Concomitant oral and intravenous pharmacokinetics of trametinib, a MEK inhibitor, in subjects with solid tumours

AIMS

The aim of this phase 1, single centre, open label study in four patients with solid tumours was to determine the absolute bioavailability of a 2 mg oral dose of trametinib. Trametinib is an orally bioavailable, reversible and selective allosteric inhibitor of MEK1 and MEK2 activation and kinase activity.

METHODS

A microtracer study approach, in which a 5 μg radiolabelled i.v. microdose of trametinib was given concomitantly with an unlabelled 2 mg oral tablet formulation, was used to recover i.v. and oral pharmacokinetic parameters, simultaneously.

RESULTS

The least-squares mean (90% confidence interval) absolute bioavailability of trametinib (2 mg tablet) was 72.3% (50.0%, 104.6%). Median tmax after oral administration was 1.5 h and the geometric mean terminal half-life was 11 days. The geometric mean clearance and volume of distribution after i.v. administration were 3.21 l h(-1) and 976 l, respectively, resulting in a terminal elimination half-life of 11 days.

CONCLUSIONS

Trametinib absolute bioavailability was moderate to high, whereas first pass metabolism was low.

Data collection methods in health services research: hospital length of stay and discharge destination

BACKGROUND

Hospital length of stay and discharge destination are important outcome measures in evaluating effectiveness and efficiency of health services. Although hospital administrative data are readily used as a data collection source in health services research, no research has assessed this data collection method against other commonly used methods.

OBJECTIVE

Determine if administrative data from electronic patient management programs are an effective data collection method for key hospital outcome measures when compared with alternative hospital data collection methods.

METHOD

Prospective observational study comparing the completeness of data capture and level of agreement between three data collection methods; manual data collection from ward-based sources, administrative data from an electronic patient management program (i.PM), and inpatient medical record review (gold standard) for hospital length of stay and discharge destination.

RESULTS

Manual data collection from ward-based sources captured only 376 (69%) of the 542 inpatient episodes captured from the hospital administrative electronic patient management program. Administrative data from the electronic patient management program had the highest levels of agreement with inpatient medical record review for both length of stay (93.4%) and discharge destination (91%) data.

CONCLUSION

This is the first paper to demonstrate differences between data collection methods for hospital length of stay and discharge destination. Administrative data from an electronic patient management program showed the highest level of completeness of capture and level of agreement with the gold standard of inpatient medical record review for both length of stay and discharge destination, and therefore may be an acceptable data collection method for these measures.

Randomized controlled trial of levamisole hydrochloride as adjunctive therapy in severe falciparum malaria with high parasitemia

BACKGROUND

Cytoadherence and sequestration of erythrocytes containing mature stages of Plasmodium falciparum are central to the pathogenesis of severe malaria. The oral anthelminthic drug levamisole inhibits cytoadherence in vitro and reduces sequestration of late-stage parasites in uncomplicated falciparum malaria treated with quinine.

METHODS

Fifty-six adult patients with severe malaria and high parasitemia admitted to a referral hospital in Bangladesh were randomized to receive a single dose of levamisole hydrochloride (150 mg) or no adjuvant to antimalarial treatment with intravenous artesunate.

RESULTS

Circulating late-stage parasites measured as the median area under the parasite clearance curves were 2150 (interquartile range [IQR], 0-28 025) parasites/µL × hour in patients treated with levamisole and 5489 (IQR, 192-25 848) parasites/µL × hour in controls (P = .25). The "sequestration ratios" at 6 and 12 hours for all parasite stages and changes in microvascular blood flow did not differ between treatment groups (all P > .40). The median time to normalization of plasma lactate (<2 mmol/L) was 24 (IQR, 12-30) hours with levamisole vs 28 (IQR, 12-36) hours without levamisole (P = .15).

CONCLUSIONS

There was no benefit of a single-dose of levamisole hydrochloride as adjuvant to intravenous artesunate in the treatment of adults with severe falciparum malaria. Rapid parasite killing by intravenous artesunate might obscure the effects of levamisole.

