-naïve patients had preexisting drug resistance mutations related to lamivudine (rtL180M+rtM204I), adefovir (rtA181V, rtQ215S, rtI233V), entecavir (intermediate susceptibility with rtL180M+rtM204IHBV variant), telbivudine (rtL180M+rtM204I), and tenofovir (rtA194T). CONCLUSIONS The findings of this study show preexisting typical HBsAg escape and NUC resistance mutations are possible. The genetic arrangement of the HBV genome with polymerase and surface genes overlapping has substantial public health and diagnostic implications and relevance.

FREQUENCY AND MUTATION PATTERNS OF RESISTANCE IN PATIENTS WITH CHRONIC HEPATITIS B INFECTION TREATED WITH NUCLEOS (T) IDE ANALOGS IN ADD-ON AND SWITCH STRATEGIES

Background Treatment for chronic hepatitis B (CHB) has improved over the last 10 years mainly due to the development of effective oral antiviral agents [nucleoside/nucleotide analogs (NUCs)]. Objectives The aim of the present study is to identify the frequency and major patterns of resistance to the hepatitis B virus (HBV) in a Turkish population of CHB patients treated with NUCs using add-on and switch therapy strategies. Patients and Methods: The investigation involved a total of 194 patients (88 were treated using add-on therapy, and 106 were treated using switch therapy). We analyzed the HBV polymerase gene by amplification and direct sequencing procedures. Results Primary drug-resistance mutations were detected in 84 patients (43%; 42 in add-on therapy, and 42 in switch therapy) taking lamivudine (LAM), 10 patients (5%; 6 in add-on therapy, and 4 in switch therapy) taking entecavir (ETV), and 16 patients (8%; 8 in add-on therapy, and 8 in switch therapy) taking adefovir (ADV). The most common LAM and ETV resistance mutations were rtM204I/V, rtL180M and rtT184A/I/S, respectively, while rtA181T/V and rtN236T substitutions were the most frequently observed ADV resistance mutations. Conclusions Patients with CHB who developed NUC resistance were managed using 2 different rescue strategies. The frequency and mutation pattern of resistance were similar in patients treated with add-on and switch strategies. These findings may be helpful in the management of rescue strategies in LAM-resistant patients.

Response to Interferon-Alpha in Chronic Hepatitis B Patients with and without Precore Mutant Strain and Effects on HBsAg Titers

Background: Chronic hepatitis B (CHB) affects 400 million people worldwide and is a major cause of morbidity and mortality. It is known that HBV DNA sequences were detected after the clearance of serum hepatitis B surface antigen (HBsAg) often in serum, liver and peripheral blood mononuclear cells. The objectives of our study were to evaluate the previous measurements of HBsAg titers versus. quantitative hepatitis B virus (HBV) DNA and ALT measurements in order to predict the nonresponse and response in interferon-alpha (IFN-α)-treated HBeAg-positive and HBeAg-negative chronic HBV patients. Methods: We investigate whether the presence of precore mutant affects the response to IFN-α therapy and on the titer of HBsAg or not. Twenty-one HBeAg-positive (group1), 38 HBeAg-negative (group 2), and 47 healthy inactive carriers (group 3) made up this study. Liver biopsy showed chronic hepatitis, there was no cirrhosis and none of the patients had IFN-α therapy before. Results: The decrease in HBsAg titers was found as statistically not significant in groups 1 (p = 0.192) and 3 (p = 0.236) and statistically significant in group 2 (p = 0.0001) within a 6-month interval. Conclusion: HBsAg titer may be a factor to predict the primary responders and nonresponders specially in HBeAg-negative patients.

Antiviral drug-associated potential vaccine-escape hepatitis B virus mutants in Turkish patients with chronic hepatitis B

BACKGROUND The hepatitis B virus (HBV) polymerase (pol) gene completely overlaps with the envelope (S) gene. Mutations in the pol gene of HBV, either from selection of primary or secondary resistance mutations, typically result in changes in the overlapping hepatitis B surface antigen (HBsAg). Recent studies have conferred a new acronym to these HBV pol/S gene overlap mutants: ADAPVEMs, for antiviral drug-associated potential vaccine-escape mutants. The present study aimed to assess the prevalence and pattern of ADAPVEMs in Turkish patients with chronic hepatitis B (CHB). METHODS The investigation was conducted between March 2007 and July 2010 and involved a total of 442 patients. These patients were in the following phases of HBV infection: immune tolerant (n=50), immune reactive (n=37), inactive carrier (n=90), HBeAg-negative CHB (n=217), and HBsAg-negative (n=12), or were hemodialysis patients (n=36). One hundred eighty-six patients were receiving nucleos(t)ide analogue (NUC) therapy and 256 patients had treatment-naïve CHB. RESULTS Seven types of ADAPVEM were detected in the total CHB patients: rtM204V/sI195M, rtM204I/sW196S, rtM204I/sW196L, rtV173L/sE164D, rtA181T/sW172*, rtA181T/sW172L, and rtA181V/sL173F. The ADAPVEMs were associated with lamivudine, telbivudine, and adefovir. The prevalence of ADAPVEMs in all CHB patients was found to be 10% (46/442). The difference in the prevalence of ADAPVEMs across the different CHB clinical phases was not significant (Pearson Chi-square, p=0.112). The prevalence of ADAPVEMs was 24% (44/186) in those undergoing NUC therapy and 0.7% (2/256) in the treatment-naïve group; this difference was significant (Pearson Chi-square, p=0.00). CONCLUSIONS We determined the prevalence and pattern of ADAPVEMs in Turkish patients in the different phases of CHB. Preferred drugs in Turkey, such as lamivudine, have the potential to cause the emergence of ADAPVEMs, with the possibility that these will spread to both individuals immunized with the hepatitis B vaccine and nonimmunized individuals. ADAPVEMs should be monitored in infected and treated patients and their public health risks assessed.

