6502 A double-blinded, placebo-controlled, randomized, phase III study of axitinib (AG-013736; A) plus gemcitabine (G) vs. G plus placebo (P) in advanced pancreatic cancer (PC) patients (pts)

Signaling adaptor protein Crk is involved in malignant feature of pancreatic cancer associated with phosphorylation of c-Met

Signaling adaptor protein Crk has been shown to play an important role in various human cancers. Crk links tyrosine kinases and guanine nucleotide exchange factors (GEFs) such as C3G and Dock180 to activate small G-proteins Rap and Rac, respectively. In pancreatic cancer, various molecular targeted therapies have provided no significant therapeutic benefit for the patients so far due to constitutive activation of KRAS by frequent KRAS mutation. Therefore, the establishment of novel molecular targeted therapy in KRAS-independent manner is required. Here, we investigated a potential of Crk as a therapeutic target in pancreatic cancer. Immunohistochemistry on human pancreatic cancer specimens revealed that the patients with high expression of Crk had a worse prognosis than those with low expression. We established Crk-knockdown pancreatic cancer cells by siRNA using PANC-1, AsPC-1, and MIA PaCa-2 cells, which showed decreased cell proliferation, invasion, and adhesion. In Crk-knockdown pancreatic cancer cells, the decrease of c-Met phosphorylation was observed. In the orthotopic xenograft model, Crk depletion prolonged survival of mice significantly. Thus, signaling adaptor protein Crk is involved in malignant potential of pancreatic cancer associated with decrease of c-Met phosphorylation, and Crk can be considered to be a potential therapeutic molecular target.

Clinical Trials Targeting the Stroma in Pancreatic Cancer: A Systematic Review and Meta-Analysis

The tumor microenvironment plays an important role in the initiation and progression of pancreatic adenocarcinoma (PDAC). In this systematic review, we provide an overview of clinical trials with stroma-targeting agents. We systematically searched MEDLINE/PubMed and the EMBASE database, using the PRISMA guidelines, for eligible clinical trials. In total, 2330 records were screened, from which we have included 106 articles. A meta-analysis could be performed on 51 articles which describe the targeting of the vascular endothelial growth factor (VEGF) pathway, and three articles which describe the targeting of hyaluronic acid. Anti-VEGF therapies did not show an increase in median overall survival (OS) with combined hazard ratios (HRs) of 1.01 (95% confidence interval (CI) 0.90-1.13). Treatment with hyaluronidase PEGPH20 showed promising results, but, thus far, only in combination with gemcitabine and nab-paclitaxel in selected patients with hyaluronic acid (HA)high tumors: An increase in median progression free survival (PFS) of 2.9 months, as well as a HR of 0.51 (95% CI 0.26-1.00). In conclusion, we found that anti-angiogenic therapies did not show an increased benefit in median OS or PFS in contrast to promising results with anti-hyaluronic acid treatment in combination with gemcitabine and nab-paclitaxel. The PEGPH20 clinical trials used patient selection to determine eligibility based on tumor biology, which underlines the importance to personalize treatment for pancreatic cancer patients.

Cationic liposomal paclitaxel plus gemcitabine or gemcitabine alone in patients with advanced pancreatic cancer: a randomized controlled phase II trial

BACKGROUND

Paclitaxel embedded in cationic liposomes (EndoTAG™-1; ET) is an innovative agent targeting tumor endothelial cells. This randomized controlled phase II trial evaluated the safety and efficacy of ET in combination with gemcitabine (GEM) in advanced pancreatic cancer (PDAC).

PATIENTS AND METHODS

Chemotherapy-naive patients with locally advanced or metastatic disease were randomly assigned to receive weekly GEM 1000 mg/m(2) or GEM plus twice-weekly ET 11, 22 or 44 mg/m(2) for 7 weeks. After a safety run-in of 100 patients, a second cohort continued treatment. End points included overall survival (OS), progression-free survival (PFS), tumor response and safety.

RESULTS

Two hundred and twelve patients were randomly allocated to the study and 200 were treated (80% metastatic, 20% locally advanced). Adverse events were manageable and reversible. Transient thrombocytopenia and infusion reactions with chills and pyrexia mostly grade 1 or 2 occurred in the ET groups. Disease control rate after the first treatment cycle was 43% with GEM and 60%, 65% and 52% in the GEM + ET cohorts. Median PFS reached 2.7 compared with 4.1, 4.6 and 4.4 months, respectively. Median OS was 6.8 compared with 8.1, 8.7 and 9.3 months, respectively.

CONCLUSIONS

Treatment of advanced PDAC with GEM + ET was generally well tolerated. GEM + ET showed beneficial survival and efficacy. A randomized phase III trial should confirm this positive trend.

Development of second-generation VEGFR tyrosine kinase inhibitors: current status

The vascular endothelial growth factor (VEGF) signaling pathway appears to be the dominant pathway involved in tumor angiogenesis, providing a rationale for targeting the VEGF receptors (VEGFR-1, -2, and -3) in the treatment of cancers. In particular, VEGF signaling is thought to be important in renal cell carcinoma (RCC) because of the deregulation of the pathway through nearly uniform loss of the von Hippel Lindau protein. The tyrosine kinase inhibitors (TKIs) sorafenib, sunitinib, and pazopanib are approved by the US Food and Drug Administration for the treatment of advanced RCC; however, these multitargeted agents inhibit a wide range of kinase targets in addition to the VEGFRs, resulting in a range of adverse effects unrelated to efficient VEGF blockade. This article reviews recent advances in the development of the second-generation VEGFR TKIs, including the more selective VEGFR TKIs tivozanib and axitinib, and focuses on the potential benefits of novel inhibitors with improved potency and selectivity.

