The triterpenoid cucurbitacin B augments the antiproliferative activity of chemotherapy in human breast cancer.

Despite recent advances in therapy, breast cancer remains the second most common cause of death from malignancy in women. Chemotherapy plays a major role in breast cancer management, and combining chemotherapeutic agents with nonchemotherapeutic agents is of considerable clinical interest. Cucurbitacins are triterpenes compounds found in plants of the Cucurbitaceae family, reported to have anticancer and anti-inflammatory activities. Previously, we have shown antiproliferative activity of cucurbitacin B (CuB) in breast cancer, and we hypothesized that combining CuB with chemotherapeutic agents can augment their antitumor effect. Here, we show that a combination of CuB with either docetaxel (DOC) or gemcitabine (GEM) synergistically inhibited the proliferation of MDA-MB-231 breast cancer cells in vitro. This antiproliferative effect was accompanied by an increase in apoptosis rates. Furthermore, in vivo treatment of human breast cancer orthotopic xenografts in immunodeficient mice with CuB at either low (0.5 mg/kg) or high (1 mg/kg) doses in combination with either DOC (20 mg/kg) or GEM (12.5mg/kg) significantly reduced tumor volume as compared with monotherapy of each drug. Importantly, no significant toxicity was noted with low-dose CuB in combination with either DOC or GEM. In conclusion, combination of CuB at a relatively low concentration with either of the chemotherapeutic agents, DOC or GEM, shows prominent antiproliferative activity against breast cancer cells without increased toxicity. This promising combination should be examined in therapeutic trials of breast cancer.

Influence of mild and moderate hepatic impairment on axitinib pharmacokinetics.

OBJECTIVE: To evaluate the effects of hepatic impairment on the pharmacokinetics and safety of a single, oral axitinib dose in subjects with mild or moderate hepatic impairment. METHODS: In this phase I, open-label, parallel-group study, a total of 24 subjects with either normal hepatic function (n = 8) or with mild (n = 8) or moderate (n = 8) hepatic impairment were administered a single, oral dose of axitinib (5 mg). Blood samples were collected at intervals up to 144 h following dosing, and plasma pharmacokinetics and safety were assessed. Changes in axitinib plasma exposures in subjects with mild or moderate hepatic impairment were predicted using computer simulations and used to guide initial dosing in the clinical study. RESULTS: Axitinib exposure was similar in subjects with normal hepatic function and those with mild hepatic impairment, but approximately twofold higher in subjects with moderate hepatic impairment. Axitinib exposure weakly correlated with measures of hepatic function but was not affected by smoking status. Axitinib protein binding was similar in the three treatment groups. No significant treatment-related adverse events were reported. CONCLUSIONS: Compared with subjects with normal hepatic function, moderate hepatic impairment increased axitinib exposure, suggesting that the oral clearance of axitinib is altered in these subjects. In addition, these data indicate a possible need for a dose reduction in subjects who develop moderate or worse hepatic impairment during axitinib treatment. A single 5-mg dose of axitinib was well tolerated in subjects with mild or moderate hepatic impairment.

Modulation of 11beta-hydroxysteroid dehydrogenase (11betaHSD) activity biomarkers and pharmacokinetics of PF-00915275, a selective 11betaHSD1 inhibitor.

CONTEXT: 11beta-Hydroxysteroid dehydrogenase type 1 (11betaHSD1) is a promising target for the treatment of type 2 diabetes mellitus. 11betaHSD1 catalyzes the intracrine conversion of inactive cortisone to the active glucocorticoid cortisol. OBJECTIVE: Demonstrating inhibition of 11betaHSD1 is challenging because there is no accessible way to directly assess the enzyme activity in vivo. Thus, it was proposed to assess the enzyme activity, in an indirect fashion, using two biomarker methods: the prednisolone generation study (conversion of oral prednisone to prednisolone in plasma) and the ratio of cortisol and cortisone metabolites in urine. DESIGN: This was a phase 1, double-blind, placebo-controlled, randomized, multiple-dose study. SETTING: The study was conducted in a clinical research unit. PARTICIPANTS: Sixty healthy adult volunteers participated in the study. INTERVENTION: Oral doses of PF-00915275 (0.3-15 mg) and prednisone (10 mg) were administered during the study. MAIN OUTCOME MEASURES: Safety, tolerability, pharmacokinetics, and pharmacodynamics of PF-00915275, a selective 11betaHSD1 inhibitor, were measured. RESULTS: Overall, multiple oral doses of PF-00915275 were safe and well tolerated. After oral administration, PF-00915275 was rapidly absorbed, slowly eliminated, and generally displayed dose-proportional increases in exposure. At the 15-mg dose, mean exposure to prednisolone was reduced by 37%, and there was a dose-dependent fall in the 5alpha-tetrahydrocortisol + 5beta-tetrahydrocortisol to tetrahydrocortisone ratio with maximum inhibition of 26% after 14 d. The urinary free cortisol to urinary free cortisone ratio, an indicator of 11betaHSD2 inhibition, did not change. CONCLUSION: PF-00915275 was safe at all doses tested. The results of the prednisolone generation test and the urinary metabolite ratios confirm that PF-00915275 is a selective 11betaHSD1 inhibitor.

