Detection of intrathecal IgG antibody for varicella and measles diagnosis by evaluation and comparison of a commercial IgG chemiluminescent immunoassay with two ELISAs.

OBJECTIVES: Analyse alternative methods of intrathecal antibody detection by comparing chemiluminescent immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA) techniques to determine if CLIA can replace ELISA in the diagnosis of CNS infections. METHODS: A panel of 280 paired samples-cerebrospinal fluid (CSF) and serum-with known antibody reactivities (Varicella, n = 60; Measles, n = 120) and negative samples (n = 100) were used to evaluate the performance of six serological test kits (Enzygnost, VirClia®, and Serion ELISA (Measles and Variella). RESULTS: For Measles virus IgG, the VirClia® IgG monotest revealed 97% and 94% positive and negative agreement to the Enzygnost as reference test, respectively. In contrast, Serion ELISA kits yielded values of 18% and 90%. For the Varicella Zoster virus (VZV) IgG, the VirClia® IgG monotest showed 97% and 90% positive and negative agreement compared to Enzygnost. The Serion ELISA kits showed values of 55% and 86%, respectively. ROC analysis revealed that the areas under the curve for Measles and VZV IgGs were 0.7 and 0.852, respectively, using the Serion kit, and 0.963 and 0.955, for Vircell S.L CLIA technique. VirClia® monotest values were calculated using an antibody index cut-off of 1.3. CONCLUSION: The findings indicate that CLIA testing can improve antibody detection in CSF samples, aiding the diagnosis of infectious neurological impairments.

The pharmacokinetics, safety and efficacy of boosted saquinavir tablets in HIV type-1-infected pregnant women.

BACKGROUND: Pregnancy affects the pharmacokinetics of most protease inhibitors. Saquinavir, when administered in a tablet formulation, has not been studied extensively in this setting. METHODS: A pharmacokinetic, prospective, multicentre trial of HIV type-1-infected pregnant women treated with saquinavir (500 mg tablets) boosted with ritonavir at a dose of 1,000/100 mg twice daily plus a nucleoside backbone was conducted. Pharmacokinetic curves were recorded for 12 h in the second trimester (week 20 +/-2), the third trimester (week 33 +/-2) and post-partum (weeks 4-6). Blood was sampled pre-dosing and at 1, 2, 3, 4, 6, 8, 10 and 12 h post-dosing. Pharmacokinetic parameters were calculated using WinNonlin software version 4.1. RESULTS: A total of 37 women were included in the analysis. Mean (+/-sd) values for saquinavir area under the curve (AUC(0-12h)) were 23.47 h*mg/l (11.92) at week 20 (n=16), 23.65 h*mg/l (9.07) at week 33 (n=31) and 25.00 h*mg/l (11.81) post-partum (n=9). There was no significant difference in the saquinavir AUC(0-12h) when comparing the data during pregnancy and post-partum. Subtherapeutic plasma concentrations of saquinavir (defined as <0.10 mg/l) were not observed throughout the study. No major safety concerns were noted. CONCLUSIONS: Saquinavir exposure in the new tablet formulation generates adequate saquinavir concentrations throughout the course of pregnancy and is safe to use; therefore, no dose adjustment during pregnancy is needed.

Unexpected Hepatotoxicity of Rifampin and Saquinavir/Ritonavir in Healthy Male Volunteers.

