Cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor, in combination with gemcitabine for advanced pancreatic cancer: a multicenter phase II Trial

The Prognostic and Predictive Role of Epidermal Growth Factor Receptor in Surgical Resected Pancreatic Cancer

The data regarding the prognostic significance of EGFR (epidermal growth factor receptor) expression and adjuvant therapy in patients with resected pancreatic cancer are insufficient. We retrospectively investigated EGFR status in 357 resected PDAC (pancreatic duct adenocarcinoma) patients using tissue immunohistochemistry and validated the possible role of EGFR expression in predicting prognosis. The analysis was based on excluding the multiple confounding parameters. A negative association was found between overall EGFR status and postoperative survival (p = 0.986). Remarkably, adjuvant chemotherapy and radiotherapy were significantly associated with favorable postoperative survival, which prolonged median overall survival (OS) for 5.8 and 10.2 months (p = 0.009 and p = 0.006, respectively). Kaplan-Meier analysis showed that adjuvant chemotherapy correlated with an obvious survival benefit in the EGFR-positive subgroup rather than in the EGFR-negative subgroup. In the subgroup analyses, chemotherapy was highly associated with increased postoperative survival in the EGFR-negative subgroup (p = 0.002), and radiotherapy had a significant survival benefit in the EGFR-positive subgroup (p = 0.029). This study demonstrated that EGFR expression is not correlated with outcome in resected pancreatic cancer patients. Adjuvant chemotherapy and radiotherapy were significantly associated with improved survival in contrary EGFR expressing subgroup. Further studies of EGFR as a potential target for pancreatic cancer treatment are warranted.

Recent Advances and Prospects for Multimodality Therapy in Pancreatic Cancer

The outcomes for treatment of pancreatic cancer have not improved dramatically in many decades. However, the recent promising results with combination chemotherapy regimens for metastatic disease increase optimism for future treatments. With greater control of overt or occult metastatic disease, there will likely be an expanding role for local treatment modalities, especially given that nearly a third of pancreatic cancer patients have locally destructive disease without distant metastatic disease at the time of death. Technical advances have allowed for the safe delivery of dose-escalated radiation therapy, which can then be combined with chemotherapy, targeted agents, immunotherapy, and nanoparticulate drug delivery techniques to produce novel and improved synergistic effects. Here we discuss recent advances and future directions for multimodality therapy in pancreatic cancer.

Dual targeting of HER1/EGFR and HER2 with cetuximab and trastuzumab in patients with metastatic pancreatic cancer after gemcitabine failure: results of the "THERAPY"phase 1-2 trial

To improve treatment efficacy, we decided to simultaneously target HER1 and HER2 with trastuzumab and cetuximab. Following promising preclinical results, we conducted a phase 1-2 trial in advanced pancreatic cancer patients after first-line gemcitabine-based chemotherapy failure. In this single-arm, non-randomized, multicenter trial, patients received weekly cetuximab (400mg/m², then 250mg/m²). They were sequentially included in two trastuzumab dose levels: 3.0 or 4.0mg/kg, then 1.5 or 2.0mg/kg/weekly. Endpoints were the objective response rate, safety, progression-free (PFS) and overall survival (OS). During phase 1 (n=10 patients), toxicities were evenly distributed except for skin toxicities that frequently caused compliance issues. The higher dose level was defined as the trastuzumab recommended dose. During phase 2 (n=39 patients), toxicities were mainly cutaneous reactions and asthenia. No objective response was observed. Nine patients were stabilized but arrested treatment due to toxicity. Median PFS was 1.8 months (95%CI: 1.7-2.0 months) and median OS was 4.6 months (95%CI: 2.7–6.6 months). Both were positively correlated with skin toxicity severity (P=0.027 and P=0.001, respectively). Conventional phase 1 dose-escalation schedules are unsuitable for targeted therapies because most cutaneous toxicities are not considered dose-limiting toxicities. The compliance issues caused by skin toxicities were particularly detrimental because of the toxicity-response correlation.

miR-21 expression and clinical outcome in locally advanced pancreatic cancer: exploratory analysis of the pancreatic cancer Erbitux, radiotherapy and UFT (PERU) trial

BACKGROUND

Locally advanced pancreatic cancer (LAPC) is associated with high mortality, and biomarker-driven treatment approach is currently lacking. This study evaluated safety and efficacy of a combination approach of chemotherapy followed by chemo-radiotherapy (CRT) +/- cetuximab, and the prognostic role of miR-21 in patients with LAPC treated with a multimodality approach.

PATIENTS AND METHODS

This was a randomised phase II trial in which patients with inoperable LAPC were offered gemcitabine and capecitabine (GEM-CAP) for 16 weeks. Patients with stable disease or response after GEM-CAP were randomised to capecitabine or UFT plus radiotherapy (RT) (A), or capecitabine or UFT plus cetuximab plus RT (B). The primary outcome of the study was overall survival (OS). Clinical outcome was compared according to baseline circulating miR-21 levels.

RESULTS

17 patients were enrolled and treated with GEM-CAP, with 13 patients achieving disease control and being randomised to arms A (n:7) and B (n:6). After a median follow-up of 61.2 months, median progression free survival (PFS) was 10.4 months and 12.7 months, median OS was 15.8 months and 22.0 months in arms A and B respectively (p > 0.05). Patients with high baseline plasma miR-21 had worse PFS (3.5 vs. 12.7 months; p:0.032) and OS (5.1 vs 15.3 months; p:0.5) compared to patients with low miR-21. Circulating miR-21 levels reflected miR-21 expression within the tissues.

CONCLUSIONS

Addition of Cetuximab to CRT following induction chemotherapy did not improve survival. High miR-21 baseline plasma expression was associated with poor clinical outcome in LAPC patients treated with induction chemotherapy followed by chemo-radiotherapy.

Biomarkers of skin toxicity induced by anti-epidermal growth factor receptor antibody treatment in colorectal cancer

Skin toxicity is a common symptom of anti-epidermal growth factor receptor (EGFR) antibody treatment and is also a predictive marker of its efficacy in colorectal cancer patients. However, severe skin disorders induced by such antibodies negatively impact on the quality of life of patients and decreases drug compliance during treatment. If we can predict the high-risk group susceptible to severe skin toxicity before treatment, we can undertake the early management of any arising skin disorders and formulate a more accurate prognosis for anti-EGFR antibody treatment. Previous studies have identified molecular markers of skin toxicity induced by anti-EGFR antibody, such as EGFR polymorphisms, the expression of inflammatory chemokines and serum levels of EGFR ligands. A clinical trial was undertaken involving the escalation of cetuximab doses, guided by the grade of skin toxicity observed, such as no or low-grade, in metastatic colorectal cancer (the EVEREST study). The dose escalation of cetuximab was confirmed by a safety profile and had the tendency to achieve a higher response rate in KRAS wild-type patients. A large, prospective randomized trial is now ongoing (EVEREST 2) and the results of this trial may contribute to personalized medicine in KRAS wild-type colorectal cancer patients.

