Meta-analysis of outcomes compared between robotic and laparoscopic gastrectomy for gastric cancer

This meta-analysis was performed to evaluate and compare the outcomes of robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) for treating gastric cancer. A systematic literature search was carried out using the PubMed database, Web of Knowledge, and the Cochrane Library database to obtain comparative studies assessing the safety and efficiency between RG and LG in May, 2013. Data of interest were analyzed by using of Review Manager version 5.2 software (Cochrane Collaboration). A fixed effects model or random effects model was applied according to heterogeneity. Seven papers reporting results that compared robotic gastrectomy with laparoscopic gastrectomy for gastric cancer were selected for this meta-analysis. Our meta- analysis included 2,235 patients with gastric cancer, of which 1,473 had undergone laparoscopic gastrectomy, and 762 had received robotic gastrectomy. Compared with laparoscopic gastrectomy, robotic gastrectomy was associated with longer operative time but less blood loss. There were no significant difference in terms of hospital stay, total postoperative complication rate, proximal margin, distal margin, numbers of harvested lymph nodes and mortality rate between robotic gastrectomy and laparoscopic gastrectomy. Our meta-analysis showed that robotic gastrectomy is a safe technique for treating gastric cancer that compares favorably with laparoscopic gastrectomy in short term outcomes. However, the long term outcomes between the two techniques need to be further examined.

A five-microRNA panel in plasma was identified as potential biomarker for early detection of gastric cancer

BACKGROUND

Circulating microRNAs (miRNAs) have been implicated as novel biomarkers for gastric cancer (GC) diagnosis. However, the mixture of GC subtypes may have led to the inconsistent circulating miRNA profiles, and the clinical performance of circulating miRNAs has not yet been evaluated independently on early detection of GC.

METHODS

A four-phase study was designed with a total of 160 cancer-free controls, 124 patients with gastric non-cardia adenocarcinoma (GNCA) and 36 patients diagnosed gastric cardia adenocarcinoma (GCA). In the discovery phase, we screened the miRNA expression profile in plasma of 40 GNCA patients (stage I) and 40 matched controls by TaqMan low density array (TLDA) chips with pooled samples. Differentially expressed miRNAs were further validated in individual sample using quantitative reverse-transcriptase PCR (qRT-PCR) in the training phase. Subsequently, in an independent validation phase, the identified miRNAs were evaluated in 48 GNCA patients (stage I) and 102 matched controls. Finally, the identified miRNAs were further assessed in an external validation phase including advanced GNCA and GCA patients. Additionally, the expression levels of identified miRNAs were measured in the media of BGC823 and MGC803 cell lines.

RESULTS

Five miRNAs (miR-16, miR-25, miR-92a, miR-451 and miR-486-5p) showed consistently elevated levels in plasma of the GC patients as compared with controls, and were identified to be potential markers for GNCA with area under the receiver operating characteristic (ROC) curves (AUCs) ranging from 0.850 to 0.925 and 0.694 to 0.790 in the training and validation phases, respectively. The five-miRNA panel presented a high diagnostic accuracy for the early-stage GNCA (AUCs=0.989 and 0.812 for the training and validation phases, respectively). Three miRNAs (miR-16, miR-25 and miR-92a) were excreted into the culture media of GC cell lines.

CONCLUSIONS

The five-miRNA panel in plasma may serve as a potential non-invasive biomarker in detecting the early-stage GC.

Tumour-initiating capacity is independent of epithelial-mesenchymal transition status in breast cancer cell lines

Background:

Epithelial–mesenchymal transition (EMT) and cancer stem cells (CSCs) are considered to be crucial for cancer biology. The purpose of this study was to determine whether EMT directly led to the acquisition of tumour-initiating capacity in breast cancer cell lines.

Methods:

Epithelial–mesenchymal transition was induced in five breast cancer cell lines and one normal breast cell line by EMT-related cytokine stimulation. Mesenchymal–epithelial transition (MET) was induced by stably overexpressing miR-200c in three mesenchymal-like breast cancer cell lines. Molecular expression and cell function analysis were performed to evaluate the effect of EMT or MET on tumour-initiating capacity and other biological characteristics.

