Summary
VRC‐HIVMAB060‐00‐AB (VRC01) is a broadly neutralizing HIV‐1 monoclonal antibody (mAb) isolated from the B cells of an HIV‐infected patient. It is directed against the HIV‐1 CD4 binding site ...and is capable of potently neutralizing the majority of diverse HIV‐1 strains. This Phase I dose‐escalation study in healthy adults was conducted at the National Institutes of Health (NIH) Clinical Center (Bethesda, MD, USA). Primary objectives were the safety, tolerability and pharmacokinetics (PK) of VRC01 intravenous (i.v.) infusion at 5, 20 or 40 mg/kg, given either once (20 mg/kg) or twice 28 days apart (all doses), and of subcutaneous (s.c.) delivery at 5 mg/kg compared to s.c. placebo given twice, 28 days apart. Cumulatively, 28 subjects received 43 VRC01 and nine received placebo administrations. There were no serious adverse events or dose‐limiting toxicities. Mean 28‐day serum trough concentrations after the first infusion were 35 and 57 μg/ml for groups infused with 20 mg/kg (n = 8) and 40 mg/kg (n = 5) doses, respectively. Mean 28‐day trough concentrations after the second infusion were 56 and 89 μg/ml for the same two doses. Over the 5–40 mg/kg i.v. dose range (n = 18), the clearance was 0·016 l/h and terminal half‐life was 15 days. After infusion VRC01 retained expected neutralizing activity in serum, and anti‐VRC01 antibody responses were not detected. The human monoclonal antibody (mAb) VRC01 was well tolerated when delivered i.v. or s.c. The mAb demonstrated expected half‐life and pharmacokinetics for a human immunoglobulin G. The safety and PK results support and inform VRC01 dosing schedules for planning HIV‐1 prevention efficacy studies.
The objective of this research is to use metabolomic techniques to discover and validate plasma metabolite biomarkers for the diagnosis of early-stage non-small cell lung cancer (NSCLC). The study ...included plasma samples from 156 patients with biopsy-confirmed NSCLC along with age and gender-matched plasma samples from 60 healthy controls. A fully quantitative targeted mass spectrometry (MS) analysis (targeting 138 metabolites) was performed on all samples. The sample set was split into a discovery set and validation set. Metabolite concentration data, clinical data, and smoking history were used to determine optimal sets of biomarkers and optimal regression models for identifying different stages of NSCLC using the discovery sets. The same biomarkers and regression models were used and assessed on the validation models. Univariate and multivariate statistical analysis identified β-hydroxybutyric acid, LysoPC 20:3, PC ae C40:6, citric acid, and fumaric acid as being significantly different between healthy controls and stage I/II NSCLC. Robust predictive models with areas under the curve (AUC) > 0.9 were developed and validated using these metabolites and other, easily measured clinical data for detecting different stages of NSCLC. This study successfully identified and validated a simple, high-performing, metabolite-based test for detecting early stage (I/II) NSCLC patients in plasma. While promising, further validation on larger and more diverse cohorts is still required.
Spermidine/spermine N1-acetyltransferase 1 (SAT1) responsible for cell polyamine catabolism is overexpressed in glioblastoma multiforme (GB). Its role in tumor survival and promoting resistance ...towards radiation therapy has made it an interesting target for therapy. In this study, we prepared a lipid nanoparticle-based siRNA delivery system (LNP-siSAT1) to selectively knockdown (KD) SAT1 enzyme in a human glioblastoma cell line. The LNP-siSAT1 containing ionizable DODAP lipid was prepared following a microfluidics mixing method and the resulting nanoparticles had a hydrodynamic size of around 80 nm and a neutral surface charge. The LNP-siSAT1 effectively knocked down the SAT1 expression in U251, LN229, and 42MGBA GB cells, and other brain-relevant endothelial (hCMEC/D3), astrocyte (HA) and macrophage (ANA-1) cells at the mRNA and protein levels. SAT1 KD in U251 cells resulted in a 40% loss in cell viability. Furthermore, SAT1 KD in U251, LN229 and 42MGBA cells sensitized them towards radiation and chemotherapy treatments. In contrast, despite similar SAT1 KD in other brain-relevant cells no significant effect on cytotoxic response, either alone or in combination, was observed. A major roadblock for brain therapeutics is their ability to cross the highly restrictive blood–brain barrier (BBB) presented by the brain microcapillary endothelial cells. Here, we used the BBB circumventing approach to enhance the delivery of LNP-siSAT1 across a BBB cell culture model. A cadherin binding peptide (ADTC5) was used to transiently open the BBB tight junctions to promote paracellular diffusion of LNP-siSAT1. These results suggest LNP-siSAT1 may provide a safe and effective method for reducing SAT1 and sensitizing GB cells to radiation and chemotherapeutic agents.