Current Status of Immunotherapy Treatments for Pancreatic Cancer

Pancreatic cancer (PC) is a lethal disease representing the seventh most frequent cause of death from cancer worldwide. Resistance of pancreatic tumors to current treatments leads to disappointing survival rates, and more specific and effective therapies are urgently needed. In recent years, immunotherapy has been proposed as a promising approach to the treatment of PC, and encouraging results have been published by various preclinical and clinical studies. This review provides an overview of the latest developments in the immunotherapeutic treatment of PC and summarizes the most recent and important clinical trials.

Advanced pancreatic cancer - how to choose an adequate treatment option

The prognosis of pancreatic adenocarcinoma is poor, making it one of the leading causes of cancer-related death. The 5-year overall survival rate remains below 5% and little progress is made during the past decade. Only about 10%-20% of patients are eligible for curative-intent surgery and the majority end up having recurring disease even after radical surgery and postoperative adjuvant chemotherapy. Chemotherapy in metastatic disease is palliative at best, aiming at disease and symptom control and prolongation of life. Treatment always causes side effects, the degree of which varies from patient to patient, depending on the patient’s general condition, concomitant morbidities as well as on the chosen treatment modality. Why is pancreatic cancer so resistant to treatment? How to best help the patient to reach the set treatment goals?

Evaluation of antiangiogenic efficacy in advanced hepatocellular carcinoma: Biomarkers and functional imaging

Many years after therapeutic wilderness, sorafenib finally showed a clinical benefit in patients with advanced hepatocellular carcinoma. After the primary general enthusiasm worldwide, some disappointments emerged particularly since no new treatment could exceed or at least match sorafenib in this setting. Without these new drugs, research focused on optimizing care of patients treated with sorafenib. One challenging research approach deals with identifying prognostic and predictive biomarkers of sorafenib in this population. The task still seems difficult; however appropriate investigations could resolve this dilemma, as observed for some malignancies where other drugs were used.

Molecular Targeted Intervention for Pancreatic Cancer

Pancreatic cancer (PC) remains one of the worst cancers, with almost uniform lethality. PC risk is associated with westernized diet, tobacco, alcohol, obesity, chronic pancreatitis, and family history of pancreatic cancer. New targeted agents and the use of various therapeutic combinations have yet to provide adequate treatments for patients with advanced cancer. To design better preventive and/or treatment strategies against PC, knowledge of PC pathogenesis at the molecular level is vital. With the advent of genetically modified animals, significant advances have been made in understanding the molecular biology and pathogenesis of PC. Currently, several clinical trials and preclinical evaluations are underway to investigate novel agents that target signaling defects in PC. An important consideration in evaluating novel drugs is determining whether an agent can reach the target in concentrations effective to treat the disease. Recently, we have reported evidence for chemoprevention of PC. Here, we provide a comprehensive review of current updates on molecularly targeted interventions, as well as dietary, phytochemical, immunoregulatory, and microenvironment-based approaches for the development of novel therapeutic and preventive regimens. Special attention is given to prevention and treatment in preclinical genetically engineered mouse studies and human clinical studies.

Assessment of Tumor Response and Resection Rates in Unresectable Colorectal Liver Metastases Following Neoadjuvant Chemotherapy with Cetuximab

To investigate efficacy and safety of cetuximab combined with neo adjuvant chemotherapy regimen in patients with unresectable colorectal liver. This was a prospective trial with rate of Ro liver metastases resection as primary end point. Between January 2010 and December 2014, 46 patients with unresectable liver metastases from colon or rectum were enrolled. Patients received Cetuximab along with neoadjuvant chemotherapy where 34 (74 %) and 12 (2 6 %) patients received FOLFOX and FOLFIRI, respectively. They were assessed for response after 2-3 cycles by CT scan. Patients with resectable disease were offered liver surgery within 3-6 weeks of the last treatment cycle. The primary end point was resection rate of liver metastases, which was evaluated in all patients. Secondary end points were response rate according to Response evaluation criteria in solid tumors (RECIST) criteria, perioperative morbidity and mortality. An objective response was observed in 28 (60.9 %) patients. Seven (15.2 %) patients were reported radiologically to have a complete response (CR); 21 (45.7 %) patients had radiological partial response (PR). An additional 12 patients (26.1 %) demonstrated stable disease (SD) and only six patients (13.0 %) had disease progression (PD). Microscopically complete resections (R0 resection) was performed in all 28 patients (60.9 %). The most frequent toxicities were skin rash and diarrhoea. There was no operative mortality. Chemotherapy with cetuximab yields high response rates compared with historical controls, and leads to significantly increased resectability. Complete resection of previously unresectable colorectal liver metastases can be performed with minimal morbidity and mortality. This therapeutic strategy involves a multimodal approach.

Progress in pancreatic cancer therapeutics: The potential to exploit molecular targets

Pancreatic ductal adenocarcinoma is an aggressive and devastating disease associated with poor survival outcomes. Even though significant advances have been made towards understanding the intricate pathology of this cancer, several important aspects remain unknown. Recently, key genetic mutations within the tumour have been identified, but the exact role they play in tumourigenesis has yet to be determined. For many years, the micro-tumour environment and stroma was thought to aid proliferation but there is now emerging research that suggests the contrary. Several novel targeted agents in pre-clinical and early clinical studies have been promising but it remains to be seen whether they will have a significant impact on patient outcomes. In this review we discuss the unique nature of pancreatic cancer biology, current treatment options and summarise the latest results from pre-clinical and clinical research. We also discuss the future strategies that are needed to improve outcomes for this disease.

Phase II clinical trials on investigational drugs for the treatment of pancreatic cancers

INTRODUCTION

Despite some recent advances in treatment options, pancreatic cancer remains a devastating disease with poor outcomes. In a trend contrary to most malignancies, both incidence and mortality continue to rise due to pancreatic cancer. The majority of patients present with advanced disease and there are no treatment options for this stage that have demonstrated a median survival > 1 year. As the penultimate step prior to Phase III studies involving hundreds of patients, Phase II clinical trials provide an early opportunity to evaluate the efficacy of new treatments that are desperately needed for this disease.

