Lipid disorders in antiretroviral-naive patients treated with lopinavir/ritonavir-based HAART: frequency, characterization and risk factors

OBJECTIVES: The aim of this study was to evaluate the frequency, characteristics and risk factors of lipid changes associated with lopinavir/ritonavir treatment in antiretroviral-naive patients. METHODS: A prospective cohort of 107 antiretroviral-naive HIV-infected patients was followed for 12 months after starting lopinavir/ritonavir-based highly active antiretroviral therapy. RESULTS: At 12 months, percentages of patients with hypercholesterolaemia and hypertriglyceridaemia were 17.4% and 40%, respectively. Mean increases in total cholesterol and triglycerides were 40.7 and 73.3 mg/dL. There was a significant increase in both low-density and high-density (HDL) cholesterol, and no increase in the total cholesterol/HDL ratio (from 4.16 at baseline to 4.49 after 12 months). Baseline cholesterol > 200 mg/dL and triglycerides > 150 mg/dL were independent risk factors for dyslipidaemia, while hepatitis C coinfection appeared to be protective. CONCLUSIONS: Patients with elevated lipid values at baseline have the greatest risk of developing hypercholesterolaemia and hypertriglyceridaemia after starting lopinavir/ritonavir. Antiretroviral-naive patients coinfected with hepatitis C have a low risk of developing hyperlipidaemia after starting lopinavir/ritonavir.     

Use of lopinavir/ritonavir in HIV-infected patients failing a first-line protease-inhibitor-containing HAART

OBJECTIVES: The long-term virological efficacy of lopinavir/ritonavir-containing highly active antiretroviral therapy (HAART) in HIV-infected patients failing a first-line protease inhibitor (PI)-based regimen is still unclear. METHODS: An observational study was carried out from December 2000-December 2002 on 111 consecutive patients starting lopinavir/ritonavir. The primary end-point was virological success (HIV RNA <50 copies/mL in two consecutive determinations). CD4 outcome, lipid levels and adverse events were recorded. The Kaplan-Meier method and log-rank test were used to estimate the time-dependent probability of reaching the end-point using intention-to-treat and on-treatment approaches. RESULTS: Ninety-six patients obtained virological success during follow-up; Kaplan-Meier analysis showed that the time-dependent probability of obtaining this end-point was 78.4% at month 12 and 85.8% at month 24. The median CD4+cell count increased by 118 cells/mm(3) from baseline to month 12 and by 153 cells/mm(3) to month 24. Thirty-one patients discontinued lopinavir/ritonavir: 16 because of drug-related toxicities, six for simplification, five because of virological failure, one patient was lost at follow-up and three died. An elevation in lipid parameters was observed, but only a minority of patients developed a grade 3 or higher hypertriglyceridaemia and/or hypercholesterolaemia. Among the 15 patients not reaching virological success, five had < or =5 mutations in the protease region known to reduce susceptibility to lopinavir/ritonavir (one discontinued lopinavir/ritonavir because of gastrointestinal intolerance), five had no mutations (two discontinued lopinavir/ritonavir because of gastrointestinal intolerance) and five showed > or =6 mutations (all discontinued lopinavir/ritonavir); however, of the patients who discontinued lopinavir/ritonavir none achieved HIV RNA <50 copies/mL on subsequent regimens. CONCLUSIONS: Lopinavir/ritonavir was highly effective and well tolerated in HIV-infected patients failing a first-line PI-based HAART.     

Lopinavir/ritonavir monotherapy as a simplification strategy in routine clinical practice

