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Bi W, Xu W, Cheng L, Xue J, Wang Q, Yu F, Xia S, Wang Q, Li G, Qin C, Lu L, Su L, Jiang S. IgG Fc-binding motif-conjugated HIV-1 fusion inhibitor exhibits improved potency and in vivo half-life: Potential application in combination with broad neutralizing antibodies. PLoS Pathog 2019; 15:e1008082. [PMID: 31805154 PMCID: PMC6894747 DOI: 10.1371/journal.ppat.1008082] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/16/2019] [Indexed: 12/23/2022] Open
Abstract
The clinical application of conventional peptide drugs, such as the HIV-1 fusion inhibitor enfuvirtide, is limited by their short half-life in vivo. To overcome this limitation, we developed a new strategy to extend the in vivo half-life of a short HIV-1 fusion inhibitory peptide, CP24, by fusing it with the human IgG Fc-binding peptide (IBP). The newly engineered peptide IBP-CP24 exhibited potent and broad anti-HIV-1 activity with IC50 values ranging from 0.2 to 173.7 nM for inhibiting a broad spectrum of HIV-1 strains with different subtypes and tropisms, including those resistant to enfuvirtide. Most importantly, its half-life in the plasma of rhesus monkeys was 46.1 h, about 26- and 14-fold longer than that of CP24 (t1/2 = 1.7 h) and enfuvirtide (t1/2 = 3 h), respectively. IBP-CP24 intravenously administered in rhesus monkeys could not induce significant IBP-CP24-specific antibody response and it showed no obvious in vitro or in vivo toxicity. In the prophylactic study, humanized mice pretreated with IBP-CP24 were protected from HIV-1 infection. As a therapeutic treatment, coadministration of IBP-CP24 and normal human IgG to humanized mice with chronic HIV-1 infection resulted in a significant decrease of plasma viremia. Combining IBP-CP24 with a broad neutralizing antibody (bNAb) targeting CD4-binding site (CD4bs) in gp120 or a membrane proximal external region (MPER) in gp41 exhibited synergistic effect, resulting in significant dose-reduction of the bNAb and IBP-CP24. These results suggest that IBP-CP24 has the potential to be further developed as a new HIV-1 fusion inhibitor-based, long-acting anti-HIV drug that can be used alone or in combination with a bNAb for treatment and prevention of HIV-1 infection.
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Affiliation(s)
- Wenwen Bi
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Wei Xu
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Liang Cheng
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jing Xue
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Fei Yu
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Shuai Xia
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Qi Wang
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Guangming Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Chuan Qin
- Key Laboratory of Human Disease Comparative Medicine, Chinese Ministry of Health, Beijing Key Laboratory for Animal Models of Emerging and Re-emerging Infectious Diseases, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- * E-mail: (LL); (LS); (SJ)
| | - Lishan Su
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail: (LL); (LS); (SJ)
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of MOE/NHC/CAMS, School of Basic Medical Sciences and Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
- Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America
- * E-mail: (LL); (LS); (SJ)
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Walker ARP, Walker BF, Wadee AA. A catastrophe in the 21st century: the public health situation in South Africa following HIV/AIDS. ACTA ACUST UNITED AC 2016; 125:168-71. [PMID: 16094927 DOI: 10.1177/146642400512500409] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
During the early 1900s, African populations in South Africa were subject to very widespread infections which especially affected the young. This resulted in high mortality rates and a low life expectancy of 20-25 years. By the mid-century, mortality rates from infections had decreased considerably. Moreover, the occurrences of non-communicable diseases, even in urban areas, remained very low. In the 1970s, the proportion of Africans aged 50 or over that reached 70 years was 38.5%, higher than that in the juxtaposed white population, which was 35.5%. And by 1985, the life expectancy of Africans reached 61 years for males and 63 years for females, probably the highest in sub-Saharan African populations. Since then, however, the African continent has been devastated by the AIDS epidemic. In 2001, HIV was responsible for the death of a third of the African population in South Africa, but even higher proportions prevailed in Botswana and in Tanzania. The calamitous advent of the HIV infection has caused major falls in life expectancy, in the case of Africans in South Africa reducing this to just 43 years. With little hope of meaningful changes occurring in sexual habits or of an early vaccine becoming available, the infectionís high morbidity/mortality burden is likely to continue.
