The synthetic caged Garcinia xanthone, cluvenone, has potent and selective cytotoxicity against numerous cancer cell lines including those that are multi-drug resistant. The direct target of this structurally and functionally unique agent is unknown and that of the parent natural product, gambogic acid (GA), presently in clinical trials, is not yet entirely clear. For the first time, using fluorescently labeled GA (GA-Bodipy), we determined that GA-Bodipy localized in mitochondria and was effectively displaced by cluvenone in competition experiments indicating that the direct target of cluvenone resided in mitochondria and was shared by GA. In agreement with these findings, treatment of HeLa cells with cluvenone or GA resulted in disruption of mitochondrial morphology within 4 h. Furthermore, experiments using the potential sensitive JC-1 dye demonstrated that cells treated with 1 μM cluvenone for 1 h had significant loss of MMP compared to control cells. Examination of Cyt c levels in leukemia cells treated with 1 μM cluvenone resulted in a 4-fold increase in levels of both cytosolic and mitochondrial Cyt c. In agreement with Cyt c release, caspase 9 activity was increased 2.6-fold after treatment of cells for 5 h with 1 μM cluvenone. Remarkably, the caspase-9 inhibitor, Z-LEHD-FMK, blocked cluvenone-induced apoptosis in a dose-dependent manner with apoptosis being completely blocked by 10 μM of the inhibitor. In conclusion, cluvenone, an agent with potent cytotoxicity against multi-drug resistant tumor cells, has direct targets in mitochondria thus setting precedence for drug discovery efforts against these targets in the treatment of refractory cancers.
Cluvenone; mitocan; mitochondria; apoptosis; Garcinia; xanthone
This study was performed to determine the dose limiting toxicity (DLT), the recommended phase II dose and the pharmacokinetic profile for SR271425, given over 1 h every 3 weeks. The initial starting dose of SR271425 was 17 mg/m2. Patient selection was based on common phase I criteria as well as additional cardiac criteria. Thirty-eight patients were accrued to 16 dose levels from 17 to 1,320 mg/m2. Patient characteristics included 24 males and 14 females ages 35–78 with an Eastern Cooperative Oncology Group performance status of 0 (ten patients), 1 (27) and 2 (1). Tumor types were typical for a phase I study. The maximum administered dose was 1,320 mg/m2 with two DLTs, both QTc grade 3 prolongation. No drug related hematological toxicity was noted. Grade 1 toxicities included rash, flushing, pruritus, weight loss, diarrhea, hypertension and fatigue. Grade 2 toxicities included yellow discoloration of the skin, nausea and vomiting. QTc prolongation and hyperbilirubinemia were the only grade 3 toxicities noted. No confirmed tumor response was observed; however, two patients had prolonged stable disease. Both Cend and area under the plasma concentration– time curve increased in a dose related manner. Plasma drug concentrations declined in a biphasic manner with a mean terminal elimination half-life (t1/2) of 7.1 h (±1.3). There was no change in clearance or volume of distribution over the dose range studied. Due to cardiac toxicity occurring with both the parent compound, SR233377, as well as this analog, this series of agents was abandoned from further clinical development.
Thioxanthone; SR271425; QTc prolongation
The synthesis of five 2-arylnaphtho[2,3-d]oxazole- 4,9-dione derivatives was accomplished by refluxing 2-amino-3-bromo-1,4-naphthoquinone with appropriate benzoyl chloride analogs at elevated temperatures. In vitro anticancer evaluation of these compounds was performed on androgen-dependent, LNCaP, and androgen-independent, PC3, human prostate cancer cell lines. In general, these compounds displayed slightly stronger cytotoxicity on the androgen-dependent LNCaP than on the androgen-independent PC3 prostate cancer cell lines. The meta-substituted 2-(3-Chloro-phenyl)-naphtho[2,3-d]oxazole-4,9- dione (10) appear to display the best cytotoxicity on both cell lines with an IC50 of 0.03 μM on LNCaP and 0.08 μM on PC3 after 5 days of exposure.
2-arylnaphtho[2,3-d]oxazole-4,9-dione; Oxazolo-1,4-naphthoquinone; Prostate cancer; Naphthoquinone; Anticancer activities
The California Cancer Consortium has performed a Phase II trial of infusional bryostatin, a protein kinase C inhibitor isolated from the marine invertebrate bryozoan, Bugula Neritina, a member of the phylum Ectoprocta, in combination with cisplatin, in patients (pts) with recurrent platinum-sensitive or resistant ovarian cancer (OC).
Pts received bryostatin 45 mcg/m2 as a 72 h continuous infusion followed by cisplatin 50 mg/m2. Cycles were repeated every 3 weeks. Dosages were chosen based on phase I data obtained by the CCC in a population of pts with mixed tumor types.
