Phase III study of gemcitabine in combination with fluorouracil versus gemcitabine alone in patients with advanced pancreatic carcinoma: Eastern Cooperative Oncology Group Trial E2297

Historical controls for metastatic pancreatic cancer: benchmarks for planning and analyzing single-arm phase II trials

We compiled and analyzed a database of cooperative group trials in advanced pancreatic cancer to develop historical benchmarks for overall survival (OS) and progression-free survival (PFS). Such benchmarks are essential for evaluating new therapies in a single-arm setting. The analysis included patients with untreated metastatic pancreatic cancer receiving regimens that included gemcitabine, between 1995 and 2005. Prognostic baseline factors were selected by their significance in Cox regression analysis. Outlier trial arms were identified by comparing individual 6-month OS and PFS rates against the entire group. The dataset selected for the generation of OS and PFS benchmarks was then tested for intertrial arm variability using a logistic-normal model with the selected baseline prognostic factors as fixed effects and the individual trial arm as a random effect. A total of 1,132 cases from eight trials qualified. Performance status and sex were independently significant for OS, and performance status was prognostic for PFS. Outcomes for one trial (NCCTG-034A) were significantly different from the other trial arms. When this trial was excluded, the remaining trial arms were homogeneous for OS and PFS outcomes after adjusting for performance status and sex. Benchmark values for 6-month OS and PFS are reported along with a method for using these values in future study design and analysis. The benchmark survival values were generated from a dataset that was homogeneous between trials. The benchmarks can be used to enable single-arm phase II trials using a gemcitabine platform, especially under certain circumstances. Such circumstances might be when a randomized control arm is not practically feasible, an early signal of activity of an experimental agent is being explored such as in expansion cohorts of phase I studies, and in patients who are not candidates for combination cytotoxic therapy.

Systemic treatment for inoperable pancreatic adenocarcinoma: review and update

There have been many clinical trials conducted to evaluate novel systemic regimens for unresectable pancreatic cancer. However, most of the trial results were negative, and gemcitabine monotherapy has remained the standard systemic treatment for years. A number of molecular targeted agents, including those against epidermal growth factor receptor and vascular endothelial growth factor receptors, have also been tested. In recent years, there have been some breakthroughs in the deadlock: three regimens, namely gemcitabine-erlotinib, FOLFIRINOX, and gemcitabine-nab-paclitaxel, have been shown to prolong the overall survival of patients when compared with gemcitabine monotherapy. In addition, emerging data suggested that the membrane protein human equilibrative nucleotide transporter 1 is a potential biomarker with which to predict the efficacy of gemcitabine. Here we review the literature on the development of systemic agents for pancreatic cancer, discuss the current choices of treatment, and provide future directions on the development of novel agents.

Efficacy of gemcitabine conjugated and miRNA-205 complexed micelles for treatment of advanced pancreatic cancer

Clinical effectiveness of gemcitabine in pancreatic cancer is hindered due to its rapid plasma metabolism and development of chemo-resistance. We have previously delineated the significant role of miRNAs in mediating the growth and proliferation of cancer stem cells (CSCs) which in turn result in chemo-resistance, invasion and metastasis. Here, we designed self-assembling, gemcitabine conjugated cationic copolymers for co-delivery of a tumor suppressor miRNA-205 (miR-205) and evaluated their in vivo efficacy in a pancreatic cancer ectopic tumor model developed using gemcitabine resistant MIA PaCa-2(R) cells. Combination formulations showed mean a particle size of <100 nm and gemcitabine payload of >10% w/w, exhibited miRNA complexation at N/P ratio of 4/1, sustained release of gemcitabine for >10 days, transfection efficiency of >90%, extended miRNA and drug stability in serum. Functional assays in gemcitabine resistant MIA PaCa-2(R) and CAPAN-1(R) pancreatic cancer cells revealed that the combination formulations effectively reversed chemo-resistance, invasion and migration. In pancreatic tumor model, the combination formulation treated group showed significant inhibition of tumor growth. Immuno-hiostochemical analysis revealed decreased tumor cell proliferation with increased apoptosis in the animals treated with miR-205 and gemcitabine combination.

Polychemotherapy or gemcitabine in advanced pancreatic cancer: a meta-analysis

BACKGROUND

Gemcitabine monotherapy is the cornerstone of treatment for advanced pancreatic cancer. To date, no clear survival benefit has been found when combination chemotherapy has been compared with gemcitabine alone, except in a few studies. This meta-analysis compared the efficacy of polychemotherapy with gemcitabine alone in advanced pancreatic cancer.

METHODS

Randomised trials comparing combination chemotherapy with gemcitabine alone were identified through electronic searches of PubMed, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials. Overall survival, reported as the hazard ratio at the 95% confidence interval, was the primary outcome measure.

RESULTS

29 trials (19 phase III and 10 small randomised trials) that included 8421 patients were identified. Overall, polychemotherapy significantly improved overall survival (hazard ratio=0.87; 95% CI, 0.81-0.93; P<0.0001), progression-free survival (hazard ratio=0.77; 95% CI, 0.70-0.84; P<0.00001), and response rate (risk ratio=1.71; 95% CI, 1.42-2.07; P<0.00001) compared with gemcitabine alone.

CONCLUSIONS

Compared with gemcitabine monotherapy, combinations of two or more drugs (particularly those with novel agents or associated with >20% response rates and triplets) improved outcomes and response rate in advanced pancreatic cancer, and they could be considered a new standard of care in advanced settings.

Comparative outcomes between initially unresectable and recurrent cases of advanced pancreatic cancer following palliative chemotherapy

OBJECTIVES

The objective of this study was to compare the clinical outcomes between initially unresectable and recurrent advanced pancreatic cancer (APC) patients after palliative chemotherapy.

METHODS

Data of a total of consecutive 269 patients with pathologically confirmed APC patients who received palliative chemotherapy between January 2006 and April 2012 were reviewed. Patients were classified into initially unresectable and recurrent group, and overall survival (OS) was compared between the 2 groups.

RESULTS

The median OS was significantly longer in the recurrent group compared with the initially unresectable group (383 vs 308 days; hazard ratio [HR], 0.59; 95% confidence interval, 0.44-0.80; P < 0.01). After adjustment for distant metastasis, performance status, and levels of carbohydrate antigen 19-9, carcinoembryonic antigen, C-reactive protein, and lactate dehydrogenase, the status of recurrent or unresectable disease remained as an independent prognostic factor with a clinically relevant HR value (HR, 0.66; 95% confidence interval, 0.48-0.90; P = 0.01). In addition, the 2-year OS rate of the recurrent group was significantly higher than that of the unresectable group (24.2% vs 9.6%, P = 0.01).

CONCLUSIONS

Our results suggested that the status of recurrent or initially unresectable disease was an independent prognostic factor in APC patients receiving palliative chemotherapy.