OBJECTIVES: The efficacy and safety of lopinavir/ritonavir monotherapy has been explored with promising results in well-controlled, randomized clinical trials. However, less information about its clinical usefulness in routine clinical practice is currently available. The objective of this study was to assess the effectiveness and safety of monotherapy with lopinavir/ritonavir as a treatment simplification strategy in HIV-infected patients with viral suppression outside a clinical trial setting. METHODS: Fifty-one subjects who were switched to lopinavir/ritonavir monotherapy and whose HIV-1 RNA was <50 copies/mL were included in this retrospective study. Data were obtained from a prospectively compiled database. The primary endpoint was the percentage of subjects who maintained viral suppression after 48 weeks of follow-up. Secondary endpoints included the incidence of adverse events and changes in CD4+ T cell count and in lipid profile. RESULTS: Two patients lost viral suppression, seven patients interrupted lopinavir/ritonavir monotherapy because of adverse events and four patients were lost before completing 48 weeks of follow-up. Thus, 38/40 (95.0%) patients maintained viral suppression when only subjects whose outcomes were available up to week 48 were considered and 38/51 (74.5%) patients maintained viral suppression when subjects who discontinued therapy or who were lost to follow-up were considered as treatment failures. The mean CD4+ T cell count significantly increased, from 541 (280) cells/mm3 at baseline to 609 (212) cells/mm3 at week 48 of follow-up (P=0.034). This increase was similar to that observed in the 48 weeks prior to lopinavir/ritonavir monotherapy (P=0.792). Although total cholesterol remained unchanged, there was a significant decrease in triglyceride levels during follow-up (P=0.029). CONCLUSIONS: Monotherapy with lopinavir/ritonavir is safe and effective as a treatment simplification approach in HIV-1-infected patients with sustained viral suppression in routine clinical practice, particularly in those patients already receiving a lopinavir/ritonavir-based antiretroviral regimen.     

High HDL-cholesterol in women with rheumatoid arthritis on low-dose glucocorticoid therapy

Background Dyslipidaemia has been described in non‐treated rheumatoid arthritis (RA), and improves after therapy with disease modifying anti‐rheumatic drugs or glucocorticoids; however, it has generally been perceived that glucocorticoids adversely affect lipid metabolism. The association of low dose glucocorticoid therapy with plasma lipid levels was evaluated in female RA patients. Materials and methods A cross‐sectional study was conducted in 78 female RA patients [mean age: 60 (12) years; mean disease duration: 13 (9) years]. Sixty‐five (83%) were on glucocorticoid therapy [total equivalent mean prednisone dose: 5·1 (1·7) mg d^?1]. Each patient was assessed through a self‐reported questionnaire, structured interview and physical examination. Blood samples were obtained for routine biochemistry, lipid profile and haematological tests. Lipid profiles of RA patients who were and were not on glucocorticoid therapy were compared. Results Clinical and laboratory features of the two groups of patients were similar, except for the Health Assessment Questionnaire and body mass index, which were significantly higher in the patients on glucocorticoid therapy. These patients had 14·7% higher serum high‐density lipoprotein cholesterol (HDL‐c) levels than untreated patients (P = 0·043), mainly at the expense of HDL2 subfraction, which was 24·4% higher (P < 0·039), whereas HDL3‐c was only 7·4% higher (P = 0·219). Serum levels of glucose and total cholesterol, triglyceride, low‐density lipoprotein cholesterol (LDL ‐c), very low‐density lipoprotein cholesterol, apolipoproteins A‐I and B were not increased in patients on glucocorticoid therapy. Conclusions Low dose glucocorticoid therapy in RA patients is associated with an increase in HDL‐c, without increasing LDL‐c or triglyceride. These lipid changes may overall be considered favourable.     

Safety and antiviral activity of lopinavir/ritonavir-based therapy in human immunodeficiency virus type 1 (HIV-1) infection

Protease inhibitor-based antiretroviral therapy has been shown to decrease the morbidity and mortality associated with human immunodeficiency virus type 1 (HIV-1) infection. However, many of the available agents in this class suffer shortcomings, including poor tolerability, difficult dosing regimens, and variable drug concentrations which may lead to generation of viral resistance. Lopinavir/ritonavir (Kaletra) has been designed specifically to address some of these shortcomings. Excellent therapeutic efficacy has been documented for lopinavir/ritonavir in multiple clinical trials in both antiretroviral-naive and -experienced patients. Development of resistance is a rare event in persons initiating therapy with lopinavir/ritonavir as their first protease inhibitor. The main side effects associated with lopinavir/ritonavir are gastrointestinal disturbances and elevations of serum lipids. Current antiretroviral therapy guidelines list lopinavir/ritonavir as the consensus first-line protease inhibitor recommended in the initial therapeutic regimen in persons infected with HIV-1.     