Cognitive testing in early-phase clinical trials: development of a rapid computerized test battery and application in a simulated Phase I study.

BACKGROUND: Inclusion of cognitive assessment in Phase I trials of novel pharmaceutical agents may help identify subtle yet meaningful CNS effects early in clinical development, and lead to a greater understanding of the pharmacokinetic/pharmacodynamic relationship prior to entering pivotal late-phase trials. AIMS: To examine issues surrounding the inclusion of a computerised cognitive test battery in Phase I clinical trials. METHODS: A 12-minute battery of five computerized cognitive tasks was administered to 28 healthy males in a double-blind, single ascending dose study using three doses of midazolam (0.6 mg, 1.75 mg and 5.25 mg) with placebo insertion. Subjects were enrolled and assessed at two Phase I units. Statistical analyses sought to determine the sensitivity of the test battery to sedation-related cognitive dysfunction, any between-site differences in outcome, and also the effects of repeated test administration (i.e., practice or learning effects). RESULTS: There were no significant differences in data collected between sites. All standard safety measurements were completed. No substantial technical issues were noted. No learning effects were observed on four of the five cognitive tasks. ANOVA comparing baseline to post-baseline results revealed significant cognitive deterioration on all five cognitive tasks 1 h following administration of 5.25 mg midazolam. The magnitude of these changes were very large according to conventional statistical criteria. Smaller but significant changes were observed on a subset of memory and learning tasks at 1 h post-dosing in 1.75 mg condition, and at 2 h post-dosing in the 5.25 mg condition. CONCLUSIONS: The cognitive test battery was well tolerated by subjects and research unit staff. The tests demonstrated minimal learning effects, were unaffected by language and cultural differences between sites, and were sensitive to the sedative effects of midazolam. Inclusion of this cognitive test battery in future studies may allow identification of cognitive impairment or enhancement early in the clinical development cycle.

Pharmacokinetics of a Novel Zolpidem Nasal Spray for Rapid Management of Insomnia: First Trial in Humans.

STUDY OBJECTIVES: The present single-dose, parallel-group, randomized, double-blind, placebo-controlled study is to evaluate the pharmacokinetics, tolerability and safety of zolpidem tartrate nasal spray (ZNS) as compared to placebo in healthy subjects. METHODS: Thirty-six healthy subjects participated in this study, with 19 male and 17 female subjects in 3 cohorts (12 subjects per cohort), who were randomly assigned to receive either an intranasal dose of ZNS 1.75 mg, 3.5 mg, 5.0 mg (n = 10 per dose), or an intranasal placebo (n = 2). Multiple venous blood samples were collected for pharmacokinetic analyses. RESULTS: Plasma zolpidem concentrations rapidly increased after intranasal ZNS 1.75, 3.5, and 5.0 mg with mean Tmax of 0.42, 0.76 and 0.50 h, respectively, followed by rapid decreases at all three doses. Cmax, AUC0-t, and AUC0-∞ were found to increase in a dose-proportional manner. Female subjects had generally higher AUC0-t, AUC0-∞, and lower weight-normalized clearance rate (CL/F) than male subjects. In this study, ZNS was safe and well tolerated over the evaluated dose range. There were no serious adverse events. CONCLUSIONS: Zolpidem was rapidly absorbed and eliminated after intranasal administration of ZNS. Dose proportionality was found at the doses ranged from 1.75 mg to 5.0 mg. Intranasal exposure of zolpidem was generally higher in female subjects than that in male subjects. It could be concluded that ZNS is safe and well tolerated over the evaluated range of intranasal doses.

Zolpidem Mucoadhesive Formulations for Intranasal Delivery: Characterization, In Vitro Permeability, Pharmacokinetics, and Nasal Ciliotoxicity in Rats.