AREAS COVERED

This review covers the results of published Phase II clinical trials in advanced pancreatic adenocarcinoma published within the past 5 years. The treatment results are framed in the context of the current standards of care and the historic challenge of predicting Phase III success from Phase II trial results.

EXPERT OPINION

Promising therapies remain elusive in pancreatic cancer based on recent Phase II clinical trial results. Optimization and standardization of clinical trial design in the Phase II setting, with consistent incorporation of biomarkers, is needed to more accurately identify promising therapies that warrant Phase III evaluation.

Novel approaches in the management of pancreatic ductal adenocarcinoma: potential promises for the future

Despite a few breakthroughs in therapy for advanced disease in the recent years, pancreatic ductal adenocarcinoma continues to remain one of the most challenging human malignancies to treat. The overall prognosis for the majority of patients with pancreatic cancer is rather dismal, and therefore, more effective treatment options are being desperately sought. The practical goals of management are to improve the cure rates for patients with resectable disease, achieve a higher conversion rate of locally advanced tumor into potentially resectable disease, and finally, prolong the overall survival for those who develop metastatic disease. Our understanding of the complex genetic alterations, the implicated molecular pathways, and the role of desmoplastic stroma in pancreatic cancer tumorigenesis has increased several folds in the recent years. This has facilitated the development of novel therapeutic strategies against pancreatic cancer, some of which are currently under evaluation in ongoing preclinical and clinical studies. This review will summarize the existing treatment approaches for this devastating disease and also discuss the promising therapeutic approaches that are currently in different stages of clinical development.

GEM-loaded magnetic albumin nanospheres modified with cetuximab for simultaneous targeting, magnetic resonance imaging, and double-targeted thermochemotherapy of pancreatic cancer cells

Background

Targeted delivery is a promising strategy to improve the diagnostic imaging and therapeutic effect of cancers. In this paper, novel cetuximab (C225)-conjugated, gemcitabine (GEM)-containing magnetic albumin nanospheres (C225-GEM/MANs) were fabricated and applied as a theranostic nanocarrier to conduct simultaneous targeting, magnetic resonance imaging (MRI), and double-targeted thermochemotherapy against pancreatic cancer cells.

Methods

Fe₃O₄ nanoparticles (NPs) and GEM co-loaded albumin nanospheres (GEM/MANs) were prepared, and then C225 was further conjugated to synthesize C225-GEM/MANs. Their morphology, mean particle size, GEM encapsulation ratio, specific cell-binding ability, and thermal dynamic profiles were characterized. The effects of discriminating different EGFR-expressing pancreatic cancer cells (AsPC-1 and MIA PaCa-2) and monitoring cellular targeting effects were assessed by targeted MRI. Lastly, the antitumor efficiency of double/C225/magnetic-targeted and nontargeted thermochemotherapy was compared with chemotherapy alone using 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and flow cytometry (FCM) assay.

Results

When treated with targeted nanospheres, AsPC-1 cells showed a significantly less intense MRI T2 signal than MIA PaCa-2 cells, while both cells had similar signal strength when incubated with nontargeted nanospheres. T2 signal intensity was significantly lower when magnetic and C225 targeting were combined, rather than used alone. The inhibitory and apoptotic rates of each thermochemotherapy group were significantly higher than those of the chemotherapy-alone groups. Additionally, both MTT and FCM analysis verified that double-targeted thermochemotherapy had the highest targeted killing efficiency among all groups.

Conclusion

The C225-GEM/MANs can distinguish various EGFR-expressing live pancreatic cancer cells, monitor diverse cellular targeting effects using targeted MRI imaging, and efficiently mediate double-targeted thermochemotherapy against pancreatic cancer cells.

Prognostic significance of epidermal growth factor receptor overexpression in pancreas cancer and nodal metastasis

BACKGROUND

Identification of molecular markers in pancreatic adenocarcinoma (PA) has the potential to guide targeted therapy. The objective of this study is to determine the prognostic significance of epidermal growth factor receptor (EGFR) expression (membrane and cytoplasmic) in resected PA and its correlation with lymph node metastasis and survival.

METHODS

EGFR overexpression was determined by immunohistochemistry, and the pattern of expression was compared between the primary tumour, adjacent normal pancreas and involved lymph nodes.

RESULTS

A total of 88 patients had curative resection. No difference was found in mEGFR overexpression between tumoural and metastatic nodal tissues (P = 0.28). Median overall survival time was 22.9 months. Overall cumulative 1-, 3- and 5-year survival was 48%, 20% and 18%, respectively. In positive mEGFR tumour expression, survival was 46% at 1 year, 8% at 3 years and 0% at 5 years (P < 0.05). Univariate analysis showed that male gender, portal vein (PV) resection, perineural, lymphovascular and peri-pancreatic invasion, positive margins and positive mEGFR expression in tumour tissue had worse survival. Multivariate analysis showed that male gender, PV resection, vascular and perineural invasion remained independent predictors of poor survival.

CONCLUSION

Positive mEGFR overexpression is associated with decreased survival; however, it is not an independent prognostic factor.

Current adjuvant therapeutic approaches for pancreatic cancer

Pancreatic cancer continues to be the fourth leading cause of death despite advancements in surgical and adjuvant therapeutic approaches. In the present review, the current cytotoxic therapeutic approaches and advanced targeted therapies are objectively discussed with consideration to the current literature.

Promising new therapies in advanced pancreatic adenocarcinomas

Pancreatic ductal adenocarcinoma is a lethal disease due to late diagnosis, early metastasis and the lack of effective therapies. In patients with metastatic disease, 1-year survival ranges from 17 to 23% and 5-year survival is less than 5%. This necessitates an urgent need for developing more effective therapies. Targeting the neoplastic cells has been largely ineffective due to the dense stroma, which is a physical barrier for effective drug delivery and also a source for different factors that promote tumor progression and immunosuppression. In this review, we focus on understanding the complex biology of this tumor as it relates to the evaluation of previously failed molecularly targeted trials and review potential new therapies that are emerging in the treatment of metastatic pancreatic ductal adenocarcinoma.

Management options in locally advanced pancreatic cancer

Pancreatic ductal adenocarcinoma is a highly lethal cancer that is rarely curable at the time of presentation. Unfortunately, most patients are diagnosed with either metastatic or locally advanced disease, which is not amenable to surgery owing to the high likelihood of incomplete resection. Given the generally poor prognosis with propensity for metastatic failure greater than that for local failure, treatment options are variable, and include chemotherapy, radiotherapy, targeted therapies, and combinations thereof. This review summarizes the current evidence for definitive management of locally advanced pancreatic adenocarcinoma, as well as the role of palliative therapies. Future directions, including the development of predictive biomarkers and novel systemic agents, are also discussed.

