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PubMed2001

The emerging roles of non-nucleoside reverse transcriptase inhibitors in antiretroviral therapy.

The availability of potent non-nucleoside reverse transcriptase inhibitor (NNRTI)-based regimens for antiretroviral therapy and concerns regarding protease inhibitor (PI)-related metabolic disturbances have led to significant shifts in treatment practices in HIV infection. NNRTI-based regimens may have several advantages over PI-based therapy for initial or prolonged therapy, including more convenient administration regimens, lower tablet volume, fewer drug interactions, and central nervous system penetration. No data from prospective clinical trials currently exist comparing the 3 approved agents (efavirenz, nevirapine or delavirdine). Both efavirenz and nevirapine have been compared to triple therapy with the PI indinavir over 48 weeks as initial therapy, with similar responses being observed with nevirapine regimens and superiority observed with efavirenz. A smaller 24-week study has suggested nevirapine may be superior to the PI nelfinavir. Limited comparative data in patients with high viral loads treated with nevirapine- or delavirdine-based regimens currently exist. However, cohort data and selected patient data from clinical trials suggest comparable activity to PI-based regimens in these patients. The superiority of efavirenz over indinavir-based regimens has been observed in comparative data in a subset of patients with high viral loads. In treatment-experienced patients, available uncontrolled data suggest these agents contribute to regimen efficacy in NNRTI-naïve, treatment-experienced patients. Efavirenz has demonstrated superiority over nelfinavir in nucleoside-experienced patients, although combining these 2 agents may represent the best approach in these circumstances. The tolerability of NNRTIs appears generally good with few individuals discontinuing in clinical studies as a result of adverse drug events. The majority of adverse events with NNRTIs occur within the first month, and are predictable and manageable without therapy interruption.

Alkynes↗
PubMed2003

Therapeutic drug monitoring: an aid to optimising response to antiretroviral drugs?

Therapeutic drug monitoring (TDM) has been proposed as a means to optimise response to highly active antiretroviral therapy (HAART) in HIV infection. Protease inhibitors (PIs) and the non-nucleoside reverse transcriptase inhibitors (NNRTIs) efavirenz and nevirapine satisfy many criteria for TDM. Nucleoside reverse transcriptase inhibitors (NRTIs) are not suitable candidates for TDM, since no clear plasma concentration-effect relationships have been established for these drugs. Several important limitations to the application of TDM for antiretroviral drugs should be recognised, including uncertainty about the best pharmacokinetic predictor of response and insufficient validation of target concentrations for individual PIs and NNRTIs. Data from two clinical trials support the use of TDM in treatment-naive HIV-infected patients who start with an indinavir- or nelfinavir-based regimen. TDM either prevented virological failures (presumably by preventing the development of resistance) or treatment discontinuations due to concentration-related toxicity. Application of routine TDM in other patient groups (treatment-experienced patients) or for drugs other than indinavir or nelfinavir (NNRTIs, other PIs, combination of PIs) is speculative at this moment. However, TDM can be used in selected patient groups (children, pregnant women, patients with renal or hepatic dysfunction) to confirm adequate drug concentrations, and for management of drug-drug interactions.TDM in treatment-experienced patients may be optimally used in conjunction with resistance testing. The integration of pharmacological and virological measures in the inhibitory quotient (IQ) needs to be standardised and elaborated further. TDM should be accompanied by careful assessment of adherence and can itself help identify non-adherence, although a drug concentration only reflects the last few drug doses taken by a patient. Additional clinical trials are needed before routine TDM can be adopted as standard of care in the treatment of HIV infection.

Anti-HIV Agents↗
PubMed2005

Herb-drug interactions: a literature review.