Eight pts with recurrent or persistent epithelial OC received 23 cycles of treatment. All pts had received previous platinum-based chemotherapy; two pts had received one prior course, five had received two prior courses, and one had received three prior courses of chemotherapy. The median age was 64 (range 32–72), and Karnofsky performance status 90 (range 80–100). A median of 3 cycles of chemotherapy were delivered (range: 1–5). The median progression-free and overall survivals were 3 and 8.2 months respectively. Best responses included two partial responses (one in a platinum-resistant pt), three pts with stable disease, and three progressions. All pts experienced Grade 3 or 4 toxicities including severe myalgias/pain/fatigue/asthenia in six pts, and severe nausea/ vomiting/constipation in two other pts. One pt experienced a seizure and liver function tests were elevated in one other.
A modest response rate is observed in pts with recurrent or persistent ovarian cancer treated with the combination of bryostatin and cisplatin. The toxicity profile, however, observed in this pt population (primarily severe myalgias), precludes tolerability and prevents this combination from further investigation at this dose and schedule. It is possible that platinum pre-exposure in OC patients exacerbates observed toxicity. Phase II dosages of investigational agents in OC pts that are determined by phase I trials in pts with other tumor types should be chosen cautiously.
Chemomodulation; Chemotherapy; Phase II; Bryostatin; Cisplatin
Patients with metastatic pancreatic cancer have limited therapeutic options. The role of the Ras-Raf-MAPK pathway and of vascular endothelial growth factor in pancreatic carcinogenesis provided the rational to evaluate the efficacy of sorafenib with or without gemcitabine in a randomized phase II study.
Patients with metastatic pancreatic cancer were randomized to sorafenib alone (arm A) or sorafenib with gemcitabine (arm B).
Arm A was closed to accrual at interim analysis due to the lack of objective response. Median PFS and OS were 2.3 and 4.3 months respectively. There was one partial response among the 37 patients in arm B. Median PFS and OS were 2.9 and 6.5 months respectively. There were more grade 3 and 4 toxicities in arm B with the most common being neutropenia (17%), thrombocytopenia (8%), alkaline phosphatase elevation (14%), venous thromboembolism (8%), diarrhea, hypokalemia and ALT elevation (5%) each. Several associations were noted between single nucleotide polymorphisms in ribonucleotide reductase, Cox-2, vascular endothelial growth factor and survival in patients treated with gemcitabine and sorafenib.
Neither sorafenib alone or sorafenib in combination with gemcitabine manifested promising activity in metastatic pancreatic cancer.
Pancreatic cancer; Sorafenib; Gemcitabine; Ribonulceotide reductase
Recent research suggests that altered redox control of melanoma cell survival, proliferation, and invasiveness represents a chemical vulnerability that can be targeted by pharmacological modulation of cellular oxidative stress. The endoperoxide artemisinin and semisynthetic artemisinin-derivatives including dihydroartemisinin (DHA) constitute a major class of antimalarials that kill plasmodium parasites through induction of iron-dependent oxidative stress. Here, we demonstrate that DHA may serve as a redox chemotherapeutic that selectively induces melanoma cell apoptosis without compromising viability of primary human melanocytes. Cultured human metastatic melanoma cells (A375, G361, LOX) were sensitive to DHA-induced apoptosis with upregulation of cellular oxidative stress, phosphatidylserine externalization, and activational cleavage of procaspase 3. Expression array analysis revealed DHA-induced upregulation of oxidative and genotoxic stress response genes (GADD45A, GADD153, CDKN1A, PMAIP1, HMOX1, EGR1) in A375 cells. DHA exposure caused early upregulation of the BH3-only protein NOXA, a proapototic member of the Bcl2 family encoded by PMAIP1, and genetic antagonism (siRNA targeting PMAIP1) rescued melanoma cells from apoptosis indicating a causative role of NOXA-upregulation in DHA-induced melanoma cell death. Comet analysis revealed early DHA-induction of genotoxic stress accompanied by p53 activational phosphorylation (Ser 15). In primary human epidermal melanocytes, viability was not compromised by DHA, and oxidative stress, comet tail moment, and PMAIP1 (NOXA) expression remained unaltered. Taken together, these data demonstrate that metastatic melanoma cells display a specific vulnerability to DHA-induced NOXA-dependent apoptosis and suggest feasibility of future antimelanoma intervention using artemisinin-derived clinical redox antimalarials.
Malignant melanoma; Dihydroartemisinin; PMAIP1; Reactive oxygen species; Oxidative stress; Apoptosis
Gefitinib potently inhibits neuroblastoma proliferation in vitro, and the gefitinib/irinotecan combination shows greater than additive activity against neuroblastoma xenografts. This Phase II pilot study estimated the rate of response to two courses of intravenous irinotecan plus oral gefitinib in children with untreated high-risk neuroblastoma.
Two courses of irinotecan [15 mg/m2/day (daily×5)×2] were combined with 12 daily doses of gefitinib (112.5 mg/m2/day). Response was assessed after six weeks. A response rate >55% was sought.