Complex Patterns of Protease Inhibitor Resistance among Antiretroviral Treatment-Experienced HIV-2 Patients from Senegal: Implications for Second-Line Therapy

Protease inhibitor (PI)-based antiretroviral therapy (ART) can effectively suppress HIV-2 plasma load and increase CD4 counts; however, not all PIs are equally active against HIV-2, and few data exist to support second-line therapy decisions. To identify therapeutic options for HIV-2 patients failing ART, we evaluated the frequency of PI resistance-associated amino acid changes in HIV-2 sequences from a cohort of 43 Senegalese individuals receiving unboosted indinavir (n = 18 subjects)-, lopinavir/ritonavir (n = 4)-, or indinavir and then lopinavir/ritonavir (n = 21)-containing ART. Common protease substitutions included V10I, V47A, I54M, V71I, I82F, I84V, L90M, and L99F, and most patients harbored viruses containing multiple changes. Based on genotypic data, we constructed a panel of 15 site-directed mutants of HIV-2_ROD9 containing single- or multiple-treatment-associated amino acid changes in the protease-encoding region of pol. We then quantified the susceptibilities of the mutants to the HIV-2 “active” PIs saquinavir, lopinavir, and darunavir using a single-cycle assay. Relative to wild-type HIV-2, the V47A mutant was resistant to lopinavir (6.3-fold increase in the mean 50% effective concentration [EC₅₀]), the I54M variant was resistant to darunavir and lopinavir (6.2- and 2.7-fold increases, respectively), and the L90M mutant was resistant to saquinavir (3.6-fold increase). In addition, the triple mutant that included I54M plus I84V plus L90M was resistant to all three PIs (31-, 10-, and 3.8-fold increases in the mean EC₅₀ for darunavir, saquinavir, and lopinavir, respectively). Taken together, our data demonstrate that PI-treated HIV-2 patients frequently harbor viruses that exhibit complex patterns of PI cross-resistance. These findings suggest that sequential PI-based regimens for HIV-2 treatment may be ineffective.     

The HIV protease inhibitor ritonavir blocks osteoclastogenesis and function by impairing RANKL-induced signaling

Highly active antiretroviral therapy (HAART), which includes HIV protease inhibitors (PIs), has been associated with bone demineralization. To determine if this complication reflects accelerated resorptive activity, we studied the impact of two common HIV PIs, ritonavir and indinavir, on osteoclast formation and function. Surprisingly, we find that ritonavir, but not indinavir, inhibits osteoclast differentiation in a reversible manner and also abrogates bone resorption by disrupting the osteoclast cytoskeleton, without affecting cell number. Ritonavir given in vivo completely blunts parathyroid hormone-induced osteoclastogenesis in mice, which confirms that the drug is bone sparing. In keeping with its antiresorptive properties, ritonavir impairs receptor activator of nuclear factor kappaB ligand-induced (RANKL-induced) activation of NF-kappaB and Akt signaling pathways, both critical to osteoclast formation and function. In particular, ritonavir is found to inhibit RANKL-induced Akt signaling by disrupting the recruitment of TNF receptor-associated factor 6/c-Src complex to lipid rafts. Thus, ritonavir may represent a bone-sparing PI capable of preventing development of osteopenia in patients currently on HAART.     

Impact of steady-state lopinavir plasma levels on plasma lipids and body composition after 24 weeks of lopinavir/ritonavir-containing therapy free of thymidine analogues

OBJECTIVES: To study the impact of lopinavir/ritonavir-containing therapy on plasma lipids and body fat of HIV-infected adults and to assess whether lopinavir plasma levels at steady state are correlated with plasma lipids and body fat after 24 weeks. METHODS: Patients had their antiretroviral therapy switched to an antiretroviral regimen containing lopinavir/ritonavir plus one or two non-thymidine analogues. Body composition was assessed by dual energy X-ray absorptiometry at baseline and at week 24 and an intensive pharmacokinetic (PK) 12 h profile was performed at week 2. RESULTS: Twenty-six patients were included. Plasma triglycerides (from 206 mg/dL to 261 mg/dL, P = 0.09) and total cholesterol (from 201 to 206 mg/dL, P = 0.03) increased from baseline to week 24. There was a significant rise in total fat (from 10.9 to 11.9 kg, P = 0.02) and limb fat (from 3.8 to 4.4 kg, P = 0.02) from baseline to week 24. We did not find any correlation between PK lopinavir levels and changes over time for triglycerides, cholesterol or body fat composition. CONCLUSIONS: There was an increase in plasma triglycerides and total cholesterol levels and a gain in both total and limb fat at 24 weeks, but these changes were not correlated with lopinavir plasma levels.     