Herbs are often administered in combination with therapeutic drugs, raising the potential of herb-drug interactions. An extensive review of the literature identified reported herb-drug interactions with clinical significance, many of which are from case reports and limited clinical observations. Cases have been published reporting enhanced anticoagulation and bleeding when patients on long-term warfarin therapy also took Salvia miltiorrhiza (danshen). Allium sativum (garlic) decreased the area under the plasma concentration-time curve (AUC) and maximum plasma concentration of saquinavir, but not ritonavir and paracetamol (acetaminophen), in volunteers. A. sativum increased the clotting time and international normalised ratio of warfarin and caused hypoglycaemia when taken with chlorpropamide. Ginkgo biloba (ginkgo) caused bleeding when combined with warfarin or aspirin (acetylsalicylic acid), raised blood pressure when combined with a thiazide diuretic and even caused coma when combined with trazodone in patients. Panax ginseng (ginseng) reduced the blood concentrations of alcohol (ethanol) and warfarin, and induced mania when used concomitantly with phenelzine, but ginseng increased the efficacy of influenza vaccination. Scutellaria baicalensis (huangqin) ameliorated irinotecan-induced gastrointestinal toxicity in cancer patients.Piper methysticum (kava) increased the 'off' periods in patients with parkinsonism taking levodopa and induced a semicomatose state when given concomitantly with alprazolam. Kava enhanced the hypnotic effect of alcohol in mice, but this was not observed in humans. Silybum marianum (milk thistle) decreased the trough concentrations of indinavir in humans. Piperine from black (Piper nigrum Linn) and long (P. longum Linn) peppers increased the AUC of phenytoin, propranolol and theophylline in healthy volunteers and plasma concentrations of rifamipicin (rifampin) in patients with pulmonary tuberculosis. Eleutheroccus senticosus (Siberian ginseng) increased the serum concentration of digoxin, but did not alter the pharmacokinetics of dextromethorphan and alprazolam in humans. Hypericum perforatum (hypericum; St John's wort) decreased the blood concentrations of ciclosporin (cyclosporin), midazolam, tacrolimus, amitriptyline, digoxin, indinavir, warfarin, phenprocoumon and theophylline, but did not alter the pharmacokinetics of carbamazepine, pravastatin, mycophenolate mofetil and dextromethorphan. Cases have been reported where decreased ciclosporin concentrations led to organ rejection. Hypericum also caused breakthrough bleeding and unplanned pregnancies when used concomitantly with oral contraceptives. It also caused serotonin syndrome when used in combination with selective serotonin reuptake inhibitors (e.g. sertraline and paroxetine). In conclusion, interactions between herbal medicines and prescribed drugs can occur and may lead to serious clinical consequences. There are other theoretical interactions indicated by preclinical data. Both pharmacokinetic and/or pharmacodynamic mechanisms have been considered to play a role in these interactions, although the underlying mechanisms for the altered drug effects and/or concentrations by concomitant herbal medicines are yet to be determined. The clinical importance of herb-drug interactions depends on many factors associated with the particular herb, drug and patient. Herbs should be appropriately labeled to alert consumers to potential interactions when concomitantly used with drugs, and to recommend a consultation with their general practitioners and other medical carers.

Animals↗
PubMedDate not supplied

Efavirenz in the management of HIV infection.

Efavirenz, which is likely to be licensed in the UK and throughout Europe shortly, represents a major advance in the treatment of HIV infection. It belongs to the non-nucleoside reverse transcriptase (NNRTI) class of drugs and, as such, it should only be prescribed with other potent therapies to avoid the development of resistance. However, in the pivotal head-to-head comparison of efavirenz with lamivudine and zidovudine, treatment over a 24-week period proved superior to treatment with a standard regimen containing indinavir. The results from prolonged follow-up of this study are eagerly awaited but it is clear that a combination of efavirenz with nucleoside analogues provides a potent proteinase inhibitor-sparing regimen which may have less toxicity. Additional data also indicate that the combination of a proteinase inhibitor (indinavir) with efavirenz provides an extremely potent regimen which is well tolerated and produces complete inhibition of plasma HIV viraemia over prolonged periods of follow-up. In common with many other currently available potent anti-HIV therapies, the optimum use of this drug is being determined by ongoing clinical studies but it is clear that ease of administration (once-daily), freedom from serious side-effects and potency when used in combination are likely to represent a very considerable advance in the management of HIV infection.

Alkynes↗
PubMed1999

Failure of double protease inhibitor therapy as a salvage therapy for HIV-infected patients resistant to conventional triple therapy.

