Population Pharmacokinetics of Liposomal Irinotecan in Patients With Cancer.

Nanoliposomal irinotecan (nal-IRI) is a liposomal formulation of irinotecan with a longer half-life (t1/2 ), higher plasma total irinotecan (tIRI), and lower SN-38 maximum concentration (Cmax ) compared with nonliposomal irinotecan. Population pharmacokinetic (PK) analysis of nal-IRI was performed for tIRI and total SN-38 (tSN38) using patient samples from six studies. PK-safety association was evaluated for neutropenia and diarrhea in 353 patients. PK-efficacy association was evaluated from a phase III study in pancreatic cancer NAPOLI1. Efficacy was associated with longer duration of unencapsulated SN-38 (uSN38) above a threshold and higher Cavg of tIRI, tSN38, and uSN38. Neutropenia was associated with uSN38 Cmax and diarrhea with tIRI Cmax . Baseline predictive factors were race, body surface area, and bilirubin. Analysis identified PK factors associated with efficacy, safety, and predictive baseline factors. The results support the benefit of nal-IRI dose of 70 mg/m2 (free-base; equivalent to 80 mg/m2 salt base) Q2W over 100 mg/m2 Q3W.

A phase II/III randomized study to compare the efficacy and safety of rigosertib plus gemcitabine versus gemcitabine alone in patients with previously untreated metastatic pancreatic cancer.

BACKGROUND: Rigosertib (ON 01910.Na), a first-in-class Ras mimetic and small-molecule inhibitor of multiple signaling pathways including polo-like kinase 1 (PLK1) and phosphoinositide 3-kinase (PI3K), has shown efficacy in preclinical pancreatic cancer models. In this study, rigosertib was assessed in combination with gemcitabine in patients with treatment-naïve metastatic pancreatic adenocarcinoma. MATERIALS AND METHODS: Patients with metastatic pancreatic adenocarcinoma were randomized in a 2:1 fashion to gemcitabine 1000 mg/m(2) weekly for 3 weeks of a 4-week cycle plus rigosertib 1800 mg/m(2) via 2-h continuous IV infusions given twice weekly for 3 weeks of a 4-week cycle (RIG + GEM) versus gemcitabine 1000 mg/m(2) weekly for 3 weeks in a 4-week cycle (GEM). RESULTS: A total of 160 patients were enrolled globally and randomly assigned to RIG + GEM (106 patients) or GEM (54). The most common grade 3 or higher adverse events were neutropenia (8% in the RIG + GEM group versus 6% in the GEM group), hyponatremia (17% versus 4%), and anemia (8% versus 4%). The median overall survival was 6.1 months for RIG + GEM versus 6.4 months for GEM [hazard ratio (HR), 1.24; 95% confidence interval (CI) 0.85-1.81]. The median progression-free survival was 3.4 months for both groups (HR = 0.96; 95% CI 0.68-1.36). The partial response rate was 19% versus 13% for RIG + GEM versus GEM, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40 cases). Other mutations detected included TP53 (13 cases) and PIK3CA (1 case). No correlation between mutational status and efficacy was detected. CONCLUSIONS: The combination of RIG + GEM failed to demonstrate an improvement in survival or response compared with GEM in patients with metastatic pancreatic adenocarcinoma. Rigosertib showed a similar safety profile to that seen in previous trials using the IV formulation.

27-Hydroxycholesterol contributes to disruptive effects on learning and memory by modulating cholesterol metabolism in the rat brain.

Cholesterol metabolism is important for neuronal function in the central nervous system (CNS). The oxysterol 27-hydroxycholesterol (27-OHC) is a cholesterol metabolite that crosses the blood-brain barrier (BBB) and may be a useful substitutive marker for neurodegenerative diseases. However, the effects of 27-OHC on learning and memory and the underlying mechanisms are unclear. To determine this mechanism, we investigated learning and memory and cholesterol metabolism in rat brain following the injection of various doses of 27-OHC into the caudal vein. We found that 27-OHC increased cholesterol levels and upregulated the expression of liver X receptor-α (LXR-α) and adenosine triphosphate (ATP)-binding cassette transporter protein family member A1 (ABCA1). In addition, 27-OHC decreased the expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CR) and low-density lipoprotein receptor (LDLR) in rat brain tissues. These findings suggest that 27-OHC may negatively modulate cognitive effects and cholesterol metabolism in the brain.

Enhanced FGFR signalling predisposes pancreatic cancer to the effect of a potent FGFR inhibitor in preclinical models.