Pharmacokinetics of reduced-dose indinavir/ritonavir 400/100 mg twice daily in HIV-1-infected Thai patients

OBJECTIVE: To study the pharmacokinetics of indinavir/ ritonavir 400/100 mg twice daily in antiretroviral-naive patients at Srinagarind Hospital in Khon Kaen, Thailand. METHODS: This was a steady-state, open-label pharmacokinetic study of 19 patients. A 12 h pharmacokinetic curve was recorded after an overnight fast. Plasma levels of indinavir and ritonavir were determined by a validated HPLC method. Virological failure was defined according to the most recent US Department of Health and Human Services guidelines as a viral load above 400 copies/ml at week 24. RESULTS: Median baseline values for CD4 and viral load were 13cells/mm3 and 167000 copies/ml, respectively. The median (interquartile ranges) for indinavir AUC, Cmax and Cmin were 18.1 (15.3-23.8) mg/l x h, 4.1 (3.6-4.8) mg/l and 0.17 (0.12-0.30) mg/l, respectively. These values represent 37%, 39% and 24% of the AUC, Cmax and Cmin values found, respectively, for the indinavir/ritonavir 800/100 mg dose in HIV-1-infected Thai patients. Short-term virological response was satisfactory. There were three subjects with an indinavir Cmin. below the target value of 0.10 mg/l, of whom one had virological failure (33%). Among the other 16 subjects with an indinavir Cmin above 0.10 mg/l, there was also one virological failure (6%) (P=0.30). CONCLUSIONS: Indinavir exposure in this reduced-dose regimen of 400 mg with 100 mg ritonavir twice daily was more than dose-proportionally lower than previously observed with the indinavir/ritonavir 800/100 mg twice daily regimen. Therapeutic Cmin levels of indinavir were achieved in >80% of the subjects and short-term virological response was satisfactory in this cohort of patients starting highly active antiretroviral therapy at an advanced disease stage with high baseline viral loads.     

Exploratory analysis for the evaluation of lopinavir/ritonavir-versus efavirenz-based HAART regimens in antiretroviral-naive HIV-positive patients: results from the Italian MASTER Cohort

OBJECTIVE: This retrospective longitudinal cohort study compared the virological and immunological responses to highly active antiretroviral therapy containing either efavirenz or lopinavir/ritonavir in previously antiretroviral-naive HIV-infected patients. PATIENTS AND METHODS: A total of 472 patients were selected (348 efavirenz and 124 lopinavir/ritonavir). The primary endpoint of this study was virological success (HIV RNA <50 copies/mL). The immunological response was assessed on the basis of either CD4+ T cell count variations (absolute and percentage) with respect to baseline values or categorical endpoints (defined as either a CD4+ T cell increase of > or =1;50 cells/mm(3) at week 24 or of > or =1;75 cells/mm(3) at week 48). RESULTS: At intention-to-treat (ITT) analysis, the adjusted odds ratio of virological success for patients who started lopinavir/ritonavir, compared with those who started efavirenz, was 0.54 (95% CI: 0.33-0.89, P = 0.016) at week 24 and 0.40 (95% CI: 0.33-0.89, P = 0.002) at week 48. However, patients receiving lopinavir/ritonavir had a more pronounced CD4+ T cell recovery, demonstrating both a mean absolute and percentage increase up to week 48 (MANOVA P < 0.0001). CONCLUSIONS: Although comparisons of drug efficacy in non-randomized studies should be viewed with caution, from a virological point of view efavirenz-containing regimens performed as well (on-treatment analysis) or better (ITT analysis) than those containing lopinavir/ritonavir. In contrast, immunological outcome appeared to favour lopinavir/ritonavir.     