A therapeutic dilemma arises once HIV-infected patients develop a break-through of HIV-replication under potent antiretroviral therapy. Therefore, we studied whether patients (n = 12) who failed double nucleoside reverse transcriptase (NRTI) plus indinavir or ritonavir triple therapy can be rescued when therapy is switched to double protease inhibitor (PI) treatment (nelfinavir and hard gel saquinavir) and stavudine. With the rescue regimen HIV-RNA levels initially dropped from 148,571 +/- 45,258 copies/ml to 9,310 +/- 6, 965 copies/ml at week 4 (p = 0.0117). However, virus load subsequently increased to almost baseline levels (131,230 +/- 37,743 copies/ml) at week 12. Likewise, CD4-cell counts could only be stabilized initially (baseline 267 +/- 51; week 4 296 +/- 65 cells/microl), but gradually declined thereafter (216 +/- 34 cells/microl week 12). Before therapy was switched, the viral protease gene from 5 analyzed patients showed 3-5 amino acid substitutions. Moreover, 4 of these patients had one amino acid substitution associated with resistance to nelfinavir. Our data suggest that HIV-infected patients resistant to indinavir or ritonavir and double NRTI combination therapy respond to double PI nelfinavir/saquinavir and D4T rescue therapy only initially but have no sustained benefit.

Anti-HIV Agents↗
PubMed1999

Drug monitoring of antiretroviral therapy for HIV-1 infection: method validation and results of a pilot study.

BACKGROUND: Antiretroviral therapy for HIV-1 infection has become increasingly complex. The availability of new and potent drugs and progress in understanding the pathogenesis of HIV-1 infection have led to the establishment of new treatment paradigms. The varying dosing regimens, associated toxicities, and the potential for drug-drug and food-drug interactions further complicate treatment. This complexity contributes to patient nonadherence. Because clinicians have no tools to monitor adherence or drug-drug interactions and because response requires that therapy exceed the known inhibiting concentration, serum monitoring of antiretroviral therapy may play a role in improving treatment of HIV-1 infection. We report methods to quantify serum concentrations of antiretroviral drugs used to treat HIV-1 infection, precision and interference studies of these methods, and results observed in a pilot evaluation of blood serum concentrations from 12 human subjects. METHODS: HPLC offers adequate sensitivity to measure peak or trough serum concentrations of delavirdine, lamivudine, nevirapine, indinavir, nelfinavir, ritonavir, and saquinavir and peak serum concentrations of stavudine, zidovudine, and didanosine with reasonable precision. RESULTS: Peak indinavir serum concentrations in most patients were in the range of 1-10 mg/L, and trough concentrations were in the range of 0.1-0.5 mg/L. Peak stavudine concentrations were in the range of 0.3-1.3 mg/L, and trough concentrations were in the range of 0.1-0.5 mg/L. Peak zidovudine concentrations were in the range of 0.1-1.1 mg/L. CONCLUSIONS: Because this was a blood serum concentration-seeking pilot study to evaluate analytic performance, we do not report on the correlation of drug response to blood concentration. However, the concentrations observed in patients are generally consistent with blood concentrations reported from studies of monotherapy.

Anti-HIV Agents↗
PubMed1999

Clinical history of efavirenz.

Efavirenz (SUSTIVA, DMP 266, EFV) is a novel non-nucleoside reverse transcriptase inhibitor, which shows good inhibitory activity against HIV-1. The pharmacokinetics of efavirenz allow for once daily dosing without regard to meals of normal composition. Efavirenz is a mild inducer of CYP 3A4. Clinically significant drug interactions have been reported with medications that are metabolised via the cytochrome P450 enzymes such as indinavir and saquinavir. Results from the studies collated for submission (003, 006, 020, 024 and ACTG 364) have demonstrated the potency and durability of once daily efavirenz in combination with zidovudine (AZT) + lamivudine (3TC), indinavir (IDV), nelfinavir (NFV), IDV + 2 NRTIs, and NFV + 2 NRTIs. Efavirenz was recently approved for commercial use in the USA and has received marketing authorisation in Europe and Canada.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[Anti-infection prophylaxis after sexual assault. Experience of the Raymond Poincaré-Garches Hospital].