Effects of exercise on swallowing and tongue strength in patients with oral and oropharyngeal cancer treated with primary radiotherapy with or without chemotherapy

Tongue strength is reduced in patients treated with chemoradiotherapy for oral/oropharyngeal cancer. Tongue strengthening protocols have resulted in improved lingual strength and swallowing in healthy individuals, as well as in patients following a neurological event. However, no studies have examined the efficacy of tongue strengthening exercises on tongue strength, swallowing, and quality of life (QOL; Head and Neck Cancer Inventory) in patients treated with chemoradiotherapy. A randomized clinical trial examined the effects of a tongue strengthening programme paired with traditional exercises vs. traditional exercises alone. Dependent variables included tongue strength, swallowing, and QOL in a group of patients with oral and oropharyngeal cancer treated with primary radiotherapy with or without chemotherapy. Differences with regard to tongue strength and oropharyngeal swallow efficiency (OPSE) were not observed within or between groups. QOL in the eating and speech domains improved following treatment in both groups. However, the experimental group demonstrated greater impairment in QOL in the social disruption domain following treatment, whereas the control group demonstrated a slight improvement in functioning. Tongue strengthening did not yield a statistically significant improvement in either tongue strength or swallowing measures in this patient cohort. Patient compliance and treatment timing may be factors underlying these outcomes.

Plasmodium falciparum histones induce endothelial proinflammatory response and barrier dysfunction

Plasmodium falciparum is a protozoan parasite of human erythrocytes that causes the most severe form of malaria. Severe P. falciparum infection is associated with endothelial activation and permeability, which are important determinants of the outcome of the infection. How endothelial cells become activated is not fully understood, particularly with regard to the effects of parasite subcomponents. We demonstrated that P. falciparum histones extracted from merozoites (HeH) directly stimulated the production of IL-8 and other inflammatory mediators by primary human dermal microvascular endothelial cells through a signaling pathway that involves Src family kinases and p38 MAPK. The stimulatory effect of HeH and recombinant P. falciparum H3 (PfH3) was abrogated by histone-specific antibodies. The release of nuclear contents on rupture of infected erythrocytes was captured by live cell imaging and confirmed by detecting nucleosomes in the supernatants of parasite cultures. HeH and recombinant parasite histones also induced endothelial permeability through a charge-dependent mechanism that resulted in disruption of junctional protein expression and cell death. Recombinant human activated protein C cleaved HeH and PfH3 and abrogated their proinflammatory effects. Circulating nucleosomes of both human and parasite origin were detected in the plasma of patients with falciparum malaria and correlated positively with disease severity. These results support a pathogenic role for both host- and pathogen-derived histones in P. falciparum-caused malaria.

Co-regulation of transcellular and paracellular leak across microvascular endothelium by dynamin and Rac

Increased permeability of the microvascular endothelium to fluids and proteins is the hallmark of inflammatory conditions such as sepsis. Leakage can occur between (paracellular) or through (transcytosis) endothelial cells, yet little is known about whether these pathways are linked. Understanding the regulation of microvascular permeability is essential for the identification of novel therapies to combat inflammation. We investigated whether transcytosis and paracellular leakage are co-regulated. Using molecular and pharmacologic approaches, we inhibited transcytosis of albumin in primary human microvascular endothelium and measured paracellular permeability. Blockade of transcytosis induced a rapid increase in paracellular leakage that was not explained by decreases in caveolin-1 or increases in activity of nitric oxide synthase. The effect required caveolin-1 but was observed in cells depleted of clathrin, indicating that it was not due to the general inhibition of endocytosis. Inhibiting transcytosis by dynamin blockade increased paracellular leakage concomitantly with the loss of cortical actin from the plasma membrane and the displacement of active Rac from the plasmalemma. Importantly, inhibition of paracellular leakage by sphingosine-1-phosphate, which activates Rac and induces cortical actin, caused a significant increase in transcytosis of albumin in vitro and in an ex vivo whole-lung model. In addition, dominant-negative Rac significantly diminished albumin uptake by endothelia. Our findings indicate that transcytosis and paracellular permeability are co-regulated through a signaling pathway linking dynamin, Rac, and actin.

Plasmodium falciparum-induced CD36 clustering rapidly strengthens cytoadherence via p130CAS-mediated actin cytoskeletal rearrangement

The adhesion of infected red blood cells (IRBCs) to microvascular endothelium is critical in the pathogenesis of severe malaria. Here we used atomic force and confocal microscopy to examine the adhesive forces between IRBCs and human dermal microvascular endothelial cells. Initial contact of the cells generated a mean ± sd adhesion force of 167 ± 208 pN from the formation of single or multiple bonds with CD36. The strength of adhesion increased by 5- to 6-fold within minutes of contact through a signaling pathway initiated by CD36 ligation by live IRBCs, or polystyrene beads coated with anti-CD36 or PpMC-179, a recombinant peptide representing the minimal binding domain of the parasite ligand PfEMP1 to CD36. Engagement of CD36 led to localized phosphorylation of Src family kinases and the adaptor protein p130CAS, resulting in actin recruitment and CD36 clustering by 50-60% of adherent beads. Uninfected red blood cells or IgG-coated beads had no effect. Inhibition of the increase in adhesive strength by the Src family kinase inhibitor PP1 or gene silencing of p130CAS decreased adhesion by 39 ± 12 and 48 ± 20%, respectively, at 10 dyn/cm(2) in a flow chamber assay. Modulation of adhesive strength at PfEMP1-CD36-actin cytoskeleton synapses could be a novel target for antiadhesive therapy.