Of the 23 children enrolled, 19 were evaluable for response. Median age at diagnosis was 3.1 years (range, 18 days – 12.7 years). Most patients were older than 24 months (n=20; 87%), male (n=18; 78%), white (n=16; 70%), had INSS 4 disease (n=19; 83%), and had adrenal primary tumors (n=18; 78%); nine patients (39%) had amplified tumor MYCN. The toxicity of gefitinib/irinotecan was mild and reversible (nausea, 5/20; diarrhea, 8/20; vomiting, 7/20). Five patients had partial responses; 9 others had a 23%–60% decrease in primary tumor volume and/or improved MIBG scans or decreased bone or bone marrow tumor burden. Median (range) systemic irinotecan exposure (AUC) was 283 ng/ml*hr (range, 163–890 ng/ml*hr) and 28 ng/ml*hr (3.6–297 ng/ml*hr) for the active metabolite, SN-38. No relation was observed between response and tumor expression of EGFR, MRP2-4, ABCG2, and Pgp.
Although the gefitinib/irinotecan combination was very tolerable and induced responses, it was not sufficiently active to warrant further investigation. Initial investigational studies of this type can preclude the necessity for larger, longer, and costlier trials.
Neuroblastoma; irinotecan; gefitinib; clinical trial; Phase II; ATP-Binding Cassette Transporters
Combined inhibition of epidermal growth factor receptor (EGFR) and Src family kinases (SFK) may lead to improved therapeutic effects. We evaluated the combination of dasatinib, an inhibitor of SFK and other kinases, and cetuximab, an anti-EGFR monoclonal antibody.
Patients and Methods
Patients with advanced solid malignancies received cetuximab intravenously on a standard weekly schedule and dasatinib orally, once daily at 3 dose levels: (1) 100 mg, (2) 150 mg, (3) 200 mg. Pharmacokinetic and pharmacodynamic studies of dasatinib were performed prior to starting cetuximab and following 14 days of treatment.
Twenty-five patients (3 dose level 1; 19 dose level 2; 3 dose level 3) were initially treated. Three patients developed dose-limiting toxicities: 1 at dose level 2 (headache) and 2 at dose level 3 (headache, nausea). Grade 3–4 toxicities in more than 2 patients included: dyspnea (4), vomiting (4), nausea (3), hypersensitivity reactions (3), headache (3) and anemia (3). Twenty-one patients developed headache (8 grade 1; 10 grade 2), which occurred after the loading of cetuximab and lasted 1–3 days. Six additional patients were treated with dasatinib starting 3 days after the loading dose of cetuximab; none developed headache after dasatinib. Dasatinib pharmacokinetics and a transient decrease in SFK PY416 levels in peripheral blood mononuclear cells were not altered by cetuximab. Patients with higher plasma TGF-alpha levels had worse progression-free survival.
Dasatinib 150 mg once daily plus weekly cetuximab is recommended for phase II studies. Early-onset headache was ameliorated by starting dasatinib after cetuximab.
dasatinib; cetuximab; Src; epidermal growth factor receptor; phase I; pharmacokinetic; pharmacodynamic
Gallbladder and cholangiocarcinomas represent a heterogeneous group of malignant diseases that commonly present at an advanced stage and that have limited therapeutic options. Based on the role of the Ras-Raf-Mek-Erk pathway and the VEGF axis in biliary carcinomas, we conducted a phase II study of sorafenib in patients with advanced biliary cancers.
Eligible patients had no prior therapy for metastatic or unresectable disease. Sorafenib was administered at 400 mg po twice daily continuously.
The study was terminated after the first stage of accrual due to failure to meet the primary objective. A confirmed response rate of 0% (0% – 11%) was observed. Thirty-nine percent of patients demonstrated stable disease (including 2 with unconfirmed PR). PFS was 3 months (95% CI: 2–4 months) and OS 9 months (95% CI: 4–12 months). The most common grade 3 and 4 toxicities included venous hand-foot skin reaction (13%), bilirubin elevation (13%), thromboembolism (10%), and AST/ALT elevation (10%) and elevated alkaline phosphatase (10%).
While treatment with sorafenib did not result in objective responses, patients with biliary cancers receiving this drug had some therapeutic benefit. Additional studies with sorafenib in combination with chemotherapy or other targeted agents may be warranted.
sorafenib; gallbladder cancer; cholangiocarcinoma; biliary cancer
MKC-1 is an orally available cell cycle inhibitor with downstream targets that include tubulin and the importin-β family. We conducted an open-label Phase II study with MKC-1 in patients with advanced pancreatic cancer.
Eligibility criteria included unresectable or metastatic pancreatic cancer, performance status of 1 or better, and failure of at least one prior regimen of chemotherapy. MKC-1 was administered orally, twice daily, initially at 100mg/m2 dosing for 14 consecutive days of a 28-day cycle. This schedule was modified during the trial to fixed and continuous dosing of 150mg per day.
20 of an original target of 33 patients were accrued, with a median age of 61 (range 44 to 81). No objective responses were observed, with one patient demonstrating stable disease. Overall survival was 101 days from the start of MKC-1 administration, and median time to progression was 42 days. The most common adverse events listed as related or possibly related to MKC-1 administration were hematologic toxicities and fatigue. One patient developed grade 5 (fatal) pancytopenia. Grade 3 and 4 events included cytopenias (lymphopenia, anemia), hyperbilirubinemia, pneumonia, mucositis, fatigue, infusion reaction, anorexia, and hypoalbuminemia.