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Affiliation(s)
- Alexander R P Walker
- Human Biochemistry Research Unit, School of Pathology of the University of the Witwatersrand, and National Health Laboratory Service, P.O. Box 1038, Johannesburg, South Africa.
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Cost-Effectiveness of Antiretroviral Therapy for Multidrug-Resistant HIV: Past, Present, and Future. AIDS Res Treat 2012; 2012:595762. [PMID: 23193464 PMCID: PMC3502757 DOI: 10.1155/2012/595762] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 10/01/2012] [Accepted: 10/02/2012] [Indexed: 11/18/2022] Open
Abstract
In the early years of the highly active antiretroviral therapy (HAART) era, HIV with resistance to two or more agents in different antiretroviral classes posed a significant clinical challenge. Multidrug-resistant (MDR) HIV was an important cause of treatment failure, morbidity, and mortality. Treatment options at the time were limited; multiple drug regimens with or without enfuvirtide were used with some success but proved to be difficult to sustain for reasons of tolerability, toxicity, and cost. Starting in 2006, data began to emerge supporting the use of new drugs from the original antiretroviral classes (tipranavir, darunavir, and etravirine) and drugs from new classes (raltegravir and maraviroc) for the treatment of MDR HIV. Their availability has enabled patients with MDR HIV to achieve full and durable viral suppression with more compact and cost-effective regimens including at least two and often three fully active agents. The emergence of drug-resistant HIV is expected to continue to become less frequent in the future, driven by improvements in the convenience, tolerability, efficacy, and durability of first-line HAART regimens. To continue this trend, the optimal rollout of HAART in both rich and resource-limited settings will require careful planning and strategic use of antiretroviral drugs and monitoring technologies.
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Cherry CL, Duncan AJ, Mackie KF, Wesselingh SL, Brew BJ. A report on the effect of commencing enfuvirtide on peripheral neuropathy. AIDS Res Hum Retroviruses 2008; 24:1027-30. [PMID: 18724802 DOI: 10.1089/aid.2007.0300] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Enfuvirtide is the first fusion inhibitor approved for use in HIV treatment and is a useful therapeutic option for highly treatment experienced individuals. Passive reporting has associated increased neuropathy rates with enfuvirtide use in some early studies but not others. The aim of this study was to describe any functional or clinical changes consistent with neuropathy among enfuvirtide users. A prospective cohort study of patients commencing or continuing enfuvirtide at a state HIV referral service, including clinical and sensory threshold monitoring, was conducted. A total of 14 patients were studied. All had advanced HIV disease and 13 (93%) had symptoms and/or signs consistent with neuropathy at baseline. Patients who entered the study on enfuvirtide-based therapy remained neurologically stable throughout follow-up. Eleven patients were assessed preand postenfuvirtide. No evidence was found for any clear effect of enfuvirtide on neuropathic symptoms, neuropathic signs, or sensory thresholds at a cohort level (p > 0.3 for all, Wilcoxon signed rank test). However, three (21%) patients experienced worsening of existing neuropathy symptoms (transient in two cases) and two (14%) patients' symptoms improved with enfuvirtide commencement. Breakthrough HIV viremia was associated with worsening symptoms in two patients at 5 and 18 months of enfuvirtide use. This study found no clear effect on peripheral nerves from enfuvirtide. Although limited by a small sample size, this study involved patients who would have been particularly vulnerable to a neurotoxin, with advanced HIV disease and a high rate of baseline neurological abnormalities. We observed no clear evidence of neurotoxicity from enfuvirtide in this population.