Nipple-sparing mastectomy and immediate breast reconstruction: Critical appraisal of five-year, single-center outcomes

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Background: Approximately 5,000 patients undergo breast reconstruction annually in the United Kingdom (2:1 ratio of immediate versus delayed respectively). Preservation of the breast envelope, i.e., skin and nipple areola complex (NAC) improves cosmesis. While skin-sparing mastectomy is an accepted modality for local control in appropriately selected patients, nipple-sparing mastectomy (NSM) remains controversial. In over 1,800 published NSM cases, the local event rate attributable to NAC preservation following NSM (therapeutic and prophylactic) is 0.16% with no evidence of deleterious impact on disease-free survival. In our cohort, patient selection criteria included: preoperative lesion characterisation; 5-mm margin acceptance; submission of separate nipple core specimens for paraffin block histological assessment and re-excision of all involved margins. This study is intended to evaluate the efficacy of loco-regional control in a consecutive cohort of patients, under uniform conditions undergoing nipple-sparing mastectomy and immediate breast reconstruction. We highlight the surgical technique used and propose in/exclusion criteria for appropriate patient selection.

Methods: 84 consecutive patients underwent NSM and IBR at Frimley Park Hospital, Surrey, UK (IJL, RD) between January 2004 and December 2008. Data was accrued retrospectively from the institution’s clinical coding, electronic records, and WinPath database. Endpoints recorded include: the incidence of (occult) malignancy at the nipple margins; NAC subcutaneous tissue loss; local (NAC) recurrence rates and disease free survival.

Results: The mean age was 51.1 years and follow-up 4.9 years. There was one case of local recurrence in a patient who declined re-excision of close/involved margins. The immediate peri-operative complication rate was within the national mastectomy breast reconstruction audit outcome guidelines.

Conclusions: In appropriately selected patients, our findings support nipple preservation at the time of mastectomy and immediate reconstruction as this enhances the cosmetic outcome without compromising oncologic safety.

Divergent roles of Toll-like receptor 2 in response to lipoteichoic acid and Staphylococcus aureus in vivo

The response of leukocytes to lipoteichoic acid (LTA), a TLR2-dependent major cell wall component of Staphylococcus aureus, is linked to the outcome of an infection. In this study we investigated the role of nonhematopoietic TLR2 in response to LTA and S. aureus by creating bone marrow chimeras. Significant leukocyte recruitment in response to LTA required IFN-gamma priming in WT C57BL/6 and TLR2(-/-)-->WT mice, but was not observed in TLR2(-/-) or WT-->TLR2(-/-) animals. LTA also induced a proinflammatory response in IFN-gamma primed primary human microvascular endothelial cells leading to leukocyte recruitment in vitro. When mice were infected with S. aureus, the most profound elevation of TNF-alpha and IL-6 was seen in TLR2(-/-) and TLR2(-/-)-->WT mice. TLR2(-/-), but not chimeric mice, demonstrated increased IL-17, blood leukocytosis and pulmonary neutrophilia compared to WT mice. Collectively, the results suggest an essential role for IFN-gamma and nonhematopoietic TLR2 for leukocyte recruitment in response to LTA. In contrast, TLR2 on both hematopoietic and nonhematopoietic cells appears to orchestrate an inhibitory response to S. aureus such that in complete TLR2 deficiency, there is an exaggerated proinflammatory response and/or skewing of the immune response towards a Th17 phenotype that may contribute to the decreased survival of TLR2(-/-) mice.

Plasmodium falciparum genome-wide scans for positive selection, recombination hot spots and resistance to antimalarial drugs

Antimalarial drugs impose strong pressure on Plasmodium falciparum parasites and leave signatures of selection in the parasite genome 1,2. Search for signals of selection may lead to genes encoding drug or immune targets 3. The lack of high-throughput genotyping methods, inadequate knowledge of parasite population history, and time-consuming adaptations of parasites to in vitro culture have hampered genome-wide association studies (GWAS) of parasite traits. Here we report genotyping of DNA from 189 culture-adapted P. falciparum parasites using a custom-built array with thousands of single nucleotide polymorphisms (SNPs). Population structure, variation in recombination rate, and loci under recent positive selection were detected. Parasite half maximum inhibitory concentrations (IC₅₀) to seven antimalarial drugs were obtained and used in GWAS to identify genes associated with drug responses. The SNP array and genome-wide parameters provide valuable tools and information for new advances in P. falciparum genetics.

