Mg Of Tenofovir Disoproxil Fumarate Research Articles

Adherence, safety, and choice of the monthly dapivirine vaginal ring or oral emtricitabine plus tenofovir disoproxil fumarate for HIV pre-exposure prophylaxis among African adolescent girls and young women: a randomised, open-label, crossover trial

Half of new HIV acquisitions in Africa occur in adolescent girls and young women. Pre-exposure prophylaxis (PrEP) with oral tenofovir disoproxil fumarate plus emtricitabine or the monthly dapivirine vaginal ring is efficacious but has lower adherence and effectiveness among adolescent girls and young women. We aimed to assess product adherence, safety, and choice of oral PrEP compared with the dapivirine ring among African adolescent girls and young women. MTN-034/REACH was a randomised, open-label, phase 2a crossover trial among HIV-seronegative, non-pregnant adolescent girls and young women aged 16-21 years at four clinical research sites in South Africa, Uganda, and Zimbabwe. Participants were randomly assigned (1:1) to either the dapivirine ring or daily oral PrEP (200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate) for 6 months, then switched to the other product option for 6 months, followed by a third 6-month period in which participants were given a choice of oral PrEP, the dapivirine ring, or neither. Fixed block randomisation was used, stratified by site. The primary adherence endpoint was use of each product during the randomised periods, with high use defined as tenofovir-diphosphate concentrations greater than or equal to 700 fmol/punch (associated with taking an average of four or more tablets per week in the previous month) and greater than or equal to 4 mg dapivirine released from the returned ring (continuous use for 28 days in the previous month) based on residual drug concentrations. The primary safety endpoint was grade 2 or higher adverse events during each randomised period of 24 weeks of ring and oral PrEP. This trial is registered at ClinicalTrials.gov, NCT03593655. From Feb 6, 2019 to Sept 9, 2021, 396 adolescent girls and young women were screened, 247 of whom were enrolled and randomly assigned (6 months of the ring followed by 6 months of oral PrEP n=124; 6 months of oral PrEP followed by 6 months of the ring n=123). Median age was 18 years (IQR 17-19). 54 grade 2 or higher product-related adverse events were reported during oral PrEP and five during dapivirine ring use, with no product-related serious adverse events. High adherence was observed in 753 (57%) of the 1316 oral PrEP visits and 806 (57%) of the 1407 dapivirine ring visits. Four women acquired HIV during follow-up. Adherence was moderately high and similar between oral PrEP and the dapivirine ring with favourable safety and tolerability. Oral PrEP and the dapivirine ring are effective, safe, and well tolerated HIV prevention options for adolescent girls and young women who would benefit from a choice of PrEP formulations to meet their needs and preferences. National Institutes of Health.

Immunoglobulin-free strategy to prevent HBV mother-to-child transmission in Cambodia (TA-PROHM): a single-arm, multicentre, phase 4 trial