MKC-1 administration was associated with substantial toxicity and did not demonstrate sufficient activity in patients with advanced pancreatic cancer to justify further exploration in this patient population.
Pancreatic cancer; Phase II; MKC-1; importin; tubulin
This phase I study aims at assessing the safety and tolerability of LY2603618, a selective inhibitor of Checkpoint Kinase 1, in combination with pemetrexed and determining the maximum tolerable dose and the pharmacokinetic parameters.
This was an open-label, multicenter, dose-escalation study in patients with advanced solid tumors. Increasing doses of LY2603618 (40–195 mg/m2) were combined with 500 mg/m2 of pemetrexed. LY2603618 was administered on Days 1 and 9 and pemetrexed on Day 8 in a 28-day cycle. For all subsequent 21-day cycles, pemetrexed was administered on Day 1 and LY2603618 on Day 2. Anti-tumor activity was evaluated as per Response Evaluation Criteria in Solid Tumors 1.0.
A total of 31 patients were enrolled into six cohorts (three at 40 mg/m2 over 4.5-hour infusion, 1-hour infusion in subsequent cohorts: three each at 40 mg/m2, 70 mg/m2, and 195 mg/m2; 13 at 105 mg/m2; six at 150 mg/m2). Four patients experienced a dose-limiting toxicity: diarrhea (105 mg/m2); reversible infusion-related reaction (150 mg/m2); thrombocytopenia (195 mg/m2); and fatigue (195 mg/m2). The maximum tolerated dose was defined as 150 mg/m2. The pharmacokinetic data demonstrated that the exposure of LY2603618 increased in a dose-dependent manner, displayed a suitable half-life for maintaining required human exposures while minimizing the intra- and inter-cycle accumulation, and was unaffected by the pemetrexed administration. The pharmacokinetic-defined biologically efficacious dose was achieved at doses ≥105 mg/m2.
LY2603618 administered approximately 24 h after pemetrexed showed acceptable safety and pharmacokinetic profiles.
LY2603618; Pemetrexed; Checkpoint kinase; inhibitor; Cancer
Background To determine the recommended phase II dose (RP2D) and assess the safety, pharmacokinetics (PKs) and pharmacodynamics of RO4929097in combination with temsirolimus. Methods Escalating doses of RO4929097 and temsirolimus were administered at three dose levels. Patients received once daily oral RO4929097 on a 3 days on/4 days off schedule every week, and weekly intravenous temsirolimus. Blood samples were collected for PK analysis. Archival tissue specimens were collected for Notch pathway biomarker analysis and genotyping of frequent oncogenic mutations. Results Seventeen patients with refractory advanced solid tumors were enrolled in three dose levels (DLs): DL1 (RO4929097 10 mg; Temsirolimus 25 mg), DL2 (RO4929097 20 mg; Temsirolimus 25 mg), and DL3 (RO4929097 20 mg; Temsirolimus 37.5 mg). The most common toxicities related to the study drug combination included: fatigue (82 %; grade 3 6 %), mucositis, (71 %; grade 3 6 %), neutropenia (59 %; grade 3 12 %), anemia (59 %; grade 3 0 %), and hypertriglyceridemia (59 %; grade 3 0 %). Two dose-limiting toxicities, grade 3 rash and grade 3 mucositis, were observed in the same patient in the first dose level prompting dose expansion. Eleven patients (73 %) had stable disease as their best response. Co-administration of RO4929097 was associated with increased clearance and reduced exposure to temsirolimus, suggestive of drug-drug interaction via CYP3A4 induction. No correlation between the expression of Notch pathway biomarkers or genotype and time to progression was noted. Conclusions RO4929097 can be safely combined with temsirolimus in patients with advanced solid tumors. The RP2D was established at 20 mg of RO4929097 combined with 37.5 mg of temsirolimus.
Electronic supplementary material
The online version of this article (doi:10.1007/s10637-013-0001-5) contains supplementary material, which is available to authorized users.
RO4929097; Temsirolimus; Clinical trial; Notch; Gamma-secretase inhibitor
Ixabepilone, which stabilizes microtubules, has low susceptibility to drug resistance mediated by P-glycoprotein or βIII-tubulin.
Materials and Methods
This study was designed to determine the maximum tolerated dose (MTD) of oral ixabepilone when administered every 6 h for three doses, every 3 weeks, to patients with refractory advanced cancers. Eighteen patients were treated with escalating doses of ixabepilone: three at cohort 1 (30 mg/dose; 90 mg on Day 1), nine at cohort 2 (40 mg/dose; 120 mg on Day 1), and six at cohort 3 (50 mg/ dose; 150 mg on Day 1). Serial plasma samples were collected during cycle 1 for pharmacokinetic (PK) measurements.
Of the 18 treated patients, eight were male and ten were female. The median age was 59 years, and most had an excellent performance status (KPS 90–100; 61%). There were two dose limiting toxicities (DLT): Grade 4 febrile neutropenia at the 120 mg dose and Grade 4 neutropenic sepsis at the 150 mg dose. Because of the severity and duration of neutropenic sepsis at level 3, level 2 (120 mg) was defined as the MTD and this cohort was expanded to nine patients. High inter-individual variability in plasma drug concentrations was observed during the study, with particularly high levels in two patients with DLT.
