Phase I study of the humanised anti-EGFR monoclonal antibody matuzumab (EMD 72000) combined with gemcitabine in advanced pancreatic cancer

Recent advances in targeted therapy for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is a fatal disease with a 5-year survival rate of 8% and a median survival of 6 mo. In PDAC, several mutations in the genes are involved, with Kirsten rat sarcoma oncogene (90%), cyclin-dependent kinase inhibitor 2A (90%), and tumor suppressor 53 (75%–90%) being the most common. Mothers against decapentaplegic homolog 4 represents 50%. In addition, the self-preserving cancer stem cells, dense tumor microenvironment (fibrous accounting for 90% of the tumor volume), and suppressive and relatively depleted immune niche of PDAC are also constitutive and relevant elements of PDAC. Molecular targeted therapy is widely utilized and effective in several solid tumors. In PDAC, targeted therapy has been extensively evaluated; however, survival improvement of this aggressive disease using a targeted strategy has been minimal. There is currently only one United States Food and Drug Administration-approved targeted therapy for PDAC – erlotinib, but the absolute benefit of erlotinib in combination with gemcitabine is also minimal (2 wk). In this review, we summarize current targeted therapies and clinical trials targeting dysregulated signaling pathways and components of the PDAC oncogenic process, analyze possible reasons for the lack of positive results in clinical trials, and suggest ways to improve them. We also discuss emerging trends in targeted therapies for PDAC: combining targeted inhibitors of multiple pathways. The PubMed database and National Center for Biotechnology Information clinical trial website (www.clinicaltrials.gov) were queried to identify completed and published (PubMed) and ongoing (clinicaltrials.gov) clinical trials (from 2003-2022) using the keywords pancreatic cancer and targeted therapy. The PubMed database was also queried to search for information about the pathogenesis and molecular pathways of pancreatic cancer using the keywords pancreatic cancer and molecular pathways.

Therapeutic Application of Monoclonal Antibodies in Pancreatic Cancer: Advances, Challenges and Future Opportunities

Pancreatic cancer remains as one of the most aggressive cancer types. In the absence of reliable biomarkers for its early detection and more effective therapeutic interventions, pancreatic cancer is projected to become the second leading cause of cancer death in the Western world in the next decade. Therefore, it is essential to discover novel therapeutic targets and to develop more effective and pancreatic cancer-specific therapeutic agents. To date, 45 monoclonal antibodies (mAbs) have been approved for the treatment of patients with a wide range of cancers; however, none has yet been approved for pancreatic cancer. In this comprehensive review, we discuss the FDA approved anticancer mAb-based drugs, the results of preclinical studies and clinical trials with mAbs in pancreatic cancer and the factors contributing to the poor response to antibody therapy (e.g. tumour heterogeneity, desmoplastic stroma). MAb technology is an excellent tool for studying the complex biology of pancreatic cancer, to discover novel therapeutic targets and to develop various forms of antibody-based therapeutic agents and companion diagnostic tests for the selection of patients who are more likely to benefit from such therapy. These should result in the approval and routine use of antibody-based agents for the treatment of pancreatic cancer patients in the future.

Advanced pancreatic cancer: The standard of care and new opportunities

Presentation of pancreatic cancer is localized, locally advanced or metastatic. With the later represented the main bulk (more than 80%). Despite the significant innovation in molecular analysis and therapeutic approach in many types of cancer in the last two decades, still the outcome of advanced pancreatic cancer is disappointing and the mortality rate approximately unchanged. In this mandated review we intended to highlight the standard of care and emerging agents for advanced pancreatic cancer treatment.

Pharmacology of Epidermal Growth Factor Inhibitors

Research into the molecular bases of malignant diseases has yielded the development of many novel agents with potential antitumor activity. Evidence for a causative role for the epidermal growth factor receptor (EGFR), which is now regarded as an excellent target for cancer chemotherapy in human cancer, leads to the development of EGFR inhibitors. Two classes of anti-EGFR agents are currently in clinical use: monoclonal antibodies directed at the extracellular domain of the receptor, and the low-molecular-weight receptor tyrosine kinase inhibitors acting intracellularly by competing with adenosine triphosphate for binding to the tyrosine kinase portion of the EGFR. The effect on the receptor interferes with key biological functions including cell cycle arrest, potentiation of apoptosis, inhibition of angiogenesis and cell invasion and metastasis. Cetuximab, a monoclonal antibody, and the receptor tyrosine kinase inhibitors gefitinib and erlotinib are currently approved for the treatment of patients with cancer. New agents with clinical activity are entering the clinic, and new combinatorial approaches are being explored with the aim of improving the potency and pharmacokinetics of EGFR inhibition, to increase the synergistic activity in combination with chemotherapy and overcome resistance to the EGFR inhibitors.