The Hemostasis Apparatus in Pancreatic Cancer and Its Importance beyond Thrombosis

Laboratory evidence of aberrant coagulation is found in the majority of patients with advanced pancreatic cancer and a clinical consequence of this is the high incidence and prevalence of vascular thromboembolic events. Other sequelae are hypothesized to be the facilitation and acceleration of mechanisms that define the malignant phenotype, such as invasion, trafficking and anchoring, establishing the metastatic niche and inducing angiogenesis. We review the in vitro and preclinical evidence that supports the role of the coagulation apparatus in the metastatic process of pancreatic cancer, with a particular emphasis on interaction of this pathway with clinically-targeted growth factor receptor pathways. Links between hemostasis, angiogenesis and epidermal growth factor pathways and their significance as therapeutic targets are considered.

A phase I, dose-escalation study of pomalidomide (CC-4047) in combination with gemcitabine in metastatic pancreas cancer

INTRODUCTION

Pomalidomide is an investigational immunomodulating drug (IMiD) that also inhibits angiogenesis and has direct anti-tumour effects. This phase I study was performed to identify the optimal dose of pomalidomide to be used in combination with gemcitabine in the treatment of patients with metastatic pancreatic cancer.

METHODS

Eligible patients had histologically documented metastatic adenocarcinoma of the pancreas. No prior gemcitabine for metastatic disease or for primary treatment of locally advanced disease was allowed although prior radiation therapy with 5-flourouracil (5-FU) or gemcitabine as a radiosensitizer was allowed. All patients received gemcitabine 1000 mg/m(2) IV on days 1, 8 and 15 of a 28 day cycle. Pomalidomide was administered orally on days 1-21 at doses escalated from 2 to 10mg daily. Patients were re-evaluated every 8 weeks; treatment continued until disease progression or intolerable toxicity occurred.

RESULTS

Twenty-three patients were enrolled with a median age of 62 and Eastern Cooperative Oncology Group (ECOG) performance status 0 (87%) and 1 (13%). The maximum tolerated dose (MTD) was 10mg/day on days 1-21. Neutropaenia was the most common grade 3/4 toxicity (38%); other grade 3/4 toxicity included deep vein thrombosis (DVT) (22%) and anaemia (9%). While efficacy was not a primary end-point of this study, 3 of 20 evaluable patients (15%) had partial responses and 10 patients (50%) had >50% decrease in CA 19-9 levels.

CONCLUSIONS

The combination of pomalidomide and gemcitabine was feasible and safe in most patients receiving first-line chemotherapy for metastatic pancreatic cancer. Neutropaenia, the dose-limiting toxicity, was brief and reversible. Intermittent dosing of pomalidomide allowed substantially higher doses than were previously reported with a continuous schedule. This combination merits further evaluation in the treatment of metastatic pancreatic cancer.

Gemcitabine plus bevacizumab compared with gemcitabine plus placebo in patients with advanced pancreatic cancer: phase III trial of the Cancer and Leukemia Group B (CALGB 80303)

PURPOSE

The combination of gemcitabine plus bevacizumab produced a 21% response rate and a median survival of 8.8 months in a multicenter phase II trial in patients with metastatic pancreatic cancer. These encouraging data led Cancer and Leukemia Group B (CALGB) to conduct a double-blind, placebo-controlled, randomized phase III trial of gemcitabine/bevacizumab versus gemcitabine/placebo in advanced pancreatic cancer patients.

PATIENTS AND METHODS

Eligible patients had no prior therapy for advanced disease, Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2, no tumor invasion of adjacent organs, and no increased bleeding risk. The primary end point was overall survival. Patients were stratified by performance status, extent of disease, and prior radiotherapy. Patients received gemcitabine at 1,000 mg/m(2) over 30 minutes on days 1, 8, and 15 every 28 days and bevacizumab at 10 mg/kg or placebo on days 1 and 15 every 28 days.

RESULTS

Between June 2004 and April 2006, 602 patients were enrolled onto the study and 535 were treated. Median overall survival was 5.8 months for gemcitabine/bevacizumab and 5.9 months for gemcitabine/placebo (P = .95). Median progression-free survival was 3.8 and 2.9 months, respectively (P = .07). Overall response rates were 13% and 10%, respectively. Patients with a performance status of 0, 1, and 2 survived a median of 7.9, 4.8, and 2.4 months, respectively. The only statistically significant differences in grades 3 and 4 toxicity occurred for hypertension (10% v 3%; P < .001) and proteinuria (5% v 1%; P = .002); venous thrombosis grade > or = 3 was equivalent in both arms (14% and 15%, respectively).

CONCLUSION

The addition of bevacizumab to gemcitabine does not improve survival in advanced pancreatic cancer patients.