P1-12-13: Comparative Pharmacokinetics (PK) of Trastuzumab Emtansine (T-DM1) in Patients Who Have or Who Have Not Received Prior Treatment for Human Epidermal Growth Factor 2 (HER2)-Positive Metastatic Breast Cancer (MBC)

Background: T-DM1, an antibody-drug conjugate composed of trastuzumab, a stable linker, and the cytotoxic agent DM1, is in development for the treatment of HER2−positive cancers. Single-agent T-DM1 3.6 mg/kg every 3 weeks (q3w) has demonstrated clinical activity in 2 phase II studies (TDM4258g and TDM4374g) in patients with pretreated HER2−positive MBC. The efficacy and safety of T-DM1 vs trastuzumab + docetaxel was investigated in patients with no prior MBC treatment in the randomized phase II study TDM4450g/BO21976. Here we report the PK of T-DM1 from that study and compare these data with those from studies that enrolled pretreated patients.

Methods: In all 3 studies, PK parameters, including maximum concentration (Cmax), area under the concentration-time curve (AUC), terminal half-life (t½), steady-state volume of distribution (Vss), and clearance (CL) were estimated by noncompartmental analysis (NCA) for serum T-DM1, serum total trastuzumab (conjugated and unconjugated), and plasma DM1. The effects of baseline trastuzumab and HER2 extracellular domain (ECD) concentration on T-DM1 exposure were explored and the relationship between T-DM1 exposure and clinical response (objective response rate [ORR] and progression-free survival [PFS]) was modeled.

Results: T-DM1 PK from evaluable patients enrolled in 3 studies are shown in Table 1. No significant correlations were observed between efficacy (as measured by ORR) and T-DM1 exposure (AUC, Cmax) after administration of T-DM1 to pretreated patients; efficacy-exposure analyses (ORR and PFS) for previously untreated patients will be presented. Patients with measurable concentrations of trastuzumab at baseline had a greater AUC during cycle 1; however, this did not impact ORR. Baseline circulating HER2 ECD concentrations also had no effect on ORR for pretreated patients. The impact of baseline trastuzumab and HER2 ECD concentrations on ORR and PFS in previously untreated patients will be presented.

Proximity induced enhancement of the Curie temperature in hybrid spin injection devices

We investigate the increase of the Curie temperature T(C) in a lateral spin injection geometry where the ferromagnetic (Ga,Mn)As injector and detector contacts are capped by a thin iron film. Because of interlayer coupling between Fe and (Ga,Mn)As T(C) gets enhanced by nearly 100% for the thinnest (Ga,Mn)As films. The use of the proximity effect might pave the way for practical implementation of spintronic devices.

Paraquat induces epigenetic changes by promoting histone acetylation in cell culture models of dopaminergic degeneration

Environmental neurotoxic exposure to agrochemicals has been implicated in the etiopathogenesis of Parkinson's disease (PD). The widely used herbicide paraquat is among the few environmental chemicals potentially linked with PD. Since epigenetic changes are beginning to emerge as key mechanisms in neurodegenerative diseases, herein we examined the effects of paraquat on histone acetylation, a major epigenetic change in chromatin that can regulate gene expression, chromatin remodeling, cell survival and cell death. Exposure of N27 dopaminergic cells to paraquat induced histone H3 acetylation in a time-dependent manner. However, paraquat did not alter acetylation of another core histone H4. Paraquat-induced histone acetylation was associated with decreased total histone deacetylase (HDAC) activity and HDAC4 and 7 protein expression levels. To determine if histone acetylation plays a role in paraquat-induced apoptosis, the novel HAT inhibitor anacardic acid was used. Anacardic acid treatment significantly attenuated paraquat-induced caspase-3 enzyme activity, suppressed proteolytic activation and kinase activity of protein kinase C delta (PKCδ) and also blocked paraquat-induced cytotoxicity. Together, these results demonstrate that the neurotoxic agent paraquat induced acetylation of core histones in cell culture models of PD and that the inhibition of HAT activity by anacardic acid protects against apoptotic cell death, indicating that histone acetylation may represent key epigenetic changes in dopaminergic neuronal cells during neurotoxic insults.

Coenzyme Q plays opposing roles on bacteria/fungi and viruses in Drosophila innate immunity

Coenzyme Q (CoQ or ubiquinone) is a lipid-soluble component of virtually all types of cell membranes and has been shown to play multiple metabolic functions. Several clinical diseases including encephalomyopathy, cerebellar ataxia and isolated myopathy were shown to be associated with CoQ deficiency. However, the role of CoQ in immunity has not been defined. In the present study, we showed that flies defective in CoQ biosynthetic gene coq2 were more susceptible to bacterial and fungal infections, while were more resistant to viruses. We found that Drosophila contained both CoQ9 and CoQ10, and food supplement of CoQ10 could partially rescue the impaired immune functions of coq2 mutants. Surprisingly, wild-type flies fed CoQ10 became more susceptible to viral infection, which suggested that extra caution should be taken when using CoQ10 as a food supplement. We further showed that CoQ was essential for normal induction of anti-microbial peptides and amplification of viruses. Our work determined CoQ content in Drosophila and described its function in immunity for the first time.