Results:

The induction of EMT did not enhance tumour-initiating capacity but, instead, conferred a CD44⁺/CD24^−/low phenotype as well as cell proliferation, migration, and resistance to doxorubicin and radiation on breast cancer cell lines. Furthermore, MET did not lead to inhibition or loss of the tumour-initiating capacity in mesenchymal-like breast cancer cell lines, but it markedly attenuated other malignant properties, including proliferation, invasion, and resistance to therapy.

Conclusions:

Epithelial–mesenchymal transition does not alter tumour-initiating capacity of breast cancer cells but some other biological characteristics. Therefore, EMT and tumour-initiating capacity may not be directly linked in breast cancer cell lines.

The status of p53 in cancer cells affects the role of autophagy in tumor radiosensitisation

The function of autophagy in cancer has been intensively studied as a possible therapeutic target due to its unique ability to influence the cancer cells' resistance to chemotherapy and radiation treatment. p53 is a pivotal tumor suppressor that induces apoptosis, cell cycle arrest, and senescence in response to various stresses, also playing an important role in the regulation of radiosensitivity. Autophagy may either promote or inhibit the survival of tumor cells, while it was found to change along with the status of p53 in cancer cells. In this mini review, we aimed to provide an overview of the intricate relationship between autophagy and the status of p53 which plays an important role in radiosensitivity. Since autophagy can react to radiation differently in cancer cells with different p53 statuses, future work elucidating the interaction between autophagy and p53 in response to radiation might provide more insight into targeted cancer radiotherapy.

Phase I study of oral rigosertib (ON 01910.Na), a dual inhibitor of the PI3K and Plk1 pathways, in adult patients with advanced solid malignancies

PURPOSE

To determine the pharmacokinetics (PK), maximum tolerated dose (MTD), safety, and antitumor activity of an oral formulation of rigosertib, a dual phosphoinositide 3-kinase (PI3K) and polo-like kinase 1 (Plk1) pathway inhibitor, in patients with advanced solid malignancies.

EXPERIMENTAL DESIGN

Patients with advanced solid malignancies received rigosertib twice daily continuously in 21-day cycles. Doses were escalated until intolerable grade ≥2 toxicities, at which point the previous dose level was expanded to define the MTD. All patients were assessed for safety, PK, and response. Urinary PK were performed at the MTD. Archival tumors were assessed for potential molecular biomarkers with multiplex mutation testing. A subset of squamous cell carcinomas (SCC) underwent exome sequencing.

RESULTS

Forty-eight patients received a median of 2 cycles of therapy at 5 dose levels. Rigosertib exposure increased with escalating doses. Dose-limiting toxicities were hematuria and dysuria. The most common grade ≥2 drug-related toxicities involved urothelial irritation. The MTD is 560 mg twice daily. Activity was seen in head and neck SCCs (1 complete response, 1 partial response) and stable disease for ≥12 weeks was observed in 8 additional patients. Tumors experiencing ≥partial response had PI3K pathway activation, inactivated p53, and unique variants in ROBO3 and FAT1, two genes interacting with the Wnt/β-catenin pathway.

CONCLUSIONS

The recommended phase II dose of oral rigosertib is 560 mg twice daily given continuously. Urinary toxicity is the dose-limiting and most common toxicity. Alterations in PI3K, p53, and Wnt/β-catenin pathway signaling should be investigated as potential biomarkers of response in future trials.

Robotic versus open gastrectomy for gastric cancer: a meta-analysis

Aim

To evaluate the safety and efficacy of robotic gastrectomy versus open gastrectomy for gastric cancer.

Methods

A comprehensive search of PubMed, EMBASE, Cochrane Library, and Web of Knowledge was performed. Systematic review was carried out to identify studies comparing robotic gastrectomy and open gastrectomy in gastric cancer. Intraoperative and postoperative outcomes were also analyzed to evaluate the safety and efficacy of the surgery. A fixed effects model or a random effects model was utilized according to the heterogeneity.

