Altered Fibrin Architecture Is Associated With Hypofibrinolysis and Premature Coronary Atherothrombosis

OBJECTIVE

Hypofibrinolysis promotes atherosclerosis progression and recurrent ischemic events in premature coronary artery disease. We investigated the role of fibrin physical properties in this particular setting.

METHODS AND RESULTS

Biomarkers of recurrent thrombosis and premature coronary artery disease (CAD) were measured in 33 young post-myocardial infarction patients with angiographic-proven CAD and in 33 healthy volunteers matched for age and sex. Ex vivo plasma fibrin physical properties were assessed by measuring fibrin rigidity and fibrin morphological properties using a torsion pendulum and optical confocal microscopy. The fibrinolysis rate was derived from continuous monitoring of the viscoelastic properties after addition of lytic enzymes. Young CAD patients had a significant increase in plasma concentration of fibrinogen, von Willebrand factor, plasminogen activator inhibitor type 1, and lipoprotein(a) as compared with controls (P<0.05). Fibrin of young CAD patients was stiffer (P=0.002), made of numerous (P=0.002) and shorter fibers (P=0.04), and lysed at a slower rate than that of controls (P=0.03). Fibrin stiffness was an independent predictor for both premature CAD and hypofibrinolysis.

CONCLUSIONS

This first detailed study of clot properties in such a group of patients demonstrated that abnormal plasma fibrin architecture is an important feature of both premature CAD and fibrinolysis rate. The determinants of this particular phenotype warrant further investigation.

Impact of prior use or recent withdrawal of oral antiplatelet agents on acute coronary syndromes

BACKGROUND

Oral antiplatelet agents (OAAs) can prevent further vascular events in cardiovascular disease. How prior use or recent discontinuation of OAA affects clinical presentation of acute coronary syndromes (ACS) and clinical outcomes (death, myocardial infarction [MI]) is unclear.

METHODS AND RESULTS

We studied and followed up for up to 30 days a cohort of 1358 consecutive patients admitted for a suspected ACS; of these, 930 were nonusers, 355 were prior users of OAA, and 73 had recently withdrawn OAA. Nonusers were at lower risk, more frequently presented with ST-elevation MI on admission, and more frequently had Q-wave MI at discharge than prior users (36.6% versus 17.5%, P<0.001; and 47.8% versus 28.2%, P<0.001, respectively). However, there was no difference regarding the incidence of death or MI at 30 days between nonusers and prior users (10.3% versus 12.4%, P=NS). In addition, prior users experienced more major bleeds within 30 days compared with nonusers (3.4% versus 1.4%, respectively; P=0.04). Recent withdrawers were admitted on average 11.9+/-0.8 days after OAA withdrawal. Interruption was primarily a physician decision for scheduled surgery (n=47 of 73). Despite a similar cardiovascular risk profile, recent withdrawers had higher 30-day rates of death or MI (21.9% versus 12.4%, P=0.04) and bleedings (13.7% versus 5.9%, P=0.03) than prior users. After multivariate analysis, OAA withdrawal was found to be an independent predictor of both mortality and bleedings at 30 days.

CONCLUSIONS

Among ACS patients, prior users represent a higher-risk population and present more frequently with non-ST-elevation ACS than nonusers. Although patients with a recent interruption of OAA resemble those chronically treated by OAA, they display worse clinical outcomes.

Determinants of hydroxychloroquine blood concentration variations in systemic lupus erythematosus

OBJECTIVE

Blood concentrations of hydroxychloroquine (HCQ) vary widely among patients with systemic lupus erythematosus (SLE). A pharmacokinetic/pharmacodynamic relationship has been found in different situations, and a very low blood concentration of HCQ is a simple marker of nonadherence to treatment. Therefore, interest in blood HCQ concentration measurement has increased, but little is known about factors that influence blood HCQ concentration variability. This study was undertaken to analyze determinants of blood HCQ concentrations.

METHODS

We conducted a retrospective analysis of patient data, including data from the Plaquenil Lupus Systemic (PLUS) study, to determine the association of epidemiologic, clinical, and biologic factors with blood HCQ concentrations. Data for nonadherent patients (blood HCQ concentration <200 ng/ml) were excluded.

