Safety Of Nucleoside Analogues Research Articles

Nucleoside analogues for the treatment of influenza: history and experience

Aim. In this study we retrospectively evaluated the clinical effectiveness and safety of nucleoside analogues (Triazavirin© and ribavirin) with that of oseltamivir for treating moderate severe influenza in adults. Materials and methods. We have used data from 191 health records of patients with moderate severe PCR confirmed influenza A and B. Control group included 57 patients treated with oseltamivir, comparison groups – 53 and 81 patients, who received Triazavirin© and ribavirin accordingly. We compared infectious intoxication syndrome duration, fever duration, duration of acute rhinitis, acute pharyngitis, acute laryngitis, acute tracheitis, acute bronchitis, cough duration as well as pneumonia occurrence. Results. No statistically significant difference in the duration of developed syndromes in Triazavirin©-treated group and oseltamivir-treated group were observed. We have noticed that fever duration had been significantly longer in ribavirin group compared to control group (4,1±2,22 days vs. 3,1±1,94 days, p<0,05) as well as more frequent pneumonia occurrence (1,2% vs. 0,0%, p>0,05). Conclusion. New nucleoside analogue Triazavirin© showed good efficacy and safety profile in adult patients with influenza. This fact provides the opportunity to recommend it for treatment of influenza along with neuraminidase inhibitors.

Real-Life State of Anti-Hepatitis B Virus Drug Choice in Child-Bearing Age Male Patients and Effect on Fertility and Fetal Safety.

Research on effects of anti-hepatitis B virus (HBV) nucleoside analogs on male fertility and birth defects is limited and safety of nucleoside analogs in pregnancy is still a concern. Chronic hepatitis B (CHB) patients in Guangdong province were surveyed using a structured questionnaire. We collected data including medication type, fertility, and birth defects. Moreover, a survey of the knowledge of antiviral nucleoside analogs safety in fertility of male patients was conducted among physicians nationwide. Semen samples of 30 patients were collected. We screened 1050 HBV-positive male patients. Reasons for not receiving antivirals in 150 patients were “did not meet criteria for antiviral therapy,” fertility, and financial. Furthermore, 900 participants received antivirals (85.71%, 900/1050), including 792 patients with children and 15.15% (120/792) took anti-HBV treatment when preparing for pregnancy. Based on whether they received antiviral therapy during conception or not, we divided patients into two groups. In the child-bearing age group, 88.33% (106/120) of patients received telbivudine (LDT), whereas the other group mainly received entecavir (ETV) (87.20%, 586/672). No significant difference occurred in birth defect incidence rates between both groups. Furthermore, 558 physicians completed questionnaires. Reasons that influenced drug selection were “patient's condition,” “fertility demand,” “financial condition,” and “compliance.” Telbivudine was the first-choice drug (32.80%, 183/558) while tenofovir (TDF) was the second (2.69%, 15/558). Additionally, 61.47% of physicians considered telbivudine or tenofovir as the first choice for male patients who met antiviral criteria, whereas 19% suggested delayed therapy and follow-up until childbirth. No significant changes occurred in semen volume, concentration, mobility, and percentage before and after administration of anti-HBV nucleoside analogs, which did not affect male fertility and birth defect incidence while the desire for pregnancy influenced drug selection and timing of administration. Further research on the effects of analogs on male fertility and fetal safety is required.

Long-term outcome of telbivudine versus entecavir in treating higher viral load chronic hepatitis B patients without cirrhosis.

Chronic hepatitis B (CHB) patients with higher hepatitis B virus (HBV) load (higher viral load [HVL], HBV DNA ≥1×107 copies/mL) require antiviral therapy, but data for evaluating the long-term outcome of this therapy with antiviral agents remain limited. We comparatively evaluated the efficacy and the safety of nucleoside analogues in 179 noncirrhotic CHB patients with HVL over 5years. The HBeAg-positive (n=104) or HBeAg-negative (n=75) patients were treated consecutively with telbivudine (LdT, n=88) or entecavir (ETV, n=91) and evaluated for viral response, drug resistance and safety. HBV DNA, viral serology, biochemistries, HBV mutation and off-therapy relapse were determined. The cumulative rates of HBV DNA negativity were 86.4% and 94.5% for LdT and ETV at year 5, respectively. The rates of early viral response (EVR, HBV DNA <103 copies/mL at month 6) under LdT and ETV treatments were 58.0% and 34.1%, respectively (P<.05). Hepatitis B e antigen (HBeAg) and Hepatitis B surface antigen (HBsAg) loss-seroconversions were 47.7% and 18.2% on LdT and 16.5% and 2.2% on ETV (P<.01). Eighteen patients (age 28.2±3.1) experienced HBsAg loss-seroconversion, followed by 33±4.6month off-therapy without a relapse. Viral mutations and serum creatine kinase elevation were 9.1% and 8.0% on LdT, but only 1.1% and 0% on ETV. Both LdT and ETV suppressed HBV replication in HVL CHB patients within 5years. LdT therapy achieved a higher EVR, HBeAg and HBsAg seroconversion, especially in the younger patients, whereas ETV caused lower drug resistance and fewer adverse events. This finding might help to identify the optimal treatment for CHB patients with HVL.