Results

Four studies involving 5780 patients with 520 (9.00%) cases of robotic gastrectomy and 5260 (91.00%) cases of open gastrectomy were included in this meta-analysis. Compared to open gastrectomy, robotic gastrectomy has a significantly longer operation time (weighted mean differences (WMD) =92.37, 95% confidence interval (CI): 55.63 to 129.12, P<0.00001), lower blood loss (WMD: -126.08, 95% CI: -189.02 to -63.13, P<0.0001), and shorter hospital stay (WMD = -2.87; 95% CI: -4.17 to -1.56; P<0.0001). No statistical difference was noted based on the rate of overall postoperative complication, wound infection, bleeding, number of harvested lymph nodes, anastomotic leakage and postoperative mortality rate.

Conclusions

The results of this meta-analysis suggest that robotic gastrectomy is a better alternative technique to open gastrectomy for gastric cancer. However, more prospective, well-designed, multicenter, randomized controlled trials are necessary to further evaluate the safety and efficacy as well as the long-term outcome.

A Randomized, Double Blind Study to Evaluate the Efficacy of Palonosetron with Dexamethasone Versus Palonosetron Alone for Prevention of Post-Operative Nausea and Vomiting in Subjects Undergoing Bariatric Surgeries with High Emetogenic Risk

Introduction:

Postoperative (PONV) and postdischarge (PDNV) nausea and vomiting are common (60-70%) after bariatric surgery. Palonosetron (Pal), a novel 5-HT3 antagonist, is an effective antiemetic with a prolonged duration of action in the setting of PDNV. We hypothesized that combination therapy with Palonosetron (Pal) and dexamethasone (Dex) would improve treatment in comparison to Palonosetron alone in patients at high risk for PONV.

Methods:

In this study, patients undergoing bariatric laparoscopic surgery under general anesthesia, a subgroup of a larger Phase IV clinical trial of patients who had laparoscopic surgery, were randomized to 8 mg Dex + 0.075mg Pal or saline + 0.075mg Pal. Data was collected postoperatively at 2, 6, 24 and 72 hrs. A Functional Living Index-Emesis (QOL-FLIE) test was administered at 96 hrs.

Results:

We enrolled 76 ASA 1-2 patients with at least 3 PONV risk factors. Both randomization groups had a low incidence of vomiting in the PACU (Pal, 0.0%; Pal + Dex, 5.4%) as well as at 72 hours (0.0% both groups). Complete response (no vomiting, no rescue medication) was not different between treatment groups at any time intervals. Cumulative success rates over the entire 72 hrs were 60.4% (Pal alone) vs. 60.0% (Pal + Dex). Nausea scores (4 point ordinal scale) were not different between groups for any time intervals. Cumulative success scores for nausea (score = “none”; 0-72 hrs) were 41.9% for the Pal group, and 55.2% for the Pal+ Dex group. The Pal + Dex group showed a trend toward greater satisfaction on the QOL-FLIE scores with the greatest differences in the “nausea domain”.

Discussion:

The combination therapy (Pal + Dex) did not significantly reduce the incidence of PONV or PDNV when compared with Pal alone although a trend was observed indicating the possible increased efficacy of multi-drug therapy. There was no change in comparative efficacy over 72 hrs, possibly due to the low incidence of PDNV in both groups.

Phase I clinical trial of oral rigosertib in patients with myelodysplastic syndromes

The multi-kinase inhibitor rigosertib (ON 01910.Na) induces mitotic arrest and apoptosis in myeloblasts, while sparing normal cells. The purpose of this study was to determine the pharmacokinetic profile, maximum-tolerated dose (MTD), safety, and clinical activity of an oral formulation of rigosertib in patients with myelodysplastic syndromes (MDS). For pharmacokinetic studies, patients received rigosertib in single escalating weekly doses. To determine the MTD, patient cohorts received escalating doses of rigosertib twice daily for 14 d of a 21-d cycle. Overall, 37 patients were treated. Rigosertib exposure increased with escalating oral doses. Mean absolute oral bioavailability ranged from 13·9% (fed) to 34·8% (fasting) in 12 patients treated at the 560 mg b.i.d. dose level. Dose-limiting toxicity (grade 3 dysuria and shortness of breath) occurred at the 700 mg b.i.d. dose. Five patients experienced grade 3 non-haematological toxicity, including symptoms of urothelial inflammation, hypotension and syncope, fatigue and abdominal pain. Encouraging signs of clinical activity included two bone marrow complete remissions in refractory anaemia with excess blasts type 1 patients previously treated with azacitidine. In addition, four patients each achieved transfusion independence and haematological improvements. In conclusion, oral rigosertib is bioavailable and well tolerated, and has clinical activity in patients with MDS.