OBJECTIVES: Rifampin is a potent inducer of the cytochrome P450 3A4 isoenzyme (CYP3A4) that metabolizes most protease inhibitor (PI) antiretrovirals. This study was designed to evaluate the steady-state pharmacokinetics and tolerability of the coadministration of the PIs saquinavir and ritonavir (a CYP3A4 inhibitor used as a pharmacoenhancer of other PIs) and rifampin when coadministered in healthy HIV-negative volunteers. METHODS: In an open-label, randomized, one sequence, two-period crossover study involving 28 healthy HIV-negative volunteers, arm 1 was randomized to receive saquinavir/ritonavir 1000/100 mg twice daily while arm 2 received rifampin 600 mg once daily for 14 days. Both arms were then to receive concomitant saquinavir/ritonavir and rifampin for 2 additional weeks. Vital signs, electrocardiography, laboratory analyses, and blood levels of total saquinavir, ritonavir, rifampin, and desacetyl-rifampin, the primary metabolite of rifampin, were measured. RESULTS: In arm 1, 10/14 (71%) and, in arm 2, 11/14 (79%) participants completed the first study phase; eight participants in arm 1 and nine in arm 2 went on to receive both saquinavir/ritonavir and rifampin. Following substantial elevations (>/= grade 2) in hepatic transaminases in participants receiving the coadministered agents, the study was discontinued prematurely. Two participants in arm 1 displayed moderate elevations after five and four doses of rifampin, respectively. In arm 2, all participants experienced severe elevations within 4 days of initiating saquinavir/ritonavir. Clinical symptoms (e.g., nausea, vomiting, abdominal pain, and headache) were more common and severe in arm 2. Clinical symptoms abated and transaminases normalized following drug discontinuation. Limited pharmacokinetic data suggest a possible relationship between transaminase elevation and elevated rifampin and desacetyl-rifampin concentrations. CONCLUSIONS: Although not confirmed in HIV-infected patients, the data indicate that rifampin should not be coadministered with saquinavir/ritonavir.

Gemini: a noninferiority study of saquinavir/ritonavir versus lopinavir/ritonavir as initial HIV-1 therapy in adults.

INTRODUCTION: : Direct comparison of the efficacy and safety of different agents is needed to guide selection of optimal treatment regimens for therapy-naive HIV-1-infected patients. METHODS: : Gemini was a 48-week, multicenter, open-label, noninferiority trial in treatment-naive HIV-1-infected adults randomized to either saquinavir/ritonavir (SQV/r) 1000 mg/100 mg twice a day or lopinavir/ritonavir (LPV/r) 400 mg/100 mg twice a day, each with emtricitabine/tenofovir 200 mg/300 mg every day. RESULTS: : A similar proportion of participants in the SQV/r (n = 167) and LPV/r (n = 170) arms had HIV-1 RNA levels <50 copies per milliliter at week 48: 64.7% vs 63.5% and estimated difference in proportion for noninferiority: 1.14%, 96% confidence interval: -9.6 to11.9 (P < 0.012), confirming that SQV/r was noninferior to LPV/r treatment. There were no significant differences in week 48 CD4 counts between arms. The rate and severity of adverse events were similar in both groups. There were no significant differences in the median change from baseline between arms in plasma lipids except for triglyceride levels, which were significantly higher in the LPV/r at week 48. CONCLUSIONS: : In treatment-naive, HIV-1-infected patients, SQV/r treatment was noninferior in virologic suppression at 48 weeks to LPV/r treatment and offered a better triglyceride profile.

Double boosted protease inhibitors, saquinavir, and lopinavir/ritonavir, in nucleoside pretreated children at 48 weeks.

OBJECTIVES: To assess the 48-week efficacy, safety, pharmacokinetics, and resistance of double boosted protease inhibitors (PI), saquinavir (SQV), and lopinavir/ritonavir (LPV/r), in children who have failed nucleoside reverse transcription inhibitors /non-nucleoside reverse transcription inhibitors-based regimens. METHODS: Fifty children at 2 sites in Thailand were treated with standard dosing of SQV and LPV/r. CD4, HIV-RNA viral load (VL), plasma drug concentrations and safety laboratory evaluations were monitored. Virologic failure was defined as having 2 consecutive VL >400 copies/mL after week 12 of therapy. Intention to treat analysis was performed. RESULTS: Baseline data were a median age of 9.3 years (interquartile range [IQR]: 7.1-11.2), Center for Disease Control and Prevention (CDC) classification N:A:B:C 4%:14%:68%:14%, VL 4.8 log10 (IQR: 4.5-5.1), CD4 7% (IQR: 3-9.5). At 48 weeks, 3 had died of bacterial infection but no cases had progressed CDC classification. Median CD4% rise was 9 (IQR: 5-16) and median HIV RNA reduction was -2.8 log10 (IQR: -3.2 to -1.4), both P < 0.001. Thirty-nine (78%) and 32 (64%) children had VL <400 and <50 with significant differences between the 2 sites. Five children (10%) had VL failure as a result of poor adherence to the drug regimen but no one had major PI mutations. Median serum cholesterol and triglyceride increased significantly (+35 mg/dL, +37 mg/dL, respectively, both P < 0.001). Mean minimum plasma concentrations (Cmin) of LPV and SQV were 4.6 and 1.24 mg/L, respectively. CONCLUSIONS: Double boosted SQV/LPV/r resulted in significant CD4 rise and VL decline at 48 weeks. Hyperlipidemia was common. Cmin of both PIs exceeded therapeutic concentrations. Poor adherence caused failure in 10%. No major PI mutations were found.