Whether the enteric absorption of the neuraminidase inhibitor oseltamivir is impaired in critically ill patients is unknown. We documented the pharmacokinetic profile of oseltamivir in patients ...admitted to intensive care units (ICUs) with suspected or confirmed pandemic (H1N1) influenza.
We included 41 patients 18 years of age and older with suspected or confirmed pandemic (H1N1) influenza who were admitted for ventilatory support to nine ICUs in three cities in Canada and Spain. Using tandem mass spectrometry, we assessed plasma levels of oseltamivir free base and its active metabolite carboxylate at baseline (before gastric administration of the drug) and at 2, 4, 6, 9 and 12 hours after the fourth or later dose.
Among the 36 patients who did not require dialysis, the median concentration of oseltamivir free base was 10.4 (interquartile range IQR 4.8-14.9) microg/L; the median concentration of the carboxylate metabolite was 404 (IQR 257-900) microg/L. The volume of distribution of the carboxylate metabolite did not increase with increasing body weight (R2=0.00, p=0.87). The rate of elimination of oseltamivir carboxylate was modestly correlated with estimations of creatinine clearance (R2=0.27, p<0.001). Drug clearance in the five patients who required continuous renal replacement therapy was about one-sixth that in the 36 patients with relatively normal renal function.
Oseltamivir was well absorbed enterically in critically ill patients admitted to the ICU with suspected or confirmed pandemic (H1N1) influenza. The dosage of 75 mg twice daily achieved plasma levels that were comparable to those in ambulatory patients and were far in excess of concentrations required to maximally inhibit neuraminidase activity of the virus. Adjustment of the dosage in patients with renal dysfunction requiring continuous renal replacement therapy is appropriate; adjustment for obesity does not appear to be necessary.
Fatty acids are well-established biomarkers used to characterize trophic ecology, food-web linkages, and the ecological niche of many different taxa. Most often, fatty acids that are examined include ...only those previously identified as “dietary” or “extended dietary” biomarkers. Fatty acids considered as nondietary biomarkers, however, represent numerous fatty acids that can be extracted. Some studies may include nondietary fatty acids (i.e., combined with dietary fatty acids), but do not specifically assess them, whereas in other studies, these data are discarded. In this study, we explored whether nondietary biomarker fatty acids can provide worthwhile information by assessing their ability to discriminate intraspecific diversity within and between lakes. Nondietary fatty acids used as biomarkers delineated variation among regions, among locations within a lake, and among ecotypes within a species. Physiological differences that arise from differences in energy processing can be adaptive and linked to habitat use by a species’ ecotype and likely explains why nondietary fatty acid biomarkers can be a relevant tool to delineate intraspecific diversity. Little is known about the nondietary-mediated differences in fatty acid composition, but our results showed that nondietary fatty acid biomarkers can be useful tool in identifying variation.
: Lung cancer is the most common cause of cancer-related deaths worldwide. Early diagnosis is crucial to increase the curability chance of the patients. Low dose CT screening can reduce lung cancer ...mortality, but it is associated with several limitations. Metabolomics is a promising technique for cancer diagnosis due to its ability to provide chemical phenotyping data. The intent of our study was to explore metabolomic effects and profiles of lung cancer patients to determine if metabolic perturbations in the SSAT-1/polyamine pathway can distinguish between healthy participants and lung cancer patients as a diagnostic and treatment monitoring tool.
: Plasma samples were collected as part of the SSAT1 Amantadine Cancer Study. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to identify and quantify metabolite concentrations in lung cancer patient and control samples. Standard statistical analyses were performed to determine whether metabolite concentrations could differentiate between healthy subjects and lung cancer patients, as well as risk prediction modeling applied to determine whether metabolic profiles could provide an indication of cancer progression in later stage patients.
: A panel consisting of 14 metabolites, which included 6 metabolites in the polyamine pathway, was identified that correctly discriminated lung cancer patients from controls with an area under the curve of 0.97 (95% CI: 0.875-1.0).
When used in conjunction with the SSAT-1/polyamine pathway, these metabolites may provide the specificity required for diagnosing lung cancer from other cancer types and could be used as a diagnostic and treatment monitoring tool.
•The first UHPLC–MS/MS assay using a stable-isotope cefazolin internal standard.•Cefazolin is extracted from adipose tissue using a hexane/buffer solvent extraction.•Cefazolin concentrations in ...adipose tissue are half the minimum inhibitory concentration.•The concentration of cefazolin was more than 26-fold higher in serum than adipose.