Protective effect of tanshinone IIA against radiation-induced ototoxicity in HEI-OC1 cells

Radiotherapy is a highly efficient treatment method for nasopharyngeal carcinoma that is often accompanied by significant ototoxic side-effects. The inner ear hair cells are particularly prone to serious injury following radiotherapy. Tanshinone IIA is a transcription factor inhibitor that is extracted from the traditional herbal medicine, Salvia miltiorrhiza Bunge. The present study investigated the effects of tanshinone IIA treatment on radiation-induced toxicity in the HEI-OC1 hair cell line. Using an MTT assay and flow cytometry, the radiation-induced weakening of the cells was observed to be alleviated when the cells were pre-treated with tanshinone IIA. Radiation exposure promoted p65/nuclear factor (NF)-κB nuclear translocation and activated the p53/p21 pathway, two processes which play a significant role in radiation-induced cell apoptosis. However, pre-treatment of the cells with tanshinone IIA inhibited p65/NF-κB nuclear translocation and p53/p21 pathway activation. These results demonstrate that tanshinone IIA is capable of protecting cochlear cells from radiation-induced injury through the suppression of p65/NF-κB nuclear translocation and the p53/p21 signaling pathway.

Phase 1 study of intravenous rigosertib (ON 01910.Na), a novel benzyl styryl sulfone structure producing G2/M arrest and apoptosis, in adult patients with advanced cancer

Rigosertib (ON 01910.Na), a synthetic novel benzyl styryl sulfone, was administered to 28 patients with advanced cancer in a Phase I trial in order to characterize its pharmacokinetic profile, determine the dose-limiting toxicities (DLT), define the recommended phase II dose (RPTD) and to document any antitumor activity. Patients with advanced malignant neoplasms refractory to standard therapy were given escalating doses of rigosertib (50, 100, 150, 250, 325, 400, 650, 850, 1,050, 1,375, 1,700 mg/m(2)/24h) as a 3-day continuous infusion (CI) every 2 weeks. An accelerated Fibonacci titration schedule with specified decreases for toxicities was used for escalation until grade ≥2 toxicity occurred. Intrapatient dose escalation was allowed if toxicity was grade ≤2 and the disease remained stable. Plasma pharmacokinetics (PK) and urinary PK assessments were studied in the 1st and 4th cycles. Twenty-nine patients (12 men and 17 women; age 36-87 y with a median of 63 y) were registered, but one died before study drug was given. Twenty-eight patients received a median of 3 cycles of therapy. Most common grade ≥2 toxicities attributable to rigosertib included fatigue, anorexia, vomiting and constipation. DLTs included muscular weakness, hyponatremia, neutropenia, delirium and confusional state. Risk factors for severe toxicities include pre-existing neurological dysfunction or advanced gynecologic cancer after pelvic surgery. Rigosertib pharmacokinetics showed rapid plasma distribution phases and urinary excretion. Elevations in plasma Cmax and AUC due to decreases in plasma clearance were associated with acute grade ≥3 toxicities. Of 22 evaluable patients, 9 (41%) achieved a best overall response of stable disease; all other patients (n=13; 59%) progressed. The median progression-free survival time was 50 days (95% confidence interval [CI]: 37-80 days). Nine (41%) patients survived for over 1 y. In summary, prolonged IV infusions of rigosertib were generally well tolerated. Nine (41%) patients achieved stable disease and 9 (41%) patients survived for over 1 year. The RPTD appears to be 850 mg/m(2)/24hr CI x 3 days. (ClinicalTrials.gov identifier: NCT01538537).