Therapeutic Antibodies in Cancer Therapy

The therapeutic arsenal in solid tumors comprises different anticancer strategies with diverse chemotherapeutic agents and a growing number of biological substances. Large clinical study-based chemotherapeutic protocols combined with biologicals have become an important component in (neo-) adjuvant therapy alongside surgery in solid cancers as well as radiation therapy in some instances. In recent years, monoclonal antibodies have entered the mainstream of cancer therapy. Their first use was as antagonists of oncogenic receptor tyrosine kinases, but today monoclonal antibodies have emerged as long-sought vehicles for the targeted delivery of potent chemotherapeutic agents and as powerful tools to manipulate anticancer immune responses. There is a growing number of FDA approved monoclonal antibodies and small molecules targeting specific types of cancer suggestive of the clinical relevance of this approach.Targeted cancer therapies , also referred to as personalized medicine, are being studied for use alone, in combination with other targeted therapies, and in combination with chemotherapy. The use of monoclonal antibodies in colorectal and gastric cancer for example have shown best outcome when combined with chemotherapy, even though single agent anti-EGFR antibodies seem to be active in particular setting of metastatic colorectal cancer patients. However, it is not well defined whether the addition of anti-VEGF - and anti-EGFR strategies to chemotherapy could improve outcome in those patients susceptible to colorectal cancer-related metastases resection. Among the most promising approaches to activating therapeutic antitumor immunity is the blockade of immune checkpoints, exemplified by the recently FDA-approved agent, Ipilimumab, an antibody that blocks the coinhibitory receptor CTLA-4. Capitalizing on the success of Ipilimumab, agents that target a second coinhibitory receptor, PD-1, or its ligand, PD-L1, are in clinical development. This section attempts to discuss recent progress of targeted agents and in tackling a more general target applicable to gastrointestinal cancer .

Structure-Directed and Tailored Diversity Synthetic Antibody Libraries Yield Novel Anti-EGFR Antagonists

We tested whether grafting an interaction domain into the hypervariable loop of a combinatorial antibody library could promote targeting to a specific epitope. Formation of the epidermal growth factor receptor (EGFR) signaling heterodimer involves extensive contacts mediated by a "dimerization loop." We grafted the dimerization loop into the third hypervariable loop of a synthetic antigen-binding fragment (Fab) library and diversified other loops using a tailored diversity strategy. This structure-directed Fab library and a naı̈ve synthetic Fab library were used to select Fabs against EGFR. Both libraries yielded high affinity Fabs that bound to overlapping epitopes on cell-surface EGFR, inhibited receptor activation, and targeted epitopes distinct from those of cetuximab and panitumumab. Epitope mapping experiments revealed complex sites of interaction, comprised of domains I and II but not exclusively localized to the receptor dimerization loop. These results validate the grafting approach for designing Fab libraries and also underscore the versatility of naı̈ve synthetic libraries.

Immunotherapy for pancreatic cancer

INTRODUCTION

Pancreatic cancer is among the most lethal malignancies resistant to conventional therapies. The vast majority of patients is diagnosed with advanced/metastatic disease and consequently has grim prognosis. Despite the available options with nab-paclitaxel and gemcitabine or 5-fluorouracil/leucovorin/oxaliplatin, chemotherapy offers a modest survival benefit. Targeted therapy in combination with chemotherapy has not shown significant improvement in treatment outcomes. The urgent need for new therapies has turned the spotlights on immunotherapy. Immunotherapy in pancreatic cancer recruits and activates T cells which recognize tumor-specific antigens.

RESULTS

Preclinical models have demonstrated that chemotherapy or targeted therapy works synergistically with immunotherapy. A growing body of evidence has already been gathered regarding the efficacy of checkpoint inhibitors, vaccines, adoptive T cell therapy, monoclonal antibodies, and cytokines in patients with pancreatic cancer.

CONCLUSIONS

Many ongoing trials are aiming to identify treatments which could combine efficacy with limited toxicity. In this article, we review the available data concerning multiple aspects of immunotherapy in pancreatic cancer.

Pancreatic cancer: role of the immune system in cancer progression and vaccine-based immunotherapy

Pancreatic cancer (PC) is the 5th leading cause of cancer related death in the developed world with more than 260,000 deaths annually worldwide and with a dismal 5-year survival. Surgery is the only potential hope of cure for PC, but, unfortunately, only 20% PC patients is resectable at the time of diagnosis. Therapeutic research efforts have mainly focused on improvements in radio/ chemo treatments and to date, there are only a few chemotherapeutic agents that have shown to be effective against PC, including gemcitabine with or without abraxane as well as a combination of 5-FU, leucovorin, oxaliplatin and irinotecan (the so-called FOLFIRINOX regimen). The survival of patients treated with these regimens is marginal and hence we are in urgent need of novel therapeutic approaches to treat pancreatic cancer. The success of immunotherapeutic strategies in other cancers and various evidences that pancreatic adenocarcinoma elicits antitumor immune responses, suggest that immunotherapies can be a promising alternative treatment modality for this deadly disease. PC immunotherapy treatments include passive immunotherapeutic approaches, such as the use of effector cells generated in vitro, and active immunotherapeutic strategies, which goal is to stimulate an antitumor response in vivo, by means of vaccination. In this review, we describe the immune suppressive mechanisms of pancreatic cancer and discuss recent preclinical and clinical efforts toward PC immunotherapy, including passive approaches, such as the use of antibodies and active strategies (vaccination), with a special mention of most recent treatment with CRS-207 and GVAX.