Response to GEMOX plus erlotinib in pancreatic cancer is associated with ERCC1 overexpression

INTRODUCTION

There are no data about the efficacy of gemcitabine in combination with oxaliplatin (GEMOX) and erlotinib for the treatment of metastatic pancreatic cancer (mPC). Thus, we performed this retrospective analysis in mPC patients to investigate the activity and safety of GEMOX plus erlotinib and correlated the benefit with ERCC1 expression, a potential biomarker for treatment response.

PATIENTS AND METHODS

Patients with untreated mPC receiving off-protocol GEMOX plus erlotinib were included. Data collection included baseline demographic, response and toxicity data as well as PFS and OS. Additionally, immunohistochemistry was performed to stain for ERCC1 expression.

RESULTS

A total of 51 patients were included. The median age was 62 years and the median ECOG performance score was 1 (range, 0-1). Objective response or disease stabilization was achieved in 54% of the patients. The median PFS was 4·4 months (95% CI 4·4-5·4) and median OS was 8·5 months (95% CI 6·1-10·9). The 27 patients, who benefited from this regimen, had a median PFS of 6·7, a median OS of 11·2 months and an overexpression of ERCC1 (histoscore 10, P ≤ 0·05) compared to nonresponders (histoscore 7·2). Myelosuppression was the most frequent side effect. The most common severe nonhematological toxicities were diarrhoea and skin toxicity in six (12%) patients each.

CONCLUSIONS

These data suggest that the combination of GEMOX plus erlotinib is safe and active in about half of the patients. Patients, who had a higher ERCC1 staining pattern, benefited most from this therapy. Prospective biomarker studies are warranted to confirm these findings.

Antiproliferative effects and mechanisms of liver X receptor ligands in pancreatic ductal adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDAC) is difficult to detect early and is often resistant to standard chemotherapeutic options, contributing to extremely poor disease outcomes. Members of the nuclear receptor superfamily carry out essential biological functions such as hormone signaling and are successfully targeted in the treatment of endocrine-related malignancies. Liver X receptors (LXRs) are nuclear receptors that regulate cholesterol homeostasis, lipid metabolism, and inflammation, and LXR agonists have been developed to regulate LXR function in these processes. Intriguingly, these compounds also exhibit antiproliferative activity in diverse types of cancer cells. In this study, LXR agonist treatments disrupted proliferation, cell-cycle progression, and colony-formation of PDAC cells. At the molecular level, treatments downregulated expression of proteins involved in cell cycle progression and growth factor signaling. Microarray experiments further revealed changes in expression profiles of multiple gene networks involved in biological processes and pathways essential for cell growth and proliferation following LXR activation. These results establish the antiproliferative effects of LXR agonists and potential mechanisms of action in PDAC cells and provide evidence for their potential application in the prevention and treatment of PDAC.

Advanced pancreatic cancer: flourishing novel approaches in the era of biological therapy

The progress in the development of systemic treatment for advanced pancreatic cancer (APC) has been slow. The mainstream treatment remains using chemotherapy including gemcitabine, FOLFIRINOX, and nab-paclitaxel. Erlotinib is the only approved biological therapy with marginal benefit. Studies of agents targeting epidermal growth factor receptor, angiogenesis, and RAS signaling have not been satisfying, and the usefulness of targeted therapy in APC is uncertain. Understanding in molecular processes and tumor biology has opened the door for new treatment strategies such as targeting insulin-like growth factor 1 receptor, transforming growth factor β, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Notch pathway. New directions also include the upcoming immunotherapy and many novel agents that act on the microenvironment. The practice of personalized medicine using predictive biomarkers and pharmacogenomics signatures may also enhance the effectiveness of existing treatment. Future treatment approaches may involve comprehensive genomic assessment of tumor and integrated combinations of multiple agents to overcome treatment resistance.

Epitope mapping of epidermal growth factor receptor (EGFR) monoclonal antibody and induction of growth-inhibitory polyclonal antibodies by vaccination with EGFR mimotope

One of the proposed approaches in cancer therapy is to induce and direct the patient's own immune system against cancer cells. In this study, we determined the epitope mapping of the rat anti-human epidermal growth factor receptor (EGFR) monoclonal antibody ICR-62 using a phage display of random peptide library and identified a 12 amino acids peptide, which was recognized as a mimotope. The peptide was synthesized and conjugated to bovine serum albumin (BSA) as carrier protein (P-BSA). We have shown that ICR-62 can react specifically with P-BSA as well as native EGFR. Two rabbits were immunized either by BSA or P-BSA and the rabbits IgGs were purified and examined for binding to the antigens, mimotope and the EGFR protein purified from the EGFR overexpressing A431 cell line. We showed that the rabbit IgG generated against the mimotope is capable of inhibiting the growth of A431 cells by 15%, but does not have any effect on the growth of EGFR-negative MDA-MB-453 cell line in vitro. Our results support the need for further investigations on the potential of vaccination with either mimotope of the EGFR or epitope displayed on the surface of phage particles for use in active immunotherapy of cancer.

Specificity delivers: therapeutic role of tumor antigen-specific antibodies in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) is among the most deadly cancers with less than 5% of the patients living beyond 5 years post-diagnosis. Lack of early diagnostic biomarkers and resistance to current therapies help explain these disappointing numbers. Thus, more effective and better-targeted therapies are needed quickly. Monoclonal antibodies offer an attractive alternative targeted therapy option for PDA because they are highly specific and potent. However, currently available monoclonal antibody therapies for PDA are still in their infancy with a low success rate and low likelihood of being approved. The challenges faced by these therapies include the following: lack of predictive and response biomarkers, unfavorable safety profiles, expression of targets not restricted to the cancer cells, flawed preclinical model systems, drug resistance, and PDA's complex nature. Additionally, discovery of novel PDA-specific antigen targets, present on the cell surface or in the extracellular matrix, is needed. Predictive and response markers also need to be determined for PDA patient subgroups so that the most appropriate effective therapy can be delivered. Serologic approaches, recombinant antibody-producing technologies, and advances in antibody engineering techniques will help to identify these predictive biomarkers and aid in the development of new therapeutic antibodies. A combinatorial approach simultaneously targeting antigens on the PDA cell, stroma, and immunosuppressive cells should be employed.

Comparison of gemcitabine combined with targeted agent therapy versus gemcitabine monotherapy in the management of advanced pancreatic cancer

PURPOSE

Targeted therapy has brought great clinical benefits for patients with multiple solid tumors, but its effects in patients with locally advanced/metastatic pancreatic cancer (LA/MPC) are disputed. This systematic evaluation compared the efficacy and safety profiles of gemcitabine combined with targeted agents (GEM + TA) versus gemcitabine administered as monotherapy or combined with placebo (GEM ± PLC) in LA/MPC patients.