LC-MS/MS quantification of a neuropeptide fragment kisspeptin-10 (NSC 741805) and characterization of its decomposition product and pharmacokinetics in rats

The kisspeptins are critical regulators of mammalian reproduction. Kisspeptin-10 ((45)YNWNSFGLRF-NH2(54), kisspeptin-112-121 or metastin 45-54, NSC 741805), an active fragment of kisspeptin, has been shown to be a potent stimulator of gonadotropin-releasing hormone and secretion of luteinizing hormone in both rodents and primates. This shorter peptide fragment may have clinical utility potential and it is important to characterize its pharmacokinetic property. Recently, the pharmacokinetics of both kisspeptin-54 and kisspeptin-10 were characterized in humans using a radioimmunoassay (RIA), which measures only the immunoreactive kisspeptin (kisspeptin-IR). In this study, a highly sensitive and specific LC-MS/MS assay was developed to quantify kisspeptin-10 levels in rat plasma. The lower limit of quantitation (LLOQ) was 0.5 ng/mL, the within-day and between-day coefficient of variations (CVs) ranged from 5.2 to 15.4% and 1.3 to 14.2%, and the accuracy values ranged from 98 to 114% and 99 to 105%, respectively. With this method, stability studies demonstrated that kisspeptin-10 degraded rapidly with decomposition half-lives of 6.8 min, 2.9 min and 1.7 min at 4 °C, 25 °C, and 37 °C, respectively. The principal decomposition product was characterized as the N-terminal tyrosine deleted kisspeptin-10 (46)NWDSFGLRF-NH2(54). Pharmacokinetic study in rats showed that low ng/mL kisspeptin-10 was detected in the first few minutes, and eliminated rapidly and became undetectable 30 min after intravenous (i.v.) bolus administration of 1.0 mg/kg kisspeptin-10.

Repair of a palmar soft tissue defect of the proximal interphalangeal joint with a transposition flap from the dorsum of the proximal phalanx

This article describes the use of a transposition flap raised from the dorsum of the proximal phalanx for coverage of the volar defects at the proximal interphalangeal joint. The flap was based on the first dorsal branch of the proper digital artery. From January 2007 to March 2009, 14 digits in 14 patients (10 males and 4 females) were treated. There were 5 index, 6 middle, 2 ring, and 1 little finger. All patients underwent surgery 2-9 hours (mean 5 hours) after injury. Soft tissue defects ranged in size from 1.2 × 1.7 cm to 2.1 × 2.3 cm (mean 1.7 × 2 cm). Flap size ranged from 1.5 × 1.7 cm to 2.4 × 2.7 cm (mean 2 × 2.4 cm). Mean pedicle length was 1.1 cm (range 0.8-1.4 cm). All flaps completely survived. At final follow-up from 24-29 months (mean 26 months), mean active motion arcs of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints were 84° (range 75-91°), 86° (range 65-100°) and 54° (range 32-80°), respectively. Our technique is useful and reliable for coverage of a palmar defect over the proximal interphalangeal joint.

Laser hosing in relativistically hot plasmas

Electron response in an intense laser is studied in the regime where the electron temperature is relativistic. Equations for laser envelope and plasma density evolution, both in the electron plasma wave and ion acoustic wave regimes, are rederived from the relativistic fluid equations to include relativistic plasma temperature effect. These equations are used to study short-pulse and long-pulse laser hosing instabilities using a variational method approach. The analysis shows that relativistic electron temperatures reduce the hosing growth rates and shift the fastest-growing modes to longer wavelengths. These results resolve a long-standing discrepancy between previous nonrelativistic theory and simulations or experiments on hosing.