OBJECTIVE: The August 1997 Directive of the Direction of General Health in France extended indications for antiretroviral treatment to risk of HIV exposure by sexual intercourse or syringe sharing. In November 1997, in collaboration with the Hauts-de-Seine MedicoJudiciary center, the Infectious Disease unit of the Raymond Poincaré Garches Hospital established a health care and anti-HIV prophylaxis clinic for victims of sexual assault. We report here the experience in 1998 and 1999. PATIENTS AND METHODS: Between January 1998 and December 1999, 109 victims of sexual assault, 105 women and 4 men, mean age 24.7 +/- 10.6 years attended the clinic. RESULTS: Mean delay from assault to antiretroviral tritherapy (AZT, 3TC, indinavir) was 18.35 +/- 17.39 hours. Mean duration of antiretroviral treatment was 17.4 +/- 11.8 days. HIV screening in perpetrators enabled early interruption of the antiretroviral treatment in 23 cases (21.1%). Sixty-two victims (62%) were still in follow-up at W4/W7. Excellent compliance to tritherapy was observed in these subjects. Clinical intolerance was observed in 46.6% with nausea-vomiting in 91.4% of the cases. Adverse effects led to interruption of indinavir in 5 cases. Initial HIV serology was negative in all cases and no case of HIV seroconversion was observed. Among the 23 known perpetrators, one was HIV-positive with an HIV-RNA at 88,000 copies. Sixty-one victims (55.9%) had been previously vaccinated against the hepatitis B virus; 16 victims were vaccinated after the assault. There were no cases of hepatitis B virus seroconversion. Search for chlamydiae in vaginal secretions was positive in 3 cases and chlamydia serology demonstrated a seroconversion in 1 case. There was no case of syphylitic seroconversion and no case of gonococcal or trichomonas infection. CONCLUSION: The low rate of attendance for follow-up in regards to the gravity of the potential risk of HIV and/or hepatitis B virus transmission and the burden and cost of the antiretroviral treatment highlight the need for better medico-psycho-social support for rape victims. For the victims who attended the clinic, antiretroviral treatment was generally well accepted and well tolerated.

Adolescent↗
PubMed2001

Amprenavir: new preparation. Another HIV protease inhibitor: no proven advance.

(1) The reference antiretroviral treatment for HIV-infected patients is a three-drug regimen combining drugs from different families, namely two nucleoside reverse transcriptase inhibitors + a protease inhibitor or a non nucleoside reverse transcriptase inhibitor. In our opinion, indinavir is the first-choice protease inhibitor. (2) The clinical file on amprenavir is limited. In particular, it is not known whether the recommended dose regimen (1 200 mg twice a day) is the best one. A 48-week trial involving 232 patients previously untreated with antiretrovirals showed that the combination of amprenavir (1 200 mg) + lamivudine (150 mg) + zidovudine (300 mg), administered twice a day, was more effective than lamivudine + zidovudine on viral load. (3) An unblinded trial involving 504 patients, who had already received a reverse transcriptase inhibitor but no protease inhibitor, compared three-drug regimens consisting of amprenavir (1 200 mg twice a day) and two reverse transcriptase inhibitors, or indinavir (800 mg three times a day) and two reverse transcriptase inhibitors, for 48 weeks. Changes in viral load and the CD4+ lymphocyte count did not favour the amprenavir-containing regimen. (4) Laboratory studies suggest that the risk of cross-resistance between amprenavir and other HIV protease inhibitors is lower than with other compounds of this class. However, it is unclear whether this means that amprenavir would be clinically effective after failure of one or several other protease inhibitors. (5) The main adverse effects of amprenavir are gastrointestinal disorders and paraesthesias. Overall, the safety profile resembles that of the other protease inhibitors. (6) Like other protease inhibitors, amprenavir can potentially interact with many other drugs, owing to its hepatic metabolism. (7) Amprenavir is taken in two daily doses irrespective of meal times, but this advantage over other protease inhibitors is cancelled out by the fact that patients have to swallow 8 large soft capsules at each intake. (8) In our opinion, pending further data, amprenavir should be used only in well-conducted clinical trials.

Anti-Infective Agents↗
PubMed2001

Combination of protease inhibitors for the treatment of HIV-1-infected patients: a review of pharmacokinetics and clinical experience.