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.

Smarter drugs emerging in pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer death in the Western world. Owing to a lack of specific symptoms and no accessible precursor lesions, primary diagnosis is commonly delayed, resulting in only 15%-20% of patients with potentially curable disease. The standard of care in advanced pancreatic cancer has improved. Apart from gemcitabine (plus erlotinib), FOLFIRINOX and the combination of gemcitabine plus nab-paclitaxel are novel and promising therapeutic options for patients with metastatic PDAC. A better molecular understanding of pancreatic cancer has led to the identification of a variety of potential molecular therapeutic targets. Many targeted therapies are currently under clinical evaluation in combination with standard therapies for PDAC. This review highlights the current status of targeted therapies and their potential benefit for the treatment of advanced PDAC.

Pancreatic Cancer: Progress in Systemic Therapy

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related deaths in the Western world. Due to lack of specific symptoms and no accessible precursor lesions, primary diagnosis is commonly delayed, resulting in the identification of only 15-20% of patients with potentially curable disease. The major limiting factor is an already locally advanced or metastatic disease at the time of diagnosis. Consequently, systemic therapy forms the backbone of treatment strategy for the majority of patients.

SUMMARY

A deeper understanding of the molecular characteristics of pancreatic cancer has led to the identification of several potential therapeutic targets. A variety of targeted therapies are currently under clinical evaluation as single agents or in combination with chemotherapy for PDAC. This review highlights the current state of chemotherapy in pancreatic cancer and provides an outlook on its future perspectives.

KEY MESSAGE

This review focuses on the current chemotherapy regimens for the systemic treatment of PDAC.

PRACTICAL IMPLICATIONS

Various neoadjuvant approaches have been explored, including chemoradiation, chemotherapy followed by chemoradiation or intensified chemotherapy without defining a standard of care so far. The standard of care is gemcitabine or 5-fluorouracil. The oral fluoropyrimidine S-1 may be a promising new agent in this setting. For first-line treatment of metastatic pancreatic cancer, no targeted therapy has yet demonstrated clinical benefit apart from the combination of the tyrosine kinase inhibitor erlotinib plus gemcitabine. Recently, novel chemotherapeutic regimens such as FOLFIRINOX and gemcitabine plus nanoparticle albumin-bound paclitaxel have been introduced. Both combinations have proved to be superior to the standard gemcitabine regimen. For second-line treatment the combination of 5-fluorouracil/leucovorin and oxaliplatin yields improved results compared to best supportive care.

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.

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.

What is recent in pancreatic cancer immunotherapy?

Pancreatic cancer (PC) represents an unresolved therapeutic challenge, due to the poor prognosis and the reduced response to currently available treatments. Pancreatic cancer is the most lethal type of digestive cancers, with a median survival of 4-6 months. Only a small proportion of PC patients is curative by surgical resection, whilst standard chemotherapy for patients in advanced disease generates only modest effects with considerable toxic damages. Thus, new therapeutic approaches, specially specific treatments such as immunotherapy, are needed. In this paper we analyze recent preclinical and clinical efforts towards immunotherapy of pancreatic cancer, including passive and active immunotherapy approaches, designed to target pancreatic-cancer-associated antigens and to elicit an antitumor response in vivo.

High vascular delivery of EGF, but low receptor binding rate is observed in AsPC-1 tumors as compared to normal pancreas

PURPOSE

Cellular receptor targeted imaging agents present the potential to target extracellular molecular expression in cancerous lesions; however, the image contrast in vivo does not reflect the magnitude of overexpression expected from in vitro data. Here, the in vivo delivery and binding kinetics of epidermal growth factor receptor (EGFR) was determined for normal pancreas and AsPC-1 orthotopic pancreatic tumors known to overexpress EGFR.

PROCEDURES

EGFR in orthotopic xenograft AsPC-1 tumors was targeted with epidermal growth factor (EGF) conjugated with IRDye800CW. The transfer rate constants (k(e), K₁₂, k₂₁, k₂₃, and k₃₂) associated with a three-compartment model describing the vascular delivery, leakage rate and binding of targeted agents were determined experimentally. The plasma excretion rate, k (e), was determined from extracted blood plasma samples. K₁₂, k₂₁, and k₃₂ were determined from ex vivo tissue washing studies at time points ≥ 24 h. The measured in vivo uptake of IRDye800CW-EGF and a non-targeted tracer dye, IRDye700DX-carboxylate, injected simultaneously was used to determined k₂₃.