Prognostic factors and survial of advanced renal cell carcinoma with predominant sarcomatoid histology

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Background: Sarcomatoid renal cell carcinoma (SRCC) is known to have aggressive clinical course and poor response to treatment. Very limited data of clinical feature, prognostic factor, and survival are available for advanced disease with predominant sarcomatoid histology. We evaluated clinical features, response to treatment, and prognostic factors for survival.

Methods: Between 2001 and 2010, 30 patients with metastatic or recurrent RCC with predominant sarcomatoid histology (sarcomatoid component 30% or more for resected kidney or exclusive sarcomatoid carcinoma on needle biopsy) were treated at our institution. We reviewed these patients' records to identify clinical and pathologic features which could affect survival. The role of nephrectomy and systemic therapy on patient outcome was also investigated.

Results: There were 20 male and 10 female patients with a median age of 58 years (range, 43–83). Twenty patients had initially metastatic disease and 16 patients (53%) had ECOG performance status (PS) of 0–1. The most frequent metastatic site was lung (57%) followed by bone (43%) and distant lymph nodes (23%). Fourteen (70%) out of 20 patients with initially metastatic disease underwent primary nephrectomy and six patients also underwent metastasectomy. The median % of sarcomatoid component was 80% (range, 30–100%). All patients (N=10) who received immunotherapy had progressive disease as their best response and only one out of 5 patients treated with sunitinib or everolimus had a partial response. With a median follow-up duration of 22 months, the median survival was 3.6 months (95% CI, 0∼7.5) with 6-month survival rate of 43%. Only ECOG PS had impact on survival (P<0.001: ECOG=0, 14.1 months; ECOG=1, 7.4 months; ECOG=2, 3.2 months, and ECOG=3, 1.64 months). Survivals for initially metastatic disease were not significantly different whether patients underwent nephrectomy or not (2.0 months vs. 3.4 months, HR=0.62, 95% CI, 0.16–2.44 after correcting for potential prognostic factors).

Conclusions: Patients with SRCC have a fulminant clinical course and the majority of patients had disease progression irrespective of any treatment. Only performance status dose have impact on overall survival.

No significant financial relationships to disclose.

Phase II study of a polyethoxylated castor oil–free, polymeric micelle formulation of paclitaxel for patients with advanced urothelial cancer previously treated with gemcitabine and platinum

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Background: Paclitaxel-loaded polymeric micelle (Genexol-PM; G-PM) is a novel polyethoxylated castor oil (Cremophor EL [CrEL])-free formulation of paclitaxel. This multicenter phase II study was designed to evaluate the efficacy and safety of the G-PM monotherapy for the treatment of gemcitabine- and cisplatin-refractory advanced urothelial cancer.

Methods: Patients with advanced urothelial cancer received G-PM 240 mg/m2 intravenously over 3 hours every 3 weeks without premedication as salvage chemotherapy after failure to gemcitabine and cisplatin combination chemotherapy. Intrapatient dose escalation of G-PM to 300 mg/m2 was carried out from the second cycle if the prespecified toxicities were not observed after the first cycle.

Results: Thirty-seven patients were enrolled in this study. Platinum-free interval was less than 6 months in 72% of patients and 64% of patients were categorized into intermediate or poor prognostic group. Overall response rate was 19% including one complete response. When response occurs it is long lasting with a median response duration of 7.8 months (range 1.5∼19.3+). The median progression-free survival was 2.7 months (95% CI, 09-4.6) with a median overall survival of 5.7 months (95% CI, 3.1-8.3). The most common major grade 3-4 non-hematologic toxicity was peripheral neuropathy (sensory type 5.6% and motor type 8.3%) followed by infection (5.6%). Grade 3 or worse hematologic toxicities were observed in only one patient.

Conclusions: G-PM showed modest activity with favorable toxicity profiles when used as salvage therapy after gemcitabine-cisplatin failure in advanced urothelial cancer.

No significant financial relationships to disclose.

A study on ruthenium-based catalysts for pharmaceutical wastewater treatment

Ruthenium-based catalysts were prepared by a saturation-dip method. Their catalytic activity was evaluated by a catalytic wet oxidation (CWO) process. The ruthenium-based catalysts were used to purify organic pharmaceutical wastewater with high concentration pyridine and pyridine derivatives that have high chemical oxygen demand (COD). In the CWO process, organic pharmaceutical wastewater was continuously pumped into fixed-bed reactors filled with Ru-based catalysts, while the organic components in wastewater were catalytically degraded by oxygen at high temperatures and pressures (temperature, 170-300 degrees C; pressure, 1.0-10 MPa). The experimental results showed that the prepared catalysts could effectively purify pharmaceutical wastewater with high concentration organic components, which are difficult to degrade biochemically, and that the removal rates of both COD and total nitrogen were over 99%.