METHODS

PubMed and EMBASE were searched for relevant randomized controlled trials published on or before April 30, 2013. The primary end points were overall survival (OS) and progression-free survival (PFS); the secondary end points were 1-year survival rate, objective response rate (ORR), and toxicity rates (TRs), defined as the prevalence of grade 3/4 adverse events. The systematic evaluation was performed by using Review Manager version 5.1.7.

FINDINGS

A total of 10 randomized controlled trials involving 3899 patients (2195 males; mean age, 63.6 years) were included in the systematic evaluation. The results reported that there was no significant difference in OS (hazard ratio [HR] = 0.97 [P = 0.85]), PFS (HR = 0.95 [P = 0.14]), or ORR (odds ratio [OR] = 0.95 [P = 0.69]) between GEM + TA and GEM ± PLC. However, a marginal difference in 1-year survival rate (OR = 0.80 [P = 0.05]) between the 2 groups was observed. The grade 3/4 TRs of anemia, diarrhea, nausea, neutropenia, thrombocytopenia, and vomiting were not significantly different between the 2 groups. However, the prevalence of grade 3/4 rash was significantly greater in the GEM + TA group (OR = 8.31 [P < 0.01]).

IMPLICATIONS

Based on the results from this analysis, the addition of targeted agents to a regimen of gemcitabine treatment does not bring survival benefits except 1-year survival rate to patients with LA/MPC.

In situ evaluation of gemcitabine-DNA interaction using a DNA-electrochemical biosensor

The electrochemical behaviour of the cytosine nucleoside analogue and anti-cancer drug gemcitabine (GEM) was investigated at glassy carbon electrode, using cyclic, differential pulse and square wave voltammetry, in different pH supporting electrolytes, and no electrochemical redox process was observed. The evaluation of the interaction between GEM and DNA in incubated solutions and using the DNA-electrochemical biosensor was studied. The DNA structural modifications and damage were electrochemically detected following the changes in the oxidation peaks of guanosine and adenosine residues and the occurrence of the free guanine residues electrochemical signal. The DNA-GEM interaction mechanism occurred in two sequential steps. The initial process was independent of the DNA sequence and led to the condensation/aggregation of the DNA strands, producing rigid structures, which favoured a second step, in which the guanine hydrogen atoms, participating in the C-G base pair, interacted with the GEM ribose moiety fluorine atoms.

The efficacy of Pistacia Terebinthus soap in the treatment of cetuximab-induced skin toxicity

This open-labeled phase II, efficacy-finding study evaluated the efficiency and safety of Pistacia terebinthus soap in metastatic colorectal cancer patients who developed cetuximab induced skin toxicity. Patients who received cetuximab plus chemotherapy and developed Grade 2 or 3 skin toxicity were treated twice daily with a soap made of oil extracted from Pistacia terebinthus. During treatment, no topical or oral antibiotics, corticosteroids or other moisturizers were used. Patients were examined 1 week later and their photographs were taken. Fifteen mCRC patients who developed skin toxicity while receiving first-line CTX in combination with chemotherapy were included into the study. Eight patients were male and the median age was 58 (25-70). Sixty percent of the patients (n:9) had Grade 3 skin toxicity. Complete response rates in patients with Grade 2 and Grade 3 skin toxicities were 100 and 33%, respectively. In the remaining patients with Grade 3 toxicity the skin toxicity regressed to Grade 1. The objective response rate was 100%, and no delay, dose reduction or discontinuation of CTX treatment due to skin toxicity was necessary. Skin toxicity reoccurred in all patients when patients stopped administering the soap and therefore they used it throughout the cetuximab treatment. Pistacia terebinthus soap seemed to be used safely and effectively in the treatment of skin toxicity induced by Cetuximab.

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.

Recent treatment advances and novel therapies in pancreas cancer: a review

PURPOSE

Over the last couple of years, we have witnessed the availability of a wide variety of different therapeutic agents and the identification of effective combinations of existing ones that have transformed the way we approach and treat pancreatic cancer. Proof of this are the recent validations that combinations of conventional chemotherapy drugs, the FOLFIRINOX regimen and gemcitabine plus nab-paclitaxel, significantly improves clinical outcomes in patients with metastatic disease. However, deeper and more sophisticated understanding of the biology of this cancer as well as the ability to develop better and perhaps more precise drugs predict that the landscape may be changing even more.

METHODOLOGY AND RESULTS

In this review, we will summarize the most recent treatment advances including FOLFIRINOX, gemcitabine plus nab-paclitaxel and discuss novel approaches such as immune-mediated therapies, drugs that disrupt the tumor-stromal compartment, PARP inhibitors for BRCA pathway-deficient pancreatic cancer and new generations of conventional chemotherapeutics, which are in early phases of clinical development and have shown promising early results. We will also discuss some examples of drugs that failed, despite very good preliminary data, in order to appraise the lessons learned from these negative clinical trials. Lastly, we will comment on ongoing adjuvant and neoadjuvant trials.

CONCLUSION

We hope that at least some of these will result in positive trials and add to our armamentarium for treating this challenging malignancy.

Intervention on toll-like receptors in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) is a devastating disease with pronounced morbidity and a high mortality rate. Currently available treatments lack convincing cost-efficiency determinations and are in most cases not associated with relevant success rate. Experimental stimulation of the immune system in murine PDA models has revealed some promising results. Toll-like receptors (TLRs) are pillars of the immune system that have been linked to several forms of malignancy, including lung, breast and colon cancer. In humans, TLRs are expressed in the pancreatic cancer tissue and in several cancer cell lines, whereas they are not expressed in the normal pancreas. In the present review, we explore the current knowledge concerning the role of different TLRs associated to PDA. Even if almost all known TLRs are expressed in the pancreatic cancer microenvironment, there are only five TLRs suggested as possible therapeutic targets. Most data points at TLR2 and TLR9 as effective tumor markers and agonists could potentially be used as e.g. future adjuvant therapies. The elucidation of the role of TLR3 in PDA is only in its initial phase. The inhibition/blockage of TLR4-related pathways has shown some promising effects, but there are still many steps left before TLR4 inhibitors can be considered as possible therapeutic agents. Finally, TLR7 antagonists seem to be potential candidates for therapy. Independent of their potential in immunotherapies, all existing data indicate that TLRs are strongly involved in the pathophysiology and development of PDA.

