Dual therapy with lopinavir/ritonavir plus lamivudine could be a viable alternative for antiretroviral-therapy-naive adults with HIV-1 infection regardless of HIV viral load or subgenotype in resource-limited settings: A randomised, open-label and non-inferiority study from China.

BACKGROUNDS: This randomised controlled, open-label, non-inferiority trial was conducted in antiretroviral-naïve HIV-1-infected patients to assess the efficacy and safety of 48-week dual therapy of LPV/r plus 3TC (DT group) compared with Chinese first-line triple-therapy regimen (TT group). METHODS: 198 were randomised to DT (n = 100) or TT (n = 98). RESULTS: Ninety-two DT patients (92%) and 88 TT patients (89.8%) achieved HIV-1 RNA <50 copies/ml at week 48 (P = 0.629). Moreover, the safety profile was similar between two groups, and no secondary HIV resistance was observed. CONCLUSION: The results suggest that dual therapy of LPV/r plus 3TC is non-inferior to the first-line triple-therapy regimen in China.

Cost-utility analysis of the fixed-dose combination of dolutegravir/abacavir/lamivudine as initial treatment of HIV+ patients in Spain / Análisis de coste-utilidad de la combinación a dosis fijas de dolutegravir/abacavir/lamivudina como tratamiento inicial de pacientes con VIH + en España

Objective: Fixed-dose combinations of antiretroviral drugs have meant an important step forward in simplifying treatment and improving compliance and has led to an increased effectiveness of therapy, a viral load decrease and improving the quality of life of patients. The single-table formulation of dolutegravir with abacavir and lamivudine (DTG/ABC/3TC) is a highly efficacious and well-tolerated once-daily regimen for HIV-infected patients. The objective of the study was to assess the incremental cost-utility ratio of the fixed-dose combination of (DTG/ ABC/3TC) versus the combinations emtricitabine/tenofovir/efavirenz (FTC/TDF/EFV), and darunavir/r (DRV/r) or raltegravir (RAL) with emtricitabine/tenofovir (FTC/TDF) or abacavir/lamivudine (ABC/3TC) as initial antiretroviral therapy in patients infected with HIV-1 from the perspective of the Spanish National Health System. Method: The ARAMIS model, which uses a microsimulation approach to simulate the individual changes in each patient from the start of treatment to death through a Markov chain of descriptive health states of the disease, was adapted to Spain. The alternatives used for comparison were the fixed-dose combination of emtricitabine/tenofovir/efavirenz (FTC/TDF/ EFV), and the fixed-dose combinations of emtricitabine/tenofovir (FTC/TDF) or abacavir/lamivudine (ABC/3TC) with darunavir/r (DRV/r) or raltegravir (RAL). The probability of achieving virological suppression by the treatments included in the model was obtained from clinical trials SINGLE, SPRING-2 and FLAMINGO and the costs were expressed in Euros (2015). The model use the perspective of the Spanish National Health System, with a lifetime horizon and a discount rate of 3% was applied to cost and effectiveness. Results: Treatment initiation with DTG/ABC/3TC was dominant when it was compared with treatment initiation with all the comparators: vs. FTC/TDF/EFV (-67 210.71Euros/QALY), vs. DRV/r + FTC/TDF or ABC/3TC (-1 787 341.44Euros/QALY), and vs. RAL + FTC/TDF or ABC/3TC (-1 005 117.13Euros/QALY). All the sensitivity analyses performed showed the consistency of these findings. Conclusions: With the premises considered, treatment initiation with DTG/ABC/3TC STR appears to be the most cost-effective option in ARTnaïve HIV infected patients from the Spanish Health System perspective (AU)