Phase I trial of M2ES, a novel polyethylene glycosylated recombinant human endostatin, plus gemcitabine in advanced pancreatic cancer

Pancreatic cancer is one of the most lethal and resistant to treatment of solid tumors. Combination therapies with various types of drugs against pancreatic cancer have been extensively investigated. Endostatin is a potent endogenous inhibitor of angiogenesis, which may be administered in combination with various chemotherapeutic agents in the treatment of several types of cancer. To the best of our knowledge, this phase I trial was the first clinical study to determine the tolerance, safety and efficacy of M₂ES, a novel polyethylene glycosylated recombinant human endostatin, administered concurrently with full-dose gemcitabine in patients with inoperable, locally advanced or metastatic pancreatic adenocarcinoma. A total of 16 patients were treated with gemcitabine (1,000 mg/m² on days 1, 8 and 15) and M₂ES (5-45 mg/m² on days 1, 8, 15 and 21) of each 28-day cycle. In 15 evaluable patients, the stable disease rate (SDR) was 40% (95% CI: 11.9-68.1%). In particular, a 75% SDR was observed in 3 out of 4 patients with a M₂ES dose level of 7.5 mg/m². The most noticeable M₂ES-related adverse events observed during the trial were grade 2 liver function abnormalities (6.3%) and grade 1 skin rash (6.3%). No dose-limiting toxicity was observed in any patients from all the dose levels. Therefore, there was no increased toxicity associated with the addition of M₂ES to gemcitabine and this combination was well tolerated.

FOLFIRI in patients with locally advanced or metastatic pancreatic or biliary tract carcinoma: a monoinstitutional experience

Pancreatic and biliary tract carcinomas are very chemoresistant. After a first-line treatment with a gemcitabine-based regimen, no second-line scheme is consolidated in clinical practice. The aim of this study was to evaluate the toxicity and the activity of the FOLFIRI regimen as first-line or second-line chemotherapy in patients with pancreatic or biliary tract tumors. Fifty-four patients (30 with pancreatic tumor, nine with gallbladder tumor, and 15 with biliary tract tumor) were treated with FOLFIRI (irinotecan 180 mg/m², day 1; leucovorin 100 mg/m² intravenously, days 1 and 2; 5-fluorouracil 400 mg/m² intravenous bolus, days 1 and 2; and 600 mg/m² in 22 h intravenously, continuous infusion days 1 and 2; every 14 days). Toxicity was recorded at each cycle according to the NCI-CTC V3.0 criteria, the response rate was verified each four cycles according to the RECIST criteria, and the progression-free survival rates as well as the overall survival rates were calculated according to the Kaplan-Meier method. Overall, the toxicity was mild. Grade 3-4 neutropenia occurred in 42.6% of patients. Grade 3-4 gastrointestinal toxicity was rare. FOLFIRI as a first-line treatment produced a response rate of 25%. In the second-line group, 9/21 patients (42.9%) obtained a stable disease as best response. In the entire population, the median progression-free survival rates were 3.1 months [95% confidence interval (CI), 1.9-4.4] and 3.5 months (95% CI, 2.6-4.4), respectively, in the first-line and the second-line cohort of patients. The median overall survival rates were 14.5 months (95% CI, 7.0-22.1) and 6.2 months (95% CI, 5.4-7.0), respectively, in the first-line and the second-line cohort of patients. FOLFIRI is feasible and well tolerated in patients with pancreatic or biliary tract tumors; it has a good activity in first line and mostly in patients with pancreatic cancer.

The RON receptor tyrosine kinase in pancreatic cancer pathogenesis and its potential implications for future targeted therapies

Pancreatic cancer remains a devastating disease with a mortality rate that has not changed substantially in decades. Novel therapies are therefore desperately needed. The RON receptor tyrosine kinase has been identified as an important mediator of KRAS oncogene addiction and is overexpressed in the majority of pancreatic cancers. Preclinical studies show that inhibition of RON function decreases pancreatic cancer cell migration, invasion, and survival and can sensitize pancreatic cancer cells to chemotherapy. This article reviews the current state of knowledge regarding RON biology and pancreatic cancer and discusses its potential as a therapeutic target.

Redox-responsive targeted gelatin nanoparticles for delivery of combination wt-p53 expressing plasmid DNA and gemcitabine in the treatment of pancreatic cancer

Background

Pancreatic adenocarcinoma is one of the most dreaded cancers with very low survival rate and poor prognosis to the existing frontline chemotherapeutic drugs. Gene therapy in combination with a cytotoxic agent could be a promising approach to circumvent the limitations of previously attempted therapeutic interventions.

Method

We have developed a redox-responsive thiolated gelatin based nanoparticle system that efficiently delivers its payload in the presence of glutathione-mediated reducing intra-cellular environment and could be successfully used for site-specific wt-p53 expressing plasmid DNA as well as gemcitabine delivery by targeting epidermal growth factor receptor (EGFR). Efficacy studies were performed in subcutaneous human adenocarcinoma bearing SCID beige mice along with molecular level p53 plasmid and apoptotic marker expression by PCR and western blot for all study groups.

Results

Efficacy studies demonstrate an improved in vivo targeting efficiency resulting in increased transfection efficiency and tumor growth suppression. In all the treatment groups, the targeted nanoparticles showed better anti-tumor activity than their non-targeted as well as non-encapsulated, naked therapeutic agent counterparts (50.1, 61.7 and 77.3% tumor regression by p53 plasmid alone, gemcitabine alone and in combination respectively). Molecular analysis revealed a higher mRNA expression of transfected p53 gene, its corresponding protein and that the tumor cell death in all treatment groups was due to the induction of apoptotic pathways.

Conclusions

Gene/drug combination treatment significantly improves the therapeutic performance of the delivery system compared to the gene or drug alone treated groups. Anti-tumor activity of the thiolated gelatin loaded wt-p53 plasmid or gemcitabine-based therapy was attributed to their ability to induce cell apoptosis, which was confirmed by a marked increase in mRNA level of proapoptotic transcription factors, as well as, protein apoptotic biomarker expression and significant decrease in the anti-apoptotic transcription factors.

Nab-paclitaxel for metastatic pancreatic cancer: clinical outcomes and potential mechanisms of action

For almost 15 years there has been stagnation in the systemic treatment of patients with pancreatic ductal adenocarcinoma (PDAC). Recently, several developments seem to indicate clinically relevant improvements in the treatment of patients with metastatic disease. One of these developments is the introduction of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) into the firstline treatment of metastatic disease. In this review, underlying preclinical and clinical data are discussed, with a special focus on mechanisms of action, the potential interaction with albumin and calcium-binding matricellular glycoproteins, such as the secreted protein acidic and rich in cysteine (SPARC), as well as the clinical outcome associated with the use of nab-paclitaxel.