On the basis of this safety profile, the MTD of oral ixabepilone was defined as 120 mg given as three 40 mg doses each separated by 6 h on Day 1 of a 3-week cycle. However, the PK variability observed makes further development of this oral formulation unlikely.
Ixabepilone; Oral administration; Phase I trial
Purpose Continuous treatment with FOLFOX therapy is associated with peripheral nerve toxicity, and to improve this inconvenient side effect various methods of administration are being investigated. A regimen of intermittent oxaliplatin administration by continuous infusion therapy, i.e., modified FOLFOX7 (mFOLFOX7) + bevacizumab, was designed with the goal of alleviating severe peripheral nerve disorders and hematological toxicity. A phase II clinical study was conducted to evaluate the efficacy and safety of this regimen. Methods Previously untreated patients were assigned to mFOLFOX7 (oxaliplatin 85 mg/m2, levofolinate [l-LV] 200 mg/m2, 5-fluorouracil [5-FU] 2400 mg/m2) + bevacizumab (5 mg/kg) administered every 2 weeks for 8 cycles, maintenance without oxaliplatin for 8 cycles, and reintroduction of mFOLFOX7 + bevacizumab for 8 cycles or until disease progression. Progression free survival (PFS) following the first dose (PFS 1) and following reintroduction of oxaliplatin (PFS 2) were used as indices for assessing the efficacy of intermittent administration. Results Fifty-two patients were enrolled, with median age of 64 years (range, 36–74). Median PFS 1 was 11.8 months (95 % confidence interval [CI], 9.5 to 13.7), median time to treatment failure was 10.3 months (95 % CI, 5.6 to 12.1), percentage of patients with neutropenia of grade 3 or higher was 7.8 %, and percentage with peripheral nerve disorders was 3.9 %. Response rate was 50 %, and 84.4 % of patients who started modified simplified LV5FU2 + bevacizumab were reintroduced to oxaliplatin. Conclusion By excluding 5-FU bolus administration and administering bevacizumab continuously the mFOLFOX7 + bevacizumab regimen with preplanned withdrawal of oxaliplatin showed high tolerability and prevented severe peripheral neuropathy and neutropenia without reducing efficacy.
Oxaliplatin; Bevacizumab; Stop-and-go; Modified FOLFOX7; Metastatic colorectal cancer
Purpose: Angiogenesis plays an essential role in tumor development, invasion and metastasis. We evaluated the efficacy and safety of dual angiogenesis blockade with bevacizumab and sorafenib in patients with metastatic breast cancer. Patients and Methods: Patients who had received no more than 2 prior chemotherapy regimens in any setting were treated with sorafenib 200 mg as a single oral dose daily plus bevacizumab intravenously 5 mg/kg every other week. Response was assessed by Response Evaluation Criteria in Solid Tumors (RECIST). The primary endpoint was progression free survival (PFS). Results: Eighteen patients were enrolled. Median age was 56 yo, all had good performance status KPS of 0 or 1, and 17 patients had received 1 or 2 prior chemotherapy regimens. Median PFS was 2.8 months. There were no complete or partial responses; 3 patients had stable disease for >6 months. Toxicity was substantial with 9 (50 %) patients reporting Grade 3 toxicity. Seven (39 %) patients discontinued therapy due to adverse events including hypertension (N = 2), GI toxicity (N = 1), sensory neuropathy (N = 1), rash (N = 1), pain (N = 1) and wound complication (N = 1). Given the lack of clear efficacy and increased toxicity, accrual was terminated. Conclusion: The combination of sorafenib and bevacizumab has substantial toxicity and minimal efficacy in patients with previously treated metastatic breast cancer. Further study of this combination is not recommended.
Bevacizumab; Sorafenib; Metastatic breast cancer
Histone deacetylase (HDAC) inhibitors, such as vorinostat, decrease Aurora kinase activity by a variety of mechanisms. Vorinostat and MLN8237, a selective Aurora A kinase inhibitor, disrupt the spindle assembly and the mitotic checkpoint at different points, suggesting that the combination could have increased antitumor activity. The purpose of this study was to determine the cytotoxicity of vorinostat and MLN8237 in pediatric tumor cell lines.
Cell survival was measured after 72 h of drug treatment using a modified methyl tetrazolium assay. For drug combination experiments, cells were exposed to medium alone (controls), single drug alone, or to different concentrations of the combination of the two drugs, for a total of 36 concentration pairs per plate. The interaction of the drug combination was analyzed using the universal response surface approach.
The cells express the target of MLN8237, Aurora A. For each cell line, the single agent IC50 for MLN8237 and for vorinostat was in the clinically relevant range. Both drugs inhibited cell survival in a concentration-dependent fashion. At concentrations of MLN8237 exceeding approximately 1 μM, there was a paradoxical increase in viability signal in all three lines that may be explained by inhibition of Aurora B kinase. The combination of MLN8237 and vorinostat showed additive cytotoxicity in all three cell lines and nearly abrogated the paradoxical increase in survival noted at high single-agent MLN8237 concentrations.