Objetivo: Las combinaciones a dosis fijas de medicamentos antirretrovirales han significado un importante paso adelante en la simplificación del tratamiento y la mejora del cumplimiento, así como hacia una mayor eficacia de la terapia, una disminución de la carga viral y una mejora de la calidad de vida de los pacientes. La formulación de un comprimido único una vez al día con dosis fijas de dolutegravir, abacavir y lamivudina (DTG/ABC/3TC) para pacientes infectados con VIH es un régimen altamente eficaz y bien tolerado. El objetivo del estudio fue evaluar la relación coste-utilidad incremental de la combinación de dosis fija de (DTG/ABC/3TC) versus las combinaciones de emtricitabina/tenofovir/efavirenz (TDF/FTC/EFV) y darunavir/r (DRV/r) o raltegravir (RAL) con emtricitabina/tenofovir (FTC/TDF) o abacavir/lamivudina (ABC/3TC) como tratamiento antirretroviral inicial en pacientes infectados con VIH-1 desde la perspectiva del Sistema Nacional de Salud Español. Método: Se adaptó en España el modelo ARAMIS. Este utiliza un enfoque de microsimulación para emular los cambios individuales en cada paciente desde el inicio del tratamiento hasta su muerte mediante una cadena de Markov de estados de salud descriptivos de la enfermedad. Las alternativas empleadas para la comparación fueron la combinación de dosis fijas de emtricitabina/tenofovir/efavirenz (TDF/FTC/EFV) y las combinaciones de dosis fijas de emtricitabina/tenofovir (FTC/TDF) o abacavir/lamivudina (ABC/3TC) con darunavir/r (DRV/r) o raltegravir (RAL). La probabilidad de lograr la supresión virológica mediante los tratamientos incluidos en el modelo se ha obtenido de ensayos clínicos individuales, SPRING2 y FLAMINGO, y los costes fueron expresados en Euros (2015). El uso del modelo de la perspectiva del Sistema Nacional de Salud español, con un horizonte de vida útil y una tasa de descuento del 3% se, aplicó a coste y efectividad. Resultados: El inicio de tratamiento con DTG/ABC/3TC fue dominante cuando se comparó con el inicio del tratamiento con el resto de comparadores: frente a TDF/FTC/EFV (-67.210,710 Euros / AVAC) vs DRV/r FTC/TDF o ABC/3TC (-1,787,341.44 Euros / AVAC) y vs RAL FTC/TDF o ABC/3TC (-1,005,117.13 Euros / AVAC). Todos los análisis de sensibilidad realizados demostraron la consistencia de estos hallazgos. Conclusiones: Con las premisas consideradas, el inicio del tratamiento con la combinación a dosis fijas de DTG/ABC/3TC parece ser la opción más rentable para el tratamiento de pacientes infectados con el VIH desde la perspectiva del Sistema Nacional de Salud español (AU)

Cost-effectiveness analysis of tenofovir disoproxil fumarate for treatment of chronic hepatitis B in China.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) is newly available for treatment of chronic hepatitis B patients in China. To date, no study has been conducted to examine the cost-effectiveness of this treatment. The aim of this study was to estimate the cost-effectiveness of TDF versus four oral nucleos(t)ide analogs [lamivudine (LAM), adefovir (ADV), telbivudine (LdT), and entecavir (ETV)] and from a pharmacoeconomic perspective to assess current drug pricing for TDF. METHODS: Based on Chinese healthcare perspectives, a Markov model was applied to simulate the lifetime (40-year time span) costs and quality-adjusted life-years (QALYs) for five different monotherapy strategies. Two kinds of rescue combination strategies (base-case: LAM + ADV then ETV + ADV; alternative: directly using ETV + ADV) were separately considered for treatment of patients refractory to monotherapy. Model parameters (including disease transition, cost, and utility) were obtained from previous Chinese population studies. Both branded and generic drugs were separately analyzed. Study model uncertainties were assessed by one-way and probabilistic sensitivity analyses. Two-way sensitivity analysis was used to explore uncertainties between efficacy and price of TDF. RESULTS: In the base-case analysis, the lowest lifetime cost and the best cost-effectiveness ratio were obtained by ETV, which was considered the reference treatment. LAM, ADV, and LdT treatments had significantly greater costs and lower efficacies. Compared to ETV, TDF was more effective but also more expensive. The incremental cost-effectiveness ratios of TDF versus ETV were much higher than the willing-to-pay threshold of $20,466 US dollars (USD) per QALY gained (3 × gross domestic product per capita of China, 2014). TDF would be the most cost-effective strategy if the annual cost did not exceed $2260 USD and $1600 USD for branded and generic drugs, respectively. CONCLUSIONS: For Chinese chronic hepatitis B patients, ETV is still the most cost-effective strategy over TDF and other nucleos(t)ide analogs, with a threshold of $20,466 USD/QALY gained.

The preclinical discovery and development of dolutegravir for the treatment of HIV.