Randomized controlled study of gemcitabine plus S-1 combination chemotherapy versus gemcitabine for unresectable pancreatic cancer

PURPOSE

The aim of this study was to evaluate efficacy and safety of gemcitabine plus S-1 (GS) combination chemotherapy in patients with unresectable pancreatic cancer.

METHODS

Patients were randomly assigned to receive GS (oral S-1 60 mg/m(2) daily on days 1-15 every 3 weeks and gemcitabine 1,000 mg/m(2) on days 8 and 15) or gemcitabine (1,000 mg/m(2) on days 1, 8, and 15 every 4 weeks). The primary endpoint was progression-free survival (PFS).

RESULTS

One hundred and one patients were randomly assigned. PFS was significantly longer in the GS arm with an estimated hazard ratio (HR) of 0.65 (95 % CI 0.43-0.98; P = 0.039; median 5.3 vs 3.8 months). Objective response rate (ORR) was also better in the GS arm (21.6 vs 6 %, P = 0.048). Median survival was 8.6 months for GS and 8.6 months for GEM (HR 0.93; 95 % CI 0.61-1.41; P = 0.714). Grade 3-4 neutropenia (44 vs 19.6 %, P = 0.011) and thrombocytopenia (26 vs 8.7 %, P = 0.051) were more frequent in the GS arm.

CONCLUSIONS

GS therapy improved PFS and ORR with acceptable toxicity profile in patients with unresectable pancreatic cancer.

Emerging concepts in pancreatic cancer medicine: targeting the tumor stroma

Pancreatic ductal adenocarcinoma is a stroma-rich and highly challenging cancer to treat. Over recent years, it has become increasingly evident that the complex network of soluble cytokines, growth factors, proteases, and components of the extracellular matrix collaboratively interact within the tumor microenvironment, sustaining and driving cancer cell proliferation, invasion, and early metastasis. More recently, the tumor microenvironment has also been appreciated to mediate therapeutic resistance in pancreatic ductal adenocarcinoma, thus opening numerous avenues for novel therapeutic explorations. Inert and soluble components of the tumor stroma have been targeted in order to break down the extracellular matrix scaffold, relieve vessel compression, and increase drug delivery to hypovascular tumors. Moreover, targeting of antiapoptotic, immunosuppressive, and pro-proliferative effects of the tumor stroma provides novel vantage points of attack. This review focuses on current and future developments in pancreatic cancer medicine, with a particular emphasis on biophysical and biochemical approaches that target the tumor microenvironment.

Phase I/II clinical trial using HLA-A24-restricted peptide vaccine derived from KIF20A for patients with advanced pancreatic cancer

Background

We previously developed an immunotherapy treatment utilizing a cancer vaccine reagent KIF20A-66 in order to treat pancreatic cancer. KIF20A-66 is HLA-A24-restricted epitope peptide derived from KIF20A, a member of kinesin super family protein 20A that is significantly transactivated in pancreatic cancer. In this report, we further demonstrated non-randomized, open-label, single centered phase I/II clinical trial of immunotherapy using the KIF20A-66 peptide for the patients with advanced pancreatic cancer.

Methods

Vaccination was performed to the patients with metastatic pancreatic cancer, in whom gemcitabine-based therapy had failed. In phase I study, KIF20A-66 peptide was subcutaneously injected weekly in a dose-escalation manner (doses of 1.0 and 3.0 mg/body, 6 patients/1 cohort). After safety was assessed, phase II study was conducted using 3.0 mg of KIF20A-66 peptide.

Results

KIF20A-66 peptide vaccination was well tolerated in the doses we examined and tumor responses after 1 month of the treatment were evaluated. Among 29 patients who completed one course of the treatment at least, stable disease (SD) was found in 21 cases, while progressive disease (PD) was found in 8 cases, indicating that the disease control rate was 72%. Objective tumor shrinkage was observed in 8 cases, including 1 case of complete response (CR). The median survival time (MST) and progression free survival time (PFS) were 142 days and 56 days, respectively. These results clearly demonstrate that overall survival of the patients was significantly prolonged, compared to the historical controls of 9 cases with unmatched HLA in the same hospital (MST: 83 days), as well as 81 cases in our and other hospitals (MST: 63 days).

Conclusion

The patients vaccinated with KIF20A-66 peptide had better prognosis than the control group with best supportive care (BSC). Thus, we concluded that KIF20A-66 vaccination is significantly effective as an immunotherapy against advanced pancreatic cancer. KIF20A-66 peptide was well tolerable in the dose of either 1.0 mg or 3.0 mg/body, and effectively induced peptide-specific response of cytotoxic T lymphocyte (CTL). Further clinical study using this peptide is a promising approach for advanced pancreatic cancer to achieve high potential benefit for better prognosis.

Clinical trial registration

UMIN-CTR, number UMIN000004919

Novel therapeutic strategies targeting tumor-stromal interactions in pancreatic cancer

Therapy-resistance and postoperative recurrence are causes of the poor prognosis in pancreatic cancer. Conventional therapies have a limited impact on the control of pancreatic cancer, resulting in the rapid re-growth of the tumor. The indispensable role of tumor-stromal interaction, which acts as a defender of cancer cells and enhances malignant potential, is being uncovered now. For example, specific signaling pathways for desmoplasia induction have been identified, such as sonic hedgehog (Shh) or connective tissue growth factor (CTGF), whose inhibition causes desmoplasia depletion and therapeutic advantages at least in in vivo mouse models of pancreatic cancer. Revolutions in drug delivery methods have led to the establishment of novel chemotherapeutic regimens, with better patient survival. Furthermore, mechanisms of immunosuppression in the pancreatic cancer-bearing host were clarified by the identification of myeloid-derived suppressor cells (MDSCs), which also promote disease progression. Strategies to target these components of the tumor stroma revealed certain anticancer effects in vitro and in vivo, suggesting the possibility of stroma-targeting therapy. Suppression of the stromal cell function increases the sensitivity of pancreatic cancer cells to therapeutic intervention. Further study will clarify the complex nature of the tumor microenvironment, the targeting of which has the potential to improve clinical outcome.

Phase I study of oxaliplatin in combination with gemcitabine, irinotecan, and 5-fluorouracil/leucovorin (G-FLIE) in patients with metastatic solid tumors including adenocarcinoma of the pancreas

PURPOSE

The aims of this study were to establish the maximum tolerated dose (MTD) of oxaliplatin in combination with fixed doses of gemcitabine, irinotecan, and 5-fluorouracil/leucovorin (G-FLIE) in solid tumors, including advanced pancreatic cancer, and to evaluate the toxicity of the regimen.

METHODS

Patients with metastatic solid tumors were treated with a regimen consisting of gemcitabine (500 mg/m(2) by fixed-dose-rate infusion), irinotecan (120 mg/m(2)), leucovorin 300 mg, bolus/infusion 5-fluorouracil (400 and 1,500 mg/m2, respectively), and oxaliplatin at doses from 50 to 85 mg/m(2) according to the escalation schema. Treatment was repeated every 14 days.