Zolpidem is a non-benzodiazepine hypnotic for the treatment of insomnia characterized by difficulties with sleep initiation. Our study aimed at developing a zolpidem mucoadhesive formulation with minimal local toxicity, prolonged nasal residence time, and enhanced absorption after intranasal delivery. In vitro permeability studies using artificial membrane and Calu-3 cell culture model indicated efficient permeability of zolpidem. Aqueous solubility of zolpidem was found to be significantly improved by hydroxypropyl-ß-cyclodextrin. Various mucoadhesive formulations were then prepared comprising zolpidem, hydroxypropyl-ß-cyclodextrin, and mucoadhesive polymers such as hydroxypropyl methylcellulose, sodium carboxymethylcellulose, and sodium alginate. Pharmacokinetic studies in rats demonstrated that intranasally administered zolpidem could achieve significantly faster absorption rate and higher plasma concentration than that from oral route. In comparison with solution formulation (ZLP-S03), the optimized mucoadhesive formulation (ZLP-B01) containing 0.25% hydroxypropyl methylcellulose was found to improve Cmax from 352.6 ± 86.0 to 555.7 ± 175.8 ng/mL, and AUC0-inf from 32,890 ± 7547 to 65,447 ± 36,996 ng·min/mL with mild nasal ciliotoxicity in rats.

Effect of axitinib on the QT interval in healthy volunteers.

PURPOSE: Axitinib is a potent and selective inhibitor of vascular endothelial growth factor receptors 1-3, approved for second-line treatment of advanced renal cell carcinoma (RCC). Preclinical studies did not indicate potential for axitinib-induced delayed cardiac repolarization. METHODS: The effect of axitinib on corrected QT (QTc) prolongation was evaluated with one-stage concentration-QTc response modeling using data from a definitive randomized crossover QT phase I study in healthy volunteers administered one single 5-mg axitinib dose alone or in the presence of steady-state ketoconazole (400 mg once daily). RESULTS: Axitinib and ketoconazole had opposite effects on heart rate: Axitinib lowered it, ketoconazole raised it. The final analysis showed a flat relationship between QTc and axitinib concentration (slope -0.0314 ms·mL/ng) for axitinib alone. Mean highest placebo-matched change from baseline in QTc was -3.0 [90 % confidence interval (CI) -5.4, -0.6] ms. At supratherapeutic axitinib exposures achieved with potent cytochrome P450 3A4/5 inhibition by ketoconazole, the model predicted mean QTc change of 6.5 (90 % CI 4.4-8.5) ms. The slope population mean estimate was -0.331 (95 % CI -0.860, 0.198) ms·mL/µg for ketoconazole alone and 0.0725 (0.0445-0.1005) ms·mL/ng for axitinib in the presence of ketoconazole. The results were then compared with those obtained based on more widely used Fridericia's, Bazett's, and study-specific correction methods. CONCLUSIONS: Since axitinib plasma concentrations observed in this study exceeded the range of concentrations observed in patients with RCC at the highest approved clinical dose (10 mg twice daily), axitinib was not associated with clinically significant QTc prolongation in target populations.

Evaluation of the effect of food on the pharmacokinetics of axitinib in healthy volunteers.

PURPOSE: To evaluate the effect of food on axitinib pharmacokinetics in healthy volunteers with two different crystal polymorphs. METHODS: Two separate open-label, randomized, single-dose, three-period, crossover trials were conducted. Study I, conducted first using 5-mg axitinib Form IV film-coated immediate-release (FCIR) tablets, enrolled 18 subjects to compare fed versus fasted states and 24 subjects to evaluate the effect of timing of food consumption on axitinib pharmacokinetics. Study II enrolled 30 subjects to assess the effect of food using 5-mg axitinib Form XLI FCIR tablets. Subjects received axitinib after overnight fasting, with limited fasting or, depending on the study design, after consuming high-fat, high-calorie or moderate-fat, standard-calorie meals. RESULTS: For Form IV FCIR, compared with overnight fasting, axitinib plasma exposure [area under the concentration curve (AUC)] was decreased 23 % when administered with food. For Form XLI FCIR, mean axitinib plasma AUC and maximum plasma concentration (C(max)) were 19 and 11 % higher, respectively, with a high-fat, high-calorie meal compared with overnight fasting. When Form XLI FCIR was administered with moderate-fat, standard-calorie meal, AUC and C(max) were 10 and 16 % lower compared with overnight fasting. Both formulations were well tolerated. Adverse events, mostly gastrointestinal (7 % with Form IV FCIR and 13 % with Form XLI FCIR), were mild to moderate in both studies. CONCLUSIONS: While axitinib Form IV FCIR was associated with higher plasma exposure after overnight fasting, axitinib Form XLI FCIR can be administered with or without food as differences in axitinib pharmacokinetics under the two conditions were not clinically meaningful.

Cucurbitacin B inhibits STAT3 and the Raf/MEK/ERK pathway in leukemia cell line K562.