INTRODUCTION: Integration of the viral genome into the host cell chromatin is a central step in the replication cycle of HIV. Blocking the viral integrase (IN) enzyme therefore provides an attractive therapeutic strategy, as evidenced by the recent clinical approval of three IN strand transfer inhibitors. Dolutegravir is a therapy that is unique in its ability to evade HIV drug resistance in treatment-naïve patients. AREAS COVERED: This review starts by providing a brief summary of the history of HIV-1 IN inhibitors. The authors follow this with details of the discovery and preclinical and clinical developments of dolutegravir. Finally, the authors provide details of dolutegravir's post-launch including the launch of the combination pill of dolutegravir, abacavir and lamivudine in August 2014. EXPERT OPINION: The launch of raltegravir, the first IN inhibitor from Merck & Co., has created new hopes for the patient. Indeed, pharmaceutical companies have not lost courage by attempting to address the major drawbacks of this first-in-class molecule. And while the drug elvitegravir has been inserted into a four-drug combination pill providing a once-daily dosing alternative, dolutegravir has demonstrated superiority in terms of its efficacy and resistance.

Development of a microdialysis system to monitor lamivudine in blood and liver for the pharmacokinetic application in herbal drug interaction and the gene expression in rats.

The aim of study is to develop a novel multiple microdialysis technique coupled to a validated chromatographic system for the measurement of protein-unbound form lamivudine and investigation of its herb-drug interaction in rat blood and liver. Furthermore, gene expression changes of drug metabolizing enzymes in rat were evaluated by microarray analysis after being treated with a traditional Chinese herbal formulation, Long-Dan-Xie-Gan-Tang (LDXGT). The analyte was separated by a reverse-phase C18 column using the mobile phase comprising methanol and 10mM KH2PO4 (15:85, v/v, adjusted to pH 6.0 with NaOH) with the flow rate of 0.8mL/min, and the UV wavelength was set at 270nm. The processes of method validation followed Food and Drug Administration (FDA) guidelines. The pharmacokinetic data demonstrated that the area under the concentration-time curve (AUC) of the lamivudine alone and the LDXGT pretreated group were 532±37.6 and 550±44.2minµg/mL in rat blood after lamivudine administration (10mg/kg, i.v.) and 682±196 and 642±153minµg/mL in rat liver, respectively. The herb-drug pharmacokinetic interaction showed that with either lamivudine alone or in combination with pretreated with LDXGT, the pharmacokinetic parameters were not significantly changed except the apparent volume of distribution (Vd) at a high dose of lamivudine (30mg/kg). In addition, microarray analysis showed that among 70 altered genes (selection criteria: |Fold change|≧2 and p<0.05), only 11 genes were involved in drug metabolism and indicated that a relatively small portion of drug metabolizing genes in liver were altered at the genome level after the therapeutic dose of LDXGT treatment. In conclusion, these studies provide constructive information to interpret the herb-drug interactions between lamivudine and a popular Chinese herbal formulation.

High dose lamivudine in HBV-related cirrhotic patients with unsatisfactory response after adefovir add-on.

BACKGROUND: Before tenofovir approval for chronic hepatitis B therapy, the clinical management of patients with suboptimal response or virological breakthrough during combination treatment with lamivudine and adefovir dipivoxil was a difficult clinical challenge. AIMS: In order to improve virologic response and reduce the risk of decompensation, we evaluate the efficacy of a high dose of lamivudine on chronic HBV patients who have previously presented an unsatisfactory response during treatment with lamivudine 100mg/day and adefovir 10mg/day. METHODS: Six patients with HBV-related liver cirrhosis were prospectively enrolled. All were HBeAg-negative and presented a suboptimal response or virological breakthrough after "adefovir add-on" because of development of clinical breakthrough during Lamivudine treatment. Lamivudine dose was increased to 200 or 300 mg, depending on viral load. After 12 months of follow-up, virological and biochemical response were evaluated. RESULTS: After 12 months of high-dose lamivudine, all patients (6/6, 100%) achieved a significant decrease of serum HBV DNA (mean reduction 2,62 ± 1,15 Log10 UI/ml, P = 0.03) and normalized ALT. In three patients (3/6, 50%), HBV DNA became undetectable within 6 months. No patient developed liver decompensation and no significant changes occurred in serum creatinine, serum and urinary electrolytes. No adverse events were registered. CONCLUSIONS: In our experience, rescue strategy with high-dose lamivudine inhibited viral replication leading to undetectability of serum HBVDNA. This rescue treatment presented a good safety profile, without adverse events during the study period. Customized increase of nucleos(t)ide analogues dose in difficult-to-treat patients may be a proficient approach in challenging clinical setting.