Relationships between drug exposure, changes in metabolic parameters and body fat in HIV-infected patients switched to a nucleoside sparing regimen

BACKGROUND: The pathogenesis of metabolic disturbances in treated HIV infection is incompletely understood. METHODS: Relationships between fasted metabolic parameters, body composition, and drug plasma concentrations were investigated in 59 patients who switched from failed nucleoside analogue treatment to ritonavir-boosted indinavir and efavirenz therapy. Metabolic parameters, peripheral fat, visceral adipose tissue (VAT) and drug plasma concentrations were measured prospectively. RESULTS: Ritonavir exposure was found to be negatively correlated with high-density lipoprotein cholesterol (HDL-c) changes, with a 2.4% decrease in HDL-c for each unit increase in ritonavir concentration ratio. Significant associations between indinavir or efavirenz concentrations and metabolic disturbances were not observed. Total cholesterol (TC) correlated positively with high body mass index (BMI) and negatively with baseline limb fat mass: each unit increase in BMI and each kilogram reduction in baseline limb fat corresponded with a TC increase of 2.4% and 4.1%, respectively. Baseline triglyceride levels were lower in those patients with relatively greater limb fat mass: each kilogram reduction of total limb fat mass was associated with a 15.7% increase in triglyceride concentration. Changes in VAT were positively correlated with TC: for every unit TC increase a 0.3% VAT increase was observed (over 48 weeks). CONCLUSIONS: Reduced limb fat mass at the start of the study treatment, increases in VAT mass, and higher plasma concentrations of ritonavir on study treatment were each--to varying degrees--associated with various metabolic disturbances.     

The influence of efavirenz on the pharmacokinetics of a twice-daily combination of indinavir and low-dose ritonavir in healthy volunteers

OBJECTIVE: This study evaluated the effect of multiple-dose efavirenz on the steady-state pharmacokinetics of the combination of indinavir (800 mg) and low-dose ritonavir (100 mg) twice a day, in which ritonavir is used to increase indinavir plasma concentrations. METHODS: Eighteen healthy male volunteers participated in this multiple-dose, 1-arm, 2-period interaction study. They took a combination of 800 mg indinavir and 100 mg ritonavir with food for 15 days. From days 15 to 29, a once-daily administration of 600 mg efavirenz was added to the combination. Pharmacokinetics of indinavir and ritonavir on days 15 and 29 were compared. RESULTS: Fourteen volunteers completed the study. The addition of efavirenz resulted in significant reductions (P <.01) in indinavir area under the curve (AUC, -25%), trough concentration (C(min), -50%), and maximum concentration (C(max), -17%). All indinavir C(min) levels on day 29 remained equivalent to or above the mean C(min) value described for the regimen of 800 mg indinavir three times a day, without ritonavir (0.15 mg/L). Changes in ritonavir AUC, C(min), and C(max) were -36%, -39%, and -34%, respectively. Pharmacokinetics of efavirenz on day 29 were comparable with published data. CONCLUSIONS: The addition of efavirenz to a combination of 800 mg indinavir and 100 mg ritonavir twice daily results in significant decreases in AUC, C(max), and especially C(min) of indinavir. The dose of indinavir or ritonavir should be increased to maintain similar indinavir drug levels after addition of efavirenz to the indinavir-ritonavir combination. Dose modifications may not be needed in antiretroviral-naive human immunodeficiency virus-infected patients if the reference C(min) of the regimen of 800 mg indinavir 3 times a day is considered to be adequate.     

The impact of outpatient diabetes management on serum lipids in urban African-Americans with type 2 diabetes.

OBJECTIVE: Treating dyslipidemia in diabetic patients is essential, particularly among minority populations with increased risk of complications. Because little is known about the impact of outpatient diabetes management on lipid outcomes, we examined changes in lipid profiles in urban African-Americans who attended a structured diabetes care program. RESEARCH DESIGN AND METHODS: A retrospective analysis of initial and 1-year follow-up lipid values was conducted among patients selected from a computerized registry of an urban outpatient diabetes clinic. The independent effects of lipid-specific medications, glycemic control, and weight loss on serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels were evaluated by analysis of covariance and multiple linear regression. RESULTS: In 345 patients (91% African-American and 95% with type 2 diabetes), HbA(1c) decreased from 9.3% at the initial visit to 8.2% at 1 year (P < 0.001); total and LDL cholesterol and triglyceride levels were significantly lower, and HDL cholesterol was higher. After stratifying based on use of lipid-specific therapy, different outcomes were observed. In 243 patients not taking dyslipidemia medications, average total cholesterol, LDL cholesterol, and triglyceride concentrations at 1 year were similar to initial values, whereas in 102 patients receiving pharmacotherapy, these lipid levels were all lower at 1 year relative to baseline (P < 0.001). Mean HDL cholesterol increased regardless of lipid treatment status (P < 0.001). After adjusting for other variables, changes in LDL cholesterol concentration were associated only with use of lipid-specific agents (P = 0.003), whereas improved HbA(1c) and weight loss had no independent effect. Lipid therapy, improved glycemic control, and weight loss were not independently related to changes in HDL cholesterol and therefore could not account for the positive changes observed. Use of lipid-directed medications, improvement in glycemic control, and weight loss all resulted in significant declines in triglyceride levels but only improved HbA(1c) and weight loss had an independent effect. CONCLUSIONS: Among urban African-Americans, diabetes management led to favorable changes in HDL cholesterol and triglyceride levels, but improved glycemic control and weight loss had no independent effect on LDL cholesterol concentration. Initiation of pharmacologic therapy to treat high LDL cholesterol levels should be considered early in the course of diabetes management to reach recommended targets and reduce the risk of cardiovascular complications in this patient population.     