Cucurbitacin B is a natural anti-cancer compound found in Cucurbitaceae. Although the anti-cancer activity of cucurbitacin B in human leukemia cells has been reported, the underlining mechanism is still unclear. To clarify its anti-cancer activity and the mechanism of action, five different leukemia cell lines (CCRF-CEM, K562, MOLT-4, RPMI-8226 and SR) of the National Cancer Institute panel were treated with cucurbitacin B. Leukemia cell growth was inhibited by cucurbitacin B with GI(50) ranged from 15.6 nM to 35.3 nM and the growth inhibition effect was attributable to G2/M phase arrest and apoptosis. Western blotting analysis of cell signaling molecules indicated that cucurbitacin B inhibits STAT3 activation and the Raf/MEK/ERK pathway in the K562 cells.

Pharmacokinetics of sunitinib malate in subjects with hepatic impairment.

This study evaluated the effect of hepatic impairment on the pharmacokinetics of sunitinib and its active metabolite, SU12662. This open-label study enrolled subjects with normal hepatic function (n = 8), mild (Child-Pugh [CP]-A; n = 8), or moderate (CP-B; n = 8) hepatic impairment. Subjects received sunitinib 50 mg as a single oral dose. Mild or moderate hepatic impairment did not significantly alter sunitinib, SU12662, or total drug (TD) systemic exposure. In subjects with normal hepatic function, mild, or moderate hepatic impairment, respectively, TD AUC(0-infinity) was 1,938, 2,002, and 1,999 ng h/ml, TD AUC(0-last) was 1,913, 1,956, and 1,958 ng h/ml, and TD C (max) was 26.0, 27.3, and 26.7 ng/ml. There were no other notable pharmacokinetic differences and sunitinib was well tolerated. The pharmacokinetic findings of this study do not indicate a need to adjust the currently approved starting dose of sunitinib (50 mg daily on Schedule 4/2) for cancer patients with mild to moderate liver impairment.

Cucurbitacin B induces apoptosis and S phase cell cycle arrest in BEL-7402 human hepatocellular carcinoma cells and is effective via oral administration.

Cucurbitacin B is an anti-cancer drug candidate and its efficacy has been demonstrated in hepatocellular carcinoma (HCC). To explore its mechanism against HCC, BEL-7402 cells were treated with cucurbitacin B in vitro. Treatment with cucurbitacin B induced S phase arrest and apoptosis. The growth inhibition effect was associated with cyclin D1 and cdc-2 down regulations. Western blotting analysis of cell signaling molecules indicated that cucurbitacin B inhibited c-Raf activation without affecting STAT3 phosphorylation. Moreover, in vivo study demonstrated that cucurbitacin B is effective against BEL-7402 xenograft when administrated orally.

Pharmacokinetics and safety of sunitinib malate in subjects with impaired renal function.

This phase I, open-label, single-dose study evaluates the effects of severe renal impairment and end-stage renal disease (ESRD) requiring hemodialysis on the pharmacokinetics, safety, and tolerability of sunitinib and its primary active metabolite, SU12662. Subjects with normal renal function (creatinine clearance > 80 mL/min), severe renal impairment (creatinine clearance < 30 mL/min), and ESRD requiring hemodialysis receive a single dose of sunitinib 50 mg. Serial blood samples are collected for quantification of plasma concentrations using a validated liquid chromatography with tandem mass spectrometry assay. Safety is monitored. Twenty-four subjects complete the study. Pharmacokinetics in subjects with severe renal impairment appear similar to those with normal renal function. Plasma exposure to sunitinib and SU12662 appears lower in subjects with ESRD compared with subjects with normal renal function or severe renal impairment. Single-dose sunitinib 50 mg is well tolerated regardless of renal function. The currently approved starting dose of sunitinib 50 mg on Schedule 4/2 is expected to be appropriate for patients with renal impairment; any subsequent dose modifications should be based on patients' ability to tolerate treatment.

Cucurbitacin B, a novel in vivo potentiator of gemcitabine with low toxicity in the treatment of pancreatic cancer.