RESULTS

The study enrolled 25 patients with a median age of 64 years and median Karnofsky performance score of 80. Patients had metastatic adenocarcinomas of pancreas (n = 9), as well as gastroesointestinal, hepatobiliary, or unknown primary tumors. With only one dose limiting toxicity (neutropenia and constipation), the MTD of oxaliplatin was not reached up to the pre-specified maximum level of 85 mg/m(2). Other toxicities predictably included cytopenias, fatigue, sensory neuropathy, nausea/vomiting, diarrhea, and constipation. Four partial responses and ten disease stabilizations were observed. The overall median time to disease progression was 17 weeks (2-110 weeks) with median overall survival of 31.5 weeks (7-139 weeks).

CONCLUSIONS

G-FLIE is a tolerable multi-agent chemotherapy regimen with the oxaliplatin dose up to 85 mg/m(2). The combination of full-dose oxaliplatin with gemcitabine, irinotecan, and 5-fluorouracil is feasible with attenuated doses of the drugs, but further optimization is necessary before assessment of efficacy.

Phase 2, multicenter, open-label study of tigatuzumab (CS-1008), a humanized monoclonal antibody targeting death receptor 5, in combination with gemcitabine in chemotherapy-naive patients with unresectable or metastatic pancreatic cancer

Tigatuzumab is the humanized version of the agonistic murine monoclonal antibody TRA-8 that binds to the death receptor 5 and induces apoptosis of human cancer cell lines via the caspase cascade. The combination of tigatuzumab and gemcitabine inhibits tumor growth in murine pancreatic xenografts. This phase 2 trial evaluated the efficacy of tigatuzumab combined with gemcitabine in 62 chemotherapy-naive patients with histologically or cytologically confirmed unresectable or metastatic pancreatic cancer. Patients received intravenous tigatuzumab (8 mg/kg loading dose followed by 3 mg/kg weekly) and gemcitabine (1000 mg/m² once weekly for 3 weeks followed by 1 week of rest) until progressive disease (PD) or unacceptable toxicity occurred. The primary end point was progression-free survival (PFS) at 16 weeks. Secondary end points included objective response rate (ORR) (complete responses plus partial responses), duration of response, and overall survival (OS). Safety of the combination was also evaluated. Mean duration of treatment was 18.48 weeks for tigatuzumab and 17.73 weeks for gemcitabine. The PFS rate at 16 weeks was 52.5% (95% confidence interval [CI], 39.3–64.1%). The ORR was 13.1%; 28 (45.9%) patients had stable disease and 14 (23%) patients had PD. Median PFS was 3.9 months (95% CI, 2.2–5.4 months). Median OS was 8.2 months (95% CI, 5.1–9.6 months). The most common adverse events related to tigatuzumab were nausea (35.5%), fatigue (32.3%), and peripheral edema (19.4%). Tigatuzumab combined with gemcitabine was well tolerated and may be clinically active for the treatment of chemotherapy-naive patients with unresectable or metastatic pancreatic cancer.

Pooled survival and response data from phase III randomized controlled trials for gemcitabine-based regimes in the treatment of advanced pancreatic cancer

Although gemcitabine remains current first-line chemotherapy for patients with advanced pancreatic cancer, median survival times have not improved significantly since its introduction 15 years ago. Of the phase III trials which have investigated alternative regimens to single-agent gemcitabine, most have used combination regimens as the investigational arm. Accurate data on median overall, progression-free survival and objective response rates is important, for two principle reasons: advising patients about their prognosis and when powering phase II trials and evaluating the results of single-armed trials. This study aims to pool results from published randomized trials to date. Twenty-one randomized phase III trials involving a total of 6348 patients were identified from 1997 to 2010. Only one trial investigating a novel agent in combination with gemcitabine showed a significantly prolonged median and progression-free survival compared with single-agent gemcitabine. Pooled median and progression-free survivals for the single-agent gemcitabine arm involving 3171 patients across all studies were 6.15 and 3.3 months, respectively. Length of survival for patients with advanced pancreatic cancer remains disappointing. Further trials of novel agents to complement or replace gemcitabine are indicated.

Predictive modeling of in vivo response to gemcitabine in pancreatic cancer

A clear contradiction exists between cytotoxic in-vitro studies demonstrating effectiveness of Gemcitabine to curtail pancreatic cancer and in-vivo studies failing to show Gemcitabine as an effective treatment. The outcome of chemotherapy in metastatic stages, where surgery is no longer viable, shows a 5-year survival <5%. It is apparent that in-vitro experiments, no matter how well designed, may fail to adequately represent the complex in-vivo microenvironmental and phenotypic characteristics of the cancer, including cell proliferation and apoptosis. We evaluate in-vitro cytotoxic data as an indicator of in-vivo treatment success using a mathematical model of tumor growth based on a dimensionless formulation describing tumor biology. Inputs to the model are obtained under optimal drug exposure conditions in-vitro. The model incorporates heterogeneous cell proliferation and death caused by spatial diffusion gradients of oxygen/nutrients due to inefficient vascularization and abundant stroma, and thus is able to simulate the effect of the microenvironment as a barrier to effective nutrient and drug delivery. Analysis of the mathematical model indicates the pancreatic tumors to be mostly resistant to Gemcitabine treatment in-vivo. The model results are confirmed with experiments in live mice, which indicate uninhibited tumor proliferation and metastasis with Gemcitabine treatment. By extracting mathematical model parameter values for proliferation and death from monolayer in-vitro cytotoxicity experiments with pancreatic cancer cells, and simulating the effects of spatial diffusion, we use the model to predict the drug response in-vivo, beyond what would have been expected from sole consideration of the cancer intrinsic resistance. We conclude that this integrated experimental/computational approach may enhance understanding of pancreatic cancer behavior and its response to various chemotherapies, and, further, that such an approach could predict resistance based on pharmacokinetic measurements with the goal to maximize effective treatment strategies.