The use of highly active antiretroviral therapy, the combination of at least three different antiretroviral drugs for the treatment of HIV-1 infection, has greatly improved the prognosis for HIV-1-infected patients. The efficacy of a combination of a protease inhibitor (PI) plus two nucleoside analogue reverse transcriptase inhibitors has been well established over a period of up to 3 years. However, virological treatment failure has been reported in 40-60% of unselected patients within 1 year after initiation of a PI-containing regimen. This observation may, at least in part, be attributed to the poor pharmacokinetic characteristics of the PIs. Given as a single agent the PIs have several pharmacokinetic limitations; relatively short plasma-elimination half-lives and a modest and variable oral bioavailability, which is, for some of the PIs, influenced by food. To overcome these suboptimal pharmacokinetics, high doses (requiring large numbers of pills) must be ingested, often with food restrictions, which complicates patient adherence to the prescribed regimen. Positive drug-drug interactions increase the exposure to the PIs, allowing administration of lower doses at reduced dosing frequencies with less dietary restrictions. In addition to increasing the potency of an antiretroviral regimen, combinations of PIs may enhance patient adherence, both of which will contribute to a more durable suppression of viral replication. The favourable pharmacokinetics of PIs in combination are a result of interactions through cytochrome P450 3A4 (CYP3A4) isoenzymes and, possibly, the multi-drug transporting P-glycoprotein (P-gp). Antiretroviral synergy between PIs and non-overlapping primary resistance patterns in the HIV-1 protease genome may further enhance the antiretroviral potency and durability of combinations of PIs. Many combinations contain ritonavir because this PI has the most pronounced inhibiting effects on CYP3A4. The combination of saquinavir and ritonavir, both in a dose of 400 mg twice-a-day, is the most studied double PI combination, with clinical experience extending over 3 years. Combination of a PI with a low dose of ritonavir (< or = 400 mg/day), only to boost its pharmacokinetic properties, seems an attractive option for patients who cannot tolerate higher doses of ritonavir. A recently introduced PI, lopinavir, has been co-formulated with low-dose ritonavir, which allows for a convenient three-capsules, twice-a-day dosing regimen. In an attempt to prolong suppression of viral replication combinations of PIs are becoming increasingly popular. However, further clinical studies are needed to identify the optimal combinations for treatment of antiretroviral naive and experienced HIV-1-infected patients. This review covers combinations of saquinavir, indinavir, nelfinavir, amprenavir and lopinavir with different doses of ritonavir, as well as the combinations of saquinavir and indinavir with nelfinavir.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

[Acute severe pancreatitis caused by anti-HIV drugs].

Acute pancreatitis in patients with HIV infection is infrequent and often not recognized. Autopsies performed on patients died for different pathologies show pancreatic lesions approximately in 50% of cases. The etiological factors associated with acute pancreatitis are related to HIV infection and particularly to drugs used to treat the syndrome or to prevent opportunistic infections. We report a case in a 38 years old male patient with AIDS without risk factors for acute pancreatitis in which the disease developed while taking Stavudine, Lamivudine and Indinavir. His conditions improved with intensive medical therapy. The subsequent medical course became complicated. The patient died after 75 days for severe abdominal haemorrhage. A review of the literature reports several cases of A.P. in HIV patients mainly related to opportunistic infections. Many authors regard the medical treatment of HIV syndrome as etiological factor but a casual relationship was never demonstrated. The aim of the present paper is to underline that besides Lamivudine also Stavudine and Indinavir might be related to acute pancreatitis. Clinical and laboratory investigations in HIV patients are therefore indicated for an earlier diagnosis and treatment.

Acute Disease↗
PubMed2002

Modulation of the multidrug resistance (MDR) phenotype in CEM MDR cells simultaneously exposed to anti HIV-1 protease inhibitors (PI's) and cytotoxic drugs.

Vinblastine, vincristine and doxorubicyn are currently used in chemotherapeutic treatments of several malignancies including HIV-1 associated tumours Kaposi's sarcoma (KS) and non-Hodgkin lymphoma (NHL). Hence, AIDS patients also affected by KS and NHL may be simultaneously subjected to highly active antiretroviral therapy (HAART) and cytotoxic drugs to combat HIV-1 infection and cancer aggressiveness. In order to assess if the combination of these therapies may affect cell growth and survival of P-glycoprotein expressing MDR variants of the human CD4+ T-lymphoblastoid CEM cell line, the protease inhibitors (PI's) ritonavir, saquinavir and indinavir were tested in an in vitro assay for their ability to potentiate the vinblastine, vincristine and doxorubicyn cytotoxicity. The results we obtained demonstrated that at the concentration of 10 micrograms/ml, ritonavir and in a lesser extent saquinavir act as MDR reversing agents. By contrast, the PI indinavir at least in the CEM cell system, does not affect the patterns of drug resistance. The level of chemosensitization exerted by ritonavir and saquinavir suggests that these PI's may render P-glycoprotein expressing MDR cells de novo susceptible to the antineoplastic drugs vinblastine, vincristine and doxorubicyn.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