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Affiliation(s)
- Catherine L. Cherry
- Infectious Diseases Unit, Alfred Hospital, Melbourne, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
- Neurovirology Laboratory, Burnet Institute, Melbourne, Australia
| | | | | | - Steven L. Wesselingh
- Infectious Diseases Unit, Alfred Hospital, Melbourne, Australia
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
- Neurovirology Laboratory, Burnet Institute, Melbourne, Australia
| | - Bruce J. Brew
- Departments of Neurology and HIV Medicine, St Vincent's Hospital, Sydney, Australia
- Faculty of Medicine, University of NSW, Sydney, Australia
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Ruof J, Dusek A, DeSpirito M, Demasi RA. Cost-Efficacy Comparison among Three Antiretroviral Regimens in??HIV-1 Infected, Treatment-Experienced Patients. Clin Drug Investig 2007; 27:469-79. [PMID: 17563127 DOI: 10.2165/00044011-200727070-00004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVE In the face of increasing antiretroviral (ARV) treatment options and costs, payers are progressively challenged with prioritising resources. The cost effectiveness of the ARV agent enfuvirtide has been shown to be comparable to that of other available HIV treatment strategies, based on Markov modeling. However, an evaluation of enfuvirtide treatment costs that considers the impact of virological and immunological responses to therapy may provide a more clinically meaningful perspective for primary HIV healthcare providers. The aim of this study was to assess the cost per unit change in efficacy (HIV RNA decreases and CD4 count increases) of three different ARV regimens for triple class-experienced HIV-1 infected patients using actual drug costs and data from randomised, controlled clinical trials. STUDY DESIGN The analysis included three steps. First, re-analysis of 48-week clinical trial data (T-20 vs Optimized Regimen Only [TORO]) to allow for a more direct comparison of enfuvirtide versus other commonly used ARV agents. All patients included in the re-analysis received a common optimised background (COB) regimen of three drugs: two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and a ritonavir-boosted protease inhibitor (PI), lopinavir. HIV RNA levels and CD4 count changes were determined for three patient groups according to the treatment received - group 1: COB + enfuvirtide; group 2: COB + PI; group 3: COB + NRTI + PI. The second step of the analysis involved calculating the annualised regimen costs ($US wholesaler acquisition cost) for each patient group. In the third step, cost-efficacy ratios were calculated and compared between groups: (a) the annualised regimen cost ($US)/change in viral load from baseline, and (b) the annualised regimen cost ($US)/change in CD4+ cell count from baseline. RESULTS One hundred and fifty-seven patients were included in this previously unplanned secondary analysis (group 1: 79 patients; group 2: 42 patients; group 3: 36 patients). HIV RNA and CD4 count changes from baseline to week 48 were -1.80, -0.89 and -0.61 log(10) copies/mL (p < 0.001 for enfuvirtide vs each non-enfuvirtide group) and +102, +57 and +52 cells/mm(3) (p < 0.05 for enfuvirtide versus each non-enfuvirtide subgroup) for groups 1, 2 and 3, respectively. The annualised costs of the combination therapies were $US 35,624, $US 27,549 and $US 30,624; and the costs per 0.50 log(10) copies/mL HIV RNA decrease were $US 9,872, $US 15,542 and $US 24,907 (p < 0.05 for enfuvirtide vs each non-enfuvirtide subgroup) for groups 1, 2 and 3, respectively. The costs per 25 cells/mm(3) CD4 count increase were $US 8,722, $US 12,127 and $US 14,636 for subgroups 1, 2 and 3, respectively. Similar patterns in regimen cost per unit change were achieved after adjusting for baseline prognostic variables. The incremental cost-efficacy ratios for group 1 versus the combination of groups 2 and 3 were $US 3,124 for HIV RNA reduction and $US 3,239 for CD4 count increase. CONCLUSION Enfuvirtide-containing regimens are associated with higher cost as well as improved virological and immunological outcomes when compared with alternative four- and five-drug regimens. When costs and outcomes are considered jointly, an enfuvirtide-based regimen is more cost efficacious than alternative regimens in this patient population.
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Affiliation(s)
- Jörg Ruof
- Roche Pharmaceuticals, Nutley, NJ 07110 USA.
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Abstract
During antiviral drug development, any essential stage of the viral life cycle can serve as a potential drug target. Since most viruses encode specific proteases whose cleavage activity is required for viral replication, and whose structure and activity are unique to the virus and not the host cell, these enzymes make excellent targets for drug development. Success using this approach has been demonstrated with the plethora of protease inhibitors approved for use against HIV. This discussion is designed to review the field of antiviral drug development, focusing on the search for protease inhibitors, while highlighting some of the challenges encountered along the way. Protease inhibitor drug discovery efforts highlighting progress made with HIV, HCV, HRV, and vaccinia virus as a model system are included. Drug Dev. Res. 67:501–510, 2006. © 2006 Wiley‐Liss, Inc.