Hepatitis B immunoglobulin and/or nucleos(t)ide analogues for prophylaxis against hepatitis b virus recurrence after liver transplantation: a systematic review.

A combination of hepatitis B immunoglobulin (HBIG) and nucleos(t)ide analogues (NUCs) is currently recommended as prophylaxis against the recurrence of hepatitis B virus (HBV) after liver transplantation (LT), but the optimal protocol is a matter of controversy. The aim of this study was the identification of factors associated with post-LT HBV recurrence in patients receiving HBIG and NUCs. We searched MEDLINE and PubMed for studies in English about the effectiveness of HBIG and NUCs [lamivudine (LAM) and/or adefovir dipivoxil (ADV)] against post-LT HBV recurrence (January 1998 to June 2010). Forty-six studies, which included 2162 HBV LT recipients, met the selection criteria. Patients receiving HBIG and LAM experienced HBV recurrence more frequently than patients receiving HBIG and ADV with or without LAM [6.1% (115/1889) versus 2.0% (3/152), P = 0.024], although they also were more frequently treated with indefinite HBIG prophylaxis (90% versus 57%, P < 0.001). For patients receiving HBIG and LAM, a lower frequency of HBV recurrence was associated with a high HBIG dosage (≥10,000 IU/day) versus a low HBIG dosage (<10,000 IU/day) during the first week after LT [3.2% (14/440) versus 6.5% (80/1233), P = 0.016], but the HBIG protocol had no impact on HBV recurrence in patients receiving HBIG and ADV. In conclusion, in comparison with the combination of HBIG and LAM, the combination of HBIG and ADV is associated with a lower rate of HBV recurrence after LT. Patients receiving HBIG and LAM should be given a high dosage of HBIG during the first week after LT, but a lower dosage can be used safely in patients receiving HBIG and ADV. Further studies with newer and more potent anti-HBV agents are definitely required.

The benefit of supplementary feeding for wasted Malawian adults initiating ART.

Food insecurity is considered to be an important contributor to HIV associated wasting in sub-Saharan Africa. Low body mass index (BMI) is a strong risk factor for early mortality during antiretroviral therapy (ART). Nutritional supplementation has become standard of care in wasted patients starting ART in many countries in the region, but there is no unequivocal evidence base for this intervention. Against this background, we performed a retrospective study to compare food supplementation versus no nutritional intervention in wasted adults starting ART in Blantyre, Malawi. All patients received free nevirapine, lamivudine, and stavudine. Participants in an effectiveness trial of two food supplements received either corn-soy blend (CSB) or ready-to-use food spread (RUFS) during the first 14 weeks of ART. Results were compared with a historical control group receiving no food supplement that was part of an observational cohort study of outcomes of the same ART regimen. Characteristics on initiation of ART were similar in the three groups, except the use of cotrimoxazole prophylaxis which was more frequent in the food-supplemented groups. Linear regression analysis showed that increase in BMI was greatest in the RUFS group and better in the CSB group than in those receiving no food supplementation at 14 weeks. These differences were no longer significant at 26 weeks. Lower BMI, CD4 count and hemoglobin, WHO clinical stage IV, male gender, and not receiving cotrimoxazole prophylaxis were independent risk factors for mortality at 14 and 26 weeks in the logistic regression analysis. Supplementary food use was not directly associated with improved survival.

The genetic toxicity effects of lamivudine and stavudine antiretroviral agents.

IMPORTANCE OF THE FIELD: The nucleoside reverse transcriptase inhibitors (NRTIs) are used in antiretroviral therapy worldwide for the treatment of HIV infections. These drugs act by blocking reverse transcriptase enzyme activity, causing pro-viral DNA chain termination. As a consequence, NRTIs could cause genomic instability and loss of heterozygosity. AREAS COVERED IN THIS REVIEW: This review highlights the toxic and genotoxic effects of NRTIs, particularly lamivudine (3TC) and stavudine (d4T) analogues. In addition, a battery of short-term in vitro and in vivo systems are described to explain the potential genotoxic effects of these NRTIs as a single drug or a complexity of highly active antiretroviral therapy. WHAT THE READER WILL GAIN: The readers will gain an understanding of a secondary effect that could be induced by 3TC and d4T treatments. TAKE HOME MESSAGE: Considering that AIDS has become a chronic disease, more comprehensive toxic genetic studies are needed, with particular attention to the genetic alterations induced by NRTIs. These alterations play a primary role in carcinogenesis and are also involved in secondary and subsequent steps of carcinogenesis.

