Median Peak Concentrations Research Articles

Gefitinib reduces oocyte quality by disturbing meiotic progression

Gefitinib is a first-line anti-cancer drug for the treatment of advanced non-small cell lung cancer (NSCLC). It has been reported that gefitinib can generate several drug-related adverse effects, including nausea, peripheral edema, decreased appetite and rash. However, the reproductive toxicity of gefitinib has not been clearly defined until now. Here we assessed the effects of gefitinib on oocyte quality by examining the critical events and molecular changes of oocyte maturation. Gefitinib at 1, 2, 5 or 10 μM concentration was added to culture medium (M2). We found that gefitinib at its median peak concentration of 1 μM did not affect oocyte maturation, but 5 μM gefitinib severely blocked oocyte meiotic progression as indicated by decreased rates of germinal vesicle breakdown (GVBD) and polar body extrusion (PBE). We further showed that gefitinib treatment increased phosphorylation of CDK1 at the site of Try15, inhibited cyclin B1 entry into the nucleus, and disrupted normal spindle assembly, chromosome alignment and mitochondria dynamics, finally leading to the generation of aneuploidy and early apoptosis of oocytes. Our study reported here provides valuable evidence for reproductive toxicity of gefitinib administration employed for the treatment of cancer patients.

PHARMACOKINETIC STUDY OF INTRAVITREAL AFLIBERCEPT IN HUMANS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

To investigate the half-life of aflibercept in aqueous humor after a single intravitreal injection in patients with neovascular age-related macular degeneration. Prospective, noncomparative, interventional case series of five eyes with neovascular age-related macular degeneration naive to anti-vascular endothelial growth factor therapy were enrolled and treated with intravitreal aflibercept. At baseline, best-corrected visual acuity, optical coherence tomography imaging, and aqueous humor (treatment eye) and blood/plasma samples were taken. Patients underwent best-corrected visual acuity, optical coherence tomography imaging, and sampling of aqueous humor from the eye and blood/plasma at six additional post-treatment time points of 4 hours and Days 1, 3, 7, 14, and 28. Concentrations of aflibercept were quantified using an enzyme-linked immunosorbent assay. Median peak concentration (Cmax) of free aflibercept in the aqueous was 122 mg/L. The median half-life of free aflibercept was 11 days in the eye. In plasma, the concentrations of free aflibercept were low and transient, reaching undetectable levels during the first week after injection, and undetectable in all patients at time points beyond 7 days. The pharmacokinetic profile in the aqueous humor described here together with the previously reported affinity of aflibercept for vascular endothelial growth factor is consistent with and adds to our understanding for the duration of its clinical efficacy.

Changes in micronutrient and inflammation serum biomarker concentrations after a norovirus human challenge

Background:To accurately assess micronutrient status, it is necessary to characterize the effects of inflammation and the acute-phase response on nutrient biomarkers.Objective:Within a norovirus human challenge study, we aimed to model the inflammatory response of C-reactive protein (CRP) and α-1-acid glycoprotein (AGP) by infection status, model kinetics of micronutrient biomarkers by inflammation status, and evaluate associations between inflammation and micronutrient biomarkers from 0 to 35 d post–norovirus exposure.Methods:Fifty-two healthy adults were enrolled into challenge studies in a hospital setting and followed longitudinally; all were exposed to norovirus, half were infected. Post hoc analysis of inflammatory and nutritional biomarkers was performed. Subjects were stratified by inflammation resulting from norovirus exposure. Smoothed regression models analyzed the kinetics of CRP and AGP by infection status, and nutritional biomarkers by inflammation. Linear mixed-effects models were used to analyze the independent relations between CRP, AGP, and biomarkers for iron, vitamin A, vitamin D, vitamin B-12, and folate from 0 to 35 d post–norovirus exposure.Results:Norovirus-infected subjects had median (IQR) peak concentrations for CRP [16.0 (7.9–29.5) mg/L] and AGP [0.9 (0.8–1.2) g/L] on day 3 and day 4 postexposure, respectively. Nutritional biomarkers that differed (P < 0.05) from baseline within the inflamed group were ferritin (elevated day 3), hepcidin (elevated days 2, 3), serum iron (depressed days 2–4), transferrin saturation (depressed days 2–4), and retinol (depressed days 3, 4, and 7). Nutritional biomarker concentrations did not differ over time within the uninflamed group. In mixed models, CRP was associated with ferritin (positive) and serum iron and retinol (negative, P < 0.05).Conclusion:Using an experimental infectious challenge model in healthy adults, norovirus infection elicited a time-limited inflammatory response associated with altered serum concentrations of certain iron and vitamin A biomarkers, confirming the need to consider adjustments of these biomarkers to account for inflammation when assessing nutritional status. These trials were registered at clinicaltrials.gov as and .