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Affiliation(s)
| | - Dennis E. Hruby
- SIGA Technologies, Inc., Corvallis, Oregon
- Department of Microbiology, Oregon State University, Corvallis, Oregon
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Krambovitis E, Porichis F, Spandidos DA. HIV entry inhibitors: a new generation of antiretroviral drugs. Acta Pharmacol Sin 2005; 26:1165-73. [PMID: 16174430 DOI: 10.1111/j.1745-7254.2005.00193.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
AIDS is presently treatable, and patients can have a good prognosis due to the success of highly active antiretroviral therapy (HAART), but it is still not curable or preventable. High toxicity of HAART, and the emergence of drug resistance add to the imperative to continue research into new strategies and interventions. Considerable progress in the understanding of HIV attachment and entry into host cells has suggested new possibilities for rationally designing agents that interfere with this process. The approval and introduction of the fusion inhibitor enfuvirtide (Fuzeon) for clinical use signals a new era in AIDS therapeutics. Here we review the crucial steps the virus uses to achieve cell entry, which merit attention as potential targets, and the compounds at pre-clinical and clinical development stages, reported to effectively inhibit cell entry.
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Affiliation(s)
- Elias Krambovitis
- Department of Applied Biochemistry and Immunology, Institute of Molecular Biology and Biotechnology, Vassilika Vouton, Heraklion, Crete, Greece.
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Dai SJ, Dou GF, Qiang XH, Song HF, Tang ZM, Liu DS, Liu XW, Yang LM, Zheng YT, Liang Q. Pharmacokinetics of sifuvirtide, a novel anti-HIV-1 peptide, in monkeys and its inhibitory concentration in vitro. Acta Pharmacol Sin 2005; 26:1274-80. [PMID: 16174446 DOI: 10.1111/j.1745-7254.2005.00163.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To study the pharmacokinetics of sifuvirtide, a novel anti-human immunodeficiency virus (HIV) peptide, in monkeys and to compare the inhibitory concentrations of sifuvirtide and enfuvirtide on HIV-1-infected-cell fusion. METHODS Monkeys received 1.2 mg/kg iv or sc of sifuvirtide. An on-line solid-phase extraction procedure combined with liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS) was established and applied to determine the concentration of sifuvirtide in monkey plasma. A four-(127)I iodinated peptide was used as an internal standard. Fifty percent inhibitory concentration (IC(50)) of sifuvirtide on cell fusion was determined by co-cultivation assay. RESULTS The assay was validated with good precision and accuracy. The calibration curve for sifuvirtide in plasma was linear over a range of 4.88-5000 microg/L, with correlation coefficients above 0.9923. After iv or sc administration, the observed peak concentrations of sifuvirtide were 10 626+/-2886 microg/L and 528+/-191 microg/L, and the terminal elimination half-lives (T(1/2)) were 6.3+/-0.9 h and 5.5+/-1.0 h, respectively. After sc, T(max) was 0.25-2 h, and the absolute bioavailability was 49%+/-13%. Sifuvirtide inhibited the syncytium formation between HIV-1 chronically infected cells and uninfected cells with an IC(50) of 0.33 microg/L. CONCLUSION An on-line SPE-LC/MS/MS approach was established for peptide pharmacokinetic studies. Sifuvirtide was rapidly absorbed subcutaneously into the blood circulation. The T(1/2) of sifuvirtide was remarkably longer than that of its analog, enfuvirtide, reported in healthy monkeys and it conferred a long-term plasma concentration level which was higher than its IC(50) in vitro.