[Evaluation of Chai Shao Liu Jun Tang for the treatment of chronic hepatitis B].

OBJECTIVE: To evaluate the effect of Chai Shao Liu Jun Tang in combination with Lamivudine for the treatment chronic hepatitis B (CHB) patients. METHODS: 405 CHB patients in Guangdong Provincial Hospital were randomly divided into 2 groups, 220 in the treated group, and 185 in the control group. The control group was treated with Lamivudine for 18 months. The treated group was treated with Lamivudine in combination with Chai Shao Liu Jun Tang for 18months. At the 3rd, 6th, 9th, 12th and 18th month during the treatment, the clinical symptoms, ALT normalization rate, HBeAg seroconversion rate, the proportion of patients with undetectable serum HBV DNA, and YMDD mutation rate were observed. RESULTS: ALT normalization rates at the 3rd, 6th, 12th, 18th month of the treatment group (69.5%, 85.9%, 90.5%, 82.7%) were higher than those in the control group (50.3%, 65.4%, 78.4%, 69.7%; P < 0.01). HBeAg seroconversion rate, rate of HBV DNA undetectable, and YMDD mutation rate at he 12th and18th month are 77.7%, 57.7%, 25.5%, 6.8%; 86.8%, 74.1%, 33.2%, 8.6% in the treatment group, and 54.6%, 36.8%, 13.0%, 14.6%; 69.2%, 37.3%, 19.5%, 20.5% in the control group (P < 0.01, or P < 0.05). CONCLUSION: Compared to lamivudine alone, Cai Shao Liu Ju Tang in combination with lamivudine is more effective and induces less YMDD mutation rate in CHB patients.

Results of up to 2 years of entecavir vs lamivudine therapy in nucleoside-naïve HBeAg-positive patients with chronic hepatitis B.

Entecavir is a potent inhibitor of hepatitis B virus (HBV) polymerase. The efficacy and safety of entecavir in nucleoside-naïve patients with hepatitis B virus e antigen (HBeAg)-positive chronic hepatitis B was established in a large, international, double-dummy study (ETV-022) where patients were randomized to entecavir 0.5 mg/day (n = 354) or lamivudine 100 mg/day (n = 355) once daily. ETV-022 had a 52-week blinded treatment phase, followed by an extended blinded treatment phase for up to 44 additional weeks (96 weeks total). Treatment was discontinued for patients achieving a protocol-defined response as determined by patient management criteria that intended to test the possibility of finite therapy, which has not previously been studied for entecavir or other anti-HBV agents in a large trial. Early results from this study have been previously presented/published separately. This paper compiles the results of up to 2 years of treatment for protocol-defined responders, virologic responders and nonresponders. For responders who discontinued therapy (per protocol), 24-week off-treatment evaluation is presented to provide a more 'complete picture' of what clinicians can expect when treating nucleoside-naïve HBeAg-positive patients with chronic hepatitis B. For patients who discontinued therapy because of nonresponse (nonresponders) and subsequently entered the rollover study ETV-901, follow-up results, including resistance profile, are provided.

Post-liver transplant hepatitis B prophylaxis: the role of oral nucleos(t)ide analogues.

PURPOSE OF REVIEW: The established gold standard for prophylaxis against hepatitis B virus (HBV) recurrence post-liver transplant is combination hepatitis B immune globulin (HBIG) and lamivudine. This therapy reduces the risk of recurrence to less than 5% at 5 years; however, the cost of HBIG has led to the investigation of alternatives. This paper reviews the HBIG-sparing alternatives achieved with lamivudine and the prospects for the newer anti-HBV agents in post-liver transplant prophylaxis. RECENT FINDINGS: When used with lamivudine as part of combination prophylaxis, low-dose intramuscular HBIG is equivalent to high-dose intravenous HBIG. There is recent evidence that in patients receiving HBIG/lamivudine, HBIG can be replaced with adefovir dipivoxil at 6-12 months post-liver transplant without precipitating recurrence. Furthermore, a recent study showed that primary prophylaxis with combination adefovir/lamivudine therapy without the use of long-term HBIG was effective and well tolerated as primary prophylaxis. SUMMARY: Although there are few studies of potent newer anti-HBV agents such as entecavir or tenofovir being used as HBV prophylaxis, the properties of these drugs suggest that they should replace lamivudine within HBV prophylaxis regimes.