Prevention of mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is based on administration of vaccine and immunoglobulins (HBIg) to newborns at birth and maternal antiviral prophylaxis for those with an HBV-DNA viral load of at 5·3 log10 IU/mL or more. Many low-income and middle-income countries face difficulty in accessing HBIg and HBV-DNA quantification. The aim of this study was to evaluate the effectiveness of an HBIg-free strategy to prevent MTCT of HBV. TA-PROHM was a single-arm, multicentre, phase 4 trial done in five maternity units in Cambodia. Pregnant women who were positive for hepatitis B surface antigen (HBsAg), aged 18 years or older were included. Women who were HCV or HIV positive, had creatinine clearance of less than 30 mL/min, severe gravid disease, and planned to give birth outside the study sites were excluded. From Oct 4, 2017, to Jan 9, 2019, HBsAg positive pregnant women who tested positive for hepatitis B e antigen (HBeAg) with a rapid diagnostic test were eligible to receive tenofovir disoproxil fumarate. From Jan 9, 2019, women who were HBeAg negative with an alanine aminotransferase concentration of ≥40 IU/L were also eligible to receive tenofovir disoproxil fumarate. Women in the tenofovir disoproxil fumarate eligible group received 300 mg of tenofovir disoproxil fumarate orally once a day from the 24th week of gestation until 6 weeks postpartum. The primary outcome was the overall proportion of infants who were HBsAg positive at 6 months of life, confirmed by positive HBV DNA quantification. For the primary outcome, the proportion (95% CI) of infants with HBsAg at 6 months was stratified according to infant's HBIg status, duration of maternal tenofovir disoproxil fumarate treatment (>4 weeks and ≤4 weeks), and study period (before and after the change in therapeutic algorithm) and was measured in a modified intention-to-treat analysis, which excluded infants lost to follow-up or who were withdrawn before 6 months. The study is registered with ClinicalTrials.gov, NCT02937779. From Oct 4, 2017, to Nov 27, 2020, 21 251 pregnant women were screened for HBsAg, of whom 1194 (6%) were enrolled in the study: 338 (28%) were eligible to receive tenofovir disoproxil fumarate. For the tenofovir disoproxil fumarate eligible group, four (1% [95% CI 0·34-3·20]) of 317 infants had HBV infection at 6 months; in the subgroup of 271 children who did not receive HBIg, four (1% [0·40-3·74]) had HBV infection at 6 months. In absence of HBIg, MTCT HBV transmission occurred in none (0% [0-1·61]) of 227 women who received tenofovir disoproxil fumarate for more than 4 weeks before giving birth and three (8% [1·75-22·47]) of 36 women who received tenofovir disoproxil fumarate for less than 4 weeks. In the tenofovir disoproxil fumarate ineligible group, seven (1% [0·40-2·02]) of 712 infants had HBV infection at 6 months; in the subgroup of 567 children who did not receive HBIg, six (1% [0·39-2·30]) had HBV infection at 6 months. An immunoglobulin-free strategy using an HBeAg rapid diagnosis test and alanine aminotransferase-based algorithm to assess eligibility for tenofovir, is effective at preventing MTCT of HBV when tenofovir was initiated at least 4 weeks before birth. French Agency for Research on AIDS and Viral Hepatitis and Emerging Infectious diseases. For the French translation of the abstract see Supplementary Materials section.

Development and validation of LC-MS/MS method for the simultaneous estimation of tenofovir disoproxil fumarate and pioglitazone HCL in human plasma

For the simultaneous detection of tenofovir and pioglitazone in a human plasma LC-MS/MS technique was utilized. API-4000 mass spectrometer was used. It should be operated in positive ion mode and contains ion source of turbo spray. Inverted C18 column was used which produces good resolution and symmetrical peaks. Metoprolol is used as internal standard. It requires acidic PH for elution but Tenofovir disoproxil fumarate and Pioglitazone requires neutral PH after extraction which is equity diluted with H2O for supernate. Finally, it provides good resolution and elution. By using Acetonitrile 100mg of Tenofovir Disoproxil fumarate and Pioglitazone HCL were dissolved and the final volume is made with H2O and Acetonitrile in 1:1 ratio to give 1mg/ml. standard stock solution are stored at -2to ± 20 C till analysis is completed. The guidelines were provided by the FDA to fulfill the essentials requires for the technique. To regulate the concentration the procedure starts with standard curve which is built form the quantitative analysis standard ranges form 1-1000ng/mL. To determine the stability freeze-thaw technique were used. To determine the stability the analyte is kept at room temperature for 24 hours. The correlation coefficients for all calibration curves were more than 0.99.

Randomised clinical trial: safety, efficacy and pharmacokinetics of HS-10234 versus tenofovir for the treatment of chronic hepatitis B infection.

HS-10234 is a novel prodrug of tenofovir developed to increase anti-viral potency and to reduce systemic toxicities. To evaluate the tolerability, pharmacokinetics and anti-viral efficacy of HS-10234 in patients with chronic hepatitis B (CHB) infection METHODS: Treatment-naïve subjects with non-cirrhotic CHB were divided into three groups (n=12/group) and randomised within each group to receive 10, 25 or 40mg of HS-10234, or 300mg of tenofovir disoproxil fumarate (TDF) once a day for 28days. Among 36 enrolled subjects, 33.3% were hepatitis B e antigen-negative with a mean hepatitis B virus (HBV) DNA level of 6.32-7.42log10 IU/mL. Nephrotoxicity and serious adverse events were not observed; all adverse events were mild or moderate and non-specific. The mean reductions in serum HBV DNA after 28days were -2.70, -2.89, -2.72 and -3.04log10 IU/mL for treatment with 10, 25 or 40mg HS-10234, and 300mg TDF, respectively. HS-10234 and its metabolite TFV showed linear, dose-proportional pharmacokinetics. The concentrations of active TFV-DP in peripheral blood mononuclear cells were higher (approximately 2- to 11-fold increase) and TFV in plasma were lower (approximately 4.5- to 25-fold reduction) in subjects taking HS-10234 than those in the TDF group. HS-10234 was well tolerated during a 4-week course. TDF and HS-10234 had comparable potency in inhibiting HBV replication. A daily dose of 10-25mg of HS-10234 is recommended for CHB treatment. (Chinese Drug Trial Identifier: CTR20161077).