Retraction RETRACTION of "Efficacy and safety of nucleoside analogues in preventing vertical transmission of the hepatitis B virus from father to infant", by L.-H. Cao, P.-L. Zhao, Z.-M. Liu, S.-C. Sun, D.-B. Xu, J.-D. Zhang and Z.-H. Shao - Genet. Mol. Res. 14 (4): 15539-15546 (2015).

The retracted article is: Cao L-H, Zhao P-L, Liu Z-M, Sun S-C, et al. (2015). Efficacy and safety of nucleoside analogues in preventing vertical transmission of the hepatitis B virus from father to infant. Genet. Mol. Res. 14: 15539-15546. The article published in Genetics and Molecular Research 14 (4): 15539-15546 (2015) is a very good paper, but it appears that the authors' group submitted this manuscript to multiple journals, which is ethical misconduct. This manuscript (similar language and identical data) was published in the Experimental and Therapeutic Medicine Journal prior to being submitted to GMR. There are parts copied from "Efficacy and safety of nucleoside analogs on blocking father-to-infant vertical transmission of hepatitis B virus", by Li-Hau Cao, Pei-Li Zhao, Zhi-Min Liu, Shao-Chun Sun, et al. Exp. Ther. Med. 9 (6): 2251-2256 (2015) - DOI: 10.3892/etm.2015.2379. The GMR editorial staff was alerted and after a thorough investigation, there is strong reason to believe that the peer review process was failure. Also, after review and contacting the authors, the editors of Genetics and Molecular Research decided to retract this article in accordance with the recommendations of the Committee on Publication Ethics (COPE). The authors and their institutions were advised of this serious breach of ethics.

Efficacy and safety of nucleoside analogs on blocking father-to-infant vertical transmission of hepatitisB virus.

The aim of the present study was to observe the efficacy and safety of nucleoside analogs in inhibiting father-to-infant vertical transmission of hepatitis B virus (HBV). Nucleoside analogs compete with HBV DNA polymerase substrate to inhibit DNA polymerase, thus preventing the replication of HBV DNA. A case group and control group were recruited for the study. Between March 2006 and March 2012 at the Liver Disease Center of Qinhuangdao Third Hospital, a total of 201 couples were recruited for the case group. In each case, the father tested positive the following HBV markers: Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), antibodies against the hepatitis B core antigen (anti-HBc) and HBV DNA. In total, 189 male patients presented with abnormal liver function (94.0%; 189/201). Prior to pregnancy, all the males in the case group were required to test negative for HBV DNA and exhibit normal liver function, while the females were required to test positive for antibodies against HBsAg (anti-HBs). In total, 188 couples comprised the control group. The couples were recruited between March 2006 and March 2012 in the Prenatal Clinic of Qinhuangdao Women's and Children's Hospital. The fathers tested positive for HBsAg, HBeAg, anti-HBc and HBV DNA. With regard to the females, HBsAg tests were all negative and anti-HBs tests were positive. In the case group, there were no HBsAg-positive or HBV DNA-positive newborns, while anti-HBs tests were all positive; thus, the father-to-infant HBV vertical transmission was successfully inhibited. In the control group, 147/188 newborns tested positive for anti-HBs at birth, accounting for 78.2%. In addition, 28 newborns were positive for HBV DNA (14.9%), and 19 newborns tested positive for HBsAg (10.1%). Statistically significant differences were observed between the two groups with regard to these parameters. However, no statistically significant differences in gestational age, birth weight, birth height, 1- and 8-min Apgar scores, presence of jaundice, other internal and surgical diseases, delivery mode and other birth information were observed when comparing the case group with the control group. Furthermore, there were no fetal malformations or stillbirths in the two groups. In the HBV DNA-positive fathers prior to pregnancy, antiretroviral therapy resulted in a reduced virus load. Therefore, blocking father-to-infant HBV vertical transmission maximally was important. The use of antiviral nucleoside analogs prior to pregnancy was shown to be safe. When the benefits outweighed the risks, the fathers who wanted to have a child continued to use antiviral therapy. However, the sample size of the present study was small, and an increased number of cases and longer follow-up times are required. In addition, the use of nucleoside analogs requires further in-depth assessment from the point of view of prenatal and postnatal care.

Efficacy and safety of nucleoside analogues in preventing vertical transmission of the hepatitis B virus from father to infant.