Failure of adefovir 20 mg to improve suboptimal response in lamivudine-resistant hepatitis B patients treated with adefovir 10 mg and lamivudine.

Nine patients with lamivudine-resistant chronic hepatitis B infection who had been treated with adefovir 10 mg/day and had had a suboptimal response but did not have genotypic resistance to adefovir were treated with high-dose adefovir (20 mg/day). The response to the increased dose of adefovir was compared with the response in 15 patients with a suboptimal response who did not receive an increase in the dose of adefovir. The increase in the dose of adefovir did not lead to a significant reduction in hepatitis B DNA when compared with patients maintained on the standard dose. These data suggest that increasing the dose of adefovir in patients with a suboptimal response does not lead to an improved response.

Why do we not yet have combination chemotherapy for chronic hepatitis B?

Despite the emergence of multidrug-resistant strains of hepatitis B virus (HBV) and previous success with combination therapy for other chronic viral infections, we are still using sequential monotherapy for chronic HBV infection. Antiviral-resistant HBV can result in major life-threatening complications. We now have complementary drugs, such as lamivudine and adefovir dipivoxil, with fundamentally different structures and associated with different signature resistance mutations, with adefovir dipivoxil showing antiviral activity against most lamivudine-resistant strains. Studies of combination therapy to date have used traditional endpoints--short-term reduction of HBV DNA levels and HBeAg seroconversion--rather than evolution of resistance. There is now an emerging body of data suggesting that combination therapy can decrease antiviral resistance in HBV infection, the endpoint likely to be of greatest long-term importance, and, rather than adding or replacing an antiviral agent after resistance develops, it is likely to be more effective in treatment-naive patients.

Prophylactic strategies for hepatitis B patients undergoing liver transplant: a cost-effectiveness analysis.

Hepatitis B immunoglobulin with lamivudine prophylaxis (LAM/HBIG) is effective in preventing Hepatitis B (HBV) recurrence posttransplant but is expensive and inconvenient. Lamivudine-resistant HBV, which has limited the usefulness of lamivudine monoprophylaxis in transplant, can now be effectively controlled with adefovir dipivoxil. We performed a cost-effectiveness analysis on the strategies of lamivudine prophylaxis with adefovir rescue(LAM/ADV) compared to combination LAM/intravenous fixed high-dose HBIG prophylaxis(LAM/ivHBIG) or LAM/intramuscular HBIG prophylaxis(LAM/imHBIG). Markov modeling was performed with analysis from societal perspective. Probability rates were derived from systematic review of the literature and cost taken from MEDICARE database. Outcome measures were incremental cost-effectiveness ratio(ICER) and cost to prevent each HBV recurrence and death. Analysis was performed at 5 years posttransplant as well as at end of life expectancy (15 years). Combination LAM/ivHBIG cost an additional USD562,000 at 15 years, while LAM/imHBIG cost an additional USD139,000 per patient compared to LAM/ADV. Although there is an estimated increase in recurrence of 53% with LAM/ADV and 7.6% increased mortality at the end of life expectancy (15 years), the ICER of LAM/ivHBIG over LAM/ADV treatment is USD760,000 per quality-adjusted life-years and for LAM/imHBIG, USD 188,000. Cost-effectiveness is most sensitive to cost of HBIG. Lamivudine prophylaxis with adefovir dipivoxil salvage offers the more cost-effective option for HBV patients undergoing liver transplant but with higher recurrence and death rate using a model that favors LAM/HBIG. Lowering the cost of HBIG maintenance will improve cost-effectiveness of LAM/HBIG strategy. In conclusion, a tailored approach based on individual risks will optimize the cost-benefit of HBV transplant prophylaxis.

Suppression of lamivudine-resistant B-domain mutants by adefovir dipivoxil in the woodchuck hepatitis virus model.