CT-guided percutaneous chemoablation using an ethanol-ethiodol-doxorubicin emulsion for the treatment of metastatic lymph node carcinoma: a comparative study

Current therapies for metastatic lymph node (LN) are a major burden on health-care systems. Alternative such as percutaneous chemoablation using interstitial injection of ethanol or ethanol-ethiodol-drug(s) mixture (EEM) has been successfully applied to solid tumor ablation of the liver, adrenal glands, lymph nodes and others. However, EEM chemoablation efficacy on two most frequent clinical lymph node presentation, isolated or confluent, has not yet been determined. This study was designed to compare the therapeutic effects of CT-guided percutaneous EEM injection (PEEMI) on patients presenting with single or multiple confluent metastatic LN localizations from various carcinoma. Thirty six patients with metastatic LN carcinoma at various anatomical regions were enrolled from 2009 to 2010 over a nine month period. They were separated into two groups: group A includes 24 single isolated metastatic lymph nodes and group B includes 12 multiple and confluent nodes. The primary end point was the ablative efficacy of PEEMI. The intratumoral (IT) EEM distribution and the occurrence of reflux were recorded. Adjuvant systemic chemotherapy was administered after the procedure. Contrast-enhanced CT scans were performed during procedure and follow-up. Six patients were tested for Fluorodeoxyglucose (FDG) fixation before and after the procedure. For group A the EEM IT distribution-to-tumor ratio was 100% vs. 50% to 80% for group B (t = 11.5, p < 0.05). The reflux frequency was 80% for group A versus 30% for group B. For group A, a complete response (CR) rates of 45.8%, 70.8%, 91.7% and a partial response (PR) rates of 54.2%, 29.2%, 8.3% were obtained at 3, 6 and 12 months after therapy. Regarding group B, a CR rate of 0%, 0%, 0% and PR rate of 16.7%, 50%, 58.3% were observed at similar period of time. Standardized rate by direct method was performed and the CR rate (74.5%) for group A was higher than for group B. The tumor FDG uptake was lower 6 months after PEEMII compared with the preoperative images. Five patients presenting with concomitant lung metastasis, had a good local response-node size reduction on postoperative CT scanning, but no response on lung nodules that were progressing. No serious adverse events were observed. A few patients had mild pain during the procedure, which resolved with peritumor injection of local anesthetic. No needle tract seeding or infection occurred. CT-guided PEEMI treatment is a simple, fast and predictable procedure that has better effectiveness on single, well circumscribed metastatic lymph node than on multiple and confluent ones. Technical improvements are expected to bring better results on large nodes that should be confirmed on larger group of patients.

A phase I study to assess oral bioavailability of a novel oral soft gelatin capsule formulation of rigosertib (ON 01910.Na) under fasted and fed conditions in patients with myelodysplastic syndromes

3081

Background: Rigosertib (ON 01910.Na) is a novel multikinase inhibitor, with selective cytotoxic effects on tumor cells without impact on normal cells. Rigosertib, administered as a 3-day continuous infusion, is now undergoing phase 3 evaluation in higher risk MDS patients refractory to hypomethylating agents. Here, we report the results of the effect of food on the absolute bioavailability of a novel rigosertib oral formulation (soft gelatin capsule) in MDS patients. Methods: This was a single-dose, three-treatment, three-period sequential design for studying the effects of food on the bioavailability of an immediate-release soft gelatin capsule formulation. The following dosing groups were tested in 12 patients: IV Dose 800 mg/m2 over 24 hours and oral dose 560 mg (2 x 280 mg capsules) under fasting and fed conditions. The oral dose was the recommended phase 2 dose, as reported previously (R.S. Komrokji et al., Oral Formulation of Rigosertib (ON 01910.Na) in Patients with Myelodysplastic Syndrome (MDS) – Phase I Study Results. Blood 2011, 118:Abstract #3797). Plasma samples were collected pre-dose, and over 32 hours (IV dose) or 8 hours (oral dose) after dose initiation. Rigosertib plasma levels were analyzed by a validated LC/MS/MS method. Pharmacokinetic parameters were estimated by noncompartmental analysis (WinNonlinÒ). Results: Rigosertib pharmacokinetic parameters are presented in the table below. The results of the present study demonstrate good oral bioavailability under fasting condition.Oral administration of rigosertib after a meal decreased Cmax and AUC by 77% and 61%, respectively, compared to fasting conditions. Conclusions: The results of this study support the potential for oral delivery of rigosertib, which could become a preferred therapy over a 3-day continuous intravenous infusion. [Table: see text]