We examined the efficacy and safety of nucleoside analogues in preventing the vertical transmission of hepatitis B virus (HBV) from father to infant. We included 201 patients who visited the liver clinic of our hospital. The patients were positive for HBV surface antigen (HBsAg), HBeAg, anti-HBc, and HBV DNA; 189 patients (94%) had abnormal liver function. In all couples, the fathers were HBV DNA-negative and had normal liver function, and the mothers were anti-HB-positive before pregnancy. The control group comprised 188 couples who visited our hospital during the same time period. The fathers in the control group were positive for HBsAg, HBeAg, anti-HBc, and HBV DNA. The mothers were HBsAg-negative and anti-HBs-positive. No infants in the case group were HBsAg-positive and HBV DNA-positive, and all were anti-HBs-positive, indicating that father to infant HBV vertical transmission was prevented in the case group. In the control group, 147 of 188 newborns (78.2%) were anti-HBs-positive at birth, 28 (14.9%) were HBV DNA-positive, and 19 (10.1%) were HBsAg-positive. A significant difference was observed between the two groups. No statistically significant difference was observed in the gestational age, birth weight, birth length, 1-min and 8-min Apgar score, jaundice, other internal and surgical diseases, delivery mode, and other birth information between the neonates born to couples in the case and control groups; there were no fetal malformations and stillbirths in the two groups. Our results showed that administration of antiretroviral therapy to HBV DNA-positive fathers before pregnancy can cause a decrease in the viral load and prevent father to infant HBV vertical transmission. The use of antiviral nucleoside analogues before pregnancy was safe in fathers, and the fathers who wanted children could continue to use anti-viral therapy. The sample size in our study was small, and further studies with a large sample size and longer follow-up time are required for determining the use of nucleoside analogues from the point view of prenatal and postnatal care.

Phase I Clinical Trial of Valacyclovir and Standard of Care Cyclophosphamide in Children With Endemic Burkitt Lymphoma in Malawi

Treatment options for Epstein-Barr virus (EBV)-associated Burkitt lymphoma in Africa are limited because of chemotherapy-associated toxicity. Since other EBV-associated diseases respond to antiviral agents, we investigated adding an antiviral agent, valacyclovir, to the current chemotherapy regimen in Malawi. In this phase I safety study, we showed that cyclophosphamide combined with valacyclovir was safe. Phase II efficacy trials should now be undertaken. Nucleoside analogues, including acyclovir, ganciclovir, and their precursors, have shown some efficacy against several Epstein-Barr virus (EBV)-associated diseases, including active EBV infection and posttransplantation lymphoproliferative disorder (PTLD). They have also been proposed as a possible treatment for EBV-associated malignancies, including endemic Burkitt lymphoma. The safety of nucleoside analogues in combination with chemotherapy in the developing world has not been studied and is necessary before any large scale efficacy trials are conducted. Children 3-15 years old meeting inclusion criteria were assigned to a 3+3 dose escalation trial of combination valacyclovir (15 and 30 mg/kg, 3 times daily for 40 days) and cyclophosphamide (CPM) (40 mg/kg day 1, 60 mg/kg on days 8, 18, and 28) or CPM monotherapy. Subjects were monitored for clinical and laboratory toxicity and had EBV levels measured regularly. Dose-limiting toxicity (DLT) was our primary outcome. We found that the combination of valacyclovir and CPM was safe and did not lead to any DLT compared with CPM monotherapy. The most common side effects were vomiting, abdominal pain, and tumor site pain, which were similar in both arms. Patients with measurable serum EBV showed decreased loads over their treatment course. We recommend a phase II valacyclovir dose of 30 mg/kg 3 times daily for 40 days. We also observed that 6 of our 12 patients with presumed Burkitt lymphoma had measurable EBV viral loads that decreased over the course of their treatment, suggesting that phase II studies should investigate this correlation further. This study paves the way for a phase II efficacy trial of combined valacyclovir and CPM in the treatment of endemic Burkitt lymphoma.

Side effects of long-term oral antiviral therapy for hepatitis B

The aim of this review is to summarize the safety profile of the five approved oral nucleoside analogs used to treat chronic hepatitis B virus (HBV) infection, focusing on both the class adverse effects and those that have been reported with individual agents, as well as their safety in pregnancy. All nucleoside analogs have a "Black Box" warning because of their potential for inhibition of human DNA polymerase gamma involved in mitochondrial DNA replication. A reduction in intracellular mitochondrial DNA levels can lead to varying clinical manifestations of mitochondrial toxicity (i.e., neuropathy, myopathy, lactic acidosis), but these side effects are rarely reported with the oral antiviral agents active against HBV. Adefovir and tenofovir are associated with a dose-dependent but usually reversible proximal renal tubular toxicity. For these reasons, patients receiving these agents should be monitored for renal toxicity and the dose modified for renal insufficiency. Prolonged use of tenofovir has also been reported to lead to reduced bone mineral density in patients with human immunodeficiency virus infection, but prospective studies in patients with HBV infection are lacking. Telbivudine treatment is associated with moderate serum creatine phosphokinase elevations in up to 12% of patients. There have been few prospective studies on the safety of nucleoside analogs during pregnancy. According to the Antiretroviral Pregnancy Registry, the incidence of birth defects associated with lamivudine and tenofovir use during pregnancy is not increased. Studies on the safety of long-term therapy with the nucleoside analogs, alone and in combination, are needed as are further studies of children, the elderly, pregnant women, and patients with renal insufficiency.