[Decrease of HIV-1 replicative capacity after serial passage in MT-4 cells under conditions of the combined antiretroviral therapy].

The replicative activity of HIV-1/IIIB was determined in MT-4 cells under conditions of combined HIV reverse transcriptase and protease inhibitors in the presence of four different drug cocktails: (1) phosphazide, didanosine, nevirapine; (2) stavudine, didanosine, nevirapine; (3) phosphazide, didanosine, nevirapine, indinavir; (4) stavudine, didanosine, nevirapine, indinavir. The concentration of every inhibitor was 10 times higher than the 50% effective concentration. Alpha interferon was used as a natural antiretroviral agent in addition. The virus was subjected to 5 serial passages in the presence of the drug cocktails and then to 5 serial passages without the agents using cocultivation of infected and uninfected cells at ratio 1:5 to increase virus activity. Virus replication in the presence of all the drug combinations resulted in the appearance of HIV-1 variants with low replicative activity that was insignificantly increased during further passages even without the antiretroviral agents. If extrapolated to the clinical practice, these results indicate that all the drug cocktails were effective inhibitors of HIV-1 replication because the virus variants with high replicative activity did not emerge. Moreover, the results showed that the clinical use of the drug cocktails was promising.

Anti-HIV Agents↗
PubMed2004

Susceptibility of HIV-2, SIV and SHIV to various anti-HIV-1 compounds: implications for treatment and postexposure prophylaxis.

Limited information is available on the activity of antiretroviral drugs against human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus (SIV) strains to guide their use in treatment or prophylaxis. We evaluated the antiviral activity of 16 approved drugs and one experimental drug, AMD3100, against two wild-type HIV-2 (ROD and EHO) isolates, two strains of SIV (mac251 and B670), and two strains of simian-human immunodeficiency virus (SHIV) that contain the reverse transcriptase (RTSHIV) or envelope glycoprotein (SHIV89.6) of human immunodeficiency virus type 1 (HIV-1) in a SIV(mac239) background. Drug susceptibility was measured conventionally by the MT-4/MTT assay, and results were analysed as fold changes in 50% effective concentration (EC50) relative to the EC50 for HIV-1 (IIIB). The nucleoside reverse transcriptase inhibitors (NRTIs) zidovudine, lamivudine, stavudine, didanosine, zalcitabine and abacavir as well as the nucleotide reverse transcriptase inhibitor tenofovir retained full activity against all six viruses except for SIV and SHIV89.6 that showed low-level resistance to didanosine. The protease inhibitors (PIs) ritonavir, indinavir, saquinavir and nelfinavir were found to be active against some HIV-2 or SIV strains. However, a significant reduction in susceptibility was seen with indinavir against SHIV89.6 (3.3-fold), and with amprenavir against HIV-2(ROD) (8.8-fold). All viruses except for RTSHIV showed a >200-fold decrease in susceptibility for the non-nucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine, delavirdine and efavirenz, indicating high-level resistance. AMD3100, a CXCR4 antagonist, was active against HIV-2 and SHIV89.6, a finding consistent with the use of the CXCR4 co-receptor by these isolates, but was inactive against SIV strains. In contrast, enfuvirtide (T-20) was active against SHIV89.6 but had reduced inhibitory activity against both HIV-2 and SIV strains predicting little therapeutic value against these viruses. These findings support the use of NRTIs, tenofovir, but not NNRTIs, for treating HIV-2-infected persons or for prophylaxis against HIV-2 and SIV. The clinical significance of the low-level resistance of HIV-2 and SIV to some PIs is unclear. Co-receptor antagonists such as AMD3100 show promising anti-HIV-2 therapeutic modalities. Both AMD3100 and enfuvirtide could be used for prophylaxis against SHIV89.6.