RESULTS

To examine homogeneous pharmacologic data, we restricted the analyses of the PLUS data to the 509 SLE patients receiving 400 mg/day. We found no association of ethnicity or smoking with blood HCQ concentrations and no pharmacokinetic drug-drug interaction with antacids or with inhibitors or inducers of cytochrome P450 enzymes. On multivariate analysis, high body mass index (P = 0.008), no treatment with corticosteroids (P = 0.04), increased time between the last tablet intake and measurement of blood HCQ concentrations (P = 0.017), low platelet count (P < 0.001), low neutrophil count (P < 0.001), and high estimated creatinine clearance (P < 0.001) were associated with low blood HCQ concentrations. In 22 SLE patients with chronic renal insufficiency (median serum creatinine clearance 52 ml/minute [range 23-58 ml/minute]) who received 400 mg/day HCQ, the median blood HCQ concentration was significantly higher than that in the 509 patients from the PLUS study (1,338 ng/ml [range 504-2,229 ng/ml] versus 917 ng/ml [range 208-3316 ng/ml]) (P < 0.001).

CONCLUSION

We provide a comprehensive analysis of determinants of blood HCQ concentrations. Because this measurement is increasingly being used, these data might be useful for clinicians.

Temporal and spatial assessment of normal cerebrospinal fluid dynamics with MR imaging

The purpose of this study was to measure normal cerebrospinal fluid (CSF) pulsations within the intracranial and upper cervical subarachnoid spaces and the ventricular system. Phase contrast cine MR sequences were performed in sagittal and axial planes on 13 volunteers with flow encoding in the craniocaudal direction. CSF pulsations displayed considerable variations in healthy subjects, depending both on measurements localization and subjects, with CSF peak velocities ranging from 0 to 7 cm/s. In the subarachnoid spaces, the highest velocities occurred in the anterior location and increased from the cerebellar pontine angle cisterns towards the lower cervical spaces. In the ventricular system, the highest velocities occurred through the aqueduct of Sylvius. CSF flow within the third ventricle seemed to reflect a circular motion. There was a caudal net CSF flow in the aqueduct whereas in the upper cervical spaces net CSF flow was caudal anteriorly and cranial laterally. Velocity profiles of CSF pulsations demonstrated arterial morphology. After the R wave, caudal systolic motion was first observed in the posterior subarachnoid spaces, soon after in the anterior subarachnoid spaces and later in the ventricular system. Considering the morphology of CSF pathways, three successively initiated phenomena may explain the temporal course of CSF motion: the systolic expansion of the main arteries at the base of the brain, the systolic expansion of the cerebrospinal axis and, finally, the systolic expansion of the choroid plexuses.

Relation between plasma trough concentration of abiraterone and prostate-specific antigen response in metastatic castration-resistant prostate cancer patients

BACKGROUND

Abiraterone (ABI) is a major oral agent for the treatment of metastatic castration-resistant prostate cancer (mCRPC) patients but its systemic exposure is subject to a large inter-individual variability. We aimed to explore the relationship between ABI trough plasma concentration and prostate-specific antigen (PSA) response in mCRPC patients and to identify the critical determinants for its activity.

PATIENTS AND METHODS

This is a monocentric prospective observational study in mCRPC patients treated with ABI. The plasmatic concentration of ABI at steady state was measured using liquid chromatography with fluorescence detection. The primary objective was to study the relationship between mean ABI plasma exposure (ABI C_min) and 3-month PSA response.

RESULTS

From 2012 to 2016, 61 mCRPC patients were eligible for pharmacokinetic/pharmacodynamic assessment. Thirty-eight patients experienced PSA response (62%, [confidence interval {CI} 95% 50-78]). In univariate analysis, ABI C_min was 1.5-fold higher in responders: 12.0 ng/mL (CI 95% 9.4-15.6) versus 8.0 ng/mL (CI 95% 5.8-11.6; P = 0.0015). In multivariate analysis, only ABI C_min was independently associated with PSA response (odds ratio = 1.12 [CI 95% 1.01-1.25], P = 0.004). By receiver operating characteristic analysis, the optimal threshold for ABI C_min was 8.4 ng/mL. Progression-free survival (PFS) was significantly higher in patients with ABI C_min above 8.4 ng/mL (hazard ratio 0.55, [CI 95% 0.31-0.99], 12.2 [CI 95% 9.2-19.5] versus 7.4 [CI 95% 5.5-14.7] months otherwise, P = 0.044).