Pharmacokinetics of vaginal progesterone in pregnancy

Characterization of pharmacokinetics is lacking for vaginal progesterone in pregnancy. Dosing of vaginal progesterone for preterm birth prevention has been empirical. Owing to pregnancy-related changes in vaginal and uterine blood flow, hepatic metabolism, renal clearance, and endogenously elevated serum progesterone, studies outside of pregnancy may not be applicable. The lack of the pharmacokinetics profile of vaginally administered progesterone in pregnancy limits the ability to define the exposure-response relationship needed to optimize dosing, which has implications for its use in research and clinical care regarding management of short cervix, prevention of recurrent preterm birth, and prevention of recurrent miscarriage. This was a study to establish the feasibility of using serum progesterone to establish basic pharmacokinetic parameters of vaginal progesterone in pregnancy for preterm birth prevention. This is a prospective study of 6 low-risk singletons at 18 0/7 to 23 6/7 weeks' gestation with body mass index 20-40. Exclusion criteria were current vaginitis, abnormal Pap smear, prescription medication use, cervical length ≤25 mm, prior preterm birth, and contraindication to progesterone. Participants received a single dose of 200 mg micronized vaginal progesterone and serum progesterone levels were evaluated every 2 hours from 0 to 12 hours and then 24 hours postdose. Primary outcome was concentration/time profile of serum progesterone. Median (range) maternal age was 27 (21.5-33.3) years, median body mass index was 26.5 (23.3-29.0) kg/m2, and median gestational age was 22.9 (21.0-23.4) weeks. Median baseline serum progesterone was 47 (40-52) ng/mL, median peak concentration was 54 (48-68) ng/mL, and median time to peak was 12 (4-15) hours. There was a trend in rising serum progesterone over baseline with a median change in peak concentration of 11 ng/mL and interquartile range of 2-22. Median percent change from baseline was an increase by 24% (interquartile range, 4%-53%). However, there was no clear elimination phase and the median area under the curve was 112 ng*h/mL with an interquartile range of -43 to239. Unlike in nonpregnant individuals, administration of vaginal progesterone in pregnant individuals only minimally impacts systemic exposure. There is a limited trend of rising serum progesterone over baseline levels, with significant inter-individual variability. Serum progesterone is unlikely to be a good candidate for establishing pharmacokinetics or dosing of vaginal progesterone in pregnancy for preterm birth prevention.

Urinary bactericidal activity of colistin and azidothymidine combinations against mcr-1-positive colistin-resistant Escherichia coli

A phase 1 clinical study was performed to assess the pharmacokinetics and safety of intravenous (i.v.) administration of colistin methanesulfonate (CMS) and azidothymidine (AZT) alone and in combination. Seven healthy subjects received three (every 12 h) 1-h i.v. infusions of 4, 2 and 2 million international units (MIU) of CMS co-administered with 200, 100 and 100 mg of AZT, respectively. In an ex vivo study, urinary bactericidal titres (UBTs) and time-kill curve determinations were performed in artificial urine spiked with colistin sulfate and AZT according to median and minimum peak concentrations in urine measured after the first and third dose using four mcr-1-positive colistin-resistant and five colistin-susceptible Gram-negative isolates. Reciprocal UBTs for the different colistin concentrations obtained in urine ranged from 1-128 and 0-2 for colistin-susceptible and colistin-resistant isolates, respectively. Combination with AZT could increase UBTs up to two dilution steps each for the Enterobacteriaceae and Acinetobacter strains tested. In contrast, the combination had no activity against Pseudomonas strains. In time-kill curves, the combination showed bactericidal activity against colistin-resistant strains even when the substances alone were not bactericidal. Thus, combination of CMS with AZT shows promising synergistic activity against Gram-negative uropathogens, including colistin-resistant Enterobacteriaceae. According to the urinary bactericidal activity, a maintenance dosage of 2 MIU of CMS combined with 100 mg of AZT twice daily may be sufficient for the treatment of urinary tract infections (UTIs) caused by colistin-susceptible strains. However, the dosage requires optimisation for efficient treatment of UTIs caused by colistin-resistant strains.