Amino Acid Sequence↗
PubMed2004

HIV-1 protease inhibitor induces growth arrest and apoptosis of human multiple myeloma cells via inactivation of signal transducer and activator of transcription 3 and extracellular signal-regulated kinase 1/2.

We previously showed that HIV-1 protease inhibitors slowed the proliferation of human myeloid leukemia cells and enhanced their differentiation in the presence of all-trans retinoic acid (ATRA). In this study, we found that protease inhibitors, including ritonavir, saquinavir, and nelfinavir, but not indinavir, induced growth arrest and apoptosis of U266, RPMI8226, and ARH77 human multiple myeloma (MM) cells in association with down-regulation of antiapoptotic protein Mcl-1. Also, protease inhibitors inhibited the survival of freshly isolated MM cells from patients. In contrast, these protease inhibitors did not affect survival of normal B cells and colony formation of myeloid committed stem cells (CFU-GM) from healthy volunteers. In addition, we found that all of the protease inhibitors, except for indinavir, blocked interleukin-6 (IL-6)-stimulated phosphorylation of both signal transducer and activator of transcription 3 (STAT 3) and extracellular signal-regulated kinase 1/2 in U266 and RPMI8226 MM cells. Moreover, the protease inhibitors inhibited both the basal and IL-6-stimulated STAT 3/DNA binding activity in U266 cells as measured by an ELISA-based assay. Furthermore, ritonavir inhibited production of vascular endothelial growth factor one of the targets of STAT 3, in U266 and RPMI8226 cells as measured by ELISA. Taken together, protease inhibitors might be useful for treatment of individuals with MM.

Apoptosis↗
PubMed2004

Antiretroviral drugs with adverse effects on adipocyte lipid metabolism and survival alter the expression and secretion of proinflammatory cytokines and adiponectin in vitro.

OBJECTIVE: The lipodystrophy syndrome is a major adverse effect of highly active antiretroviral therapy (HAART), associated with altered circulating levels and adipose tissue mRNA expression of proinflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor (TNF)alpha, and adiponectin. Proinflammatory cytokines and adiponectin, which are secreted by adipose tissue, regulate fat metabolism, insulin sensitivity and adipose cell apoptosis. We examined the direct effects of individual antiretrovirals on lipid metabolism and cytokine and adiponectin production by cultured adipocytes. METHODS: Differentiating 3T3-F442A cells and differentiated 3T3-L1 adipocytes were treated for 12 or 4 days, respectively, with protease inhibitors (PIs) indinavir, nelfinavir, amprenavir, lopinavir and ritonavir, or nucleoside reverse transcriptase inhibitors (NRTIs) stavudine and zidovudine, at near-Cmax concentrations. Lipid metabolism was estimated by Oil Red O staining of intracellular lipids, mRNA expression of fatty acid synthase and adipocyte lipid binding protein 2, and insulin activation of lipogenesis. Apoptosis was estimated by flow cytometry. The expression and secretion of proinflammatory cytokines (IL-6, TNFalpha and IL-1beta) and adiponectin were evaluated by real-time reverse transcription PCR and ELISA. RESULTS: Chronic treatment of 3T3-F442A differentiating adipocytes and differentiated 3T3-L1 adipocytes with PIs and NRTIs reduced lipid accumulation, mRNA expression of lipid markers and insulin-induced lipogenesis. IL-6, TNFalpha, IL-1beta and adiponectin expression and secretion were markedly altered in differentiating 3T3-F442A adipocytes. PIs had either no effect on differentiated 3T3-L1 adipocytes (TNFalpha expression and sucretion) or their effect was less marked than in 3T3-F442A cells. Indinavir and amprenavir did not alter cytokine secretion and expression by mature adipocytes. The effects of stavudine and zidovudine on differentiating and mature adipocytes were similar, despite the difference in treatment procedure. The drugs with the strongest effect on TNFalpha expression also increased adipocyte apoptosis, in contrast to the drugs that only moderately increased TNFalpha expression. CONCLUSIONS: These results suggest that increased cytokine and decreased adiponectin secretion and expression induced by some PIs and NRTIs may contribute to the adipose tissue loss (via apoptosis and lipid leakage) and insulin resistance associated with the lipodystrophy syndrome.