MLN8237 and vorinostat are active in vitro against cancer cell lines. These results provide important preclinical support for the development of future clinical studies of MLN8237and vorinostat.
Vorinostat; Histone deacetylase inhibitor; MLN8237; Aurora kinase inhibitor; Cytotoxicity
Cilengitide (EMD121974) is a cyclized pentapeptide that is a potent and selective integrin antagonist which has shown activity in malignant gliomas. In all previous studies, cilengitide has been administered in an intermittent fashion. However, cilengitide has a short half-life of 3-5 hours with no evidence of drug accumulation. These data prompted the initiation of this phase I study of continuous infusion cilengitide.
Cilengitide was administered as a continuous infusion without break in 4-week cycles. Plasma samples for pharmacokinetic studies were obtained weekly in cycle 1 immediately prior to and 2 hours after infusion bag change.
Thirty-five patients were treated (median age 56; 23 males) at dose levels of 1, 2, 4, 8, 12, 18, 27, and 40 mg/hr. Toxicities were limited to grade ≤ 2 and showed no relation to dose. Fatigue was most common (17%), while all other toxicities were reported in <10% of patients. No dose-limiting toxicities were observed, and therefore the maximum tolerated dose was not reached. Pharmacokinetic analysis showed that values for clearance and volume of distribution were comparable across dose levels, and the steady-state concentration increased proportionally with dose.
Cilengitide can be safely administered as a continuous infusion at doses up to at least 40 mg/hr, which represents the maximum feasible dose due to drug solubility and delivery limitations. The pharmacokinetics of continuous infusion cilengitide are linear and consistent with the results obtained using a twice weekly infusion.
CLEFMA or 4-[3,5-bis(2-chlorobenzylidene-4-oxo-piperidine-1-yl)-4-oxo-2-butenoic acid] is a curcuminoid being developed as an anticancer drug. We recently reported that it potently inhibits proliferation of various cancer cells. In this project, we investigated the effect of CLEFMA on gene expression profile in H441 lung adenocarcinoma cells, and studied its mechanism of action. In microarray data, we observed a deregulation of genes involved in redox and glutamate metabolism. Based on the affected ontologies, we hypothesized that antiproliferative activity of CLEFMA could be a result of the induction of reactive oxygen species (ROS). We tested this hypothesis by determining the level of glutathione (GSH) and ROS in H441 cells treated with CLEFMA. We observed a rapid depletion of intracellular GSH/GSSG ratio. Using a cell-permeable fluorogenic substrate, we found that CLEFMA significantly induced ROS in a time- and dose-dependent manner (p<0.05). Flow-cytometry with a mitochondria-selective fluorescent reporter of ROS indicated that the CLEFMA-induced ROS was of mitochondrial origin. In contrast to the cancer cells, the normal lung fibroblasts (CCL-151) did not show any increase in ROS and were resistant to CLEFMA-induced cell death. Furthermore, the addition of antioxidants, such as catalase, superoxide dismutase and N-acetylcysteine, rescued cancer cells from CLEFMA-induced cell death. Gene expression pathway analysis suggested that a transcription factor regulator Nrf2 is a pivotal molecule in the CLEFMA-induced deregulation of redox pathways. The immunoblotting of Nrf2 showed that CLEFMA treatment resulted in phosphorylation and nuclear translocation of Nrf2 in a time-dependent fashion. Based on these results, we conclude that induction of ROS is critical for the antiproliferative activity of CLEFMA and the Nrf2-mediated oxidative stress response fails to salvage H441 cells.
CLEFMA; Curcumin; Cancer; Reactive oxygen species; Oxidative stress
Vandetanib is an orally active small molecule tyrosine kinase inhibitor (TKI) with activity against several pathways implicated in malignancy including the vascular endothelial growth factor receptor pathway, the epidermal growth factor receptor pathway, the platelet derived growth factor receptor β pathway, and REarranged during Transfection pathway. To determine if vandetanib-mediated inhibition of receptor tyrosine kinases is a potential therapeutic strategy for pediatric acute leukemia, these studies aimed to characterize the activity of vandetanib against acute leukemia in vitro. Treatment of leukemia cell lines with vandetanib resulted in a dose-dependent decrease in proliferation and survival. Vandetanib’s anti-leukemic activity appeared mediated by multiple mechanisms including accumulation in G1 phase at lower concentrations and apoptosis at higher concentrations. Alterations in cell surface markers also occurred with vandetanib treatment, suggesting induction of differentiation. In combination with DNA damaging agents (etoposide and doxorubicin) vandetanib demonstrated synergistic induction of cell death. However in combination with the anti-metabolite methotrexate, vandetanib had an antagonistic effect on cell death. Although several targets of vandetanib are expressed on acute leukemia cell lines, expression of vandetanib targets did not predict vandetanib sensitivity and alone are therefore not likely candidate biomarkers in patients with acute leukemia. Interactions between vandetanib and standard chemotherapy agents in vitro may help guide choice of combination regimens for further evaluation in the clinical setting for patients with relapsed/refractory acute leukemia. Taken together, these preclinical data support clinical evaluation of vandetanib, in combination with cytotoxic chemotherapy, for pediatric leukemia.