Deregulation of miR-146a expression in a mouse model of pancreatic cancer affecting EGFR signaling

Aberrant expression of microRNAs (miRNAs) plays important roles in the development and progression of pancreatic cancer (PC). Expression analysis of miR-146a in human PC tissues showed decreased expression in about 80% of samples compared to corresponding non-cancerous tissue. Moreover, expression of miR-146a in eight PC cell lines, and in pancreatic tissues obtained from transgenic mouse models of K-Ras (K), Pdx1-Cre (C), K-Ras;Pdx1-Cre (KC) and K-Ras;Pdx1-Cre;INK4a/Arf (KCI), showed down-regulation of miR-146a expression in KCI mice which was in part led to over-expression of its target gene, epidermal growth factor receptor (EGFR). Treatment of PC cells with CDF, a novel synthetic compound, led to re-expression of miR-146a, resulting in the down-regulation of EGFR expression. Moreover, re-expression of miR-146a by stable transfection or treatment with CDF in vivo (xenograft animal model) resulted in decreased tumor growth which was consistent with reduced EGFR, ERK1, ERK2, and K-Ras expression. Further knock-down of miR-146a in AsPC-1 cells led to the up-regulation of EGFR expression and showed increased clonogenic growth. In addition, knock-down of EGFR by EGFR siRNA transfection of parental AsPC-1 cells and AsPC-1 cells stably transfected with pre-miR-146a resulted in decreased invasive capacity, which was further confirmed by reduced luciferase activity in cells transfected with pMIR-Luc reporter vector containing miR-146a binding site. Collectively, these results suggest that the loss of expression of miR-146a is a fundamental mechanism for over-expression of EGFR signaling and that re-expression of miR-146a by CDF treatment could be useful in designing personalized strategy for the treatment of human PC.

KRAS mutations in codon 12 or 13 are associated with worse prognosis in pancreatic ductal adenocarcinoma

OBJECTIVE

Mutations in the KRAS and P53 genes belong to the most frequently observed genetic alterations in pancreatic ductal adenocarcinoma. The aim of this study was to examine the frequency and prognostic impact of KRAS mutations. In addition, we attempted to define molecular subgroups with distinct biologic behavior by combination of KRAS sequencing data with p53 protein expression data.

METHODS

KRAS mutational analyses were performed in a study group of 153 patients by Sanger sequencing. Immunohistochemistry for p53 was performed on tissue microarrays.

RESULTS

KRAS mutations in codon 12 or 13 were found in 68% of cases. Nuclear staining for p53 was detectable in 110 (68%) of 162 evaluable cases. We found no correlation between KRAS mutational status and p53 expression. KRAS mutational status but not p53 immunohistochemistry was an independent prognostic factor in the study group (P = 0.02). In a stratified analysis according to KRAS mutational status, p53 expression failed to define prognostic groups beyond the impact of KRAS mutational status.

CONCLUSIONS

Our results support the crucial role of KRAS mutational status in pancreatic cancer biology. KRAS mutational status may serve as a prognostic marker. However, its predictive role for targeted therapies remains to be evaluated.

Clinicopathological and prognostic significances of EGFR, KRAS and BRAF mutations in biliary tract carcinomas in Taiwan

BACKGROUND AND AIM

Biliary tract carcinomas (BTCs) are difficult to diagnose and treat. Epidermal growth factor receptor (EGFR) represents a therapeutic target for the BTCs. Mutations of the EGFR gene and the activation of its downstream pathways, including KRAS and BRAF, predict the sensitivity to anti-EGFR treatment. The aims of this study were to analyze the EGFR, KRAS and BRAF mutations in BTCs and their association with clinical outcomes.

METHODS

Paraffin-embedded specimens containing 137 BTCs resected at the National Taiwan University Hospital between 1995 and 2004 were analyzed. The exons 18-21 of EGFR gene, the codon 12, 13 and 61 of KRAS gene, and BRAF V600E mutation were analyzed. We examined the correlation between these mutations and the overall survival, tumor location, stage, and differentiation in BTCs.

RESULTS

Thirteen (9.5%) BTC patients had EGFR mutations while 23 (16.8%) patients had KRAS mutations. Only one patient had BRAF mutation. Factors influencing survival on univariate analysis were tumor stage, tumor differentiation, and EGFR mutation. On multivariate analysis, EGFR mutation and tumor stage were independent prognostic factors. A correlation between KRAS or BRAF mutations and prognosis was not observed.

CONCLUSIONS

EGFR and KRAS mutations are not uncommon in BTCs. BRAF mutation is rare in BTCs. EGFR mutation was an independent prognostic marker in BTCs in addition to tumor stage and differentiation. No simultaneous EGFR and KRAS mutations in extrahepatic cholangiocarcinoma and gallbladder carcinoma were found. EGFR and KRAS mutations should be evaluated when tailoring molecular-targeted therapy to patients with BTCs.

Predicting response to epidermal growth factor receptor-targeted therapy in colorectal cancer

The discovery over 20 years ago by the Nobel Laureate Stanley Cohen of epidermal growth factor and its receptor, followed by the recognition that this receptor is overexpressed in multiple cancer types, has been of phenomenal significance. From these events the 'Holy Grail' of targeted therapy has looked increasingly realistic. Over the last 5 years this work has come of age with the licensing of multiple agents targeting this important mitogenic pathway in multiple tumor types. However, these agents and the technology behind them, while impressive, have resulted in lower clinical response rates than anticipated. In this review we will focus on the epidermal growth factor receptor-targeted therapies in colorectal cancer, why our expectations from these therapies have not yet been fulfilled and how we may predict those cancers that are likely to respond or be resistant to these therapies through a greater appreciation of the intricacy, diversity and dynamism of cellular signaling mechanisms.

Clinical experiences with G17DT in gastrointestinal malignancies

The development of new agents for the treatment of gastrointestinal malignancies is increasing in pace and importance. The discovery of novel targets, namely the epidermal growth factor receptor and vascular endothelial growth factor, have sparked an explosion of new agents being tested in gastrointestinal malignancies. Clearly, novel agents and approaches are required. G17DT is a novel immunoconjugate designed to elicit a humoral response against the N-terminal end of G17 gastrin. In this overview, the authors summarize the clinical research focused on gastrointestinal tract cancers to date. In total, there is a clear signal of efficacy with this compound, although further testing is required in order for this efficacy to be demonstrated in a manner that will support regulatory approval.