Pharmacokinetics and pharmacodynamics of pergolide mesylate after oral administration in horses with pituitary pars intermedia dysfunction

Published information on the pharmacokinetic and pharmacodynamic properties of pergolide is limited. The aim of this study was to investigate the pharmacokinetic and pharmacodynamic properties of oral pergolide in horses with pituitary pars intermedia dysfunction (PPID). The study design was a nonrandomized clinical trial. Six horses with PPID diagnosed by thyrotropin-releasing hormone (TRH) stimulation tests received pergolide at 4 μg/kg for 18 d. Plasma samples for determination of pergolide and ACTH concentration were collected 0.5 h before and 2 and 12 h after each administration of pergolide. Maximum plasma concentrations after the first oral dose of pergolide (0.104–0.684 ng/mL; median 0.261 ng/mL; interquartile range [IQR] 0.184–0.416 ng/mL) were not significantly different to the maximum steady-state concentration at day 18 (0.197–0.628 ng/mL; median 0.274; IQR 0.232–0.458 ng/mL). Chronic administration was not associated with drug accumulation (R = 1.09) and pergolide concentration reached steady state within 3 d. Throughout, concentrations of pergolide fluctuated considerably, with median plasma peak concentrations more than four times higher than median trough concentrations. Plasma ACTH concentration reduced significantly within 12 h of administration with further reductions occurring up to 10 d after the initiation of treatment. Although there were parallel fluctuations in the concentrations of pergolide and ACTH, timing of ACTH measurement in relation to the administration of pergolide did not have a significant effect. Alterations in the response to TRH were identified at 8 d with no further change being identified at 18 d. A small number of horses were studied. Oral pergolide results in significant suppression of pars intermedia activity within hours. Pergolide and ACTH concentrations fluctuated in tandem although correlation was poor. Fluctuations in pergolide concentration were consistent with a terminal elimination half-life of less than 12 h. To reduce the level of fluctuation of ACTH, twice-daily dosing of pergolide may be more appropriate.

Continuous infusion versus intermittent bolus doses of fentanyl for analgesia and sedation in neonates: an open-label randomised controlled trial

ObjectiveAdequate data on fentanyl pharmacokinetics in neonates are lacking. The study was performed to compare serum concentrations and clinical outcome between continuous infusion (CI) and intermittent bolus (IB) doses of...

Peak plasma concentration of direct oral anticoagulants in obese patients weighing over 120 kilograms: A retrospective study

BackgroundDue to a paucity of data on the efficacy and safety of direct oral anticoagulants (DOACs) in patients with a body mass index >40 kg/m2 or a weight >120 kg, the use of DOACs in this group is not recommended. ObjectivesTo determine the proportion of obese patients with body weight >120 kg with a peak plasma concentration of DOACs lower than the expected median trough level derived from population pharmacokinetic studies for each DOAC. MethodsPatients with body weight >120 kg taking DOACs for any indication underwent a peak drug concentration measurement at steady state. Results38 patients were included in the analysis. The mean age was 64 ± 11 years, and 30 (79%) were males. The median body weight was 132.5 kg (interquartile range [IQR] 127‐146.5). The median peak concentrations (IQR) were 148 ng/mL (138‐240), 138 ng/mL (123‐156.5), 215 ng/mL (181‐249) for apixaban, dabigatran, and rivaroxaban, respectively. Two patients (5%, 95% confidence interval [CI]: 0.5%‐18%) had a peak plasma concentration lower than the median trough and eight (21%, 95% CI: 11%‐37%) had a peak plasma concentration below the fifth percentile (10th percentile for dabigatran) peak concentration. ConclusionsMost patients in our study had peak plasma concentration higher than the median trough level for each of the three DOACs. However, 21% had a peak plasma concentration that was below the usual on‐therapy range of peak concentration for the corresponding DOAC.

Serum bactericidal activity of colistin and azidothymidine combinations against mcr-1-positive colistin-resistant Escherichia coli

To examine the serum bactericidal activity of colistin sulphate (CS) and azidothymidine (AZT) combinations, time-kill curves were performed in native and heat-inactivated human serum with five colistin-resistant and four colistin-susceptible Gram-negative strains. Serum samples were spiked according to median and minimum plasma peak concentrations measured in a phase 1 clinical study in which seven healthy subjects received three (q12h) 1-h intravenous infusions of 4, 2 and 2 MIU colistin methanesulfonate (CMS) co-administered with 200, 100 and 100 mg AZT, respectively. This trial was performed to assess pharmacokinetics and safety of CMS/AZT combination therapy. Minimum bactericidal concentrations of CS in native, but not heat-inactivated, serum were strongly reduced compared with Mueller-Hinton broth for all tested Enterobacteriaceae, except one colistin-resistant (serum-resistant) strain. For colistin-susceptible strains, the minimum CS concentration after 2 MIU CMS was already bactericidal in native and heat-inactivated serum. Median, but not minimum, CS concentrations after 2 MIU CMS were sufficient to kill the serum-resistant, colistin-resistant Escherichia coli strain in native serum. In heat-inactivated serum, even the median CS concentration after 2 MIU CMS was not bactericidal for all colistin-resistant strains. In general, combinations with AZT accelerated killing of colistin-resistant E. coli or showed bactericidal activity even if the substances alone were not bactericidal. Thus, combination with AZT potentiates the bactericidal effect of colistin against colistin-resistant E. coli. Although the dosage of 2 MIU CMS plus AZT may be sufficient to treat infections with colistin-susceptible strains, for infections caused by colistin-resistant E. coli, dosing should be further optimised.