Quantification of tenofovir disoproxil fumarate and emtricitabine in generic pre-exposure prophylaxis tablets obtained from the internet.

In this study, we addressed the recent concerns over the authenticity of generic pre-exposure prophylaxis (PrEP) purchased online by sampling 14 generic PrEPs from different manufacturers and suppliers and measuring tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) content using high-performance liquid chromatography. We confirmed that all the PrEP tablets contained 94.3% to 104.9% of the 300 mg of TDF claimed on the label and 97.3% to 104.4% of the 200 mg FTC claimed on the label.

Telepharmacy service brings HIV preventive to rural Iowans.

An innovative telepharmacy service in Iowa offers convenience and discretion while delivering the benefits of preexposure prophylaxis (PrEP) to people in rural parts of the state who are at risk for HIV infection. Angela Hoth, clinical pharmacist for University of Iowa (UI) Health Care and project manager for TelePrEP, described the program as “a public health-partnered, virtual pharmacist telemedicine model to provide HIV prevention within Iowa.” “What that means,” she explained, “is that we partner with public health to identify people who may benefit from PrEP.” The Iowa Department of Public Health’s 2017 HIV surveillance report stated that 125 Iowans were newly diagnosed with HIV infection that year and 2,790 were living with HIV. Federal guidelines recommend PrEP—in most cases, a daily oral fixed-dose combination regimen consisting of 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate—for patients at substantial risk for HIV infection. A PrEP indication was approved in 2012 for Truvada, Gilead Sciences Inc.’s emtricitabine–tenofovir disoproxil fumarate combination product.

Bone Age and Mineral Density Assessments Using Plain Roentgenograms in Tenofovir-exposed Infants in Malawi and Brazil Enrolled in HIV Prevention Trials Network 057.

Tenofovir disoproxil fumarate (TDF) use during pregnancy has been increasing, and studies linking bone toxicity with exposure to TDF have raised concern for its use in infants. Hand/wrist and spine radiographs were obtained at 3 days and 12 weeks of age in infants born to HIV-infected pregnant women enrolled in the HIV Prevention Trials Network 057 pharmacokinetic study of TDF conducted in Malawi and Brazil assigned to 3 TDF dosing cohorts. In cohort 1, mothers received 600 mg of TDF during labor. In cohort 2, infants received 4 mg/kg dose on days 0, 3 and 5. In cohort 3, a 900 mg maternal dose was given during labor, followed by a 6 mg/kg infant dose on days 0, 3 and 5 of life. Across all 3 cohorts, 89 infants had radiographs performed at either time point, and 85 had radiographs performed at both time points. Metaphyseal lucency was present in 1 case in Brazil and 2 in Malawi. Fifteen percent of infants from Brazil and 9% of infants from Malawi presented bone age discrepancies. No other abnormalities were identified in Brazil, whereas in Malawi, there were 7 more cases of wrist osteopenia, 2 of spine osteopenia and 3 other abnormalities. Bone abnormalities were not uncommon in the overall cohort of HIV-exposed infants. Because of very limited study drug exposure at the time of birth, it is unlikely that TDF was associated with these findings. Untreated maternal HIV disease and/or maternal nutritional status could potentially be related to fetal bone development. This association should be explored in future cohort studies.

Safety and efficacy of the HIV-1 attachment inhibitor prodrug BMS-663068 in treatment-experienced individuals: 24 week results of AI438011, a phase 2b, randomised controlled trial