RESULTS

The vascular exchange of IRDye800CW-EGF in the orthotopic tumor (K₁₂ and k₂₁) was higher than in the AsPC-1 tumor as compared to normal pancreas, suggesting that more targeted agent can be taken up in tumor tissue. However, the cellular associated (binding) rate constant (k₂₃) was slightly lower for AsPC-1 pancreatic tumor (4.1 × 10(-4) s(-1)) than the normal pancreas (5.5 × 10(-4) s(-1)), implying that less binding is occurring.

CONCLUSIONS

Higher vascular delivery but low cellular association in the AsPC-1 tumor compared to the normal pancreas may be indicative of low receptor density due to low cellular content. This attribute of the AsPC-1 tumor may indicate one contributing cause of the difficulty in treating pancreatic tumors with cellular targeted agents.

Phase I study of matuzumab in combination with 5-fluorouracil, leucovorin and cisplatin (PLF) in patients with advanced gastric and esophagogastric adenocarcinomas

BACKGROUND

To evaluate the safety and tolerability of two different weekly doses of the fully humanized epidermal growth factor receptor (EGFR)-targeting monoclonal antibody matuzumab combined with high-dose 5-fluorouracil, leucovorin and cisplatin (PLF) in the first-line treatment of patients with EGFR-positive advanced gastric and esophagogastric adenocarcinomas.

METHODS

Patients were treated in two matuzumab dose groups with the first cohort of patients receiving 400 mg matuzumab in combination with PLF. Based on the safety observations the next cohort of patients received 800 mg matuzumab. The study was conducted in two parts, with phase A, designed to assess the safety and tolerability of the combination, and phase B designed to be a treatment continuation for those patients benefiting from treatment. Treatment cycles were 7 weeks each. Each patient received the dose of matuzumab they were assigned to at study entry for the duration of the study.

RESULTS

Fifteen EGFR-positive patients were enrolled into the two matuzumab dose groups; 400 mg dose n=7; 800 mg dose n=8. All patients experienced at least one adverse event (AE). No patient experienced any serious AE which was considered to be related to matuzumab. Two grade 3 AEs possibly related to matuzumab occurred in 2 different patients (13.3 %), both in the 800 mg dose group. No dose-limiting toxicity (DLT) was observed in the 400 mg group. The maximum tolerated dose of matuzumab was not reached. The best confirmed overall response rate was 26.7 %.

CONCLUSION

Matuzumab, in combination with PLF, demonstrated an acceptable safety profile with modest anti-tumor activity.

Current status of experimental therapeutics for head and neck cancer

As with many cancers, early detection of head and neck cancer increases a patient's survival rate. If diagnosed early, its five-year survival nears 90% with standard therapy alone. Unfortunately, the average survival rate for head and neck cancer is low due to the difficulty in early detection and achieving a sustainable response. Conventional treatments are not adequate for the majority of advanced or recurrent head and neck cancer patients because of the remarkable resistance of tumors to chemotherapy and radiation, and the situation is especially devastating for the first time treatment failure. The major limitations of these treatments are the lack of specificity for the tumor cell and unacceptable toxicity to the patient. As a result, current research in therapeutics for advanced, chemotherapy-resistant or recurrent head and neck cancer patients has focused on new treatment modalities that exploit biological differences between tumor and normal cells. These therapies include monoclonal antibodies, molecular inhibitors, gene therapy and photodynamic therapy. This article reviews the current preclinical and clinical evidence of these experimental therapeutics as they relate to head and neck cancer.

Monoclonal antibody-induced cytokine-release syndrome

Monoclonal antibodies (mAbs) are widely used in anti-inflammatory and tumor therapy. Although effective, mAbs can cause a variety of adverse effects. An important toxicity seen with a few mAbs is cytokine-release syndrome (CRS). These mAbs include: alemtuzumab, muromonab-CD3, rituximab, tosituzumab, CP-870,893, LO-CD2a/BTI-322 and TGN1412. By contrast, over 30 mAbs used clinically are not associated with CRS. In this review, the clinical aspects of CRS, the mAbs associated with CRS, the cytokines involved and putative mechanisms mediating cytokine release will be discussed. This will be followed by a discussion of the poor predictive value of studies in animals and the prospects for creating in vitro screens. Finally, approaches to decreasing the probability of CRS, decreasing the severity or treating CRS, should it occur, will be described.