Targeting the Ras-ERK pathway in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PAC) stands as the poorest prognostic tumor of the digestive tract with limited therapeutic options. PAC carcinogenesis is associated with the loss of function of tumor suppressor genes such as INK4A, TP53, BRCA2, and DPC4, and only a few activated oncogenes among which K-RAS mutations are the most prevalent. The K-RAS mutation occurs early in PAC carcinogenesis, driving downstream activation of MEK and ERK1/2 which promote survival, invasion, and migration of cancer cells. In PAC models, inhibition of members of the Ras-ERK pathway blocks cellular proliferation and metastasis development. As oncogenic Ras does not appear to be a suitable drug target, inhibitors targeting downstream kinases including Raf and MEK have been developed and are currently under evaluation in clinical trials. In this review, we describe the role of the Ras-ERK pathway in pancreatic carcinogenesis and as a new therapeutic target for the treatment of PAC.

Margin status, recurrence pattern, and prognosis after resection of pancreatic cancer

BACKGROUND

Controversy persists as to whether positive operative margins are an independent prognostic factor for resected pancreatic cancer. This study evaluated the impact of the resection margin status on the patterns of recurrence and prognosis after resection for pancreatic cancer.

METHODS

A total of 208 patients with pancreatic cancer who underwent resection with curative intent were studied retrospectively. All patients underwent pancreatectomy (164 pancreatoduodenectomies, 42 distal pancreatectomies, and 2 total pancreatectomies) intended to achieve R0 resection. They were divided into three groups on the basis of the following margin status: R(>1 mm), R(0-1 mm), and R(0 mm). The postoperative survival and recurrence patterns were evaluated in relation to the margin status. Multivariate analyses were performed to evaluate the factors influencing the overall survival.

RESULTS

The resection margin was R(>1 mm) in 134 patients (65%), R(0-1 mm) in 40 (19%), and R(0 mm) in 34 patients (16%). The margin status correlated with the rate of local recurrence; 8% in R(>1 mm), 20% in R(0-1 mm), and 50% in R(0 mm) patients. In contrast, the incidence of recurrence at other sites, such as the lymph nodes, peritoneum, liver and other distant organs, were almost identical among the three groups. The median survival time was 26 months in R(>1 mm), 30 months in R(0-1 mm), and 23 months in R(0 mm) patients (P = not significant). The multivariate analyses revealed that lymph node metastases and poor differentiation were correlated with poor survival.

CONCLUSION

In the setting of pancreatectomy, when we evaluated the definitions of R0 resection, the margin status influenced the local recurrence rate but had no impact on the patients' survival.

Randomized double-blinded, placebo-controlled phase II trial of simvastatin and gemcitabine in advanced pancreatic cancer patients

BACKGROUND

Statins have potential antineoplastic properties via arrest of cell-cycle progression and induction of apoptosis. A previous study demonstrated in vitro and in vivo antineoplastic synergism between statins and gemcitabine. The present randomized, double-blinded, phase II trial compared the efficacy and safety of gemcitabine plus simvastatin (GS) with those of gemcitabine plus placebo (GP) in patients with locally advanced and metastatic pancreatic cancer.

METHODS

Patients were randomly assigned to receive a 3-week regimen with GS (gemcitabine 1,000 mg/m(2) on days 1, 8, and 15 plus simvastatin 40 mg once daily) or GP (gemcitabine 1,000 mg/m(2) on days 1, 8, and 15 plus placebo). The primary end point was time to progression (TTP).

RESULTS

Between December 2008 and April 2012, 114 patients were enrolled. The median TTP was not significantly different between the two arms, being 2.4 months (95 % CI 0.7-4.1 months) and 3.6 months (95 % CI 3.1-4.1 months) in the GS and GP arms, respectively (P = 0.903). The overall disease control rate was 39.7 % (95 % CI 12.2-33.8 %) and 57.1 % (95 % CI 19.8-44.2 %) in the GS and GP arms, respectively (P = 0.09). The 1-year expected survival rates were similar (27.7 and 31.7 % in the GS and GP arms, respectively; P = 0.654). Occurrence of grade 3 or 4 adverse events was similar in both arms, and no patients had rhabdomyolysis.

CONCLUSIONS

Adding low-dose simvastatin to gemcitabine in advanced pancreatic cancer does not provide clinical benefit, although it also does not result in increased toxicity. Given the emerging role of statins in overcoming resistance to anti-EGFR treatment, further studies are justified to evaluate the efficacy and safety of combined simvastatin and anti-EGFR agents, such as erlotinib or cetuximab, plus gemcitabine for treating advanced pancreatic cancer.

Cetuximab: still an option in the treatment of pancreatic cancer?

INTRODUCTION

In this review, we analyzed the current literature about cetuximab to clarify its role in the treatment of pancreatic cancer. Using single-agent gemcitabine has been the standard treatment for more than 15 years for advanced pancreatic cancer. The attempts at improving the results by combining it with several other drugs, such as fluorouracil, cisplatin, irinotecan, oxaliplatin, or pemetrexed produced no clear survival benefit. Recently, however, new combination chemotherapy regimens (e.g., FOLFIRINOX, nab-paclitaxel plus gemcitabine) achieved a significant survival benefit compared to gemcitabine alone.

AREAS COVERED

Epidermal growth factor receptor (EGFR) transmembrane glycoprotein has been demonstrated to be overexpressed in pancreatic cancer, and it correlates with more advanced disease, poor survival, and the presence of metastases. Therefore, inhibition of the EGFR signaling pathway could be an attractive therapeutic target in this tumor. Although several combinations of EGFR inhibitors with chemotherapy demonstrate inhibition of tumor-induced angiogenesis, tumor cell apoptosis, and regression in xenograft models, these benefits remain to be confirmed.

EXPERT OPINION

The encouraging results from preclinical and early clinical studies with cetuximab in pancreatic cancer were not confirmed in a Phase III trial. Cetuximab failed to demonstrate improved patient outcome when paired with various chemotherapeutic regimens and/or other biological agents.

Monoclonal antibodies and other targeted therapies for pancreatic cancer

Pancreatic cancer continues to be a challenging disease to treat because of its aggressive nature, advanced stage at the time of diagnosis, and limited treatment options that are available. Traditional cytotoxic chemotherapy provides modest benefit to patients with pancreatic adenocarcinoma. Recently, a FOLFIRINOX regimen revealed improved response in overall and progression-free survival over single-agent gemcitabine in metastatic pancreatic cancer, but there is still much needed advancement in the systemic treatment of pancreatic cancer. There is a growing interest in the development of novel agents, while our understanding of molecular pathogenesis of pancreatic adenocarcinoma continues to expand. With identification of various molecular pathways in pancreatic cancer tumorigenesis, potential targets for drug development have been pursued with the use of monoclonal antibodies and small-molecule inhibitors. Although preclinical studies with multiple targeted therapies demonstrated encouraging results in pancreatic cancer, only erlotinib, an epidermal growth factor receptor inhibitor, showed a marginal survival benefit in a phase III clinical trial, when combined with gemcitabine. As further signaling pathways and their importance in pancreatic cancer tumorigenesis are better understood, further clinical trials will need to be designed to study these targeted agents as single agents, in combination with other novel agents or in combination with cytotoxic chemotherapy. In this review, we present the current knowledge on targeted therapy in pancreatic adenocarcinoma and its application in clinical practice.