Phase I study of oral rigosertib in patients with advanced solid tumors

3017

Background: Rigosertib (ON 01910.Na) is a new multi-targeted inhibitor of several kinases, including polo-like kinase 1 and PI-3 kinase, and is in advanced trials for myelodysplastic syndrome and pancreatic cancer as an IV agent. An oral formulation with good oral bioavailability has entered phase 1 in patients (pts) with advanced solid tumors to determine the dose limiting toxicities (DLT), recommended phase II dose, pharmacokinetic (PK) profiles, and to document any antitumor activity of this compound. Methods: Pts with histologically confirmed solid tumors refractory to standard therapy were given escalating doses of rigosertib (70, 140, 280, 560, 700 mg) twice daily continuously. Doses were escalated until intolerable grade 2 or grade 3/4 toxicities, at which point the previous dose level was expanded to define the MTD. All pts were assessed for safety, PK, PD and response. Urinary PK assessments were also performed at the MTD. Results: 25 pts (median age= 59; median ECOG PS= 1) received a median of 6 weeks of therapy at 5 dose levels: (70 mg n=3; 140 mg n=2 ; 280 mg n=3; 560 mg n=10; 700 mg n=7). The DLT was dysuria at 700 mg and led to expansion at 560 mg bid. There were no DLTs in the expansion cohort. Grade 2/3 toxicities related to rigosertib included dysuria (5/1), cystitis (4/0), urinary frequency (3/0), hematuria (2/1), abdominal pain (2/0), pelvic pain (1/1), nausea (1/0), distention/bloating (1/0) and hyponatremia (0/1). Improvements in dysuria were seen with oral hydration and sodium bicarbonate. A confirmed PR occurred in 1 pt (HN squamous cell ca, 42+ weeks), and SD was observed in 2 pts with ovarian cancer (56 weeks, 28 weeks), and 1 pt each with pancreatic neuroendocrine (40 weeks), carcinoid (32 weeks), nasopharyngeal (24 weeks) and renal cell (32+ weeks) tumors. Preliminary PK data reveal plasma rigosertib levels above the predicted pharmacodynamically active levels. Conclusions: The MTD of oral rigosertib administered twice daily continuously is 560mg. Dysuria is the dose limiting and most common toxicity and can be managed with oral hydration and sodium bicarbonate. Antitumor activity has been observed. Final safety and efficacy results, plasma and urinary PK relationships, and mutational analyses from archival tissue will be presented.

Radioprotective effects of ON 01210.Na upon oral administration

ON 01210.Na (Ex-RAD), a chlorobenzylsulfone derivative was investigated for its pharmacologic and radioprotective properties when administered via oral and subcutaneous (SC) routes. The goals of the study were to assess the comparative bioavailability of ON 01210.Na when administered by oral versus SC routes and to demonstrate that the oral drug delivery of ON 01210.Na afforded survival advantage similar to SC dosing. Pharmacokinetics was studied after two doses, 24 h apart, of ON 01210.Na (500 mg/kg) administered to male C3H/Hen mice (7-9 weeks) via SC injection or oral route. The dose response (100 to 750 mg/kg) and survival advantage of ON 01210.Na administered at 24 h and 15 min prior to 7.5 or 8 Gy whole body irradiation from a ¹³⁷Cs source (dose rate 1 Gy/min) were studied in these mice. Effects on the hematopoietic system were investigated by complete blood count and granulocyte-macrophage colony forming unit assay. A significant survival advantage and hematopoietic protection were observed after prophylactic oral ON 01210.Na and results were comparable to SC administration. These findings correlated well with pharmacokinetic data. Both SC and oral ON 01210.Na showed significant survival advantage against radiation toxicity and ON 01210.Na mediated hematopoietic protection plays key role in enhanced survival of mice. Oral administration holds better clinical promise as an effective countermeasure not only for early-responders in a nuclear accident, but also for the at-risk civilian population.