Anti-Thymocyte Globulin Kills Leukemic Stem Cells in Vitro

Background: Although curative treatment for acute myeloid leukemia, the success of allogeneic hematopoietic cell transplantation (HCT) is limited due to leukemia relapse and graft-versus-host disease (GvHD). Rabbit anti-thymocyte globulin (ATG) used for GvHD prophylaxis does not increase relapse (Walker et al: Lancet Oncol 2016). The non-increase in relapse could be because ATG has a direct anti-leukemic effect (Dabas et al: BBMT 2016). Multiple studies have suggested that a high number of leukemic stem cells (LSCs, also called leukemia initiating cells) remaining after therapy is associated with relapse. Therefore, targeting LSCs may be important for treating or preventing relapse. We demonstrated ATG's cytotoxic effect against acute myeloid leukemia (AML) blasts (Dabas et al: BBMT 2016). However, ATG's effect on LSCs has not been evaluated. In this study, we investigated in vitro ATG-induced complement-independent cytotoxicity (CIC, presumably direct induction of apoptosis) and complement-dependent cytotoxicity (CDC) against LSCs. This was also compared to ATG-induced CIC and CDC against healthy hematopoietic stem cells (HSCs).Methods:Frozen peripheral blood mononuclear cells (PBMNCs) from 15 patients newly diagnosed with AML were used as the source of LSCs. Frozen mononuclear cell apheresis samples from 15 healthy stem cell donors were used as the source of HSCs. We measured by flow cytometry CIC and CDC induced by ATG at 10 mg/L (the median peak concentration achieved with 4.5 mg/kg ATG given over day -2, -1 and 0) and 50 mg/L. CIC was induced by incubating cells with ATG in the presence of heat-inactivated (complement-depleted) fetal bovine serum for 4 hours. As a negative control for the calculation of background, cells were cultured under the same conditions except without ATG. CDC was induced by incubating cells with ATG in the presence of human serum as a source of complement for 15 minutes. As a negative control (for background), cells were incubated with ATG in the presence of heat-inactivated human serum (no complement). The LSCs and HSCs were phenotypically defined as CD45dim/neg, side scatterlow, CD34+, CD38neg and negative for CD14, CD16, CD19, CD56, CD235a and CD41a. For CIC, dying/dead cells were identified as Annexin V positive (Annexin V+). For CDC, dead cells were identified as 7-amino-actinomycin D positive (7AAD+).Results: ATG induced both CIC and CDC of LSCs at the concentration of 50 mg/L but not 10 mg/L. For CIC, the median percent Annexin V+ LSCs after incubation with 50 mg/L ATG was 22.3% vs 18.4% for background (p=0.0043, Wilcoxon matched pairs test). For CDC, the median percent 7AAD+ LSCs after incubation with 50 mg/L ATG was 37.2% vs 2% background (p=0.0004, Wilcoxon matched pairs test). Next, we compared the cytotoxicity of 50 mg/L ATG against LSCs versus healthy HSCs. For CIC, a significantly greater percent of LSCs than HSCs was killed (P=0.0363, Mann-Whitney rank sum test) (Figure 1). Similarly, for CDC, there was a trend toward a greater percent of LSCs than HSCs killed (P=0.0971) (Figure 2).Conclusion: ATG kills LSCs in vitro via both CIC and CDC. However, the degree of the killing is minor and only observed at a higher ATG concentration than typically achieved in patients. Our data also suggest that if high dose ATG was used in patients (resulting in ≥50 mg/L concentration), LSCs could be killed to a greater degree than healthy HSCs. [Display omitted] [Display omitted] DisclosuresDaly:Sanofi-Genzyme: Other: Advisory Board.