Multicenter phase II trial to investigate safety and efficacy of gemcitabine combined with cetuximab as adjuvant therapy in pancreatic cancer (ATIP)

BACKGROUND

To investigate whether addition of cetuximab to standard adjuvant chemotherapy with gemcitabine improves outcome in pancreatic cancer, specifically whether the rate of disease-free survival (DFS) at 18 months (primary end point) exceeds the previously reported 35% of gemcitabine alone.

PATIENTS AND METHODS

Prospective, open-label, multicenter, nonrandomized phase II study in 76 patients with R0- or R1-resected ductal adenocarcinoma of the pancreas included between October 2006 and November 2008. Gemcitabine and cetuximab were administered for 24 weeks. Secondary end points included overall survival (OS) and toxic effect.

RESULTS

Seventy-three patients received cetuximab. Median DFS was 10.0 [95% confidence interval (CI) 8.9-13.6] months and the DFS rate at month 18 of 27.1% (16.7%-37.6%) was inferior to 35%. Median OS was 22.4 (18.2-27.9) months. Subgroup analyses revealed a nonsignificant increase in DFS for patients with versus without skin toxic effect ≥ grade 2 (median 14.7 versus 8.3 months, P = 0.073) and wild-type versus mutated K-Ras (median 11.5 versus 9.3 months, P = 0.57). Grade 3/4 toxic effects included neutropenia (11.0%), thrombopenia (7%), skin toxic effect (7%) and allergic reactions (7%).

CONCLUSION

Addition of cetuximab to adjuvant gemcitabine does not seem to improve DFS or OS of unstratified pancreatic cancer patients. Trends for improved DFS in patients with wild-type K-Ras and skin toxic effect remain to be confirmed.

Pharmacokinetics, pharmacodynamics and physiologically-based pharmacokinetic modelling of monoclonal antibodies

Development of monoclonal antibodies (mAbs) and their functional derivatives represents a growing segment of the development pipeline in the pharmaceutical industry. More than 25 mAbs and derivatives have been approved for a variety of therapeutic applications. In addition, around 500 mAbs and derivatives are currently in different stages of development. mAbs are considered to be large molecule therapeutics (in general, they are 2-3 orders of magnitude larger than small chemical molecule therapeutics), but they are not just big chemicals. These compounds demonstrate much more complex pharmacokinetic and pharmacodynamic behaviour than small molecules. Because of their large size and relatively poor membrane permeability and instability in the conditions of the gastrointestinal tract, parenteral administration is the most usual route of administration. The rate and extent of mAb distribution is very slow and depends on extravasation in tissue, distribution within the particular tissue, and degradation. Elimination primarily happens via catabolism to peptides and amino acids. Although not definitive, work has been published to define the human tissues mainly involved in the elimination of mAbs, and it seems that many cells throughout the body are involved. mAbs can be targeted against many soluble or membrane-bound targets, thus these compounds may act by a variety of mechanisms to achieve their pharmacological effect. mAbs targeting soluble antigen generally exhibit linear elimination, whereas those targeting membrane-bound antigen often exhibit non-linear elimination, mainly due to target-mediated drug disposition (TMDD). The high-affinity interaction of mAbs and their derivatives with the pharmacological target can often result in non-linear pharmacokinetics. Because of species differences (particularly due to differences in target affinity and abundance) in the pharmacokinetics and pharmacodynamics of mAbs, pharmacokinetic/pharmacodynamic modelling of mAbs has been used routinely to expedite the development of mAbs and their derivatives and has been utilized to help in the selection of appropriate dose regimens. Although modelling approaches have helped to explain variability in both pharmacokinetic and pharmacodynamic properties of these drugs, there is a clear need for more complex models to improve understanding of pharmacokinetic processes and pharmacodynamic interactions of mAbs with the immune system. There are different approaches applied to physiologically based pharmacokinetic (PBPK) modelling of mAbs and important differences between the models developed. Some key additional features that need to be accounted for in PBPK models of mAbs are neonatal Fc receptor (FcRn; an important salvage mechanism for antibodies) binding, TMDD and lymph flow. Several models have been described incorporating some or all of these features and the use of PBPK models are expected to expand over the next few years.

Molecularly targeted therapies in metastatic pancreatic cancer: a systematic review

Pancreatic cancer is the fourth leading cause of cancer-related death. Most patients present with an advanced stage of disease that has a dismal outcome, with a median survival of approximately 6 months. Evidently, there is a clear need for the development of new agents with novel mechanisms of action in this disease. A number of biological agents modulating different signal transduction pathways are currently in clinical development, inhibiting angiogenesis and targeting epidermal growth factor receptor, cell cycle, matrix metalloproteinases, cyclooxygenase-2, mammalian target of rapamycin, or proteasome. This is the first systematic review of the literature to synthesize all available data coming from trials and evaluate the efficacy and safety of molecular targeted drugs in unresectable and metastatic pancreatic cancer. However, it should be stressed that although multiple agents have been tested, only 9 phase 3 trials have been conducted and one agent (erlotinib) has been approved by the Food and Drug Administration for use in clinical practice. As knowledge accumulates on the molecular mechanisms underlying carcinogenesis in the pancreas, the anticipated development and assessment of molecularly targeted agents may offer a promising perspective for a disease which, to date, remains incurable.

Molecular-targeted agents combination therapy for cancer: developments and potentials

Although chemotherapy has advanced into the era of targeted drugs, the antitumor efficacies of current therapies are limited, most likely because of the high degree of cancer clonal heterogeneity, intratumor genetic heterogeneity and cell signal complexity. As shutdown of a single target does not necessarily eradicate the cancer, the use of combinations of molecular-targeted agents (MATs) has been proposed, and some pioneering research has been conducted to examine the efficacy of this strategy. In this article, the clinical and preclinical studies that are underway in an attempt to improve the anticancer efficacy of chemotherapies through combination strategies are summarized. Studies of combining cytotoxic agents with MATs, coinhibiting two or more targets in a single pathway or coinhibiting parallel or compensatory pathways as well as specific combinations will be introduced, and the antitumor potentials of each combination strategy will be evaluated.