3T3-L1 Cells↗
PubMed2005

Lipid profiles for antiretroviral-naive patients starting PI- and NNRTI-based therapy in the Swiss HIV cohort study.

BACKGROUND: Blood lipid abnormalities in patients on highly active antiretroviral therapy (HAART) have been associated with exposure to protease inhibitors (PIs), particularly ritonavir. First therapy with a non-nucleoside reverse transcriptase inhibitor (NNRTI) leads to relatively favourable lipid profiles. We report on medium-term lipid profiles (up to 5 years) for antiretroviral-naive patients starting NNRTI- and PI-based HAART in the Swiss HIV Cohort Study. METHODS: Since April 2000, blood samples taken at visits scheduled every 6 months have been analysed for cholesterol and triglyceride concentrations. For 1065 antiretroviral-naive patients starting HAART after April 2000, we estimated changes in concentration over time using multivariate linear regression with adjustment for baseline covariates, use of lipid-lowering drugs and whether the sample was taken in a fasting state. RESULTS: Non-high density lipoprotein (HDL) cholesterol levels increase with increasing exposure to either PI- or NNRTI-based therapy, HDL cholesterol levels increase and triglyceride levels decrease with increasing exposure to NNRTI-based therapy, whereas triglyceride levels increase with increasing exposure to PI-based therapy. Between NNRTI-based therapies, there is a slight difference in triglyceride levels, which tend to increase with increasing exposure to efavirenz and to decrease with increasing exposure to nevirapine. Of the three common PI-based therapies, nelfinavir appears to have a relatively favourable lipid profile, with little change with increasing exposure. Of the other two PI therapies, lopinavir with ritonavir has a more favourable profile than indinavir with ritonavir, with smaller increases in both non-HDL cholesterol and triglycerides and an increase in HDL cholesterol. Increasing exposure to abacavir is associated with a decrease in the level of triglycerides. CONCLUSION: In general, NNRTI-based therapy is associated with a more favourable lipid profile than PI-based therapy, but different PI-based therapies are associated with very different lipid profiles. Nelfinavir appears to have a relatively favourable lipid profile. Of the two boosted PI therapies, lopinavir appears to have a more favourable lipid profile than indinavir.

Antiretroviral Therapy, Highly Active↗
PubMed1998

Cost-effectiveness of post-exposure prophylaxis following sexual exposure to HIV.

OBJECTIVES: To assess the cost-effectiveness, relative to other health-related interventions in the U.S., of post-exposure prophylaxis (PEP) following potential HIV exposure through sexual contact with a partner who may or may not be infected, and to compare the relative cost-effectiveness of dual- and triple-combination PEP. METHODS: Standard techniques of cost-utility analysis were used to assess the cost-effectiveness of PEP with a four-week regimen of zidovudine and lamivudine, or zidovudine, lamivudine, and indinavir. Due to a lack of empirical data on the effectiveness of PEP with combination drug regimens, the analysis assumed that combination PEP was no more effective than PEP with zidovudine alone. The main outcome variable is the cost per quality-adjusted life year (QALY) saved by the program. RESULTS: Providing PEP to a cohort of 10,000 patients who report receptive anal intercourse with a partner of unknown HIV status (who is assumed to be infected with probability equal to 0.18) would prevent about 20 infections, at an average net cost of about US$ 70,000 per infection averted. The cost-utility ratio, US$ 6316 per QALY saved, indicates that PEP is highly cost-effective in this instance. Moreover, triple-combination PEP would need to be about 9% more effective than dual-combination PEP for the addition of indinavir to the regimen to be considered cost-effective. Prophylaxis following receptive vaginal exposure is cost-effective only when it is nearly certain that the partner is infected; PEP for insertive anal and vaginal intercourse does not appear to be cost-effective. CONCLUSIONS: From a purely economic standpoint, PEP should be restricted to partners of infected persons (e.g., serodiscordant couples), to patients reporting unprotected receptive anal intercourse (including condom breakage), and possibly to cases where there is a substantial likelihood that the partner is infected. Providing PEP to all who request it does not appear to be an economically efficient use of limited HIV prevention and treatment resources.

Anti-HIV Agents↗