A Population-Based Cross-Over Randomized Controlled Trial of Breast Cancer Screening with Alternate Mammography and Ultrasound for Women Aged 40 to 49 Years in Taiwan

Background: As there is paucity of data on population-based screening for breast cancer using mammography and ultrasound for oriental young women aged 40-49 years, the peak of incidence rate and high proportion of dense breast, we aimed to evaluate the relative performance of detecting breast cancer between ultrasound and mammography and also to assess complementary efficacy of ultrasound to mammography screening.Methods: A total of 79,691 female residents aged 40-49 years were invited from community in Taiwan since late 2003. These participants were first randomly assigned to mammography (n=20040), ultrasound (n=20088), and control group (n=39563). The two former groups were further done by a cross-over design with mammography and ultrasound on alternate year until 2008. Detection rate and annual incidence rate of interval cancer as a percentage of the control group (I/E ratio) were compared between mammography and ultrasound.Results: The attendance rate of the first round was 59% (11921/20040) for mammography and 56% (11249/20088) for ultrasound. The repeated attendance rate of both groups was 85% in the second round and 91% in the third round. In the first round of screen, the detection rate of breast cancer for the mammography group (0.34%) was 1.5-fold compared with the ultrasound group (0.22%). The additional detection rate was 0.16% contributed from a subsequent ultrasound screen and 0.36% contributed from a subsequent mammogram screen. The combination of mammography with ultrasound was as three to four times as likely to detect breast cancer compared with the control group (annual incidence rate was 0.17%). The I/E ratio was lower after mammography screening than that after ultrasound screening.Conclusion: The current randomized controlled trial not only demonstrated higher detection rate and better performance using mammography but also indicated the complementary role of ultrasound applied to young Taiwanese women. This further suggests the optimal screening modality for young women in Asian country is to combine mammography with ultrasound.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 73.

Safety, reactogenicity and immunogenicity of Francisella tularensis live vaccine strain in humans

We evaluated the safety, reactogenicity and immunogenicity of escalating doses of a new Francisella tularensis Live Vaccine Strain (LVS) lot by scarification (SCAR) or subcutaneously (SQ) in humans. Subjects (N=10/group) received one dose of LVS via SCAR at 10(5),10(7) or 10(9)cfu/ml or SQ at 10(2), 10(3),10(4) or 10(5)cfu/ml; 14 subjects received placebo. All doses/routes were well tolerated. When compared to placebo, vaccination with 10(7) SCAR and 10(9) SCAR resulted in significantly higher serologic response frequencies, as measured by ELISA for IgG, IgM, IgA and microagglutination; whereas vaccination with 10(5) SCAR, 10(7) SCAR 10(9) SCAR and 10(5) SQ elicited a significantly higher interferon-gamma response frequency.

Fetal anatomic evaluation in the overweight and obese gravida

OBJECTIVES

To evaluate the rate of completion of anatomic surveys of fetuses in overweight and obese gravid patients as compared with normal controls.

METHODS

This was a retrospective review of anatomic ultrasound scans performed between 2004 and 2007. Women were stratified by prepregnancy body mass index (BMI) into normal weight (BMI, 18.5-24.9 kg/m(2)), overweight (BMI, 25.0-29.9 kg/m(2)) and obese Class I (BMI, 30.0-34.9 kg/m(2)), Class II (BMI, 35.0-39.9 kg/m(2)) and Class III (BMI >or= 40.0 kg/m(2)) groups. Rates of completion of basic and comprehensive scans, gestational age at completion and number of scans required were compared.

RESULTS

For the 7140 patients included, completion rates for both the basic (normal weight, n = 2253 (79%); overweight, n = 1771 (76%); obese Class I, n = 767 (72%), Class II, n = 323 (61%) and Class III, n = 171 (49%)) and comprehensive (normal weight, n = 1234 (43%); overweight, n = 930 (40%); obese Class I, n = 404 (38%), Class II, n = 215 (41%) and Class III, n = 108 (31%)) surveys decreased significantly with increasing BMI (P < 0.00001). For surveys completed, the mean number of scans required was significantly higher for obese patients (basic: normal weight 1.3 vs. obese Class III 1.9; comprehensive: normal weight 1.7 vs. obese Class III, 2.2)(P < 0.00001). The overall completion rate improved at each gestational week, but was best between 20 and 23 weeks for obese patients.

CONCLUSIONS

As maternal BMI increases, the rate of completion of anatomic surveys decreases and the number of scans required increases. Delaying the initial survey until 20 weeks' gestation may improve the capacity to complete the examination in a single visit. It should be noted that these results represent completion rates at a tertiary referral center, and therefore may not reflect community experience.