Pharmacokinetics and estimated bioavailability of grapiprant, a novel selective prostaglandin E2 receptor antagonist, after oral administration in fasted and fed dogs

AIMS: To assess the effect of food intake on the pharmacokinetics of grapiprant administered orally at 2 mg/kg, and to estimate its oral bioavailability in dogs.METHODS: Eight healthy female Labrador Retriever dogs, aged 4–10 years were used. In the initial trial two dogs were administered a 0.5 mg/kg I/V bolus of grapiprant dissolved in ethanol. In the second trial, six dogs were assigned to two treatment groups, using a randomised cross-over design, and received 2 mg/kg of grapiprant orally, as pure powder, after fasting for 12 hours or after being fed. Blood samples were collected at preassigned times up to 36 hours after administration, and concentrations of grapiprant in plasma determined using validated high performance liquid chromatography.RESULTS: After I/V administration in the two dogs the terminal half life was 5.30 and 6.06 hours, clearance was 444 and 476 mL/hours/kg, and volume of distribution was 3,642 and 3,883 mL/kg. Compared with fasted dogs, oral administration in fed dogs resulted in reduced median peak concentrations in plasma (1,598 vs. 614 ng/mL) and delayed median time of peak concentration (1.0 vs. 3.0 hours). The estimated bioavailability in fasted and fed dogs was 111.9 and 59.1%, respectively. Concentrations of grapiprant in plasma following oral administration, in either fed or fasted dogs, remained higher than 164 ng/mL for up to 6 hours. This concentration has been estimated to be the minimal effective concentration required to control pain in dogs.CONCLUSION AND RELEVANCE: Oral administration of 2 mg/kg grapiprant in fed and fasted dogs resulted in different pharmacokinetics of the drug, but did not influence the length of time when concentrations in plasma exceeded theoretical effective concentrations. Further studies are necessary to verify these findings using pharmacokinetic-pharmacodynamic studies and in clinical subjects.

Pharmacokinetics of the Antischistosomal Lead Ozonide OZ418 in Uninfected Mice Determined by Liquid Chromatography-Tandem Mass Spectrometry.

One of the major neglected tropical diseases, schistosomiasis, is currently treated and controlled with a single drug, praziquantel. The quest for an alternative drug is fueled by the lack of activity of praziquantel against juvenile Schistosoma worms and the fear of emerging resistance. The synthetic ozonide OZ418 has shown high activity against Schistosoma mansoni, S. haematobium, and S. japonicum in vivo, but its drug disposition remains unknown. To bridge this gap, our study determined the basic pharmacokinetic (PK) parameters of a single oral dose (400 mg/kg of body weight) of OZ418 in uninfected mice. First, a simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify OZ418 concentrations in mouse plasma was successfully developed and validated according to U.S. FDA guidelines. This method proved to be selective, accurate (93 to 103%), precise (5 to 16%), and devoid of significant matrix effects (90 to 102%) and provided excellent recovery (101 to 102%). A median peak concentration of 190 (range, 185 to 231) μg/ml was reached at 2 h (2 to 3 h) posttreatment. A naive pooled noncompartmental PK analysis estimated a mean area under the plasma concentration-versus-time curve (AUC) of 9,303 μg h/ml (7,039.2 to 11,908.5 μg h/ml) and a half-life of 38.7 h (20 to 64.6 h). Thus, the OZ418 level in plasma remained well above its in vitro 50% inhibitory concentrations (IC50s) of 27.4 μg/ml (adult S. mansoni worms at 72 h) for at least 75 h. Consistently, OZ418 degraded little in plasma at 37°C (<20% in 121 h) and weakly inhibited cytochrome P450 (CYP450) metabolism (IC50 of 37 to 144 μM). Our results provide a first insight into the disposition of OZ418, paving the way for further studies of its biological fate and effect.

Determination of dabigatran and rivaroxaban by ultra-performance liquid chromatography-tandem mass spectrometry and coagulation assays after major orthopaedic surgery

Major orthopaedic surgery is associated with an increased risk of venous thromboembolism. Direct oral anticoagulants (DOACs) are recommended as thromboprophylactic agents after orthopaedic surgery. Although routine monitoring of DOACs in general is not required, measuring DOAC concentration may be necessary in clinical settings. The effects of DOACs on routine coagulation assays in spiked material are studied extensively, however, few data are available on DOAC concentration in patients after major orthopaedic surgery.We measured trough and peak DOAC concentrations with UPLC-MS/MS and routine coagulation tests in a prospective study including 40 patients receiving thromboprophylactic treatment with dabigatran 220mg od and 40 patients receiving rivaroxaban 10mg od after major orthopaedic surgery.For rivaroxaban, the median trough concentration with UPLC-MS/MS was 17.1ng/mL and median peak concentration was 149ng/mL. The anti-Xa assay displayed a good correlation, but a positive bias in comparison to the reference method. Furthermore, trough levels were mostly below the LOD of the anti-Xa assay. For dabigatran, the median trough concentration with UPLC-MS/MS was 12.1ng/mL, and median peak level was 80.8ng/mL. A positive bias was found when results from coagulation assays were compared to UPLC-MS/MS data. However, the addition of glucuronidated metabolites to dabigatran concentration UPLC-MS/MS data generally resolved most of this bias. Age was found to have a significant influence on dabigatran pharmacokinetics, irrespective of kidney function, whereas no effect of age was found during rivaroxaban treatment. In both treatment groups, female subjects displayed faster pharmacokinetics in comparison to male subjects, although not reaching significance.We conclude that UPLC-MS/MS is the method of choice to measure trough concentrations of DOACs in patients after orthopaedic surgery. Current coagulation assays are not suited for this purpose. We found large heterogeneity in both peak and trough concentrations of DOACs, and showed that pharmacokinetics of novel oral anticoagulants may be influenced by age and gender. Whether patients with high or low trough concentrations are at increased risk for bleeding or thromboembolic events respectively remains to be established.