BACKGROUND: Fibroblast growth factor receptor (FGFR) signalling has been implicated in pancreas carcinogenesis. We investigated the effect of FGFR inhibition in pancreatic cancer in complementary cancer models derived from cell lines and patient-derived primary tumour explants. METHODS: The effects of FGFR signalling inhibition in pancreatic cancer were evaluated using anti-FRS2 shRNA and dovitinib. Pancreatic cancers with varying sensitivity to dovitinib were evaluated to determine potential predictive biomarkers of efficacy. Primary pancreatic explants with opposite extreme of biomarker expression were selected from 13 tumours for in vivo dovitinib treatment. RESULTS: Treatment with anti-FRS2 shRNA induced significant in vitro cell kill in pancreatic cancer cells. Dovitinib treatment achieved similar effects and was mediated by Akt/Mcl-1 signalling in sensitive cells. Dovitinib efficacy correlated with FRS2 phosphorylation status, FGFR2 mRNA level and FGFR2 IIIb expression but not phosphorylation status of VEGFR2 and PDGFRß. Using FGFR2 mRNA level, a proof-of-concept study using primary pancreatic cancer explants correctly identified the tumours' sensitivity to dovitinib. CONCLUSION: Inhibiting FGFR signalling using shRNA and dovitinib achieved significant anti-cancer cancer effects in pancreatic cancer. The effect was more pronounced in FGFR2 IIIb overexpressing pancreatic cancer that may be dependent on aberrant stimulation by stromal-derived FGF ligands.

A multicenter phase 1 study of PX-866 in combination with docetaxel in patients with advanced solid tumours.

BACKGROUND: This phase I, dose-finding study determined the safety, maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D), pharmacokinetics, and antitumour activity of PX-866, a phosphatidylinositol 3-kinase inhibitor, combined with docetaxel in patients with incurable solid tumours. METHODS: PX-866 was administered at escalating doses (4-8 mg daily) with docetaxel 75 mg m⁻² intravenously every 21 days. Archived tumour tissue was assessed for potential predictive biomarkers. RESULTS: Forty-three patients were enrolled. Most adverse events (AEs) were grade 1 or 2. The most frequent study drug-related AE was diarrhoea (76.7%), with gastrointestinal disorders occurring in 79.1% (docetaxel-related) and 83.7% (PX-866-related). No dose-limiting toxicities were observed. The RP2D was 8 mg, the same as the single-agent MTD. Co-administration of PX-866 and docetaxel did not affect either drug's PKs. Best responses in 35 evaluable patients were: 2 partial responses (6%), 22 stable disease (63%), and 11 disease progression (31%). Eleven patients remained on study for >180 days, including 8 who maintained disease control on single-agent PX-866. Overall median progression-free survival (PFS) was 73.5 days (range: 1-569). A non-significant association between longer PFS for PIK3CA-MUT/KRAS-WT vs PIK3CA-WT/KRAS-WT was observed. CONCLUSION: Treatment with PX-866 and docetaxel was well tolerated, without evidence of overlapping/cumulative toxicity. Further investigation with this combination is justified.

Soybean isoflavone alleviates ß-amyloid 1-42 induced inflammatory response to improve learning and memory ability by down regulation of Toll-like receptor 4 expression and nuclear factor-κB activity in rats.

ß-amyloid 1-42 (Aß1-42)-induced learning and memory impairment in rats is believed to be associated with inflammation. Cytokine production is a key pathologic event in the progression of inflammatory processes. In this rat study, soybean isoflavones (SIF) was used to investigate it's protective effects on inflammation caused by ß-amyloid 1-42 (Aß1-42), which is associated with learning and memory impairment in Alzheimer disease. We characterized the learning and memory ability. cytokine profiles of circulating interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) in the serum and the expression of Toll like receptor4 (TLR4) and nuclear factor-κB p65 (NF-κB p65) mRNA and protein in the brain tissue following intracerebroventricular administration of Aß1-42 by miniosmotic pump for 14 days. The results showed that functional deficits of learning and memory in SIF treatment groups were significantly improved compared to the control group without SIF treatment in water maze test. The serum IL-1ß and TNF-α level were significantly increased, and the expressions of TLR4 and NF-κB p65 mRNA and protein in the brain were up-regulated, indicating inflammation response was initiated following administration of Aß1-42. After intragastric pre-treatment with SIF, inflammatory cytokines was significantly reduced and also SIF reversed the Aß1-42 induced up-regulation of TLR4 and NF-κB p65 mRNA and protein expression in the brain and expression of NF-κB p65 in nuclei. These results suggested that SIF reduced the cytokine cascade and inflammatory response induced by Aß1-42 which could result in the improvement of spatial learning and memory ability impairment in the rats.

Integrated preclinical and clinical development of mTOR inhibitors in pancreatic cancer.