CONCLUSIONS

We showed that ABI trough concentration correlates with PSA response and PFS. Moreover, we could determine a cut-off value of plasmatic concentration for PSA response. Altogether, ABI concentration monitoring appears as a new approach to improve clinical outcome in mCPRC patients.

Sorafenib in advanced melanoma: a critical role for pharmacokinetics?

BACKGROUND

Inter-patient pharmacokinetic variability can lead to suboptimal drug exposure, and therefore might impact the efficacy of sorafenib. This study reports long-term pharmacokinetic monitoring of patients treated with sorafenib and a retrospective pharmacodynamic/pharmacokinetic analysis in melanoma patients.

PATIENTS AND METHODS

Heavily pretreated patients with stage IV melanoma were started on sorafenib 400 mg twice daily (bid). In the absence of limiting toxicity, dose escalation of 200 mg bid levels was done every 2 weeks. Plasma sorafenib measurement was performed at each visit, allowing a retrospective pharmacodynamic/pharmacokinetic analysis for safety and efficacy.

RESULTS

In all, 19 of 30 patients underwent dose escalation over 400 mg bid, and 28 were evaluable for response. The overall disease control rate was 61% (95% confidence interval (CI): 42.6-78.8), including three confirmed responses (12%). Disease control rate and progression-free survival (PFS) were improved in patients with high vs low exposure (80% vs 32%, P=0.02, and 5.25 vs 2.5 months, P=0.005, hazard ratio (HR)=0.28 (95% CI: 0.11-0.73)). In contrast, drug dosing had no effect on PFS. In multivariate analysis, drug exposure was the only factor associated with PFS (HR=0.36 (95% CI: 0.13-0.99)). Diarrhoea and anorexia were correlated with drug dosing, while hypertension and hand-foot skin reaction were correlated with drug exposure.

CONCLUSIONS

Although sorafenib had modest efficacy in melanoma, these results suggest a correlation between exposure and efficacy of sorafenib. Therefore, dose optimisation in patients with low exposure at standard doses should be evaluated in validated indications.

Vemurafenib pharmacokinetics and its correlation with efficacy and safety in outpatients with advanced BRAF-mutated melanoma

Vemurafenib is a BRAF kinase inhibitor approved for first-line treatment of metastatic BRAF (V600) -mutant melanoma. However, data on the pharmacokinetic/pharmacodynamic (PK/PD) relationship are lacking. The aim of this prospective, multicenter study was to explore the PK/PD relationship for vemurafenib in outpatients with advanced BRAF-mutated melanoma. Fifty-nine patients treated with single-agent vemurafenib were prospectively analyzed. Vemurafenib plasma concentration (n = 159) was measured at days 15, 30, 60, and 90 after treatment initiation. Clinical and biological determinants (including plasma vemurafenib concentration) for efficacy and safety were assessed using Cox's model and multivariate stepwise logistic regression. Median progression-free survival (PFS) and overall survival were 5.0 (95 % confidence interval [95 % CI] 2.0-6.0) and 11.0 (95% CI 7.0-16.0) months, respectively. Twenty-nine patients (49 %) experienced any grade ≥3 toxicity and the most frequent grade ≥2 toxicity was skin rash (37 %). Severe toxicities led to definitive discontinuation in seven patients (12 %). Grade ≥2 skin rash was not statistically associated with better objective response at day 60 (p = 0.06) and longer PFS (hazard ratio 0.47; 95 % CI 0.21-1.08; p = 0.075). Grade ≥2 skin rash was statistically increased in patients with ECOG  ≥ 1 (odds ratio 4.67; 95 % CI 1.39-15.70; p = 0.012). Vemurafenib concentration below 40.4 mg/L at day 15 was significantly associated with a shorter PFS (1.5 [0.5-5.5] vs. 4.5 [2-undetermined] months, p = 0.029). Finally, vemurafenib concentration was significantly greater in patients developing grade ≥2 rash (61.7 ± 25.0 vs. 36.3 ± 17.9 mg/L, p < 0.0001). These results suggest that early plasma drug monitoring may help identify outpatients at high risk of non-response or grade ≥ 2 skin rash.