Results of a Phase I-II Study of Fenretinide and Rituximab for Patients with B-Cell Lymphomas

Background:Despite improved treatment options, indolent non-Hodgkin lymphoma (NHL) and Mantle Cell Lymphoma (MCL) remain incurable for most patients. Fenretinide (4-hydroxy(phenyl)retinamide; 4-HPR), an orally bioavailable synthetic retinoid, has been shown to induce apoptotic cell death in a variety of tumor types, presumably via intratumoral induction of oxygen free radicals. Our group has shown single-agent fenretinide anti-B-NHL activity as well as synergy with anti-CD20 antibody therapy when tested in vitro (Shan et al Clin Cancer Res. 2001) and in human xenograft models (Gopal et al, Blood 2004). These preclinical data support the first trial to evaluate this strategy of fenretinide and rituximab in patients with B-cell malignancies. Here we report results from a phase I-II study evaluating the safety and efficacy of fenretinide with rituximab for indolent NHL and MCL.Methods:This was an open-label, phase I/II study conducted at the Fred Hutchinson Cancer Research Center (FHCRC) and Seattle Cancer Care Alliance, Seattle, WA (ClinicalTrials.gov identifier: NCT00288067). The study was approved by the institutional review board at FHCRC and written informed consent was obtained from all patients. Major eligibility criteria included: CD20 positive lymphoid malignancy, radiographically measurable disease, ECOG PS ²2, and adequate organ function. The phase I portion evaluated the safety of dosing single agent fenretinide at 900 mg/m2 PO BID for days 1-5 of a 7 day cycle and allowed de-escalation for excess toxicity. The phase II portion added 375 mg/m2 IV rituximab weekly on weeks 5-9 then every 3 months. All patients could remain on therapy until disease progression or unacceptable toxicity. Response assessment occurred approximately every 3 months. Correlative studies included fenretinide pharmacokinetics, serum retinol concentrations, and evaluation of tumor expression of BCL-2 family proteins. Response was scored by standard criteria (Cheson 1999).Results:Thirty-two patients enrolled in the study: 7 patients in phase I, and 25 patients in phase II. The median age was 64 years (range, 40 - 78), 81% were male, and the median number of prior therapies was 1 (range, 0 - 10) with 22 (69%) having received prior rituximab and 8 (25%) with rituximab-refractory disease. Histologies included 13 CLL/SLL, 10 follicular (FL), 7 mantle cell (MCL), 1 lymphoplasmacytic, and 1 marginal zone. No dose limiting toxicities were observed in the phase I portion, and 900 mg/m2 was the dose level delivered in combination with rituximab for the phase II component. The most common treatment-related adverse events (AE) of any grade were reversible night blindness (n=18, 56%), other eye disorders (n=17, 53%), rash (n=12, 38%), and photosensitivity (n=8, 25%). The most common treatment related AEs of grade 3 or higher included: maculopapular rash, night blindness, and decreased lymphocyte count. Three patients (9%) discontinued treatment early due to toxicity (rash-2, GI toxicity-1). One patient with MCL in the phase I portion experienced stable disease (SD) lasting 35 months. In the phase II portion of the study, 5 (20%) patientÕs disease responded (Figure), with 2 (8%) achieving complete remission (both SLL/CLL), and 3 (12%) achieving partial remission (2 FL, 1 MCL). In addition 16 (64%) patients had SD. The median progression-free survival was 9 months (range, 6 - 31 months), and the median overall survival was not reached (range, 33 months to not reached). Median time to progression of responders was 14.5 months. The one-month median peak and trough concentrations of fenretinide were 11.45 µM and 2.5 µM, respectively. Correlative studies assessing Bcl-2, BAX, and apoptosis in the 13 patients with circulating tumor cells were not able to associate these data with response, or survival.Discussion:In this phase I/II study, the combination of fenretinide and rituximab was well tolerated with predictable, reversible toxicities with up to 4.5 years of continuous therapy. Though the ORR was modest (20%), the majority had of patients had disease control (ORR + SD=84%) which lasted for > 6 months. Further study of this novel combination should focus on identifying the subset of B-NHL that is most likely to respond or the rational addition of other agents to augment these anti-tumor effects. [Display omitted] DisclosuresPagel:Actinium Pharmacetuicals, Inc.: Equity Ownership. Gopal:Merck: Research Funding; Emergent/Abbott: Research Funding; Cephalon/Teva: Research Funding; BioMarin: Research Funding; Sanofi-Aventis: Honoraria; Millenium: Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Spectrum: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Piramal: Research Funding; Biogen Idec, BMS: Research Funding.