Inhibition of amyloid precursor protein processing enhances gemcitabine-mediated cytotoxicity in pancreatic cancer cells

Pancreatic adenocarcinoma or pancreatic cancer is often diagnosed at a very late stage at which point treatment options are minimal. Current chemotherapeutic interventions prolong survival marginally, thereby emphasizing the acute need for better treatment options to effectively manage this disease. Studies from different laboratories have shown that the Alzheimer disease-associated amyloid precursor protein (APP) is overexpressed in various cancers but its significance is not known. Here we sought to determine the role of APP in pancreatic cancer cell survival and proliferation. Our results show that pancreatic cancer cells secrete high levels of sAPPα, the α-secretase cleaved ectodomain fragment of APP, as compared with normal non-cancerous cells. Treatment of cells with batimastat or GI254023X, inhibitors of the α-secretase ADAM10, prevented sAPPα generation and reduced cell survival. Additionally, inhibition of sAPPα significantly reduced anchorage independent growth of the cancer cells. The effect of batimastat on cell survival and colony formation was enhanced when sAPPα downregulation was combined with gemcitabine treatment. Moreover, treatment of batimastat-treated cells with recombinant sAPPα reversed the inhibitory effect of the drug thereby indicating that sAPPα can indeed induce proliferation of cancer cells. Down-regulation of APP and ADAM10 brought about similar results, as did batimastat treatment, thereby confirming that APP processing is important for growth and proliferation of these cells. These results suggest that inhibition of sAPPα generation might enhance the effectiveness of the existing chemotherapeutic regimen for a better outcome.

A retrospective study of S-1 and oxaliplatin combination chemotherapy in patients with refractory pancreatic cancer

PURPOSE

The aim of this study was to evaluate S-1 and oxaliplatin combination chemotherapy (SOX) in patients with refractory pancreatic cancer (PC).

METHODS

Consecutive patients with advanced PC refractory to gemcitabine who were treated with oral S-1 (80 mg/m²) on days 1-14 and intravenous oxaliplatin (100 mg/m²) on day 1 every 3 weeks were studied retrospectively. The primary end point was the objective response rate (ORR). The secondary end points were progression-free survival (PFS), overall survival (OS), the disease control rate (DCR), and safety.

RESULTS

Between March 2009 and October 2011, 30 patients were treated with SOX, with a median of two courses (range 1-8). The ORR and DCR were 10.0 and 50.0 %, respectively. Median PFS and OS were 3.4 months (95 % confidence interval [CI] 1.3-5.3) and 5.0 months (95 % CI 3.4-7.4), respectively. The median PFS and OS were 5.6 and 9.1 months in patients receiving S-1 and oxaliplatin as a second-line treatment. Major grade 3 or 4 adverse events included neutropenia (10.0 %), anemia (3.3 %), and diarrhea (6.7 %).

CONCLUSIONS

SOX was well tolerated and moderately effective in patients with refractory PC.

Clinical impact of pentraxin family expression on prognosis of pancreatic carcinoma

Background:

Inflammatory mediators may have decisive roles at different stages of tumour development. Mediators within the pentraxin family may be used as strong biomarkers in prognosis of advanced pancreatic carcinoma patients.

Methods:

Using pancreatic carcinoma cell lines and gene transfectant, we measured long pentraxin (PTX3) level in culture solution and carried out cellular migration assay in vitro. In vivo study of the treatment-naive patients with advanced pancreatic carcinoma assigned to undergo gemcitabine therapy was prospectively conducted to measure and investigate the role of plasma PTX3, C-reactive protein (CRP), and eight inflammatory mediators by using collected clinical data.

Results:

Elevated PTX3 production was observed in several cell lines, and a direct relationship between migratory activity and PTX3 level was identified in vitro. High PTX3 level (117 days) was significantly less than that of patients with low PTX3 level (357 days, P<0.001). Multivariate analysis of the pancreatic carcinoma revealed a strong correlation between pentraxin family member expression and prognosis of pancreatic carcinoma. The relationship between PTX3 expression and the expression of other pro-inflammatory mediators indicated that PTX3 level is positively correlated with levels of CRP, interleukin-6, and macrophage-inhibitory factor.

Conclusion:

Pentraxin family members, especially PTX3, may be used as promising biomarkers in the prognosis of pancreatic carcinoma patients.

Global, multicenter, randomized, phase II trial of gemcitabine and gemcitabine plus AGS-1C4D4 in patients with previously untreated, metastatic pancreatic cancer

BACKGROUND

We evaluated AGS-1C4D4, a fully human monoclonal antibody to prostate stem cell antigen (PSCA), with gemcitabine in a randomized, phase II study of metastatic pancreatic cancer.

PATIENTS AND METHODS

Patients with Eastern Cooperative Oncology Group (ECOG) performance status 0/1 and previously untreated, metastatic pancreatic adenocarcinoma were randomly assigned 1:2 to gemcitabine (1000 mg/m(2) weekly seven times, 1 week rest, weekly three times q4weeks) or gemcitabine plus AGS-1C4D4 (48 mg/kg loading dose, then 24 mg/kg q3weeks IV). The primary end point was 6-month survival rate (SR). Archived tumor samples were collected for pre-planned analyses by PSCA expression.

RESULTS

Between April 2009 and May 2010, 196 patients were randomly assigned to gemcitabine (n = 63) or gemcitabine plus AGS-1C4D4 (n = 133). The 6-month SR was 44.4% (95% CI, 31.9-57.5) in the gemcitabine arm and 60.9% (95% CI, 52.1-69.2) in the gemcitabine plus AGS-1C4D4 arm (P = 0.03), while the median survival was 5.5 versus 7.6 months and the response rate was 13.1% versus 21.6% in the two arms, respectively. The 6-month SR was 57.1% in the gemcitabine arm versus 79.5% in the gemcitabine plus AGS-1C4D4 arm among the PSCA-positive subgroup and 31.6% versus 46.2% among the PSCA-negative subgroup.

CONCLUSIONS

This randomized, phase II study achieved its primary end point, demonstrating an improved 6-month SR with addition of AGS-1C4D4 to gemcitabine among patients with previously untreated, metastatic pancreatic adenocarcinoma. ClinicalTrials.gov identifier: NCT00902291.

Pancreatic cancer: why is it so hard to treat?

No common malignancy is as rapidly and inevitably fatal as pancreatic ductal adenocarcinoma (PDA). This grim fact has driven substantial research efforts into this disease in recent decades. Unfortunately, the investment has yet to result in a meaningful increase in 5-year survival. This has prompted many pancreatic cancer researchers and advocates to redouble their efforts, but also requires one to step back and ask why the previous efforts were lacking and to consider why pancreatic cancer is so difficult to treat. The difficulties are legion. PDA is characterized by an insidious clinical syndrome, but is rarely diagnosed at a time when surgical resection is feasible. We lack markers of early detection and screening programs remain unproven even in high risk populations. The location of the tumor in the retroperitoneum, the advanced age of patients, and the systemic effects of disease limit the options for local therapy. Chemotherapy may provide a small benefit, but most efforts to improve on the current regimens consistently and stubbornly fail in advanced clinical trials. The molecular and cellular features of ductal pancreatic tumors are aggressive and underlay multiple levels of therapeutic resistance. Non-cell-autonomous features including stromal proliferation, reduced vascular density and immune suppression also contribute to therapeutic resistance. Growing awareness of these the fundamental features of PDA has begun to guide ongoing research efforts. Clinical trials are now specifically targeting these tumor properties and actively focusing on the therapeutic implications of tumor stroma. As reviewed here, reflecting on the fundamental question of why pancreatic cancer is so difficult to treat is a necessary and informative exercise that will aid our efforts to improve patient outcomes. These efforts will lead to improvements in clinical trial design, expand our focus to include the molecular and histologic implications of novel treatment paradigms, and ultimately change the lives of our patients.