BMS-663068 is an oral prodrug of BMS-626529, an attachment inhibitor that binds to HIV-1 gp120, blocking viral attachment to host CD4 cells. AI438011 is an ongoing trial investigating the efficacy, safety, and dose-response of BMS-663068 in treatment-experienced, HIV-1-infected patients. Herein we present the results of the primary analysis. AI438011 is a phase 2b, randomised, active-controlled trial, at 53 hospitals and outpatient clinics across ten countries in North and South America, Europe, and Africa. Individuals with an HIV-1 RNA viral load of at least 1000 copies per mL and a BMS-626529 half-maximum inhibitory concentration lower than 100 nmol/L were randomly assigned (1:1:1:1:1) to receive either BMS-663068 at 400 mg twice daily, 800 mg twice daily, 600 mg once daily, or 1200 mg once daily or ritonavir-boosted atazanavir (300 mg of atazanavir and 100 mg of ritonavir once daily), each with 400 mg of raltegravir twice daily and 300 mg of tenofovir disoproxil fumarate once daily as a backbone. The sponsor, participants, and investigators were masked for BMS-663068 dose but not for allocation. Primary endpoints were the proportion of patients with an HIV-1 RNA viral load less than 50 copies per mL (response rate) at week 24 and the frequency of serious adverse events and adverse events leading to discontinuation, up to the week 24 analysis. The primary analyses included all patients who received at least one dose of study drug (modified intention-to-treat population). This study is registered at ClinicalTrials.gov, NCT01384734. Between July 26, 2011, and July 16, 2012, 581 participants were assessed for eligibility. Of these, 254 patients were randomly assigned to receive either BMS-663068 (n=52 for the 400 mg twice daily group, n=50 for the 800 mg twice daily group, n=51 for the 600 mg once daily group, and n=50 for the 1200 mg once daily group) or ritonavir-boosted atazanavir (n=51). 200 patients received at least one dose of BMS-663068, and 51 patients received at least one dose of ritonavir-boosted atazanavir. At week 24, 40 (80%) of 50 patients in the BMS-663068 400 mg twice daily group, 34 (69%) of 49 patients in the 800 mg twice daily group, 39 (76%) of 51 patients in the 600 mg once daily group, and 36 (72%) of 50 patients in the 1200 mg once daily group had an HIV-1 RNA viral load less than 50 copies per mL, compared with 38 (75%) of 51 patients in the ritonavir-boosted atazanavir group. Serious adverse events were noted in 13 (7%) of 200 patients in the BMS-663068 groups and five (10%) of the 51 patients in the ritonavir-boosted atazanavir group. Four (2%) of the 200 patients in the BMS-663068 groups and two (4%) of the 51 patients in the ritonavir-boosted atazanavir group discontinued because of adverse events. No serious adverse events or adverse events leading to discontinuation were BMS-663068-related. Grade 2-4 adverse events related to study drug(s) occurred in 17 (9%) of 200 patients across the BMS-663068 groups and 14 (27%) of 51 patients in the ritonavir-boosted atazanavir group. For the BMS-663068 groups these events were mostly single instances with no dose relation and for the ritonavir-boosted atazanavir group these were mostly gastrointestinal or hepatobiliary disorders associated with hyperbilirubinaemia. In a comparison with ritonavir-boosted atazanavir, efficacy and safety of BMS-663068 up to the week 24 analysis support continued development of BMS-663068, which is being assessed in a phase 3 trial in heavily treatment-experienced individuals. Bristol-Myers Squibb.

Pharmacokinetics of Single- and Multiple-Dose Emtricitabine in Healthy Male Chinese Volunteers

Emtricitabine (FTC) is used for the treatment of HIV infection and pre-exposure chemoprophylaxis. It is often used in combination with tenofovir disoproxil fumarate (TDF). This study was designed to evaluate FTC pharmacokinetics in healthy male Chinese volunteers. Sixty subjects were recruited into this single-centre, randomised, open-label study and randomly received single (groups A, B and C) or multiple oral doses (once daily for 6 days; groups D, E and F) of 200-mg FTC capsules alone (A and D), or combined with 300-mg TDF tablets (B and E), or 200 mg of FTC plus 300 mg of TDF with a high-fat diet (C and F), respectively. FTC was well-tolerated in all groups. After a single dose, there were no differences in the mean AUC_0-_∞ values; however, there were significant differences in the mean T_max values (1.05, 1.40 and 2.10 h for groups A, B and C, respectively; p < 0.05). In the multiple-dose study, our results were significantly different from published t_1/2 values following single-dose FTC.