Evaluation of hepatitis B virus transmission and antiviral therapy among hepatitis B surface antigen-positive pregnant women

The aim of the present study was to assess the potential risk of hepatitis B virus (HBV) vertical transmission among Turkish parturient women and to evaluate the efficacy and safety of antiviral agents.

Retreatment of Chronic Hepatitis C Infection with Telaprevir: Preliminary Results in Turkey

BACKGROUND The use of pegylated interferon alpha and ribavirin (PegIFN/RBV) for the retreatment of chronic hepatitis C virus (HCV) infection without a sustained virological response (SVR) prior to PegIFN/RBV treatment has resulted in low success rates. AIMS To investigate the efficacy and safety of telaprevir (TVR) in combination with PegIFN/RBV in patients infected with HCV genotypes 1 and 4 who were previously treated with PegIFN/RBV and failed to achieve SVR. STUDY DESIGN Multi-center, retrospective, cross-sectional study. METHODS The study included 111 patients: 80 prior relapsers, 25 prior null responders, and six prior partial responders to PegIFN/RBV treatment. The patients were given TVR/PegIFN/RBV for 12 weeks, followed by a 12-week PegIFN/RBV treatment; virological response results were assessed at weeks 4, 12, and 24. Treatment was discontinued in patients with HCV RNA >1000 IU/mL at week 4 or with negative RNA results at week 4 but >1000 IU/mL at week 12. Rapid virological response (RVR), early virological response (EVR), extended rapid virological response (eRVR), and virological response at 24th week of treatment were evaluated. The side effects of combination therapy and the rates of treatment discontinuation were investigated. RESULTS The mean age of the patients was 56.02±9.96 years and 45.9% were male. Ninety-one percent of the patients were infected with viral genotype 1, 69.6% with the interleukin (IL) 28B genotype CT and 20.2% were cirrhotic. The RVR rate was 86.3% in prior relapsers, 56% in prior null responders, and 50% in prior partial responders (p=0.002). EVR rates in those groups were 91.3%, 56%, and 83.3%, respectively (p<0.001). eRVR rates were 83.8% in prior relapsers, 48% in prior null responders, and 50% in prior partial responders (<0.001). The virological response at the 24th week of treatment was found to be the highest in prior relapsers (88.8%); it was 56% in prior null responders and 66.7% in prior partial responders (p<0.001). Common side effects were fatigue, headache, anorexia, malaise, anemia, pruritus, dry skin, rash, dyspepsia, nausea, pyrexia, stomachache, and anorectal discomfort. All treatments were discontinued due to side effects in 9.9% of patients. CONCLUSION High virological response rates were obtained with TVR/PegIFN/RBV treatment. Although side effects were frequently observed, the discontinuation rate of combination therapy was low.

Conjugative Resistance to Tazobactam Plus Piperacillin Among Extended-spectrum Beta-lactamase-producing Nosocomial Klebsiella pneumoniae