Determinants of the interindividual variability in serum cytidine deaminase activity of patients with solid tumours

AIMS

Cytidine deaminase (CDA) activity in cancer patients' serum has been proposed as a predictive biomarker for efficacy and toxicity of nucleoside analogues. However, discrepant results about its predictive value have been reported due to the high interindividual variability in CDA activity. This study aimed at identifying determinants of this interindividual variability.

METHODS

From December 2014 to November 2015, 183 patients were prospectively included. Serum CDA activity, biological and clinical characteristics as well as five common single nucleotide polymorphisms (SNPs) in the CDA gene (c.-451C > T, c.-92A > G, c.-33_-31delC, c.79A > C, c.435 T > C) were analysed. Associations between clinical characteristics, pharmacogenetic variants and CDA activity were univariately tested. P < 0.1-candidate variables were analysed through a multivariate analysis. The association between CDA activity and toxicity was assessed for the 56 gemcitabine-treated patients. Intraindividual variability in CDA activity was explored in six pancreatic cancer patients treated with gemcitabine.

RESULTS

Median CDA activity was 3.97 U mg^-1 (range 1.53-15.49 U mg^-1 ). A univariate analysis showed that CDA activity was statistically associated with Eastern Cooperative Oncology Group performance status, mild or severe malnutrition, inflammatory syndrome, leucocyte count, neutrophil count, albumin, C-reactive protein and -c.-33_-31delC single nucleotide polymorphism. A multivariate analysis identified that only neutrophil count (P < 0.0001) and severe malnutrition (P = 0.0278) were independently associated with CDA activity. Low CDA activity (<2 U mg^-1 ) was not statistically associated with severe gemcitabine-related toxicities (P = 0.16). A decrease in CDA activity was observed during the longitudinal follow-up of six pancreatic cancer patients treated with gemcitabine (P = 0.03).

CONCLUSIONS

These results suggest that neutrophil count and malnutrition should be considered for the interpretation of pretherapeutic CDA activity.

[Efficacy of Spirolept vaccine against human leptospirosis as estimated by passive protection of laboratory rodents]

OBJECTIVE

This study had for aim to assess the serological response induced by the Spirolept vaccine against human leptospirosis.

METHOD

A serological follow-up was made on 31 patients at a risk of occupational exposure. The antibody titers of vaccinated patients were assessed by MAT and ELISA. In a second step, vaccinal protection was studied in vivo by checking the seroprotective effect of the human sera injected in an animal model (Meriones unguiculatus) naturally susceptible to the disease. The passive protection was studied by comparing the death rate on five batches of animals to which the bacterium was inoculated. Thus, four batches of animals were injected subcutaneously with a pooled sera of vaccinated people sampled at D0, D15, D135, and D320 after Spirolept vaccination. One control batch was given PBS. One day after injection, the latter batch was inoculated with the homologous strain Verdun of Leptospira interrogans ss icterohemorrhagiae (serogroup Icterohemorrhagiae) used to make the vaccine.

RESULTS

The death rate was significantly decreased as soon as D15 after the first injection, even with pooled sera of vaccinated people negative for the MAT.

COMMENTS

The Spirolept vaccine induces a protective response against icterohemorrhagiae, which can be transmitted to the animal model and thus is linked to a humoral response.

Genetic relationships between efficiency traits and gut microbiota traits in growing pigs fed a conventional or a high fiber diet