Generating energetic electrons through staged acceleration in the two-plasmon-decay instability in inertial confinement fusion

A new hot-electron generation mechanism in two-plasmon-decay instabilities is described based on a series of 2D, long-term (~10 ps) particle-in-cell and fluid simulations under parameters relevant to inertial confinement fusion. The simulations show that significant laser absorption and hot-electron generation occur in the nonlinear stage. The hot electrons are stage accelerated from the low-density region to the high-density region. New modes with small phase velocities develop in the low-density region in the nonlinear stage and form the first stage for electron acceleration. Electron-ion collisions are shown to significantly reduce the efficiency of this acceleration mechanism.

Phase I study of Rigosertib, an inhibitor of the phosphatidylinositol 3-kinase and Polo-like kinase 1 pathways, combined with gemcitabine in patients with solid tumors and pancreatic cancer

PURPOSE

Rigosertib, a dual non-ATP inhibitor of polo-like kinase 1 (Plk1) and phosphoinositide 3-kinase pathways (PI3K), and gemcitabine have synergistic antitumor activity when combined in preclinical studies. This phase I study aimed to determine the recommended phase II dose (RPTD) of the combination of rigosertib and gemcitabine in patients with cancer.

EXPERIMENTAL DESIGN

Patients with solid tumors who failed standard therapy or were candidates for gemcitabine-based therapy were eligible. Gemcitabine was administered on days 1, 8, and 15 on a 28-day cycle and rigosertib on days 1, 4, 8, 11, 15, and 18. Pharmacokinetic studies were conducted during an expansion cohort of patients with advanced pancreatic ductal adenocarcinoma (PDA).

RESULTS

Forty patients were treated, 19 in the dose-escalation phase and 21 in the expansion cohort. Dose levels evaluated were (gemcitabine/rigosertib mg/m(2)): 750/600 (n = 4), 750/1,200 (n = 3), 1,000/600 (n = 3), 1,000/1,200 (n = 3), and 1,000/1,800 (n = 6 + 21). One dose-limiting toxicity (death) occurred at the highest dose level (1,000/1,800) tested. Non-dose-limiting ≥grade II/III toxicities included neutropenia, lymphopenia, thrombocytopenia, fatigue, and nausea. Grade III/IV neutropenia, thrombocytopenia, and fatigue were seen in two, one, and two patients in the expansion cohort. Partial responses were observed in PDA, thymic cancer, and Hodgkin lymphoma, including gemcitabine-pretreated PDA. The pharmacokinetic profile of rigosertib was not affected by gemcitabine.

CONCLUSION

The RPTD established in this study is rigosertib 1,800 mg/m(2) and gemcitabine 1,000 mg/m(2). This regimen is well tolerated with a toxicity profile of the combination similar to the profile of gemcitabine alone. Antitumor efficacy was observed in patients who previously progressed on gemcitabine-based therapy.

Mammosphere cells from high-passage MCF7 cell line show variable loss of tumorigenicity and radioresistance

Mammosphere culture of cancer cell lines is an important approach used for enrichment of stem-like cancer cells (SLCs), but over-subcultured cell lines have been experimentally shown to change properties over time. It remains unclear if mammosphere cells (MSs) derived from high-passage cancer cell lines retain the tumorigenicity and radioresistance seen in MSs from primary or low-passage cell lines. In this study, we report that mammospheres derived from MCF-7 sublines after different passage numbers were consistently enriched for CD44+/CD24(-/low) cells but were not consistently enriched for tumorigenic and radioresistant cells. The tumorigenicity and radioresistance of MSs were associated with their sphere-forming ability, proliferation ability in vitro, and intracellular reactive oxygen species (ROS) levels. The radioresistant MSs showed significant cell cycle arrest in G2/M phase after X-ray irradiation and expressed higher ataxia telangiectasia mutated (ATM) mRNA levels. These results suggest that MSs from high-passage cancer cell lines were not consistently enriched for stem-like cancer cells with higher tumorigenicity and enhanced radioresistance.