BACKGROUND AND PURPOSE: Pancreatic cancer is a highly aggressive malignancy, and improvement in systemic therapy is necessary to treat this frequently encountered metastatic disease. The current targeted agents used in combination with gemcitabine improved objective response rates, but with little or no improvements in survival and also increased toxicities in pancreatic cancer patients. Recently, we showed that the triterpenoid cucurbitacin B inhibited tumour growth in pancreatic cancer cells by inhibition of the JAK/STAT pathway, and synergistically increased antiproliferative effects of gemcitabine in vitro. EXPERIMENTAL APPROACH: The anti-tumour effects and toxicities of cucurbitacin B in combination with gemcitabine were tested against human pancreatic cancer cells in a murine xenograft model. KEY RESULTS: Combined therapy with cucurbitacin B and gemcitabine at relatively low doses (0.5 mg x kg(-1) and 25 mg x kg(-1) respectively) resulted in highly significant tumour growth inhibition of pancreatic cancer xenografts (up to 79%). Remarkably, this therapy was well tolerated by the animals, as shown by histology of visceral organs, analysis of serum chemistry, full blood counts and bone marrow colony numbers. Western blot analysis of the tumour samples of mice who received both cucurbitacin B and gemcitabine, revealed stronger inhibition of Bcl-XL, Bcl-2 and c-myc, and higher activation of the caspase cascades, than mice treated with either agent alone. CONCLUSIONS AND IMPLICATIONS: Combination of cucurbitacin B and gemcitabine had profound anti-proliferative effects in vivo against xenografts of human pancreatic cancer cells, without any significant signs of toxicity. This promising combination should be examined in therapeutic trials of pancreatic cancer.

Electrocardiographic characterization of the QTc interval in patients with advanced solid tumors: pharmacokinetic- pharmacodynamic evaluation of sunitinib.

PURPOSE: To evaluate the effects of sunitinib, a multitargeted tyrosine kinase inhibitor, on the QT interval in patients with cancer. EXPERIMENTAL DESIGN: Patients received sunitinib loading doses (150-200 mg) on days 3 and 9 and maintenance doses (50 mg/d) on days 4 to 8. Moxifloxacin (day 1), placebo (day 2), and granisetron [with placebo (day 2) or sunitinib (days 3 and 9)] were also administered. Treatment effects were evaluated by time-matched, serial electrocardiograms, and manually overread. RESULTS: Twenty-four of 48 patients were QT/PK evaluable. Moxifloxacin produced a time-matched, maximum mean placebo-adjusted corrected QT interval (QT(c)F) of 5.6 ms [90% confidence interval (CI), 1.9-9.3]. Sunitinib QT(c)F changes correlated with exposure, but not T(max). Maximum mean time-matched, placebo-adjusted QT(c)F was 9.6 ms (90% CI, 4.1-15.1) at steady state/therapeutic concentrations (day 3) and 15.4 ms (90% CI, 8.4-22.4) at supratherapeutic concentrations (day 9). No patient had a QT(c)F >500 ms. Concomitant granisetron produced no significant QT(c)F prolongation. Sunitinib-related adverse events were as previously described. CONCLUSIONS: Sunitinib has a dose-dependent effect on QT interval. The increased risk of ventricular arrhythmias must be weighed against the therapeutic benefit sunitinib provides to patients with advanced cancer.

Cucurbitacin B induces apoptosis by inhibition of the JAK/STAT pathway and potentiates antiproliferative effects of gemcitabine on pancreatic cancer cells.

Pancreatic cancer is an aggressive malignancy that is generally refractory to chemotherapy, thus posing experimental and clinical challenges. In this study, the antiproliferative effect of the triterpenoid compound cucurbitacin B was tested in vitro and in vivo against human pancreatic cancer cells. Dose-response studies showed that the drug inhibited 50% growth of seven pancreatic cancer cell lines at 10(-7) mol/L, whereas clonogenic growth was significantly inhibited at 5 x 10(-8) mol/L. Cucurbitacin B caused dose- and time-dependent G(2)-M-phase arrest and apoptosis of pancreatic cancer cells. This was associated with inhibition of activated JAK2, STAT3, and STAT5, increased level of p21(WAF1) even in cells with nonfunctional p53, and decrease of expression of cyclin A, cyclin B1, and Bcl-XL with subsequent activation of the caspase cascade. Interestingly, the combination of cucurbitacin B and gemcitabine synergistically potentiated the antiproliferative effects of gemcitabine on pancreatic cancer cells. Moreover, cucurbitacin B decreased the volume of pancreatic tumor xenografts in athymic nude mice by 69.2% (P < 0.01) compared with controls without noticeable drug toxicities. In vivo activation of JAK2/STAT3 was inhibited and expression of Bcl-XL was decreased, whereas caspase-3 and caspase-9 were up-regulated in tumors of drug-treated mice. In conclusion, we showed for the first time that cucurbitacin B has profound in vitro and in vivo antiproliferative effects against human pancreatic cancer cells, and the compound may potentate the antiproliferative effect of the chemotherapeutic agent gemcitabine. Further clinical studies are necessary to confirm our findings in patients with pancreatic cancer.