Therapeutic antibodies for the treatment of pancreatic cancer

Pancreatic cancer is a devastating disease with the worst mortality rate and an overall 5-year survival rate lower than 5%. In the U.S., this disease is the fourth leading cause of death and represents 6% of all cancer-related deaths. Gemcitabine, the current standard first-line treatment, offers marginal benefits to patients in terms of symptom control and prolongation of life. Since 1996, about 20 randomized phase III trials have been performed to improve the efficacy of gemcitabine, with little success regarding a significant improvement in survival outcomes. The need for novel therapeutic strategies, such as target therapy, is obvious. Monoclonal antibodies have finally come of age as therapeutics and several molecules are now approved for cancer therapies. This review aims to give a general view on the clinical results obtained so far by antibodies for the treatment of pancreatic cancer and describes the most promising avenues toward a significant improvement in the treatment of this frustrating disease.

Matuzumab plus epirubicin, cisplatin and capecitabine (ECX) compared with epirubicin, cisplatin and capecitabine alone as first-line treatment in patients with advanced oesophago-gastric cancer: a randomised, multicentre open-label phase II study

BACKGROUND

Clinical data showed promising antitumour activity with feasible tolerability for matuzumab plus epirubicin, cisplatin and capecitabine (ECX) chemotherapy in untreated advanced oesophago-gastric (OG) cancer. The aim was to evaluate the efficacy of matuzumab plus ECX versus ECX alone.

PATIENTS AND METHODS

In this multicentre, randomised open-label phase II study, 72 patients with metastatic OG cancer were randomly assigned to either 800 mg matuzumab weekly plus epirubicin 50 mg/m², cisplatin 60 mg/m² on day 1 and capecitabine 1250 mg/m² daily in a 21-day cycle (ECX) or the same ECX regimen alone. The primary end point was objective response. Secondary end points included progression-free survival (PFS), overall survival (OS), quality of life, safety and tolerability.

RESULTS

Following random assignment, 35 patients (median age 59 years) received ECX/matuzumab and 36 patients (median age 64 years) ECX. The addition of matuzumab to ECX did not improve objective response: 31% for ECX/matuzumab [95% confidence interval (CI) 17-49] compared with 58% for the ECX arm (95% CI 41-74) P = 0.994 (one sided). There was no significant difference in median PFS: 4.8 months (95% CI 2.9-8.1) for ECX/matuzumab versus 7.1 months (95% CI 4.4-8.5) for ECX, or in median OS: 9.4 months (95% CI 7.5-16.2), compared with 12.2 months (95% CI 9.8-13.8 months). Grade 3/4 treatment-related toxicity was observed in 27 and 25 patients in the ECX/matuzumab and ECX groups, respectively.

CONCLUSION

Matuzumab 800 mg weekly combined with ECX chemotherapy does not increase response or survival for patients with advanced OG cancer. Therefore, ECX/matuzumab should not be examined further in phase III trials.

A review of kinases implicated in pancreatic cancer

The current 5-year survival rate of pancreatic cancer is about 3% and the median survival less than 6 months because the chemotherapy and radiation therapy presently available provide only marginal benefit. Clearly, pancreatic cancer requires new therapeutic concepts. Recently, the kinase inhibitors imatinib and gefitinib, developed to treat chronic myelogenous leukaemia and breast cancer, respectively, gave very good results. Kinases are deregulated in many diseases, including cancer. Given that phosphorylation controls cell survival signalling, strategies targeting kinases should obviously improve cancer treatment. The purpose of this review is to summarize the present knowledge on kinases potentially usable as therapeutic targets in the treatment of pancreatic cancer. All clinical trials using available kinase inhibitors in monotherapy or in combination with chemotherapeutic drugs failed to improve survival of patients with pancreatic cancer. To detect kinases relevant to this disease, we undertook a systematic screening of the human kinome to define a 'survival kinase' catalogue for pancreatic cells. We selected 56 kinases that are potential therapeutic targets in pancreatic cancer. Preclinical studies using combined inhibition of PAK7, MAP3K7 and CK2 survival kinases in vitro and in vivo showed a cumulative effect on apoptosis induction. We also observed that these three kinases are rather specific of pancreatic cancer cells. In conclusion, if kinase inhibitors presently available are unfortunately not efficient for treating pancreatic cancer, recent data suggest that inhibitors of other kinases, involved more specifically in pancreatic cancer development, might, in the future, become interesting therapeutic targets.

Immunotherapy combined with chemotherapy in the treatment of tumors

This article provides a broad overview of the data, including laboratory and clinical studies, currently available on the combination of immunotherapy and chemotherapy for treating cancer. The various forms of immunotherapy combined with chemotherapy include monoclonal antibodies, adoptive lymphocyte transfer, or active specific immunotherapy, such as tumor proteins, irradiated tumor cells, tumor cell lysates, dendritic cells pulsed with peptides or lysates, or tumor antigens expressed in plasmids or viral vectors. This discussion is not limited to malignant brain tumors, because many of the studies have been conducted on various cancer types, thereby providing a comprehensive perspective that may encourage further studies that combine chemotherapy and immunotherapy for treating brain tumors.