Phase I/II study of the pharmacokinetics, safety and antiretroviral activity of tenofovir alafenamide, a new prodrug of the HIV reverse transcriptase inhibitor tenofovir, in HIV-infected adults

Tenofovir alafenamide (formerly GS-7340) is a new oral prodrug of tenofovir, a nucleotide analogue that inhibits HIV-1 reverse transcription. Unlike the currently marketed tenofovir prodrug, tenofovir disoproxil fumarate, tenofovir alafenamide is stable in plasma and then rapidly converted into tenofovir once inside cells. The pharmacokinetics, safety and antiviral activity of 40 or 120 mg of tenofovir alafenamide compared with 300 mg of tenofovir disoproxil fumarate when administered as monotherapy once daily for 14 days in HIV-1-infected, treatment-naive subjects was studied. Administration of 40 mg of tenofovir alafenamide for 14 days resulted in lower tenofovir Cmax (13 versus 207 ng/mL) and lower systemic exposures (AUC0-t, 383 versus 1810 ng · h/mL) compared with subjects who received tenofovir disoproxil fumarate. There were higher intracellular tenofovir concentrations within peripheral blood mononuclear cells with both 40 mg of tenofovir alafenamide (8.2 μM) and 120 mg of tenofovir alafenamide (16.9 μM) compared with 300 mg of tenofovir disoproxil fumarate (0.9 μM). The most commonly observed adverse events were headache, nausea and flatulence, which occurred similarly across the three groups. After 14 days, the mean changes in HIV-1 RNA were -0.94 log₁₀copies/mL for the tenofovir disoproxil fumarate group, -1.57 log₁₀ copies/mL for the 40 mg of tenofovir alafenamide group and -1.71 log₁₀ copies/mL for the 120 mg of tenofovir alafenamide group. The mean first-phase HIV-1 RNA decay slopes were -0.36, -0.63 and -0.64 for the tenofovir disoproxil fumarate group, the 40 mg of tenofovir alafenamide group and the 120 mg of tenofovir alafenamide group, respectively. No resistance mutations to either tenofovir alafenamide or tenofovir disoproxil fumarate were detected. Tenofovir alafenamide, a new once-daily oral prodrug of tenofovir, showed more potent anti-HIV-1 activity and higher intracellular tenofovir levels compared with tenofovir disoproxil fumarate, while maintaining lower plasma tenofovir exposure at 40 mg with good tolerability over 14 days of monotherapy.

Pharmacokinetics and Safety of Single-Dose Tenofovir Disoproxil Fumarate and Emtricitabine in HIV-1-Infected Pregnant Women and Their Infants

Tenofovir (TFV) is effective in preventing simian immunodeficiency virus (SIV) transmission in a macaque model, is available as the oral agent tenofovir disoproxil fumarate (TDF), and may be useful in the prevention of mother-to-child transmission of human immunodeficiency virus (HIV). We conducted a trial of TDF and TDF-emtricitabine (FTC) in HIV-infected pregnant women and their infants. Women received a single dose of either 600 mg TDF, 900 mg TDF, or 900 mg TDF-600 mg FTC at labor onset or prior to a cesarean section. Infants received no drug or a single dose of TDF at 4 mg/kg of body weight or of TDF at 4 mg/kg plus FTC at 3 mg/kg as soon as possible after birth. All regimens were safe and well tolerated. Maternal areas under the serum concentration-time curve (AUC) and concentrations at the end of sampling after 24 h (C(24)) were similar between the two doses of TDF; the maximum concentrations of the drugs in serum (C(max)) and cord blood concentrations were higher in women delivering via cesarean section than in those who delivered vaginally (P = 0.04 and 0.046, respectively). The median ratio of the TFV concentration in cord blood to that in the maternal plasma at delivery was 0.73 (range, 0.26 to 1.95). Without TDF administration, infants had a median TFV concentration of 12 ng/ml 12 h after birth. Following administration of a single dose of TDF at 4 mg/kg, infant TFV concentrations fell below the targeted level, 50 ng/ml, by 24 h postdose. In HIV-infected pregnant women and their infants, 600 mg of TDF is acceptable as a single dose during labor. Low concentrations at birth support infant dosing as soon after birth as possible. Rapidly decreasing TFV levels in infants suggest that multiple or higher doses of TDF will be necessary to maintain concentrations that are effective for viral suppression.