Phase II Trial of Erlotinib Plus Gemcitabine Chemotherapy in Korean Patients with Advanced Pancreatic Cancer and Prognostic Factors for Chemotherapeutic Response

Background/Aims

Erlotinib and gemcitabine combined chemotherapy is becoming the treatment of choice in advanced pancreatic cancer. We evaluated the effectiveness of treatment with erlotinib plus gemcitabine and the prognostic factors for chemotherapeutic response in Korean pancreatic cancer patients.

Methods

Sixty-nine patients with advanced pancreatic cancer who were treated with daily erlotinib 100 mg orally and gemcitabine 1,000 mg/m²/30 min intravenous infusion on days 1, 8, and 15 of each 4-week cycle from 2006 to 2009 were included in this study. This study was a phase II single-center trial.

Results

All 69 patients with advanced pancreatic cancer were chemotherapy-naïve. The objective response rate was 18.8%, and the overall tumor-stabilization rate was 49.2%. The median overall survival was 7.7 months (95% confidence interval [CI], 6.0 to 9.4 months). The median progression-free survival was 1.9 months (95% CI, 1.4 to 2.5 months). Prognostic factors for good chemotherapeutic response were good performance status and the presence of skin rash during chemotherapy. Patients with lower performance scores showed worse chemotherapeutic responses (odds ratio [OR], 7.6; 95% CI, 2.4 to 24.8). Poor responses were predicted by the absence of skin rash during chemotherapy (OR, 3.0; 95% CI, 1.4 to 6.3).

Conclusions

Erlotinib and gemcitabine chemotherapy is a tolerable treatment regimen and has a favorable therapeutic effect in Korean patients with advanced pancreatic cancer.

Therapeutic advances in pancreatic cancer

Despite our improved understanding of pancreatic cancer biology and ability to perform more complex pancreatic cancer surgeries that produce better short-term outcomes, major progress toward increasing survival times has been painstakingly slow. Through the often-repeated, dismal survival statistics, it is easy to lose sight of real progress that has been made in pancreatic cancer therapy. It is particularly interesting to observe the extent to which these advances are interdependent and the effects they have had on practice. For example, during the past 5-10 years, we have seen widespread adoption of pancreatic imaging protocols that allow for objectively defined criteria of resectability. This has led to the definition of "borderline resectable pancreatic cancer"--a new clinical category that has affected the design of clinical trials. A major change in our surgical approach has been the move to minimally invasive pancreatectomy, which continues to gain broader acceptance and use, particularly for left-sided lesions. Although many new agents have been developed aimed at putative molecular targets, recent breakthroughs in therapy for advanced disease have arisen from our ability to safely give patients combination cytotoxic chemotherapy. We are now faced with the challenge of combining multidrug, cytotoxic chemotherapies with newer-generation agents. Ultimately, the hope is that drug combinations will be selected based on biomarkers, and strategies for pancreatic cancer therapy will be personalized, which could prolong patients' lives and reduce toxicity. We review the major advances in pancreatic cancer therapy during the last 5 years, and discuss how these have set the stage for greater progress in the near future.

Role of neoadjuvant therapy and adjuvant therapy in treatment of pancreatic cancer

Pancreatic cancer is a highly malignant tumor that has a low resection rate. In Western countries, pancreatic cancer is the fourth cause of death in malignant tumors. Combined therapy is particularly important for the treatment of pancreatic cancer. Preoperative neoadjuvant therapy and postoperative adjuvant therapy are important parts of combined treatment for pancreatic cancer. Adjuvant therapy can improve survival and quality of life of patients with pancreatic cancer, and neoadjuvant therapy can reduce the primary lesion and lymph node metastasis, provide patients with the possibility of surgery to improve radical resection, decrease intraoperative bleeding and postoperative complications, and improve postoperative survival and life quality of patients. This article reviews the role of adjuvant therapy and neoadjuvant therapy in the management of pancreatic cancer.

Treatment options for advanced pancreatic cancer: a review

Advanced pancreatic adenocarcinoma historically has a poor prognosis and the mortality rate has remained unchanged for over a decade. Common treatment options for patients with advanced pancreatic cancer include chemoradiation and/or chemotherapy. Single-agent gemcitabine has been considered the standard of care since 1997. Recently published findings indicate that the oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) treatment regimen significantly improves overall survival compared with gemcitabine. Research has shifted to focus on understanding the causes the resistance of pancreatic cancer to chemotherapy and potential methods to overcome it. This review will focus on the current treatment options, the evolution of targeted therapy, novel agents on the horizon and potential options to ameliorate chemoresistance.

Gemcitabine plus erlotinib for advanced pancreatic cancer: a systematic review with meta-analysis

BACKGROUND

This study aims to comprehensively summarize the currently available evidences on the efficacy and safety of gemcitabine plus erlotinib for treating advanced pancreatic cancer.

METHODOLOGY/PRINCIPAL FINDINGS

PubMed, EMBASE, The Cochrane Library and abstracts of recent major conferences were systematically searched to identify relevant publications. Studies that were conducted in advanced pancreatic cancer patients treated with gemcitabine plus erlotinib (with or without comparison with gemcitabine alone) and reporting objective response rate, disease control rate, progression-free survival, time-to-progression, overall survival, 1-year survival rate and/or adverse events were included. Data on objective response rate, disease control rate, 1-year survival rate and adverse events rate, respectively, were combined mainly by using Meta-Analyst software with a random-effects model. Data on progression-free survival, time-to-progression and overall survival were summarized descriptively. Sixteen studies containing 1,308 advanced pancreatic cancer patients treated with gemcitabine plus erlotinib were included. The reported median progression-free survival (or time-to-progression), median overall survival, 1-year survival rates, objective response rates and disease control rates were 2-9.6 months, 5-12.5 months, 20%-51%, 0%-28.6% and 25.0%-83.3%, respectively. The weighted 1-year survival rate, objective response rate and disease control rate based on studies reporting robust results were 27.9%, 9.1% and 57.0%, respectively. According to the studies with relevant data, the incidences of total and severe adverse events were 96.3% and 62.9%, respectively. The most frequently reported adverse events were leucopenia, rash, diarrhea, vomitting, neutropenia, thrombocytopenia, anaemia, stomatitis, drug-induced liver injury, fatigue and fever. Compared with gemcitabine alone, the progression-free survival and overall survival with gemcitabine plus erlotinib were significantly longer, but there were also more deaths and interstitial lung disease-like syndrome related to this treatment.