Acute leukemia; Vandetanib; Vascular endothelial growth factor; Tyrosine kinase inhibitor; Combination therapy
Based on the promising activity and tolerability of flavopiridol administered with a pharmacokinetically-derived dosing schedule in chronic lymphocytic leukemia (CLL), we conducted a phase I study using this schedule in patients with advanced solid tumors.
Flavopiridol was given IV as a 30-min loading dose followed by a 4-hr infusion weekly for 4 weeks repeated every 6 weeks. Dose-escalation was in cohorts of three patients using the standard 3+3 phase I study design. Blood samples were obtained for pharmacokinetic and pharmacodynamic studies.
Thirty-four eligible patients with advanced solid tumors received a total of 208 doses (median 7, range 1–24). Total doses ranged from 40 – 105 mg/m2. The primary dose limiting toxicity was cytokine release syndrome (CKRS). No antitumor responses were observed. The mean peak plasma concentration across all doses was 1.65 ± 0.86 µM. Area under the concentration-versus-time curve (AUC0–∞) ranged from 4.31 to 32.2 µM·hr with an overall mean of 13.6 ± 7.0 µM·hr. Plasma flavopiridol concentrations and AUC increased proportionally with dose. There was no correlation between cytokine levels and clinical outcomes.
The maximum-tolerated dose of flavopiridol is 20 mg/m2 bolus followed by 20 mg/m2 infusion over 4 hours given weekly for 4 weeks on a 6-week cycle in patients with advanced solid tumors. Flavopiridol PK was notably different, and there was a higher frequency of CKRS, despite prophylactic steroids, seen in this patient group compared to previous studies with CLL using a similar dosing schedule.
Flavopiridol; CDK inhibitor; Phase I trial; Solid tumors
Sunitinib is associated with a robust objective response rate in patients with metastatic clear cell renal cell carcinoma (RCC). The primary objective of this phase II clinical trial was to assess the overall response rate for sunitinib in patients with papillary metastatic RCC as well as other non-clear cell histologies. A Simon 2-stage design was used to determine the number of papillary metastatic RCC patients for enrollment, and allowed for descriptive response data for other non-clear cell histologies. Twenty-three patients were enrolled, including 8 with papillary renal cell carcinoma (RCC) and the remainder with other non-clear cell histologies (unclassified in 5 patients). All patients received 50 mg of oral sunitinib in cycles of 4 weeks followed by 2 weeks of rest (4/2). The trial was stopped early because of slow accrual; no responses were observed in the 8 patients with papillary RCC. In the 22 evaluable patients, best response to sunitinib included a partial response in 1 patient with unclassified RCC, stable disease in 15, and progression in 6. The median progression-free survival was 5.5 months (95% CI, 2.5–7.1) in all 23 patients, and 5.6 months for the 8 papillary patients (95% CI, 1.4–7.1). The robust objective responses sunitinib had produced in clear cell RCC could not be demonstrated in this study comprised of patients with non-clear cell histologies.
Papillary renal cell carcinoma; Non-clear cell renal cell carcinoma; Sunitinib; Phase II trial
This phase I trial assessed the safety, maximally tolerated dose (MTD) and pharmacokinetics of TRKA/CDK inhibitor PHA-848125AC in adult patients with advanced/metastatic solid tumors.
Patients and methods
Patients with relapsed or refractory solid tumors, for which no standard therapy existed, were eligible. PHA-848125AC was administered orally in two schedules: daily for 7 consecutive days in 2-week cycles (i.e. 7 days on/7 days off q2wks; S1) or daily for 4 consecutive days a week for 3 weeks in 4-week cycles (i.e. 4 days on/3 days off × 3wks q4wks; S2).
Thirty-seven patients were treated in this study, 22 in S1 and 15 in S2. The recommended phase II dose (RP2D) was 150 mg/day for either schedule. The dose-limiting toxicities (DLTs) in S1 included ataxia (Grade 2–4) and tremors (Grade 2–3). In S2, DLTs included tremors (Grade 2–3), elevated lipase (Grade 3), increased creatinine (Grade 2), and nausea and vomiting (Grade 3). These events were all reversible. In S2, out of 14 patients evaluable for efficacy, 2 patients with thymic carcinoma, showed partial response and stable disease was observed in 3 patients. Stable disease was observed in 6 out 14 patients evaluable for efficacy on S1. Drug pharmacokinetics demonstrated a half-life of approximately 33 h, and dose-proportionality with accumulation by a factor of 3 after repeated administrations.
The RP2D of PHA-848125AC was 150 mg/day on both schedules. Based on the responses noted in thymic carcinoma, a phase II study for patients with that disease is currently enrolling.