Novel agents for the treatment of adenocarcinoma of the pancreas

Pancreatic cancer is a particularly challenging malignancy, given its usually advanced stage at diagnosis and its rather limited treatment options. Gemcitabine has been standard therapy for advanced pancreatic cancer for well over a decade. The addition of capecitabine or erlotinib to gemcitabine has resulted in modestly improved, although still poor, overall survival. The majority of the recently completed randomized trials, however, have failed to demonstate an improvement of newer treatments over single-agent gemcitabine. Efforts currently underway center on new cytotoxic chemotherapy drugs, as well as novel targeted agents inhibiting various molecular pathways. Newly discovered proteins and cellular elements involved in tumor growth and invasion are potential therapeutic targets, and have become the focus of current trials, as well as future clinical trials. A better understanding of the biology of the disease at the basic science level, and epidemiology and risk factors from a public-health perspective, are needed. Continued research is clearly warranted with the goal of improving survival and optimizing treatment outcomes in locally advanced and metastatic pancreatic cancer.

Refinement of the population pharmacokinetic model for the monoclonal antibody matuzumab: external model evaluation and simulations

OBJECTIVES

A developed population pharmacokinetic model of the humanized monoclonal antibody (mAb) matuzumab was evaluated by external evaluation. Based on the estimates of the final model, simulations of different dosing regimens and the covariate effect were performed.

METHODS

The development dataset included 90 patients, and the evaluation dataset included 81 patients; the two sets of patients were from three different studies. In all studies, the patients had different types of advanced carcinoma - mainly colon, rectal and pancreatic cancer. They received matuzumab as multiple 1-hour intravenous infusions in a wide range of dosing regimens (development dataset: from 400 mg every 3 weeks to 2000 mg in the first week followed by 1600 mg weekly; evaluation dataset: from 100 mg weekly to 800 mg weekly). In addition to 1256 serum mAb concentrations for model development, there were 1124 concentrations available for model evaluation. Serum concentration-time data were simultaneously fitted using NONMEM software. The developed two-compartment model - with the parameters central volume of distribution (V(1)) and peripheral volume of distribution (V(2)), intercompartmental clearance and linear clearance (CLL), an additional nonlinear elimination pathway (Michaelis-Menten constant: the concentration with the half-maximal elimination rate and V(max): the maximum elimination rate) and covariate relations - was evaluated by an external dataset. Different simulation scenarios were performed to demonstrate the impact of the incorporated covariate effect and the influence of different dosing regimens and dosing strategies on the concentration-time profiles.

RESULTS

The developed model included the covariate fat-free mass (FFM) on V(1) and on CLL. The evaluation did not support the covariate FFM on V(1) and, after deletion of this covariate, the model parameters of the refined model were estimated. The model showed good precision for all parameters: the relative standard errors (RSEs) were <42% for the development dataset and < or = 51% for the evaluation dataset (excluding the higher RSEs for the correlation between V(2) and V(max) and the interindividual variability on V(2) for the evaluation dataset). The model showed good robustness for the ability to estimate highly precise parameters for the combined dataset of 171 patients (RSE <29%). Simulations revealed that variability in concentration-time profiles for minimum and maximum steady-state concentrations was reduced to a marginal extent by a proposed dose adaptation.

CONCLUSION

The population pharmacokinetic model for matuzumab was improved by evaluation with an external dataset. The new model obtained precise parameter estimates and demonstrated robustness. After correlation with efficacy data simulation results in particular could serve as a tool to guide dose selection for this 'targeted' cancer therapy.

A novel mechanism for anti-EGFR antibody action involves chemokine-mediated leukocyte infiltration

Overexpression of the epidermal growth factor receptor (EGFR) is a hallmark of squamous cell carcinoma of the head and neck (SCCHN). Monoclonal antibodies (mAbs) against EGFR are currently used for therapy of recurrent or metastatic disease; however, their mode of action is not completely understood. To investigate the immunological effects of anti-EGFR mAb, we generated a three-dimensional spheroid model of EGFR-expressing SCCHN and used this model to study the effect of anti-EGFR mAb on leukocyte migration toward tumors. Pretreatment with the blocking anti-EGFR mAb EMD 72000, its F(ab')2 fragments or an EGFR tyrosine kinase inhibitor led to substantially increased leukocyte infiltration into EGFR overexpressing tumor spheroids, but not into those with low EGFR expression. Nonblocking anti-EGFR mAb or fibroblast-specific mAb did not affect leukocyte infiltration, suggesting that the observed increase in leukocyte infiltration depends on interference with EGFR activation. Using a human cytokine macroarray, we demonstrated that the blockade of EGFR by anti-EGFR mAb in EGFR-overexpressing SCCHN cells leads to differential expression of several cytokines and chemokines, including the chemokine MCP-1/CCL-2. The significant upregulation of MCP-1/CCL2 on exposure to anti-EGFR mAb was confirmed by quantitative PCR and enzyme-linked immunospot analyses. Moreover, blocking anti-MCP-1 antibody inhibited leukocyte migration toward tumor cells induced by anti-EGFR mAb, pointing to an important role of MCP-1/CCL2 in anti-EGFR mAb-induced leukocyte migration. Our findings demonstrate that anti-EGFR mAb induces leukocyte infiltration to tumor spheroids by upregulating chemokine expression. This novel mechanism for anti-EGFR mAb action may contribute to the antitumor effects of anti-EGFR mAb in vivo.