Evaluation of SNPs in the chicken HMGA2 gene as markers for body weight gain

A QTL affecting body weight in chickens has been mapped to GGA1, between the markers GCT0006 and MCW0106. The gene HMGA2, which was previously identified as a candidate gene for determining body height in humans and mice, is also conspicuously close to the MCW0106 marker in chickens. Subsequently, 14 SNP markers of HMGA2 were genotyped in CAU chicken resource populations, and the associations between body weight and those SNP markers that displayed polymorphisms were analysed. Three SNPs (rs13849241, rs15231472 and rs13849381) were found to be significantly correlated with body weight in chickens (P < 0.05). Furthermore, haplotypes constructed based on these three SNPs were also discovered to be associated with body weight in chickens at the ages of 6, 7, 9 and 12 weeks. These results suggest that the chicken HMGA2 gene is indeed involved in body weight gain.

Computational identification of citrus microRNAs and target analysis in citrus expressed sequence tags

MicroRNAs (miRNAs) are a new family of small RNA molecules found in plants and animals. We developed a comprehensive strategy for identifying new miRNA homologues by mining the repository of available citrus expressed sequence tags (ESTs). By adopting a range of filtering criteria, we identified a total of 38 potential miRNAs--nine, five, nine and 15 miRNAs in Citrus trifoliata (ctr-miRNAs), C. clementina (ccl-miRNAs), C. reticulata (crt-miRNAs) and C. sinensis (csi-miRNAs), respectively--from more than 430,000 EST sequences in citrus. Using the potential miRNA sequences, we conducted a further BLAST search of the mRNA database and found six potential target genes in these citrus species. Eight miRNAs were selected in order to verify their existence in citrus using Northern blotting, and the functions of several miRNAs in miRNA-mediated gene regulation are experimentally suggested. It appears that all these miRNAs regulate expression of their target genes by cleavage, which is the most common situation in gene regulation mediated by plant miRNAs. Our achievement in identifying new miRNAs in citrus provides a powerful incentive for further studies on the important roles of these miRNAs.

The availability of 16S rRNA for the identification of forensically important flies (Diptera: Muscidae) in China

Many species of Muscidae are cosmopolitan synanthropic insects. It is frequently found on dead bodies after death, so an accurate identification of each species is necessary for the correct estimation of the postmortem interval (PMI). Identification species of Muscidae is traditionally performed through their morphological features. However, the morphological similarity of Muscidae in the level of species usually poses a challenge for forensic entomologists. Therefore a molecular method used 16S rRNA sequence on mitochondrial DNA was established for species identification. In this study, a 289 base pair region of mitochondrial DNA (mtDNA) coding for 16S rRNA was investigated for identification of the following forensically important species of Muscidae. The specimens were from four genera, including 18 Musca domestica (Linnaeus, 1758), 2 Ophyra spinigera (Stein, 1910), 2 Ophyra chalcogaster (Wiedemann, 1824), 1 Morellia hortorum (Fallén, 1817), and 1 Fannia canicularis (Linnaeus, 1761). 16S rDNA region allowed the identification of these species of Muscidae, indicating the possibility of separation congeneric species with molecular method.

Indications of proton-dominated cosmic-ray composition above 1.6 EeV

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d<X(max)>/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

Environmental neurotoxic pesticide increases histone acetylation to promote apoptosis in dopaminergic neuronal cells: relevance to epigenetic mechanisms of neurodegeneration

Pesticide exposure has been implicated in the etiopathogenesis of Parkinson's disease (PD); in particular, the organochlorine insecticide dieldrin is believed to be associated with PD. Emerging evidence indicates that histone modifications play a critical role in cell death. In this study, we examined the effects of dieldrin treatment on histone acetylation and its role in dieldrin-induced apoptotic cell death in dopaminergic neuronal cells. In mesencephalic dopaminergic neuronal cells, dieldrin induced a time-dependent increase in the acetylation of core histones H3 and H4. Histone acetylation occurred within 10 min of dieldrin exposure indicating that acetylation is an early event in dieldrin neurotoxicity. The hyperacetylation was attributed to dieldrin-induced proteasomal dysfunction, resulting in accumulation of a key histone acetyltransferase (HAT), cAMP response element-binding protein. The novel HAT inhibitor anacardic acid significantly attenuated dieldrin-induced histone acetylation, Protein kinase C delta proteolytic activation and DNA fragmentation in dopaminergic cells protected against dopaminergic neuronal degeneration in primary mesencephalic neuronal cultures. Furthermore, 30-day exposure of dieldrin in mouse models induced histone hyperacetylation in the striatum and substantia nigra. For the first time, our results collectively demonstrate that exposure to the neurotoxic pesticide dieldrin induces acetylation of core histones because of proteasomal dysfunction and that hyperacetylation plays a key role in dopaminergic neuronal degeneration after exposure of dieldrin.