Tropomyosin receptor kinase A; Cyclin-dependent kinase; PHA-848125AC; Phase I clinical trial; Investigational agent
S-trans,trans-Farnesylthiosalicylic Acid (FTS, salirasib) inhibits Ras-dependent cell growth by dislodging all isoforms of Ras, including mutant Ras, from the plasma membrane. This study evaluated the activity, safety, and toxicity of salirasib in preclinical models and patients with metastatic pancreatic adenocarcinoma (PDA).
Patients and methods
In the preclinical study, salirasib was tested, alone and in combination with gemcitabine, in patient derived xenografts (PDX) of PDA. In the clinical study, treatment-naïve patients with advanced, metastatic PDA were treated with a standard dose schedule of gemcitabine and salirasib 200–800 mg orally (PO) twice daily (bid) for 21 days every 28 days. Tissue from preclinical models and patients’ biopsies were collected pre-treatment and on Cycle (C) 1, Day (D) 9 to characterize the effect of gemcitabine and salirasib on activated Ras protein levels. Plasma samples for pharmacokinetics were collected for salirasib administered alone and in combination.
Salirasib inhibited the growth of 2/14 PDX models of PDA and modulated Ras signaling in these tumors. Nineteen patients were enrolled. No DLTs occurred. Common adverse events included hematologic and gastrointestinal toxicities and fatigue. The median overall survival was 6.2 months and the 1 year survival 37 %. In 2 patients in whom paired tissue biopsies were available, Ras and KRas protein levels were decreased on C1D9. Salirasib exposure was not altered by gemcitabine and did not correlate with PD outcomes.
The combination of gemcitabine and salirasib appears well-tolerated, with no alteration of salirasib exposure, and exerted clinical and PD activity in PDA.
Salirasib; Gemcitabine; Pancreatic cancer; Phase I; RAS
Vorinostat (V) at levels >2.5 μM enhances chemotherapy in vitro. Yet the approved oral dose of 400 mg inconsistently achieves this level in patients. We developed an intermittent oral pulse-dose schedule of V to increase serum levels. We combined V with the cyclin dependent kinase inhibitor flavopiridol (F) which increases V-induced apoptosis.
One week before combination treatment, V alone was given daily for 3d (cycle −1). Then V was given on d1-3 and d8-10, and F on d2 and d9, every 21-d. Due to neutropenia, this was modified to V on d1-3 and d15–17, and F on d2 and d16, every 28-d. Bolus and split-dose F schedules were studied.
34 patients were treated. On the 21-d schedule, the maximum tolerated dose (MTD) was V 600 mg/d and F 60 mg/m2 bolus. On the 28-d schedule, the MTD was V 800 mg/d and F 30 mg/m2 over 30 min and 30 mg/m2 over 4 h. V Cmax at the 800 mg dose was 4.8 μM (± 2.8). V Cmax ≥2.5 μM was achieved in 86% of patients at the MTD. F increased the Cmax of V by 27% (95% CI 11%–43%). F Cmax of ≥2 μM was achieved in 90% of patients. 8 patients had stable disease for on average 5.5 m (range 1.6–13.2 m).
Intermittent high dose oral V in combination with F is feasible and achieves target serum levels >2.5 μM. V concentrations higher than previously reported with oral dosing were achieved.
CDKs and CDK inhibitors; Histone deacetylase inhibitors; Phase I trials; Combination chemotherapy; Pharmacokinetics
The HGF/MET signaling pathway regulates a wide variety of normal cellular functions that can be subverted to support neoplasia, including cell proliferation, survival, apoptosis, scattering and motility, invasion, and angiogenesis. MET over-expression (with or without gene amplification), aberrant autocrine or paracrine ligand production, and missense MET mutations are mechanisms that lead to activation of the MET pathway in tumors and are associated with poor prognostic outcome. We report here preclinical development of a potent, orally bioavailable, small-molecule inhibitor LY2801653 targeting MET kinase. LY2801653 is a type-II ATP competitive, slow-off inhibitor of MET tyrosine kinase with a dissociation constant (Ki) of 2 nM, a pharmacodynamic residence time (Koff) of 0.00132 min−1 and t1/2 of 525 min. LY2801653 demonstrated in vitro effects on MET pathway-dependent cell scattering and cell proliferation; in vivo anti-tumor effects in MET amplified (MKN45), MET autocrine (U-87MG, and KP4) and MET over-expressed (H441) xenograft models; and in vivo vessel normalization effects. LY2801653 also maintained potency against 13 MET variants, each bearing a single-point mutation. In subsequent nonclinical characterization, LY2801653 was found to have potent activity against several other receptor tyrosine oncokinases including MST1R, FLT3, AXL, MERTK, TEK, ROS1, DDR1/2 and against the serine/threonine kinases MKNK1/2. The potential value of MET and other inhibited targets within a number of malignancies (such as colon, bile ducts, and lung) is discussed. LY2801653 is currently in phase 1 clinical testing in patients with advanced cancer (trial I3O-MC-JSBA, NCT01285037).
Electronic supplementary material
The online version of this article (doi:10.1007/s10637-012-9912-9) contains supplementary material, which is available to authorized users.
MET inhibitor; LY2801653; MST1R; MKNK; ROS1