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Affiliation(s)
- Shu-jia Dai
- Laboratory of Metabolism of Biotechnology Derived Drugs, Beijing Institute of Radiation Medicine, Beijing 100850, China
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Sax PE, Losina E, Weinstein MC, Paltiel AD, Goldie SJ, Muccio TM, Kimmel AD, Zhang H, Freedberg KA, Walensky RP. Cost-effectiveness of enfuvirtide in treatment-experienced patients with advanced HIV disease. J Acquir Immune Defic Syndr 2005; 39:69-77. [PMID: 15851916 DOI: 10.1097/01.qai.0000160406.08924.a2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Enfuvirtide (ENF) has been shown to improve short-term virologic responses when given to highly treatment-experienced patients with advanced HIV disease. Because of the high cost of ENF compared with other antiretroviral agents, our objectives were to determine the potential long-term clinical impact and cost-effectiveness of ENF in these patients. METHODS We used a computer simulation model of HIV disease to project life expectancy, quality-adjusted life expectancy, cost, and cost-effectiveness of ENF in treatment-experienced patients. Input data were from the T-20 versus Optimized Regimen Only (TORO) 1 and 2 trials, 2 studies comparing ENF plus an optimized background regimen (OBR) with an OBR alone. RESULTS ENF plus an OBR increased projected discounted quality-adjusted life expectancy from 45.4 months with an OBR alone to 54.9 months, a difference of 9.5 quality-adjusted life-months. At the current annual ENF cost of US 18,500 dollars per year (in 2001 US dollars), the incremental cost-effectiveness ratio for ENF plus an OBR was US 69,500 dollars per quality-adjusted life-year (QALY) compared with an OBR alone. When 48-week virologic suppression rates for ENF plus an OBR were varied from a 50% reduction to a 250% increase in the suppression rate attributable to ENF, gains in quality-adjusted life expectancy ranged from 4.5 to 25.9 quality-adjusted life-months compared with an OBR alone, with cost-effectiveness ratios ranging from US 97,900 dollars per QALY to US 52,300 dollars per QALY gained. If ENF is continued after the HIV RNA level returns to the pretreatment baseline, the cost-effectiveness ratio increases to US 168,200 dollars per QALY. CONCLUSIONS In highly treatment-experienced patients, ENF plus an OBR provides substantial gains in quality-adjusted life expectancy compared with an OBR alone. Although ENF plus an OBR is less cost-effective than other commonly used interventions in HIV disease, its use may be justified, given the poor prognosis of these patients and their otherwise limited options for antiretroviral therapy.
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Affiliation(s)
- Paul E Sax
- Division of Infectious Disease and the Partners AIDS Research Center, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Espona M, Ferrández O, Grau S, Carmona A. Enfuvirtida: primer fármaco de una nueva familia de antirretrovirales. FARMACIA HOSPITALARIA 2005; 29:375-83. [PMID: 16433570 DOI: 10.1016/s1130-6343(05)73699-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Enfuvirtide or T-20 is the first drug approved by the FDA and the EMEA within the group of fusion inhibitors. Its mechanism of action is based on the blockade of the entry of the HIV to the body cells. Enfuvirtide is recommended in combination with other antiretroviral drugs for the treatment of patients infected by HIV that have developed resistance or intolerance to other prior antiretroviral therapies. Clinical trials have shown the effectiveness and safety of the treatment with this drug. Side effects most commonly reported are local reactions in the injection site. Enfuvirtide contributes to increase the therapeutic arsenal available for the management of the HIV infection, providing rescue therapy for patients in which prior treatments have failed.