Adult woodchucks (Marmota monax) chronically infected with woodchuck hepatitis virus (WHV) were treated orally with lamivudine (15 mg/kg per day) for 57 weeks. After 20 weeks of treatment a 2-3 log reduction in serum WHV DNA was detected. Serum titers of WHV then increased gradually, in the presence of lamivudine treatment, reaching pre-treatment values by week 40. Viral recrudescence was associated with development of mutations in the B domain of the WHV polymerase gene. Mutations observed in the highly conserved FLLA motif of the B domain were L564V, L565M, and A566T, with A566T being the most frequently observed. Beginning on week 57 of lamivudine treatment, one group (n = 3) was treated orally with adefovir dipivoxil at a dose of 15 mg/kg per day plus lamivudine, and a second group (n = 3) was treated with H2O placebo plus lamivudine. In woodchucks treated with adefovir dipivoxil, two had the A566T mutation, and one had both A566T and L565V. In the group maintained on lamivudine monotherapy, A566T alone was present in one animal, another carried both A566T and L565V, and in the third, no B-domain mutations were detected. There was a 4.5 log reduction in serum WHV DNA after 12 weeks of treatment with the adefovir/lamivudine combination, while in the lamivudine monotherapy controls, WHV DNA decreased by only 0.83 log (P > 0.001). A slight recurrence in serum titers of WHV DNA was observed one week after withdrawal of adefovir treatment but no further increase in viral load was observed during the remainder of the 12-week post-treatment follow-up period. The results demonstrate that supplemental adefovir dipivoxil treatment is effective in suppressing replication of lamivudine-resistant B-domain mutants in the woodchuck model of hepatitis B virus infection.

Drug resistance mutations during structured treatment interruptions.

BACKGROUND: We assessed whether treatment interruptions induce selection of mutations associated with drug resistance in the Swiss-Spanish Intermittent Treatment Trial (SSITT). Patients had been on HAART without previous failure and had undetectable viraemia for at least 6 months. Their HAART was interrupted for 2 weeks and restarted for 8 weeks. After four of these cycles, treatment was definitively interrupted at week 40. METHODS: Genotypic resistance testing was performed in 87/97 Swiss patients: in those failing treatment before week 40, at the time of first viral rebound > 500 copies/ml off treatment and preceding failure to reach RNA < 50 copies/ml after 8 weeks of re-treatment; for patients without virological failure, on the first sample with HIV-1 RNA > 1000 copies/ml after week 40. RESULTS: Mutations associated with drug resistance were detected in 9/25 (36%) patients with virological failure during the first 40 weeks and in 6/59 (10%) patients after week 40. Overall, drug resistance mutations were detected in 17% of patients, all but two with the 184V/I mutation. Among the 74 patients receiving lamivudine, the M184V/I mutation was detected in 13/74 (17.6%) patients. A wild-type codon at position 184 was detected in previous samples in all but two. The relative risk for virological failure was 2.55-fold higher in patients with the M184V/I mutation than in patients without detectable mutation (P=0.007). CONCLUSIONS: The M184V/I mutation is frequently selected during repeated treatment interruptions.

Development of resistance and perspectives for future therapies against hepatitis B infections: lessons to be learned from HIV.

Several first-generation nucleoside analogues have been tested against chronic hepatitis B virus (HBV) infection, but trials were unsuccessful or accompanied by toxicity. Recently, oral second-generation nucleoside analogues have been developed that have potent activity against HBV. The best-studied compound so far is lamivudine ((-)2'-deoxy-3'-thiacytidine; 3TC). Lamivudine is an inhibitor of reverse transcriptase (RT) activity and is in clinical use in human immunodeficiency virus (HIV)-infected individuals. As several studies on the use of lamivudine for hepatitis B show, the development of resistance in the viral polymerase under lamivudine treatment, however, causes a significant clinical problem. All other drugs in advanced clinical development for HBV are nucleosides; cross-resistance is therefore expected in most cases. The history of HIV treatment demonstrates that new classes of drugs, the protease inhibitors and non-nucleosidic inhibitors of RT, allowed for a longer-term clinical benefit when used in combination with nucleoside analogues. The development of non-nucleosidic compounds with different modes of action therefore appears very important for the treatment of chronic hepatitis B as well.

To AIDS and back with Norvir, D4T, 3TC and nutritional therapies. An interview with Michael Golk.

AIDS: Michael Golk, a person with AIDS who is successfully maintaining a non-detectable viral load using Norvir combined with D4T and 3TC, describes his treatment regimen and use of nutritional supplements. Changes in Golk's nutritional supplement list (36 supplements were used) and the regimen and reasons for these changes are discussed. Changes are suggested to treat metabolic imbalances, such as high levels of triglycerides and high cholesterol, and to stimulate ATP production. The value of delavirdine vs. nevirapine in therapy is also discussed.^ieng