Association of total bilirubin with indinavir and lopinavir plasma concentrations in HIV-infected patients receiving three different double-boosted dosing regimens

OBJECTIVES: The purpose of this study was to determine the pharmacokinetics and tolerability of three different indinavir and lopinavir/ritonavir dosing regimens. METHODS: HIV-infected adults receiving lopinavir/ritonavir 400/100 mg twice daily with food had nine plasma samples taken over a 12 h dosing interval at baseline (BL), after adding indinavir 600 mg twice daily for 10 days (R1), indinavir 800 mg twice daily for 5 days (R2) and lopinavir/ritonavir 533/133 mg plus indinavir 600 mg twice daily for 10 days (R3). Plasma samples were assayed using HPLC. RESULTS: A total of 12 patients completed the BL visit [10 male; mean (SD) age=43.9 (5.8) years] and 9, 7 and 7 completed R1, R2 and R3 visits, respectively. Two subjects discontinued treatment due to hypertriglyceridaemia. Compared with BL, the R3 lopinavir AUC (P<0.05) and Cmin (P=0.0025) were significantly higher and the R2 AUC trended higher (P=0.09). The indinavir AUC (P=0.030) and Cmax (P=0.035) were significantly higher for R2 compared with R1. There was a trend for increased total bilirubin (TB) after the addition of indinavir (P=0.09). Lopinavir and indinavir AUC, Cmax and Cmin were associated with TB during univariate analyses (P<0.01) while only lopinavir AUC (P=0.0004) and indinavir AUC (P=0.0028) were associated with TB during multivariate analysis. Only indinavir AUC was significant when both drugs were included in the model (P=0.0028). CONCLUSIONS: Elevated lopinavir and indinavir concentrations are associated with elevated TB.     

Specific HIV protease inhibitors inhibit the ability of HPV16 E6 to degrade p53 and selectively kill E6-dependent cervical carcinoma cells in vitro

Although HIV protease inhibitor (PI) drugs predominantly target HIV proteases 1 and 2, it is also known that part of their efficacy is due to selective inhibition of the proteasome. The pathogenicity of high-risk human papilloma virus (HPV) is dependent on expression of viral E6 proteins which inappropriately activate the 26S proteasome to degrade p53 and other cellular proteins that are detrimental to viral replication. Comparison of the ability of the PIs indinavir, ritonavir, amprenavir, lopinavir, atazanavir, nelfinavir and saquinavir to inhibit E6-mediated proteasomal degradation of mutant p53 in E6-transfected C33A cells showed that 15 microM lopinavir, 1 mM indinavir or 125 microM ritonavir treatment for 24 h produced a stable increase in the level of nuclear p53 in these cells with minimal cell death. After 4 h exposure of HPV16+ve SiHa cells to 15 microM lopinavir, a transient increase in wild-type p53 expression was observed associated with a 7% reduction in the chymotryptic activity of the 205 proteasome and apoptosis after 24h. Comparison of growth rates of PI treated SiHa, CaSki, C33A, C33A-E6 and non-transformed NIH/3T3 cells showed that SiHa were the most sensitive, whereas NIH/3T3 were least affected. In conclusion, these data show that specific HIV PIs such as lopinavir and possibly indinavir, can induce selective toxicity of HPV-transformed cervical carcinoma cells expressing wild-type p53 and may form the basis of a topically applied alternative to surgery for the treatment of HPV-related premalignant lesions of the cervix.     