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Affiliation(s)
- M Espona
- Servicio de Farmacia, IMAS, Hospital del Mar, Passeig Marítim 25, 08003 Barcelona, Spain
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Fung HB, Guo Y. Enfuvirtide: a fusion inhibitor for the treatment of HIV infection. Clin Ther 2004; 26:352-78. [PMID: 15110129 DOI: 10.1016/s0149-2918(04)90032-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2004] [Indexed: 11/26/2022]
Abstract
BACKGROUND Drug resistance continues to be a major challenge in the treatment of HIV-1 infection. Virtually all currently available antiretroviral medications inhibit the viral reverse transcriptase or protease. Enfuvirtide is the first fusion inhibitor approved by the US Food and Drug Administration for use in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced patients. OBJECTIVE This paper describes the pharmacologic properties and clinical usefulness of enfuvirtide. METHODS Relevant information was identified through searches of MEDLINE (1990 to October 2003), International Pharmaceutical Abstracts (1970 to October 2003), and meeting abstracts of major HIV/AIDS conferences (1996-2003) using the search terms enfuvirtide, pentafuside, T-20, DP-178, and fusion inhibitor. RESULTS In vitro, enfuvirtide exhibits activity against HIV-1 isolates that are resistant to all other classes of anti-retroviral medications. Enfuvirtide blocks the entry of HIV-1 into host cells by interfering with virus-cell fusion, making it unique among licensed antiretroviral medications. In human adults, enfuvirtide has a volume of distribution of 5.48 L, is highly bound to plasma protein (92%), has a plasma elimination half-life of 3.8 hours, and is catabolized by peptidases and proteinases in various tissues. Dose adjustment does not appear necessary on the basis of age, race, or body weight, but may be warranted in women weighing <50 kg. A literature review did not identify any data on the disposition of enfuvirtide in patients with hepatic or renal insufficiency. Clinical trials suggest that enfuvirtide reduces plasma HIV-1 RNA levels in highly treatment-experienced patients taking an optimized antiretroviral regimen. Pivotal trials indicated a mean change in HIV-1 RNA of -1.48 log(10) copies/mL in the enfuvirtide arm at week 48, compared with -0.63 log(10) copy/mL in the control arm ( P<0.001 ). The mean absolute increase on CD4 cell count was 46 cells/mm(3) (91 cells/mm(3)) in the enfuvirtide arm vs 45 cells/mm(3) in the control arm; P<0.001 ). The most commonly reported (>15 cases per 100 patient-years of exposure) adverse events (AEs) in clinical trials included injection-site reactions, diarrhea, nausea, fatigue, insomnia, peripheral neuropathy, headache, vomiting, and fever. The most commonly reported (> or =2%) laboratory abnormalities (grade III or IV) were eosinophilia, anemia, and increases in amylase, lipase, triglycerides, creatine phosphokinase, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase. In clinical trials, serious AEs leading to study discontinuation occurred in 12.9% ( 114/885 ) of patients in the enfuvirtide arm, compared with 10.7% ( 12/112 ) in the control arm ( P = NS ). The recommended dosage of enfuvirtide is 90 mg SC BID in adults and 2 mg/kg SC BID in children. Efficacy studies in children are ongoing. CONCLUSION Although additional studies are needed, enfuvirtide appears to be a promising agent, in combination with other antiretroviral agents, for the treatment of HIV infection in treatment-experienced patients.
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Affiliation(s)
- Horatio B Fung
- Critical Care Center, Veterans Affairs Medical Center, Bronx, New York 10468, USA.
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Abstract
BACKGROUND The use of highly-active anti-retroviral therapy (HAART) for treating HIV infections is increasing. Recent studies have demonstrated that HAART is improving both the length and quality of life in HIV-infected patients. Resistant strains of HIV arise when drug adherence is poor. This can lead to the transmission of drug-resistant strains of HIV to susceptible individuals. This can lead to suboptimal first-line therapy, if the resistance profile of the transmitted virus is unknown. OBJECTIVES To review the mechanisms of how drug resistance arises; the methods used to characterise drug resistance; the problems arising with compliance leading to the development of drug-resistant HIV strains; the evidence for the incidence, prevalence and trends in the transmission of resistant HIV strains in different risk groups; and the evidence of suboptimal response to first-line therapy where transmission of a resistant HIV strain has occurred. On the basis of this, a case is presented for the routine resistance testing of all newly diagnosed HIV-infected individuals. STUDY DESIGN Literature review. RESULTS AND CONCLUSIONS There is evidence, though limited at present, that transmission of drug-resistant HIV strains can lead to suboptimal response to first-line therapy in newly diagnosed HIV-infected individuals. As the use of HAART can only increase in the future, and compliance will always be a problem in such HAART-treated patients, baseline resistance testing should become a routine part of their management.
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Affiliation(s)
- Julian W Tang
- Department of Virology, Windeyer Institute of Medical Sciences, Royal Free and University College Medical Schools, 46 Cleveland Street, London W1T 4JF, UK
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