A Randomized Crossover Study to Determine Relative Bioequivalence of Tenofovir, Emtricitabine, and Efavirenz (Atripla) Fixed-Dose Combination Tablet Compared With a Compounded Oral Liquid Formulation Derived From the Tablet

A Randomized Crossover Study to Determine Relative Bioequivalence of Tenofovir, Emtricitabine, and Efavirenz (Atripla) Fixed-Dose Combination Tablet Compared With a Compounded Oral Liquid Formulation Derived From the Tablet

Virologic Response of Zidovudine, Lamivudine, and Tenofovir Disoproxil Fumarate Combination in Antiretroviral-Naive HIV-1-Infected Patients

High rates of virologic failure have been reported in antiretroviral-naive patients receiving triple-nucleoside reverse transcriptase inhibitor (NRTI) combinations containing tenofovir disoproxil fumarate (TDF) with lamivudine (3TC) and didanosine or 3TC and abacavir (ABC). A regimen of once-daily zidovudine (ZDV), 3TC, ABC, and TDF showed an acceptable virologic success rate, however. This was a pilot prospective cohort study. Treatment-naive subjects were offered a fixed-dose combination of ZDV/3TC (300 mg/150 mg) twice daily and 300 mg of TDF once daily. Fifty-one patients were enrolled between April 2002 and March 2005. At baseline, the median CD4 count was 230 cells/microL (range: 23-425 cells/microL), 20 (39%) of 51 subjects had CD4 counts of < 200 cells/microL, the median HIV-1 viral load was 4.89 log (3.14 to >5.87 log), and 24 (47%) of 51 subjects had a viral load >5 log. The median follow-up was 12 months (range: 1 week to 38 months). On-treatment analysis showed a median HIV RNA load decrease of -1.7 log after 1 to 2 weeks of treatment and -2.41 log after 1 month, and 34 (89%) of 38 subjects had a viral load < 50 copies/mL at month 6, 21 (78%) of 27 at month 12, and 13 (81%) of 16 after 18 months (intent-to-treat results were 34 [72%] of 47 subjects, 21 [56%] of 36 subjects, and 13 [50%] of 25 subjects at months 6, 12, and 18, respectively). The median CD4 count increase at month 18 was 142 cells/microL. Nine (17.6%) of 51 treatment interruptions for adverse effects were seen. Six viral failures occurred, including 2 with K65R mutations (alone or associated with Y115F and M184V). The combination of ZDV/3TC + TDF in treatment-naive HIV-infected subjects induces a rapid and sustained HIV-1 RNA decrease and is associated with a good immunologic response. No severe adverse events occurred. This triple-NRTI combination needs to be evaluated further.

Randomized controlled study of tenofovir and adefovir in chronic hepatitis B virus and HIV infection: ACTG A5127

Chronic hepatitis B virus (HBV) infection is an important cause of morbidity and mortality in subjects coinfected with HIV. Tenofovir disoproxil fumarate (TDF) and adefovir dipivoxil (ADV) are licensed for the treatment of HIV-1 and HBV infection, respectively, but both have in vivo and in vitro activity against HBV. This study evaluated the anti-HBV activity of TDF compared to ADV in HIV/HBV-coinfected subjects. ACTG A5127 was a prospective randomized, double-blind, placebo-controlled trial of daily 10 mg of ADV versus 300 mg of TDF in subjects with HBV and HIV coinfection on stable ART, with serum HBV DNA >/= 100,000 copies/mL, and plasma HIV-1 RNA </= 10,000 copies/mL. This study closed early based on results of a prespecified interim review, as the primary noninferiority end point had been met without safety issues. Fifty-two subjects were randomized. At baseline, 73% of subjects had a plasma HIV-1 RNA < 50 copies/mL, 86% were HBeAg positive, 94% were 3TC resistant, median serum ALT was 52 IU/L, and 98% had compensated liver disease. The mean time-weighted average change in serum HBV DNA from baseline to week 48 (DAVG(48)) was -4.44 log(10) copies/mL for TDF and -3.21 log(10) copies/mL for ADV. There was no difference in toxicity between the 2 treatment arms, with 11 subjects (5 ADV and 6 TDF) experiencing elevations of serum ALT on treatment. In conclusion, over 48 weeks, treatment with either ADV or TDF resulted in clinically important suppression of serum HBV DNA. Both drugs are safe and efficacious for patients coinfected with HBV and HIV.