Long-term efficacy and safety of first-line therapy with once-daily saquinavir/ritonavir.

BACKGROUND: The aim of this study was to assess the long-term efficacy and safety of first-line treatment with once-daily saquinavir/ritonavir plus two nucleoside reverse transcriptase inhibitors (NRTIs). METHODS: A total of 272 antiretroviral-naive patients with a CD4+ T-cell count of 200-350 cells/mm3 were treated with two NRTIs and saquinavir/ritonavir 1,600/100 mg per day for > 24 weeks. Patients were followed up every 12 weeks for CD4+ T-cell counts, HIV RNA levels, clinical and laboratory toxicities. Intention-to-treat analyses were used for the first 24 weeks of treatment and as-treated analysis after week 24. RESULTS: The median baseline CD4+ T-cell count was 269 cells/mm3 and HIV RNA was 4.7 log10 copies/ml. At a median follow-up time of 56 (interquartile range [IQR] 25-113) weeks, 262/272 (96.3%) had HIV RNA < 400 copies/ml, with a median HIV RNA decline of -2.89 (IQR 3.31--2.37) log10 copies/ml (P < 0.001) and a median rise in CD4+ T-cell count of 192 (IQR 117-317) cells (P < 0.001). At weeks 24, 48, 72 and 96, 249/272 (91.5%), 157/164 (95.7%), 113/126 (89.7%) and 84/90 (93.3%) had HIV RNA < 400 copies/ml, respectively; at the same time points, 83.8%, 92.7%, 85.7% and 85.6% had HIV RNA < 50 copies/ml. Drug-related adverse events were reported in 6.30%. Significant rises in total cholesterol, triglyceride, low-density lipoprotein and high-density lipoprotein were seen. CONCLUSION: First-line highly active antiretroviral therapy with once-daily saquinavir/ritonavir plus two NRTIs showed strong antiviral efficacy.

Pharmacokinetic analysis to assess forgiveness of boosted saquinavir regimens for missed or late dosing.

OBJECTIVES: One potential concern of once-daily protease inhibitor administration is low trough concentrations and ultimately the 'forgiveness' or robustness in comparison with the originally licensed twice-daily dose. To give an estimation of 'forgiveness', we determined the length of time plasma drug concentrations were below target in HIV-infected patients receiving saquinavir/ritonavir regimens. METHODS: Seventy-seven pharmacokinetic profiles (saquinavir/ritonavir 1000/100 mg twice daily, n = 34; 1600/100 mg once daily, n = 26; 2000/100 mg once daily, n = 17) from five studies were combined, presented as twice- and once-daily percentiles (P10-P90) and compared. At percentiles where trough concentrations fell below the alleged minimum effective concentration (MEC; 100 ng/mL), the length of time below MEC was determined. RESULTS: Saquinavir concentrations were below MEC at P10 for 0.7 h for twice-daily saquinavir/ritonavir when compared with 8.6 and 6.6 h for 1600/100 and 2000/100 mg once daily, respectively. At P25, 1600/100 mg once daily produced suboptimal concentrations for 5.5 h in contrast to 0.5 h for 2000/100 mg once daily. CONCLUSIONS: Here, we provide substantive data that indicate once-daily saquinavir, in particular 1600/100 mg, is not as robust as the twice-daily regimen based on a population of UK patients; this raises concern over late or missed doses. However, pharmacokinetic data can only ever be a guide to the impact on long-term efficacy.

Synergistic inhibition of protease-inhibitor-resistant HIV type 1 by saquinavir in combination with atazanavir or lopinavir.