Higher doses of cefazolin are required in obese patients for preoperative antibiotic prophylaxis, owing to its low lipophilicity. An ultra high performance liquid chromatography-tandem mass spectrometry method was developed to quantify cefazolin in serum and adipose tissue from 6 obese patients undergoing cesarean delivery, and using stable-isotope labeled cefazolin as an internal standard. The method has a 2μg/g lower limit of quantitation. The concentration in adipose tissue was 3.4±1.6μg/mL, which is less than half of the reported minimum inhibitory concentration of 8μg/mL for cefazolin. Serum cefazolin concentrations were more than 30-fold higher than in adipose tissue.
Background: Prescription claims data have been used to estimate refill medication adherence through calculations of cumulative medication acquisition (CMA) and cumulative medication gap (CMG) values. ...Few studies have assessed the validity of these calculated rates. Objectives: We sought to assess the validity of CMA and CMG calculated from the Manitoba prescription claims database (DPIN) against pill count medication adherence, targeting overall medications and angiotensin converting enzyme inhibitors (ACEIs). Methods: Using a survey of a convenience sample of subjects recruited through community pharmacies, subjects who were eligible for study (ie, 65 years or older, noninstitutionalized, taking 2 or more "discrete" prescribed medications, including an ACEI, and willing to provide informed consent) were studied. Pill counts were conducted on all prescribed medicines during 3 home interviews over the course of 4 months. Ten months of DPIN data also were collected on each subject. Results: The concordance between CMA and pill count for overall medications was 411/522 (79%) and for ACEIs was 89/101 (88%) with no systematic differences (McNemar's P = 0.68 and P = 0.097, respectively). CMG and pill count showed even better concordance of 438/514 (85%) for overall medications and 96/101 (95%) for ACEIs, although systematic differences were noted for overall medications (McNemar's P = 0.0012) but not for ACEIs (McNemar's P = 0.500). Spearman's rank correlations were weak for all comparisons. Conclusions: The high concordance between prescription claims database and pill counts suggested that the rate with which patients refill their medications usually is consistent with the rate they consume them. DPIN is not accurate for nondiscrete dosage forms or medications prescribed for "as-required" use.
While assessing the ability of mammalian lung tissue to metabolize theophylline, a new metabolite was isolated and characterized. The metabolite was produced by the microsomal fraction of lungs from ...several species, including rat, rabbit, dog, pig, sheep and human tissue. Metabolite production was blocked by boiling the microsomal tissue. This new metabolite, theophylline-7β-d-ribofuranoside (theonosine), was confirmed by several spectral methods and by comparison to an authentic synthetic compound. Tissue studies from rats, rabbits, dogs, and humans for cofactor involvement demonstrated an absolute requirement for NADP and enhanced metabolite production in the presence of magnesium ion. It remains to be demonstrated whether theonosine may contribute to the known pharmacological effects of theophylline.
Background:
Some investigators have recommended the convenient practice of administering vancomycin doses during the last hour of the hemodialysis treatment. Accepting that a greater amount of ...vancomycin is lost to dialysis with this recent approach, the objective of this study is to determine the pharmacokinetics of vancomycin and assess the adequacy of this dosing regimen in maintaining therapeutic predialysis concentrations.
Methods:
A sampling of 22 consecutive patients administered intradialytic vancomycin, 1 g, intravenously (IV) and maintenance doses of 500 mg during the last hour of high-flux dialysis sessions was studied. A population-modeling program and Bayesian pharmacokinetic analysis were used to identify all global and unique pharmacokinetic parameters of interest based on measured vancomycin predialysis concentrations.
Results:
For the 22 patients studied, this regimen achieved the targeted predialysis concentration range of 5 to 20 μg/mL for 96% of levels, whereas more narrowly within 5 to 15 μg/mL for 86% of levels. Average amount of vancomycin removed during a standardized 3- to 4-hour dialytic session ranged from 30% ± 7% to 38% ± 8%. Average elimination half-life of vancomycin on hemodialysis treatment was 5.4 hours (interquartile range, 5.0 to 5.9 hours). Patients showed an average predialysis plasma concentration of 11 ± 3 μg/mL for the first 7 days of therapy.
Conclusion:
Our results indicate that intradialytic dosing with vancomycin using a 1-g IV load and 500 mg IV with subsequent high-flux dialysis sessions conveniently maintains adequate predialysis plasma concentrations. The lack of drug accumulation with this regimen provides convincing support for a limited blood sampling approach to plasma concentration determinations.
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