In pigs, the gut microbiota composition plays a major role in the process of digestion, but is influenced by many external factors, especially diet. To be used in breeding applications, genotype by diet interactions on microbiota composition have to be quantified, as well as their impact on genetic covariances with feed efficiency (FE) and digestive efficiency (DE) traits. This study aimed at determining the impact of an alternative diet on variance components of microbiota traits (genera and alpha diversity indices) and estimating genetic correlations between microbiota and efficiency traits for pigs fed a conventional (CO) or a high-fiber (HF) diet. Fecal microbes of 812 full-siblings fed a CO diet and 752 pigs fed the HF diet were characterized at 16 weeks of age by sequencing the V3-V4 region of the 16S rRNA gene. A total of 231 genera were identified. Digestibility coefficients of nitrogen, organic matter, and energy were predicted analyzing the same fecal samples with near infrared spectrometry. Daily feed intake, feed conversion ratio, residual feed intake and average daily gain (ADG) were also recorded. The 71 genera present in more than 20% of individuals were retained for genetic analyses. Heritability (h²) of microbiota traits were similar between diets (from null to 0.38 ± 0.12 in the CO diet and to 0.39 ± 0.12 in the HF diet). Only three out of the 24 genera and two alpha diversity indices with significant h² in both diets had genetic correlations across diets significantly different from 0.99 (P < 0.05), indicating limited genetic by diet interactions for these traits. When both diets were analyzed jointly, 59 genera had h² significantly different from zero. Based on the genetic correlations between these genera and ADG, FE, and DE traits, three groups of genera could be identified. A group of 29 genera had abundances favorably correlated with DE and FE traits, 14 genera were unfavorably correlated with DE traits, and the last group of 16 genera had abundances with correlations close to zero with production traits. However, genera abundances favorably correlated with DE and FE traits were unfavorably correlated with ADG, and vice versa. Alpha diversity indices had correlation patterns similar to the first group. In the end, genetic by diet interactions on gut microbiota composition of growing pigs were limited in this study. Based on this study, microbiota-based traits could be used as proxies to improve FE and DE in growing pigs.

Evaluation of the new heterogeneous ACMIA immunoassay for the determination of whole-blood cyclosporine concentrations in bone marrow, kidney, heart, and liver transplant recipients

Cyclosporine (CyA) has a narrow therapeutic index. Determination of CyA concentrations correlate with rejection or adverse effects like nephropathy. Cyclosporine is assayed based on either chromatographic or many different immunoenzymologic techniques. The investigators evaluated a new heterogeneous immunoassay of CyA on RxL Dimension. The pretreatment step is automatically performed in the apparatus. Linearity, intra- and interday precision, limit of quantification, dilutions, and stability of the equipment were compared with the EMIT method for patient determinations. The heterogeneous immunoassay showed a good linearity between 0 and 500 ng/mL, and intra- and inter-day precision with a coefficient of variation below 9.2%. The investigators observed reproducible and accurate dilutions of high concentrations (500 to 2000 ng/mL). The correlation with the EMIT technique was valid: ACMIA = 0.964 EMIT + 0.156 (r = .96) for different types of transplant (n = 116). Finally, this new system improves the determination of CyA concentrations.

Digestive efficiency traits in growing pigs are genetically correlated with sow litter traits in the Large White breed

Digestive efficiency traits are promising selection criteria to improve feed efficiency in pigs. However, the genetic relationships between digestive efficiency and sow reproductive traits are mostly unknown and need to be estimated. In this study, reproductive traits were available for 61 601 litters recorded on 21 719 Large White purebred sows. The traits were comprised of the number of born alive (NBA) and the number of weaned piglets (NWP), the number of stillbirths (NSB) and piglet mortality during suckling (PM). For a subset of 32518 litters, the mean (MBW) and CV of piglet birth weights (CVBW) were deduced from individual piglet weights as well as the proportion of piglets weighing less than 1 kg (PPL1K). Growth and feed efficiency traits were available for 4 643 Large White male pigs related to sows with reproductive performances. They comprised average daily gain (ADG), daily feed intake (DFI) and feed conversion ratio (FCR). A subset of 1 391 pigs had predictions for digestibility coefficients (DC) of energy, organic matter and nitrogen obtained by analysing faecal samples with near-infrared spectrometry. Estimated heritabilities were low for NBA, NSB, NWP and PM (0.08 ± 0.01 to 0.11 ± 0.01) and low to moderate for litter weight characteristics (0.14 ± 0.02 to 0.38 ± 0.01). Heritability estimates were moderate to high for ADG, DFI and FCR (0.37 ± 0.04 to 0.54 ± 0.05) and moderate for DC traits (0.26 ± 0.06 to 0.38 ± 0.07). Genetic correlations were low between ADG, or alternatively FCR, and reproductive traits. They were significantly different from zero with MBW (0.19 ± 0.06 with ADG and -0.15 ± 0.06 with FCR) and PPL1K (-0.19 ± 0.07 with ADG and 0.18 ± 0.07 with FCR). All genetic correlations between DFI and reproductive traits were low and not significantly different from zero. Genetic correlations between DC traits and NBA were significantly different from zero for DC of organic matter and energy (<-0.25 ± 0.11). DC traits were moderately correlated with MBW (>0.30 ± 0.11), CVBW (<-0.36 ± 0.11) and PPL1K (<-0.37 ± 0.11) at the genetic level. Genetic correlations between DC traits and PM were significantly negative and hence favourable (<-0.38 ± 0.12). Finally, genetic correlations between DC traits and NWP were close to zero. These results suggested that sows closely related to growing pigs with the best digestive efficiency would produce heavier and more homogeneous piglets, with slightly smaller litter sizes at birth but better survival. Hence, there is usable genetic variation in DC that could be exploited to define new selection strategies in maternal lines aiming at improving not only feed efficiency but also piglet survival.