BACKGROUND: Double-boosted protease inhibitors (PIs) are under investigation for the treatment of patients who are unable to take nucleoside reverse transcriptase inhibitors because of cross-resistance and/or intolerance. Evidence of synergistic inhibition of wild-type HIV has been reported for saquinavir with atazanavir or lopinavir. METHODS: We investigated the activity of these two combinations against a panel of six site-directed mutant HIV-1 strains and 14 clinically derived recombinant HIV-1 strains presenting a range of PI-resistance profiles. RESULTS: No evidence of synergy was observed against wild-type virus for either combination. The combination of saquinavir and lopinavir showed evidence of synergy against four viruses displaying high-level resistance to lopinavir and low-level resistance to saquinavir. Similarly, evidence of synergy between saquinavir and atazanavir was only observed in two viruses which were more susceptible to saquinavir than to atazanavir. CONCLUSIONS: We hypothesize that differences between the PIs in intracellular protein-binding behaviour or inhibition of drug transporters (P glycoprotein, MDR1 and MDR2) could result in intracellular levels of saquinavir being increased by co-administration with lopinavir or atazanavir. The effect of this increase would be masked in cases involving viruses that were susceptible to atazanavir or lopinavir. In virus resistant to lopinavir or atazanavir but susceptible to saquinavir, the majority of the antiviral effect is due to saquinavir; thus even small increases in intracellular concentration could significantly increase virus inhibition. These results confirm that in vitro synergy can be observed between PIs and suggest that the degree of synergy observed might depend on the resistance profile of the virus.

The safety, efficacy, and pharmacokinetic profile of a switch in antiretroviral therapy to saquinavir, ritonavir, and atazanavir alone for 48 weeks and a switch in the saquinavir formulation.

BACKGROUND: Toxicities observed with current combination antiretroviral therapy (CART) warrant a search for novel options, such as class-sparing regimens. Ritonavir-boosted double-protease inhibitor (PI)-only regimens are such an option but are prone to pharmacokinetic interactions. METHODS: This 48-week randomized study examined the safety and efficacy of a switch in CART to a once-daily regimen of saquinavir (SQV), ritonavir (RTV), and atazanavir (ATV) that did not include nucleoside reverse-transcriptase inhibitors (NRTIs). The study also assessed the pharmacokinetic profile of a change in the SQV formulation, from 200 mg to 500 mg, in 2 regimens (SQV-RTV twice per day plus NRTIs [arm 1] and SQV-RTV-ATV once per day without NRTIs [arm 2]) in human immunodeficiency virus type 1-infected subjects (plasma human immunodeficiency virus RNA level, <50 copies/mL). Patients underwent an initial SQV formulation change or a CART change to SQV-RTV-ATV with intense pharmacokinetic sampling. All patients were subsequently assigned to receive SQV-RTV-ATV (1500, 100, and 300 mg once per day, respectively) without NRTIs for 48 weeks. The primary end point was the percentage of patients who experienced virologic failure. RESULTS: Of 25 subjects enrolled, scleral icterus was the most common adverse event (3 patients [12.5%]). Three subjects (12.5%) experienced virologic failure; and mean (+/- standard error of the mean) increase in the CD4(+) lymphocyte count was 63 +/- 36 cells/ mu L over 48 weeks (P=.012). The SQV geometric mean area under the time curve parameters were not significantly altered for the 2 SQV formulations (arm 1, 23.32 vs. 18.76 ngxh/mL [geometric mean ratio, 0.80] for the 200-mg vs. 500-mg formulations, respectively; arm 2, 50.31 vs. 44.79 ngxh/mL [geometric mean ratio, 0.88], for the 200-mg vs. 500-mg formulations, respectively). CONCLUSIONS: A CART regimen of SQV-RTV-ATV alone demonstrated sustained virologic efficacy and was associated with significant increases in the CD4(+) lymphocyte count.

Absence of resistance mutations in antiretroviral-naive patients treated with ritonavir-boosted saquinavir.