HIV prevention research in a resource-limited setting: the experience of planning a trial in Cambodia

On Aug 13 2004 all work was stopped and never resumed on a study being prepared in Cambodia to determine whether daily oral tenofovir disoproxil fumarate was safe and effective in preventing the sexual transmission of HIV infection. The study was to have been a randomised double-blind trial that recruited 960 HIV-negative women engaged in sex work to receive either 300 mg of tenofovir disoproxil fumarate once daily or an identical placebo for 12 months. Trial development was suspended in response to a statement from the Cambodian Prime Minister. Before the statement concerns about the trial had been raised by a group representing women engaged in sex work in Cambodia. There has since been much commentary about the trial and its surrounding issues through the media and the internet. The commentary asserted that: the trial was purely motivated by the commercial interests of a pharmaceutical company the drug had not been adequately assessed before it was proposed as a possible prevention agent affected communities were inadequately consulted during study preparations the researchers would not be providing participants with safe sex counselling and condoms during the trial to increase HIV incidence recruitment practices would not adequately incorporate informed consent and medical treatment for trial-related injury and HIV care for seroconverters would not be available to participants. Along with this commentary the researchers were accused of engaging or intending to engage in practices that were inconsistent with the standards of research ethics. To better inform public discussion we provide our perspective on the design and development stages of the trial focusing particularly on issues raised by commentators. (excerpt)

Emtricitabine/tenofovir disoproxil fumarate.

Gilead Sciences is developing a fixed-dose co-formulation of two of its reverse transcriptase inhibitors, emtricitabine [Emtriva] and tenofovir disoproxil fumarate [Viread], for once-daily dosing in combination with other antiretrovirals for the treatment of HIV infection. Each co-formulated tablet will contain 300 mg of tenofovir disoproxil fumarate and 200 mg of emtricitabine. Emtricitabine [Emtriva] is a nucleoside reverse transcriptase inhibitor (NRTI) with demonstrated potent activity against HIV and hepatitis B virus (HBV). It was first approved in the US by the FDA in July 2003 and is indicated for adults aged > or =18 years. Safety and effectiveness in paediatric patients have not been established. In antiretroviral-treatment-experienced patients, the use of emtricitabine may be considered for adults with HIV strains that are expected to be susceptible to the drug as assessed by genotypic or phenotypic testing. The recommended dose of emtricitabine is one 200 mg capsule daily, with or without food. In the European Union, emtricitabine is indicated in combination with other antiretroviral agents for the treatment of HIV in adults and children, where it is also licensed as an oral 10 mg/mL solution. The oral solution is for use in infants older than 4 months, children and patients unable to swallow hard capsules, and patients with renal impairment who require dose reduction. Tenofovir disoproxil fumarate [Viread] is a nucleotide reverse transcriptase inhibitor that is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced patients. The drug was first approved in the US in October 2001, followed by further approvals in the European Union, Australia, Iceland, Brazil, Canada and Switzerland. The drug has been launched in all these countries. In February 2003, the EMEA's advisory committee adopted a positive opinion to extend the indication of tenofovir disoproxil fumarate in all 15 member states to include the product's use in antiretroviral-naïve HIV-infected patients. In July 2003, Japan Tobacco signed an agreement with Gilead for the commercialisation of tenofovir disoproxil fumarate and emtricitabine and the future co-formulation of these two drugs within Japan. Under the terms of the agreement, Japan Tobacco will be submitting an application to the Japanese Ministry of Health, Labour and Welfare for regulatory approval of tenofovir disoproxil fumarate and emtricitabine. On 15 March 2004, Gilead announced the submission of a New Drug Application (NDA) to the US FDA and a Marketing Authorisation Application (MAA) to the EMEA for marketing approval of the fixed-dose co-formulation of emtricitabine and tenofovir disoproxil fumarate. The MAA will be reviewed under the centralised procedure, which, when finalised, will provide one marketing authorisation in all 25 member states of the enlarged European Union. Gilead anticipates launching the combination pill on the US market early in 2005. Regulatory filings for marketing approval in Japan by Japan Tobacco are also expected during 2004. In August 2003, Gilead announced that enrollment had begun in a 48-week phase III study (Study 934) evaluating the efficacy of a once-daily regimen of Viread and Emtriva versus Combivir. The open-label, multicentre trial will enroll up to 500 treatment-naive, HIV-infected patients in the US and Europe. Patients in one arm will receive Viread 300 mg, Emtriva 200mg and efavirenz 600 mg once daily. Patients in the comparator arm will receive Combivir) (lamivudine 150 mg/zidovudine 300 mg) twice daily and efavirenz 600 mg once daily.