CONCLUSIONS/SIGNIFICANCE

Gemcitabine plus erlotinib represent a new option for the treatment of advanced pancreatic cancer, with mild but clinically meaningful additive efficacy compared with gemcitabine alone. Its safety profile is generally acceptable, although careful management is needed for some specific adverse events.

Tumor-specific expression of organic anion-transporting polypeptides: transporters as novel targets for cancer therapy

Members of the organic anion transporter family (OATP) mediate the transmembrane uptake of clinical important drugs and hormones thereby affecting drug disposition and tissue penetration. Particularly OATP subfamily 1 is known to mediate the cellular uptake of anticancer drugs (e.g., methotrexate, derivatives of taxol and camptothecin, flavopiridol, and imatinib). Tissue-specific expression was shown for OATP1B1/OATP1B3 in liver, OATP4C1 in kidney, and OATP6A1 in testis, while other OATPs, for example, OATP4A1, are expressed in multiple cells and organs. Many different tumor entities show an altered expression of OATPs. OATP1B1/OATP1B3 are downregulated in liver tumors, but highly expressed in cancers in the gastrointestinal tract, breast, prostate, and lung. Similarly, testis-specific OATP6A1 is expressed in cancers in the lung, brain, and bladder. Due to their presence in various cancer tissues and their limited expression in normal tissues, OATP1B1, OATP1B3, and OATP6A1 could be a target for tumor immunotherapy. Otherwise, high levels of ubiquitous expressed OATP4A1 are found in colorectal cancers and their metastases. Therefore, this OATP might serve as biomarkers for these tumors. Expression of OATP is regulated by nuclear receptors, inflammatory cytokines, tissue factors, and also posttranslational modifications of the proteins. Through these processes, the distribution of the transporter in the tissue will be altered, and a shift from the plasma membrane to cytoplasmic compartments is possible. It will modify OATP uptake properties and, subsequently, change intracellular concentrations of drugs, hormones, and various other OATP substrates. Therefore, screening tumors for OATP expression before therapy should lead to an OATP-targeted therapy with higher efficacy and decreased side effects.

Combination chemotherapy of serine protease inhibitor nafamostat mesilate with oxaliplatin targeting NF-κB activation for pancreatic cancer

In this study, we assessed if nafamostat mesilate may enhance anti-tumor effects of oxaliplatin on Panc-1 cells and pancreatic cancer mouse model. In combination treatment with nafamostat mesilate and oxaliplatin, NF-κB activation was inhibited by suppressing IκBα phosphorylation, and caspase-8-mediated apoptosis was more prominent than that treated with oxaliplatin alone, both in vitro and in vivo. Nafamostat mesilate reduced proliferation rate of Panc-1 cells as compared with oxaliplatin alone in vitro and enhanced oxaliplatin-induced tumor growth inhibition in vivo. Combination chemotherapy using nafamostat mesilate and oxaliplatin induces synergistic cytotoxicity in pancreatic cancer and could be a novel strategy for treatment.

Incidence, prognosis, and possible treatment strategies of peritoneal carcinomatosis of pancreatic origin: a population-based study

OBJECTIVES

Peritoneal carcinomatosis (PC) is an important cause of morbidity and mortality among patients with pancreatic cancer. In an era where therapeutic options for PC of multiple origins are emerging, our aim was to provide population-based data on incidence, treatment, and prognosis of PC of pancreatic origin.

METHODS

All patients with a condition diagnosed as nonendocrine pancreatic cancer between 1995 and 2009 in the area of the Eindhoven Cancer Registry were included.

RESULTS

In total, 2924 patients had a diagnosis of pancreatic cancer of which 265 patients (9%) presented with synchronous PC. An increasing trend could be noted in patients treated with chemotherapy in more recent years (11% in 1995-1999 and 22% in 2005-2009; P = 0.060). Median survival in patients presenting with PC was only 6 weeks (95% confidence interval, 5-7 weeks) and did not improve over time, contrasting improvements among patients with nonmetastasized disease (19-30 weeks) and patients with metastasized disease confined to the liver (8-12 weeks).

CONCLUSION

Prognosis of patients with pancreatic cancer presenting with PC remains extremely poor. Treatment options are scarce and, given the magnitude of the problem, efforts should be undertaken to develop effective treatments in experimental and clinical studies.

Metastatic pancreatic cancer: are we making progress in treatment?

Development of systemic treatment for advanced pancreatic cancer (APC) has been challenging. After fluorouracil, gemcitabine (GEM) became the treatment of choice based on its benefit of symptom relief. Many cytotoxic agents have been combined with GEM in search of regimens with improved survival benefit. However, there were only marginal benefits in people with good performance status. Recently, the combination regimen consisting of oxaliplatin, irinotecan, fluorouracil, and leucovorin (FOLFIRINOX) was found to achieve unprecedented survival benefit and has become the preferred option for patients with good clinical conditions. On the other hand, many biological agents have been combined with GEM, but only erlotinib was found to derive statistically significant survival advantage. However, the effect was too small to be appreciated clinically. The effort in development of targeted therapy in APC continues. This paper summarized key findings in the development of chemotherapy and targeted therapy for APC patients and discussed future directions in management.

VEGF remains an interesting target in advanced pancreas cancer (APCA): results of a multi-institutional phase II study of bevacizumab, gemcitabine, and infusional 5-fluorouracil in patients with APCA

BACKGROUND

We investigated the safety and efficacy of bevacizumab combined with gemcitabine followed by infusional 5-fluorouracil (5-FU) in patients with advanced pancreas cancer (APCA).

DESIGN

Patients with untreated APCA received bevacizumab 10 mg/kg, gemcitabine 1000 mg/m(2) over 100 min, and 5-FU 2400 mg/m(2) over 48 h on days 1 and 15 of each 28-day cycle. The primary end point was the proportion of patients with progression-free survival (PFS) at 6 months from initiation of therapy. If PFS at 6 months was ≥41%, the regimen would be considered promising.

RESULTS

Forty-two patients were enrolled in the study; of which, 39 were evaluable for primary end point. PFS at 6 months was 49% (95% CI 34% to 64%). Median PFS was 5.9 months (95% CI 3.5 to 8.1) and median overall survival (OS) was 7.4 months (95% CI 4.7 to 11.2). Partial response and stable disease occurred in 30% and 45% of patients, respectively. Treatment-related hypertension and normal baseline albumin correlated with an improved response rate, PFS and OS. Grade 3 to 4 toxicities included fatigue (14%), hypertension (5%), and venous thrombosis (5%).

CONCLUSIONS

The study met its primary end point. Further investigation of anti-VEGF therapy in combination with fluoropyrimidine-based therapy is warranted in APCA. Treatment-related hypertension and normal baseline albumin may predict for the efficacy of bevacizumab and should be investigated in prospective studies.