BACKGROUND: The purpose of this work was to determine the efficacy of inhibiting mammalian target of rapamycin (mTOR) in pancreatic cancer preclinical models and translate preclinical observations to the clinic. METHODS: Temsirolimus (20 mg Kg(-1) daily) was administered to freshly generated pancreatic cancer xenografts. Tumour growth inhibition was determined after 28 days. Xenografts were characterised at baseline by gene expression and comparative genomic hybridisation. Patients with advanced, gemcitabine-resistant pancreatic cancer were treated with sirolimus (5 mg daily). The primary end point was 6-month survival rate (6mSR). Correlative studies included immunohistochemistry assessment of pathway expression in baseline tumours, drug pharmacokinetics (PKs), response assessment by FDG-PET and pharmacodynamic effects in peripheral-blood mononuclear cells (PBMCs). RESULTS: In all, 4 of 17 xenografts (23%) responded to treatment. Sensitive tumours were characterised by gene copy number variations and overexpression of genes leading to activation of the PI3K/Akt/mTOR pathway. Activation of p70S6K correlated with drug activity in the preclinical studies. Sirolimus was well tolerated in the clinic, showed predictable PKs, exerted pathway inhibition in post-treatment PBMCs and resulted in a 6mSR of 26%. No correlation, however, was found between activated p70S6K in tumour tissues and anti-tumour effects. CONCLUSION: Sirolimus activity in pancreatic cancer was marginal and not predicted by the selected biomarker.

Phase I study of troxacitabine administered by continuous infusion in subjects with advanced solid malignancies.

BACKGROUND: Troxacitabine is a novel L-nucleoside analogue. Preclinical studies showed improved activity with infusions of at least 3 days compared with bolus regimens, especially at concentrations >20 ng/ml. This phase I study tested the feasibility of achieving a troxacitabine steady-state concentration of 20 ng/ml for at least 72 h in patients with solid tumors. PATIENTS AND METHODS: Patients with solid tumors received troxacitabine as a progressively longer infusion on days 1-4 of a 28-day cycle. The initial length of infusion and infusion rate were 48 h and 3 mg/m(2)/day. RESULTS: Twenty-one patients were treated at infusion lengths that increased from 48 to 72 h and then 96 h. The infusion rate was decreased from 3 to 1.88 mg/m(2)/day due to toxicity. Dose-limiting toxicities consisted of grade 4 neutropenia (three) and grade 3 constipation (one). The maximum tolerated dose of continuous infusion troxacitabine in patients with solid tumors is 7.5 mg/m(2) administered over 96 h. This dose level resulted in steady-state drug concentration of at least 20 ng/ml for 72 h. CONCLUSIONS: Administration of troxacitabine by continuous infusion achieved the prospectively defined target plasma concentration. Pharmacokinetics (PK) modeling coupled with real-time PK assessment was an efficient approach to conduct hypothesis-driven phase I trials.

Biologically active gamma-lactones and methylketoalkenes from Lindera benzoin.

Brine shrimp lethality-directed fractionation of the 95% EtOH extract of ripe berries from Lindera benzoin led to the isolation of three new C21 alkane-alkene gamma-lactones designated isolinderanolide, isolinderenolide, and linderanolide as well as the known series of C17 and C19 obtusilactones (isoobtusilactone A, obtusilactone A, isoobtusilactone, and obtusilactone) previously isolated from Lindera obtusiloba. The novel (6Z,9Z,12Z)-pentadecatrien-2-one, the known (6Z,9Z)-pentadecadien-2-one, and the known (+)-(Z)-nerolidol were also isolated as bioactive compounds. The structural elucidation and biological activities of these compounds are reported.

Bioactive neolignans from Endlicheria dysodantha.

From bioactivity-directed fractionation of the EtOH extract of Endlicheria dysodantha, dysodanthin A and dysodanthin B, which are new hexahydrobenzofuranoid neolignans, have been isolated. In addition, the known neolignans, compound 4, which is a burchellin analogue, and megaphone acetate [1] were isolated. All four neolignans showed activities in the brine shrimp lethality test; compounds 1-3 also inhibited the growth of crown gall tumors on potato discs and were cytotoxic to human tumor cells in culture. This is the first report of these neolignans isolated from the genus Endlicheria and of their completely assigned 1H-and 13C-nmr data.

Tubulosine: an antitumor constituent of Pogonopus speciosus.

From the antitumor-bioactive sap of Pogonopus speciosus, tubulosine [1] was isolated, by activity-directed fractionation using the brine shrimp lethality test, as the major antitumor constituent. 1H-nmr assignments, obtained from HETCOR and COSY, and X-ray crystallographic results are reported for the first time. Psychotrine [2] was also isolated, and its spectral data are also reported.

Majorenolide and majorynolide: a new pair of cytotoxic and pesticidal alkene-alkyne delta-lactones from Persea major.

From the EtOH extract of the bark of Persea major, two bioactive compounds, majorynolide [1] and majorenolide [2], were isolated by activity-directed fractionation using brine shrimp. Their structures have been elucidated on the basis of spectral data as a pair of new alkene-alkyne delta-lactones, each with an exocyclic alkylidene methine carbon. Both 1 and 2 are moderately cytotoxic, and 2 is selectively pesticidal.

Goniotriol from Goniothalamus giganteus.

The known styrylpyrone, goniotriol, has been isolated from Goniothalamus giganteus. Its bioactivities are reported, and its structure and relative stereochemistry have been determined by X-ray crystallography as 6R-(7R,8R-dihydro-7,8-dihydroxystyryl)-5S,6R-dihydro-5-hydroxy-2-p yrone.