Phase I study of epirubicin, cisplatin and capecitabine plus matuzumab in previously untreated patients with advanced oesophagogastric cancer

To evaluate the safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of the humanised antiepidermal growth factor receptor monoclonal antibody matuzumab combined with epirubicin, cisplatin and capecitabine (ECX) in patients as first-line treatment for advanced oesophagogastric cancer that express epidermal growth factor receptor (EGFR). This was a phase I dose escalation study of matuzumab at 400 and 800 mg weekly and 1200 mg every 3 weeks combined with ECX (epirubicin 50 mg m⁻², cisplatin 60 mg m⁻² on day 1 and capecitabine 1000 mg m⁻² daily). Patients were treated until disease progression, unacceptable toxicity or for a maximum of eight cycles. Twenty-one patients were treated with matuzumab at three different dose levels (DLs) combined with ECX. The main dose-limiting toxicity (DLT) was grade 3 lethargy at 1200 mg matuzumab every 3 weeks and thus 800 mg matuzumab weekly was the maximum-tolerated dose (MTD). Other common toxicities included rash, nausea, stomatitis and diarrhoea. Pharmacokinetic evaluation demonstrated that the coadministration of ECX did not alter the exposure of matuzumab. Pharmacodynamic studies on skin biopsies demonstrated inhibition of the EGFR pathway. Objective response rates of 65% (95% confidence interval (CI): 43–82), disease stabilisation of 25% (95% CI: 11–47) and a disease control rate (CR+PR+SD) of 90% were achieved overall. The MTD of matuzumab in combination with ECX was 800 mg weekly, and at this DL it was well-tolerated and showed encouraging antitumour activity. At the doses evaluated in serial skin biopsies, matuzumab decreased phosphorylation of EGFR and MAPK, and increased phosphorylation of STAT-3.

Monoclonal antibodies in the treatment of pancreatic cancer

Human pancreatic cancer is a malignant disease with almost equal incidence and mortality. Effective diagnostic and therapeutic strategies are still urgently needed to improve its survival rate. With advances in structural and functional genomics, recent work has focused on targeted molecular therapy using monoclonal antibodies. This review summarizes the target molecules on the tumor cell surface and normal tissue stroma, which are related to pancreatic cancer oncogenesis, tumor growth or resistance to chemotherapy, as well as molecules involved in regulating inflammation and host immunoresponses. Targeted molecules include cell-surface receptors, such as the EGF receptor, HER2, death receptor 5 and IGF-1 receptor. Effects of monoclonal antibodies against these target molecules alone or in combination with chemotherapy, small-molecule signal transduction inhibitors, or radiation therapy are also discussed. Also discussed are the use of toxin or radioisotope conjugates, and information relating to the use of these targeting agents in pancreatic cancer clinical trials. Although targeted molecular therapy with monoclonal antibodies has made some progress in pancreatic cancer treatment, especially in preclinical studies, its clinical application to improve the survival rate of pancreatic cancer patients requires further investigation.

Recent advances relating to the clinical application of naked monoclonal antibodies in solid tumors

This review focuses on the recent advances in clinical data regarding antibody-based therapy in the management of solid tumors. We also discuss perspectives on antibody-based therapy in the future. Thorough understanding of the complex interactions between components of the immunological response has led to interest in the concept of immune-mediated therapy for solid tumors. Over the last few years, several humanized and chimeric monoclonal antibodies (MAbs) targeting human epidermal receptor 2 (HER2), epidermal growth factor receptor (EGFR), and vascular endothelial growth factor (VEGF) have been employed in treating solid tumors, including breast, colorectal, lung, head and neck, and gynecologic cancers. Trastuzumab, bevacizumab, cetuximab, and panitumumab are MAbs that are most widely used in clinical practice with acceptable rates of adverse events. Combination of MAbs with small-molecule inhibitors of the same pathway could potentially increase the efficacy and specificity of antibody-based treatment. Immune-mediated effects may be further exploited with the use of bivalent molecules.

The anti-EGFR monoclonal antibody blocks cisplatin-induced activation of EGFR signaling mediated by HB-EGF

Cisplatin is a key agent in combination chemotherapy for various types of solid tumor. We now show that cisplatin activates signaling by the epidermal growth factor receptor (EGFR) by inducing cleavage of heparin-binding epidermal growth factor-like growth factor (HB-EGF). Matuzumab, a monoclonal antibody to EGFR, inhibited cisplatin-induced EGFR signaling, likely through competition with the soluble form of HB-EGF for binding to EGFR. Matuzumab enhanced the antitumor effect of cisplatin in nude mice harboring human non-small cell lung cancer xenografts. Our findings shed light on the mechanism by which monoclonal antibodies to EGFR might augment the efficacy of cisplatin.