Systemic therapies for pancreatic cancer--the role of pharmacogenetics

Effective systemic treatment of pancreatic cancer remains a major challenge, with progress hampered by drug resistance and treatment related toxicities. Currently available cytotoxic agents as monotherapy or in combination have provided only a modest survival benefit for patients with advanced disease. Disappointing phase III results with gemcitabine-based combinations in patients with advanced pancreatic cancer might be related to poor efficacy of systemic therapies in unselected patients. Future research strategies should prioritize identification of predictive markers through pharmacogenetic investigations. The individualization of patient treatment through pharmacogenetics may help to improve outcome by maximizing efficacy whilst lowering toxicity. This review provides an update on the pharmacogenetics of pancreatic cancer treatment and its influence on treatment benefits and toxicity.

Systemic therapies for pancreatic cancer--the role of pharmacogenetics

Effective systemic treatment of pancreatic cancer remains a major challenge, with progress hampered by drug resistance and treatment related toxicities. Currently available cytotoxic agents as monotherapy or in combination have provided only a modest survival benefit for patients with advanced disease. Disappointing phase III results with gemcitabine-based combinations in patients with advanced pancreatic cancer might be related to poor efficacy of systemic therapies in unselected patients. Future research strategies should prioritize identification of predictive markers through pharmacogenetic investigations. The individualization of patient treatment through pharmacogenetics may help to improve outcome by maximizing efficacy whilst lowering toxicity. This review provides an update on the pharmacogenetics of pancreatic cancer treatment and its influence on treatment benefits and toxicity.

EGFR and HER2 inhibition in pancreatic cancer

The aim of this study was to investigate the effect of lapatinib, a selective inhibitor of EGFR/HER2 tyrosine kinases, on pancreatic cancer cell lines both alone and in combination with chemotherapy. Two cell lines, BxPc-3 and HPAC, displayed the greatest sensitivity to lapatinib (IC(50)<2 μM). Lapatinib also demonstrated some activity in three K-Ras mutated pancreatic cancer cell lines which displayed resistance to erlotinib. Drug effect/combination index (CI) isobologram analysis was used to study the interactions of lapatinib with gemcitabine, cisplatin and 5'deoxy-5'fluorouridine. Concentration-dependent anti-proliferative effects of lapatinib in combination with chemotherapy were observed. To evaluate the potential effect of lapatinib in pancreatic cancer tumours, and to identify a subset of patient most likely to benefit from lapatinib, expression of EGFR and HER2 were investigated in 72 pancreatic cancer tumour specimens by immunohistochemistry. HER2 membrane expression was observed in only 1 % of cases, whereas 44 % of pancreatic tumours expressed EGFR. Based on our in vitro results, lapatinib may provide clinical benefit in EGFR positive pancreatic ductal adenocarcinoma.

Overview of whole body gamma knife for locally advanced pancreatic cancer

Pancreatic cancer is a disease that seriously threatens the health of human beings. The treatment options currently available for pancreatic cancer are still limited. In this article, we describe the principle of whole body gamma knife and SBRT (a treatment similar to whole body gamma knife) for the treatment of advanced pancreatic cancer. By improving the absorbed dose in the lesion, whole body gamma knife can control tumor progression and improve survival in patients with pancreatic cancer with low side effects. Despite that controversy still exists, the advantages of SBRT in the treatment of pancreatic cancer have been gradually recognized in foreign countries.

Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors

Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer.

Effects of 12-O-tetradecanoylphorbol-13-acetate in combination with gemcitabine on Panc-1 pancreatic cancer cells cultured in vitro or Panc-1 tumors grown in immunodeficient mice

In the present study, the effects of 12-O-tetra-decanoylphorbol-13-acetate (TPA) alone or in combination with gemcitabine on the growth of Panc-1 pancreatic cancer cells cultured in vitro or grown in NCr immunodeficient nude mice were investigated. Combinations of TPA and gemcitabine synergi-stically inhibited the growth and induced apoptosis in Panc-1 cells. The combination of TPA (0.16 nM) and gemcitabine (0.5 µM) induced a marked increase in phosphorylated c-Jun NH2-terminal kinase (JNK) in the Panc-1 cells. In animal experiments, NCr nude mice with established Panc-1 tumors received daily intraperitoneal (i.p.) injections of TPA (50 ng/g body weight/day) or gemcitabine (0.5 µg/g body weight/day) alone or in combination for 26 days. Treatment with daily i.p. injections of low doses of TPA or gemcitabine alone had a modest inhibitory effect on the growth of the tumors. However, the combination of low doses of TPA and gemcitabine more potently inhibited the growth of Panc-1 tumors than either agent used individually. Treatment with TPA or gemcitabine alone or in combination did not affect the body weight of the animals. Clinical trials with TPA alone or in combination with gemcitabine on patients with pancreatic cancer are warranted in order to confirm our results.

Heart Rate Variability and Baroreflex Sensitivity during Fosinopril, Irbesartan and Atenolol Therapy in Hypertension

OBJECTIVE

To evaluate the effects of long-term therapy with fosinopril, irbesartan and atenolol on the autonomic control of the cardiovascular system in hypertensive patients.

METHODS

We enrolled 58 patients (mean age 38 +/- 10 years) with never-treated mild hypertension with no evidence of target organ damage. The study was single blind. Patients were assigned to receive fosinopril 10-20 mg/day, irbesartan 150-300 mg/day or atenolol 50-100 mg/day for 14 weeks. Dosage was titrated to reach an average office blood pressure (BP) of <140/90mm Hg. Before therapy all patients underwent a 24-hour Holter ECG to evaluate heart rate variability (HRV) through nonlinear methods, 24-hour ambulatory BP monitoring (ABPM), and measurement of baroreflex sensitivity (BRS) using a Portaprés device; all measurements were repeated after therapy.

RESULTS

All three therapies significantly and equally decreased BP, both office (systolic/diastolic blood pressure 152 +/- 11/97 +/- 7mm Hg vs 129 +/- 7/85 +/- 4mm Hg after fosinopril, 151 +/- 11/97 +/- 6mm Hg vs 133 +/- 9/87 +/- 8mm Hg after irbesartan, 149 +/- 13/96 +/- 9mm Hg vs 132 +/- 9/87 +/- 7mm Hg after atenolol; p < 0.001) and ABPM values. HRV calculated with nonlinear methods and BRS were significantly increased after atenolol whereas no significant change was found in the fosinopril and irbesartan treatment groups.

CONCLUSIONS

All three therapies significantly and similarly reduced BP without modifying heart rate, except for atenolol, which significantly decreased it. Although angiotensin directly increases sympathetic tone, neither fosinopril nor irbesartan modified cardiovascular autonomic function; this is likely to be connected to the fairly good basal autonomic function of the population evaluated. Atenolol is associated with a significant increase in HRV and BRS probably through an improvement of parasympathetic tone.