We studied the genetic origins of piperacillin-tazobactam resistance among nosocomial Klebsiella pneumoniae strains. A total of 30 nosocomial isolates resistant to piperacillin-tazobactam were obtained from various regions of Turkey. Isoelectric focusing demonstrated at least 2 enzymes common to all strains: I at a pI of 8.0 and the other at 5.4. Piperacillin-tazobactam resistance was successfully transferred from all of the strains to Escherichia coli. Of the piperacillin-tazobactam-resistant transconjugates, 23 were also resistant to ceftazidime. However, 7 transconjugates were susceptible to ceftazidime but resistant to piperacillin-tazobactam, producing a single enzyme focusing at pI 5.4. Piperacillin resistance caused by this enzyme was reversed by clavulanate and by increased amounts of tazobactam, which indicates that this enzyme confers resistance due to its high amount. Sequence analysis revealed this enzyme to be TEM-1. This study demonstrates that transferable hyper-produced TEM-1 causes piperacillin-tazobactam resistance in Klebsiella strains in Turkish hospitals.We studied the genetic origins of piperacillin?tazobactam resistance among nosocomial Klebsiella pneumoniae strains. A total of 30 nosocomial isolates resistant to piperacillin?tazobactam were obtained from various regions of Turkey. Isoelectric focusing demonstrated at least 2 enzymes common to all strains: 1 at a pI of 8.0 and the other at 5.4. Piperacillin?tazobactam resistance was successfully transferred from all of the strains to Escherichia coli. Of the piperacillin?tazobactam-resistant transconjugates, 23 were also resistant to ceftazidime. However, 7 transconjugates were susceptible to ceftazidime but resistant to piperacillin?tazobactam, producing a single enzyme focusing at pI 5.4. Piperacillin resistance caused by this enzyme was reversed by clavulanate and by increased amounts of tazobactam, which indicates that this enzyme confers resistance due to its high amount. Sequence analysis revealed this enzyme to be TEM-1. This study demonstrates that transferable hyper-produced TEM-1 causes piperacillin?tazobactam resistance in Klebsiella strains in Turkish hospitals.

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

BACKGROUND 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. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSION 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.

A case report: antiviral triple therapy with telaprevir in a haemodialysed HCV patient in Turkey.

A 49-year-old woman was diagnosed with chronic hepatitis C 7 years ago. She began haemodialysis at the same time. She was on the waiting list for kidney transplantation (KTx). The real-time PCR technique revealed an HCV RNA viral load of 212 000 IU/ml, genotype 1a, IL28B the rs12979860 minor allele heterozygous CT (rs8099917 TT homozygous). She had a history of first antiviral treatment for 48 weeks of PEG-IFN-alpha 2a, 135 μg/week in 2011, but the HCV infection relapsed. Considering her relatively young age, candidacy for renal transplant, and the heterozygous pattern of IL28B, we decided to proceed with a second (and last) antiviral treatment using triple therapy with telaprevir at the regular dose of 750 mg every 8 hours + PEG-IFN-alpha 2a 135 μg/week sc + 200 mg RBV three times a week. At the end of 6-month therapy, HCV RNA was found to be negative at months 3, 5, and 6.The patient has reached the sustained virological response (SVR) and is ready for KTx. All renal transplant candidates (dialysis-dependent, or not) with HCV should be assessed for antiviral treatment given the increased risk of progressive liver disease due to immunosuppressive therapy, increased life expectancy compared to other HCV-positive patients on dialysis, and the inability to receive interferon after transplantation.

The sustained virologic response of nonresponder hepatitis C virus patients with retreatment

BACKGROUND Pegylated interferon and ribavirin combination therapy remain the first-line treatment for chronic hepatitis C virus (HCV) infection. In contrast to the large number of studies in treatment-naive patients, the effectiveness of retreatment in patients who have previously failed pegylated interferon based therapy is not much reported. OBJECTIVES The aim of this retrospective study was to focus on the efficacy of pegylated interferon alpha and ribavirin in retreated chronic hepatitis C patients. PATIENTS AND METHODS All patients were treated with pegylated interferon alpha either 2a (180 μg) or 2b (1.5μg/kg) subcutaneously once weekly for a 48-week period, plus ribavirin 1000-1200 mg/day. The patient who had a negative HCV RNA at the end of 48 weeks were followed up for 24 weeks, and the patients who relapsed in the post-treatment follow-up period of 24 weeks were treated again with pegylated interferon alpha; but if the first treatment was administered with pegylated interferon alpha 2a, the second was administered with pegylated interferon alpha 2b and if pegylated interferon alpha 2b, then the second with pegylated interferon alpha 2a. RESULTS We evaluated the outcome of our patients with chronic HCV who achieved a viral response at the end of the therapy, but did not achieve sustained virologic response; 54% (38/70) of patients did achieve sustained virologic response, while 46% (32/70) of patients did not (eight patients did not achieve early virologic response, five patients were nonresponders at 24th week of the treatment, the remaining 19 patient had negative HCV at the end of the therapy but did not achieve sustained virologic response). We began from 19 patients to 8 patients, who had negative HCV RNA at the end of the treatment, but did not achieve sustained virologic response, interferon plus ribavirin therapy again. If the patient had interferon alpha 2a, we gave in the second tour alpha 2b; and if alpha 2b, then alpha 2a. The early virologic response of these nine patients were found to be 63% (5/8). These 5 patients who had rapid virologic response and early virologic response at the second therapy achieved sustained virologic response this time. CONCLUSIONS These findings suggest that the standard 48-week treatment is insufficient and that an extended course of treatment may be necessary. Relapse is a poorly understood clinical outcome in the treatment of chronic HCV patients. Retreatment can give a chance to some patients specially who have early virologic response and negative HCV RNA at the end of the first therapy.