BACKGROUND: There are few data on the selection of resistance by ritonavir-boosted saquinavir (SQV/r), particularly in antiretroviral (ARV)-naive patients. OBJECTIVE: To assess the incidence of virological failure and evolution of resistance in ARV-naive individuals receiving SQV/r in the induction phase of the Staccato trial. METHODS: ARV-naive subjects (n = 272) received SQV/r 1,600/100 mg once daily with two nucleoside reverse transcriptase inhibitors (NRTIs) for at least 24 weeks. Patients were defined as having virological failure (VF) when there were two consecutive HIV-1 RNA measurements > 500 copies/ml after week 12. Viral genotypes (reverse transcriptase [RT] and protease [PRO]) were determined at baseline in all patients and as close as possible to the time of initial failure in patients experiencing VF. RESULTS: VF was observed in 9/272 patients receiving SQV/r 1,600/100 mg once daily with two NRTIs (3.3%) and occurred 19-48 weeks after treatment initiation. Eight of these patients were evaluable at failure. No major PRO mutations were detected, but 2/8 displayed single new minor PRO substitutions (M36I, L10I) at VF that were known or suspected not to have been present at baseline; both these substitutions exist as natural polymorphisms. A third patient displayed a single new RT mutation (M184I). CONCLUSIONS: SQV/r plus two NRTIs (1,600/100 mg once daily) is an effective initial treatment option for ARV-naive patients, resulting in a low rate of viral rebound (3.3%). Furthermore, no major protease mutations were detected following VF, suggesting that future treatment options are preserved.

Efficacy, safety and pharmacokinetics of once-daily saquinavir soft-gelatin capsule/ritonavir in antiretroviral-naive, HIV-infected patients.

CONTEXT: Once-daily HIV treatment regimens are being used in clinical practice with the objective of improving patient acceptance and adherence. OBJECTIVE: To evaluate the efficacy and safety of saquinavir-soft-gelatin capsule (SGC)/ritonavir combination (1600 mg/100 mg) vs efavirenz (600 mg) both once daily and combined with 2 nucleoside analogs twice daily. SETTING: Twenty-six centers in the United States, Canada, and Puerto Rico. PATIENTS: A total of 171 antiretroviral naive HIV-infected individuals were enrolled in a 48-week, phase 3, open-label, randomized study. MAIN OUTCOME MEASURE: Proportion of patients with HIV-RNA levels < 50 copies/mL. The pharmacokinetic profile of saquinavir-SGC was analyzed in a subset of randomly selected patients. RESULTS: In the primary intent-to-treat population at week 48, 51% (38/75) and 71% (55/77) of patients in the saquinavir-SGC/ritonavir and efavirenz groups, respectively, achieved HIV-RNA suppression < 50 copies/mL (P = .5392, 95% 1-sided confidence interval [CI] = -33.5%). In the on-treatment (OT) population, 73% (38/52) and 93% (54/58) of patients in the saquinavir-SGC/ritonavir and efavirenz groups, respectively, had effective viral suppression < 50 copies/mL (P = .5015, 95% 1-sided CI = -33.4%). Mean CD4+ cell counts increased by 239 and 204 cells/microliters (mcL), in the saquinavir-SGC/ritonavir and efavirenz groups, respectively, in the OT analysis (P = .058). Both regimens were reasonably well tolerated, although more gastrointestinal adverse events were reported with saquinavir-SGC/ritonavir. Pharmacokinetic profiles in 6 patients showed an observed median Cmin at 24 hours of 429 ng/mL (range, 68-1750 ng/mL). CONCLUSIONS: Once-daily efavirenz was statistically superior to once-daily saquinavir-SGC/ritonavir. Gastrointestinal adverse effects were commonly associated with treatment failure in the saquinavir-SGC/ritonavir arm of the study.

Effect of omeprazole on the pharmacokinetics of saquinavir-500 mg formulation with ritonavir in healthy male and female volunteers.