Correlation of sorafenib plasma concentrations and clinical toxicity: A prospective population pharmacodynamic and pharmacokinetic study

e14585

Background: Sorafenib is an angiogenesis inhibitor recently approved for the treatment of metastatic renal cell carcinoma and hepatocarcinoma. This oral multi-targeted kinase inhibitor blocks the VEGF, PDGF receptors, BRAF and c-kit. In clinical trials, severe toxicities included rash, hand-foot syndrome and diarrhea. We investigated the relationship between severe toxicity and sorafenib plasmatic exposure. Patients and methods: From February 2008 to December 2008, 32 patients (pts) were treated with sorafenib (800 mg given daily). Clinical and blood exams were performed at baseline and every 2 weeks. Toxicity events were graded according to National Cancer Institute Common Toxicity Criteria 3.0. The sorafenib area under the plasma concentration-time curve over 12 hours (AUC0–12) was determined every 2 weeks by gradient elution liquid chromatography, data analysis with one-compartment disposition and a population approach using NONMEM software. Grade 3 toxicity free survival was estimated by Kaplan-Meier method. Results: Pts (23 males), ECOG 0–1 (27 pts), median age 62.8 years (range 37–78), with metastatic hepato-carcinoma (11), melanoma (6), thyroid cancer (8), renal cell carcinoma (7), received a median treatment duration of 94 days (range : 7–330). 20 pts experienced grade 3 toxicities with 33 events: hand-foot hyperkeratosis (14), diarrhea (5), cutanous rash (4), asthenia (2), anorexia (2), dyspnea (1), scrotal toxicity (1), post surgical complication (1), hypertension (1), increase creatinine level (1), digestive hemorrhage (1). The median AUC0–12 was 62.4 mg/L.h, ranging from 28.7 to 202.2 mg/L.h. Amongst pts experiencing grade 3 toxicity, two groups of 16 pts were defined with the median AUC0- 12 as cut off: low exposure (Lw) and high exposure (Hi). Six Lw pts experienced grade 3 toxicity versus 14 Hi pts (exact Fisher Test p=0.009). The probability of free grade 3 toxicity survival was higher for Lw (Logrank test p=0.004). Conclusions: These results show that grade 3 toxicity occurrence may be related to high plasma sorafenib exposure. This supports the need for therapeutic drug monitoring to prevent toxicity grade 3 occurrence and therefore optimize the clinical management of patients under sorafenib.

No significant financial relationships to disclose.

[Therapeutic monitoring of immunosuppressive drugs: interest of calcineurin activity assessment in liver transplantation]

Therapeutic monitoring of calcineurin inhibitors (ciclosporin and tacrolimus) consists in pharmacokinetic monitoring. Pharmacodynamics based on calcineurin activity may be particularly interesting in liver transplantation due to the large intra- and interindividual variability of pharmacokinetics of ciclosporin and tacrolimus. A recent investigation on the pharmacokinetic-pharmacodynamic relationship of tacrolimus showed that monitoring of calcineurin activity in PBMC may be particularly relevant within the first three post-transplantation months. Thereafter, the monitoring of trough blood concentrations of tacrolimus remains adequate. Moreover, two clinical investigations carried out within the early and late post-transplantation periods reported a promising result which is a positive correlation between calcineurin activity and incidence of graft rejection, whatever graft type and calcineurin inhibitors. In each study, transplanted recipients with a graft rejection exhibited a greater trough calcineurin activity compared to patients without graft rejection. However, prospective investigations are required because of the small cohorts of patients enrolled in both studies. The aim of these investigations will be to confirm the interest of calcineurin activity monitoring as a marker of cellular immunity and its positive link with pharmacokinetic monitoring.