Safety, pharmacokinetics, and pharmacodynamics of PD 0348292, an oral, direct factor Xa inhibitor, after single and multiple dosings in healthy subjects

The objective of this study was to evaluate PD 0348292 safety, pharmacokinetics, and pharmacodynamics in healthy subjects. Three phase 1 studies were conducted. Studies 1001 and 1021 were single ascending-dose studies in healthy subjects randomized to oral PD 0348292 (2.5-150 and 0.1-2.5 mg, respectively) or placebo. Study 1003 was a multiple ascending-dose study in which 3 cohorts of young subjects received multiple doses of PD 0348292 (5-30 mg) every 12 hours or placebo, and 1 cohort of elderly subjects received a single dose (5 mg) of PD 0348292 or placebo. Drug plasma concentrations were measured. The effects of PD 0348292 on thrombin generation and typical coagulation measures such as prothrombin time, and international normalized ratio were evaluated. Single doses of PD 0348292 were well tolerated. Minor bleeding-related adverse events were observed following multiple doses of PD 0348292. PD 0348292 exposure increased less than proportionally at doses > 20 mg. Median peak concentrations occurred 3 to 4 hours following administration, and the mean terminal t1/2 value was approximately 10 hours. PD 0348292 demonstrated robust and concentration-dependent inhibition of thrombin generation, and modest and dose-related increases in typical coagulation measures. The safety, pharmacokinetics, and pharmacodynamics of PD 0348292 were acceptable for future clinical development.

Are the Present Doses of Anti Tubercular Drugs Adequate for Severe Disease?

Are the Present Doses of Anti Tubercular Drugs Adequate for Severe Disease?

Racing Induces Changes in the Blood Concentration of Serum Amyloid A in Thoroughbred Racehorses

Intensive exercise results in the increased blood concentration of the acute phase proteins in horses competing in some sport disciplines. In this study, the blood level of serum amyloid A (SAA) was analyzed in Thoroughbred racehorses during 5 days after completion of the race. Samples were collected from 25 healthy Thoroughbred horses beginning with 4 hours after the race and repeated daily up to the fifth day after the race. Serum amyloid A analysis was performed using commercial enzyme-linked immunosorbent assay kit, and the results were presented as median, interquartile range (IQR), and range. Data were analyzed using Friedman's nonparametric analysis of variance. The acute phase response (APR) was reflected by an increased SAA level after the race, reaching significantly higher concentrations on days 1 (P < .001) and 2 (P = .005) and falling below the level of the first sample on day 5 (P = .006). The median peak concentration observed on day 1 after the race was 3.84 mg/L (IQR, 2.32 to 8.86). Racing induces minute changes in SAA concentration typical for the exercise-induced APR; however, the significance of this reaction in the context of horse health and fitness remains unclear.

Poor Penetration of Antibiotics Into Pericardium in Pericardial Tuberculosis

Pericardial tuberculosis (TB) is associated with high therapy failure and high mortality rates. Antibiotics have to penetrate to site of infection at sufficient non-protein bound concentrations, and then enter bacteria to inhibit intracellular biochemical processes. The antibiotic concentrations achieved in pericardial fluid in TB pericarditis have never been measured before. We recruited two cohorts of patients with TB pericarditis, and left a pigtail catheter in-situ for serial drug concentration measurements over 24h. Altogether, 704 drug concentrations were comodeled for pharmacokinetic analyses. The drug concentrations achieved in pericardial fluid were compared to the minimum inhibitory concentrations (MICs) of clinical Mycobacterium tuberculosis isolates. The total rifampicin concentration pericardial-to-serum ratios in 16 paired samples were 0.19±0.33. The protein concentrations of the pericardial fluid in TB pericarditis were observed to be as high as in plasma. The non-protein bound rifampicin concentrations in pericardial fluid were 4-fold lower than rifampicin MICs in the pilot study, and the peak concentration was 0.125 versus 0.208mg/L in the second (p=0.001). The rifampicin clearance from pericardial fluid was 9.45L/h versus 7.82L/h in plasma (p=0.002). Ethambutol peak concentrations had a pericardial-to-plasma ratio of 0.55±0.22; free ethambutol peak concentrations were 2.30-lower than MICs (p<0·001). The pericardial fluid pH was 7.34. The median pyrazinamide peak concentrations were 42.93mg/L versus a median MIC of 800mg/L at pH7.34 (p<0.0001). There was no significant difference between isoniazid pericardial fluid and plasma concentrations, and isoniazid peak concentrations were above MIC. This is the first study to measure anti-TB drug concentrations, pH and protein in the pericardial TB fluid. Pericardial concentrations of the key sterilizing drugs for TB were below MIC, which could contribute to poor outcomes. A new regimen that overcomes these limitations might need to be crafted.