INTRODUCTION: Recent studies have described reduced absorption of certain protease inhibitors when administered with agents known to increase gastric pH. No clinically significant interactions between saquinavir absorption and gastric pH have previously been shown. We evaluated the effect of omeprazole, a proton-pump-inhibitor, on the pharmacokinetics of the recently developed saquinavir-500 mg formulation co-administered with ritonavir. METHODS: Eighteen healthy subjects (n = 6 women and 12 men) received 1000/100 mg saquinavir/ritonavir twice daily in an open-label study for 15 days. On days 11-15, subjects were administered omeprazole 40 mg daily with the morning dose. Serial plasma samples were collected for 12-h pharmacokinetic profiles of saquinavir and ritonavir on days 10 and 15 and safety analysis on days 1, 4, 10, 15 and 29. RESULTS: The geometric mean and 95% confidence interval (CI), for the area under time-concentration curve (AUC; ng h/ml), trough plasma concentration (C trough; ng/ml) and maximum observed plasma concentration (Cmax; ng/ml) of saquinavir were 20599 (14396-29360) and 37511 (28733-48970); 737 (482-1127) and 1521 (1039-2227); 3227 (2370-4393) and 5611 (4507-7710) on days 10 and 15, respectively, with geometric mean ratios of 1.82, 2.06 and 1.75. No significant changes were observed in saquinavir elimination half life, ritonavir pharmacokinetic parameters or in safety laboratory tests. No unexpected adverse events attributed to study medication were noted. CONCLUSIONS: In the presence of omeprazole, total saquinavir plasma exposure is significantly increased (82% increase in AUC). The mechanism of this interaction requires elucidation. Despite the significant increase in saquinavir exposure, no short term toxicities were observed.

The 5(th) International Workshop on Clinical Pharmacology of HIV Therapy.

The 5(th) International Workshop on Clinical Pharmacology of HIV Therapy was held at the Università Cattolica del Sacro Cuore, Rome, Italy on April 1 - 3, 2004. More than 180 participants registered for this workshop demonstrating the growing interest in antiretroviral pharmacology. The purpose of this meeting was to present and discuss antiretroviral pharmacokinetics, pharmacodynamics, drug interactions, therapeutic drug monitoring-related research and the assays necessary for measuring antiretroviral concentrations. A total of 31 oral and 48 poster presentations were accepted to this meeting, the largest number of accepted submissions in the 5-year history of this workshop. Herein, examples of the research that was presented are highlighted.

Probiotics, soluble fiber, and L-Glutamine (GLN) reduce nelfinavir (NFV)- or lopinavir/ritonavir (LPV/r)-related diarrhea.

PURPOSE: Highly active antiretroviral therapy (HAART) can be associated with diarrhea and other gastrointestinal (GI) side effects. Reducing these side effects may improve treatment durability and quality of life (QOL). This study assessed the impact of nutritional co-therapies known to reduce diarrhea in HIV-positive men treated with nelfinavir (NFV)- or lopinavir/ritonavir (LPV/r)-containing regimens. METHODS: Thirty-five HIV-positive men treated with NFV (n = 27) or LPV/r (n = 8) with diarrhea (> or = two liquid stools/day [d]) participated in a 12-week prospective study. Twenty-eight subjects were randomly assigned supplements (S), seven received standard of care (C). Group S received probiotics (1.2g/d) and soluble fiber (11g/d). If diarrhea persisted at week 4, 30g/d L-Glutamine (GLN) was added. Diarrhea incidence, as well as supplement and antidiarrheal use, was assessed monthly. RESULTS: Weight, CD4 count, and HIV RNA were unchanged in both groups. Diarrhea completely resolved in 10 of 28 (36 percent) S subjects. The mean (+/-SD) number of stools/d declined [3.40+/-1.25 to 2.54+/-1.34 (p < 0.01)]. Diarrhea (loose, watery stools/d) lessened in S from 2.84+/-1.42 to 0.74+/-1.03 (p < 0.0001). Fifteen S subjects did not obtain full relief with probiotics and fiber, but stools/d decreased from 4.08+/-1.35 to 3.06+/-1.68 (p < 0.05) after starting GLN. In C, stools/d, 4.14+/-4.86 to 3.44+/-1.68(p = 0.678) and incidence of diarrhea/d, 3.00+/-4.82 to 1.36+/-1.29 (p= 0.361) was unchanged. In S, loperamide use decreased from 1.69+/-2.34 to 0.31+/-0.69 mg/d (p < 0.01); 18 versus eight subjects used loperamide at 0 and 12 weeks, respectively. CONCLUSION: Probiotics, soluble fiber, and GLN significantly reduced diarrhea for subjects receiving NFV or LPV/r. Nutritional co-therapies show clinical benefit in HIV-positive men with diarrhea.