Lopinavir/ritonavir combined with twice-daily 400 mg indinavir: pharmacokinetics and pharmacodynamics in blood, CSF and semen

OBJECTIVES: To evaluate the steady-state blood plasma (BP), CSF and seminal plasma (SP) pharmacokinetics (PK) of twice-daily indinavir 400 mg and lopinavir/ritonavir. METHODS: Ten HIV-1-positive men on lopinavir/ritonavir participated in a PK study. PK sampling was performed before and 2 weeks after adding indinavir to lopinavir/ritonavir-containing regimens. BP, CSF and SP RNA levels, CD4 counts and blood chemistry were checked at baseline and 2 weeks after indinavir. RESULTS: At baseline: lopinavir parameters (n=10) in BP were within expected levels. Median lopinavir trough concentrations (n=5) in CSF and SP were below the limit of detection (BLD) (i.e. <10 ng/mL) and 248 ng/mL (range 96-2777), respectively. After indinavir: lopinavir C(max), C(min) and AUC(0-12) increased by 9%, 46% and 20%, respectively (P<0.32, P<0.32 and P<0.20). In two of four men lopinavir concentrations in CSF were detectable at 27 and 29 ng/mL. Median SP lopinavir concentration was 655 ng/mL (20-2734). Median indinavir PK parameters were C(max) 3365 ng/mL (range 2130-5194), C(min) 293 ng/mL (14-766), T(max) 2.25 h (1-3), AUC(0-12) 22452 ng/mL.h (11243-33661), and t(1/2) 2.8 h (1.4-3.7). Median indinavir concentrations in CSF and SP were 39 ng/mL (21-86) and 592 ng/mL (96-983). Two of eight men who initially had detectable BP viral load (VL) became BLD (<50 copies/mL) after the addition of indinavir, and in 2/4 men with low-level viraemia in SP (BPVL BLD) their SPVL became BLD after addition of indinavir. CONCLUSIONS: Adding indinavir 400 mg twice daily to lopinavir/ritonavir-containing regimens did not significantly alter the median lopinavir PK parameters. However, wide interpatient variability in lopinavir concentrations was seen. In contrast plasma indinavir levels were >80 ng/mL in seven of eight plasma samples, and all CSF and semen samples collected.     

Assessment of lopinavir pharmacokinetics with respect to developmental changes in infants and the impact on weight band-based dosing

Improved antiretroviral therapies are needed for the treatment of HIV-infected infants, given the rapid progression of the disease and drug resistance resulting from perinatal exposure to antiretrovirals. We examined longitudinal pharmacokinetics (PK) data from a clinical trial of lopinavir/ritonavir (LPV/r) in HIV-infected infants in whom therapy was initiated at less than 6 months of age. A population PK analysis was performed using NONMEM to characterize changes in lopinavir (LPV) PK relating to maturational changes in infants, and to assess dosing requirements in this population. We also investigated the relationship between LPV PK and viral dynamic response. Age and ritonavir concentrations were the only covariates found to be significant. Population PK of LPV was characterized by high apparent clearance (CL/F) in young infants, which decreased with increasing age. Although younger infants had lower LPV concentrations, the viral dynamics did not correlate with initial LPV exposure. Monte Carlo simulations demonstrated that WHO weight band-based dosing recommendations predicted therapeutic LPV concentrations and provided drug exposure levels comparable to those resulting from US Food and Drug Administration (FDA)-suggested dosing regimens.     

Lopinavir plus ritonavir: a novel protease inhibitor combination for HIV infections

Lopinavir is a protease inhibitor (PI) for the treatment of HIV infection that was specifically designed to overcome the shortcomings of earlier agents in this class. It is the only PI coformulated with ritonavir, whose pharmacological boosting effect results in a highly potent, well-tolerated, clinically effective antiretroviral agent with a high genetic barrier to resistance. Lopinavir/ritonavir is a recommended first-line option for antiretroviral-naive patients initiating PI-based therapy, and has an equally important role in the management of treatment-experienced individuals. Its favorable pharmacological and clinical characteristics have recently prompted investigators to explore its potential novel applications in HIV monotherapy and double-boosted regimens.