Venom Concentrations and Clotting Factor Levels in a Prospective Cohort of Russell's Viper Bites with Coagulopathy.

BackgroundRussell’s viper envenoming is a major problem in South Asia and causes venom induced consumption coagulopathy. This study aimed to investigate the kinetics and dynamics of venom and clotting function in Russell’s viper envenoming.Methodology/Principal FindingsIn a prospective cohort of 146 patients with Russell’s viper envenoming, we measured venom concentrations, international normalised ratio [INR], prothrombin time (PT), activated partial thromboplastin time (aPTT), coagulation factors I, II, V, VII, VIII, IX and X, and von Willebrand factor antigen. The median age was 39y (16–82y) and 111 were male. The median peak INR was 6.8 (interquartile range[IQR]:3.7 to >13), associated with low fibrinogen [median,<0.01g/L;IQR:<0.01–0.9g/L), low factor V levels [median,<5%;IQR:<5–4%], low factor VIII levels [median,40%;IQR:12–79%] and low factor X levels [median,48%;IQR:29–67%]. There were smaller reductions in factors II, IX and VII over time. All factors recovered over 48h post-antivenom. The median INR remained >3 at 6h post-antivenom but had reduced to <2, by 24h. The aPTT had also returned to close to normal (<50sec) at 24h. Factor VII, VIII and IX levels were unusually high pre-antivenom, median peak concentrations of 393%, 307% and 468% respectively. Pre-antivenom venom concentrations and the INR (r = 0.20, p = 0.02) and aPTT (r = 0.19, p = 0.03) were correlated (non-parametric Spearman analysis).ConclusionsRussell’s viper coagulopathy results in prolonged aPTT, INR, low fibrinogen, factors V, VIII and X which recover over 48h. Severity of clotting abnormalities was associated with venom concentrations.

Exploratory biomarker results from early investigation of PEGPH20 in combination with gemcitabine (Gem) in patients with pancreatic cancer (PDA).

300 Background: PEGPH20 (PEG), a PEGylated recombinant human hyaluronidase, has anti-tumor activity as a single agent and in combination with chemotherapy in preclinical models. A Phase 1b study of PEG + Gem (P+G) in patients (pts) with advanced PDA showed good anti-tumor activity, particularly in pts with HAhigh tumors (ECCO 2013). In this study, we investigated pharmacodynamic (PD) markers including plasma(soluble) HA (sHA), dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and 18Fluorodeoxyglucose positron emission tomography (PET/CT) to explore additional correlates for PEG activity. Methods: 28 pts with stage IV PDA were treated with PEG at 1, 1.6, or 3µg/kg IV twice weekly for Wks 1-4 and Wks 5-7, followed by 1 wk rest, plus Gem at 1000 mg/m2 IV once weekly for Wks 1-7, then 1 wk rest. Thereafter, P+G was given once weekly for 3 wks in 4-wk cycles. Serial plasma samples were collected and analyzed in a quantitative assay for PEG and sHA. Exploratory imaging by DCE-MRI was performed on selection pts at baseline, 8hr, 24hr and end of cycle 1, PET/CT was performed at baseline and at the end of each cycle. Results: PEG pharmacokinetics was well-characterized by a 2-compartment PK model, peak plasma concentration increased in a dose-proportional manner after a single or repeat administration of PEG. Dose- and time-dependent increases in sHA were observed within 2-3 days after 1.0, 1.6, or 3.0 µg/kg of PEG administration. The median peak concentrations were 3,736; 48,150; and 74,950ng/mL, respectively, and increased with increasing doses. sHA reached steady state approximately 1 wk after repeated PEG administration, consistent with the expected hyaluronidase activity of PEG. Exploratory analysis with DCE-MRI from 6 pts showed an early increase (24hrs) in tumor perfusion (Ktrans) in target lesions. PET/CT from 5 pts showed an average reduction in the maximum standardized uptake value (SUVmax) of 37% at EOC1, and partial metabolic responses using EORTC criteria were achieved in 4 of 5 pts. These results suggest that P+G has measurable biological activity in metastatic PDA Conclusions: Plasma sHA concentration, DCE-MRI and PET/CT are PD markers for evaluation of P+G activity.