Combination of active specific immunotherapy or adoptive antibody or lymphocyte immunotherapy with chemotherapy in the treatment of cancer

Successful treatment of cancer patients with a combination of monoclonal antibodies (mAb) and chemotherapeutic drugs has spawned various other forms of additional combination therapies, including vaccines or adoptive lymphocyte transfer combined with chemotherapeutics. These therapies were effective against established tumors in animal models and showed promising results in initial clinical trials in cancer patients, awaiting testing in larger randomized controlled studies. Although combination between immunotherapy and chemotherapy has long been viewed as incompatible as chemotherapy, especially in high doses meant to increase anti-tumor efficacy, has induced immunosuppression, various mechanisms may explain the reported synergistic effects of the two types of therapies. Thus direct effects of chemotherapy on tumor or host environment, such as induction of tumor cell death, elimination of regulatory T cells, and/or enhancement of tumor cell sensitivity to lysis by CTL may account for enhancement of immunotherapy by chemotherapy. Furthermore, induction of lymphopenia by chemotherapy has increased the efficacy of adoptive lymphocyte transfer in cancer patients. On the other hand, immunotherapy may directly modulate the tumor's sensitivity to chemotherapy. Thus, anti-tumor mAb can increase the sensitivity of tumor cells to chemotherapeutic drugs and patients treated first with immunotherapy followed by chemotherapy showed higher clinical response rates than patients that had received chemotherapy alone. In conclusion, combination of active specific immunotherapy or adoptive mAb or lymphocyte immunotherapy with chemotherapy has great potential for the treatment of cancer patients which needs to be confirmed in larger controlled and randomized Phase III trials.

Matuzumab short-term therapy in experimental pancreatic cancer: prolonged antitumor activity in combination with gemcitabine

PURPOSE

The epidermal growth factor receptor ErbB-1 is commonly expressed in pancreatic cancer and ErbB-1 targeting has shown promising results. We wanted to evaluate matuzumab (EMD72000), a fully humanized ErbB-1-specific monoclonal antibody in combination with gemcitabine in experimental pancreatic cancer.

EXPERIMENTAL DESIGN

Using the human pancreatic cancer cell line L3.6pl, we investigated matuzumab in vitro and in vivo. ErbB-1 phosphorylation and downstream pathway activation were evaluated by Western blot. Proliferation and migration assays and fluorescence-activated cell sorting analysis were done. For in vivo studies, we used an orthotopic nude mice model in which 40 mg/kg of matuzumab+/-100 mg/kg of gemcitabine were administered twice weekly. Different treatment durations (7, 14, 21, and 25 days) and varying time points of treatment initiation (days 8, 15, 22, and 29) were evaluated. Ki67, CD31, and phosphorylated p44/42 mitogen-activated protein kinase (MAPK) immunohistochemistry were done.

RESULTS

ErbB-1 phosphorylation and downstream MAPK and AKT signaling were significantly reduced by matuzumab. Matuzumab significantly inhibited proliferation and migration in vitro, and induced tumor cell apoptosis in a dose-dependant manner. Matuzumab therapy significantly lowered tumor volume in vivo, reduced lymph node and liver metastases, and decreased microvessel density and tumor cell proliferation. These effects were significantly enhanced when gemcitabine was added. A significant and prolonged antitumor activity was even evident with short-term therapy (7 days) and with a late onset of therapy (day 22 after tumor cell injection).

CONCLUSIONS

Matuzumab is an effective agent with long-lasting antiproliferative, proapoptotic, antiangiogenic, and antimetastatic activity in human pancreatic cancer models. These effects might be potentiated by gemcitabine.

Pancreatic cancer: from molecular pathogenesis to targeted therapy

Pancreatic cancer is a deadly malignancy with still high mortality and poor survival despite the significant advances in understanding, diagnosis, and access to conventional and novel treatments. Though cytotoxic chemotherapy based on the purine analogue gemcitabine remains the standard approach in adjuvant and palliative setting the need for novel agents aiming at the main pathophysiological abnormalities and molecular pathways involved remains soaring. So far, evidence of clinical benefit, though small, exists only from the addition of the targeted agent erlotinib on the standard gemcitabine chemotherapy. Apart from the popular monoclonal antibodies and small molecules tyrosine kinase inhibitors, other novel compounds being tested in preclinical and clinical studies target mTOR, NF-kappaB, proteasome and histone deacetylase. These new drugs along with gene therapy and immunotherapy, which are also under clinical evaluation, may alter the unfavorable natural course of this disease. In this review we present the main pathophysiological alterations met in pancreatic cancer and the results of the florid preclinical and clinical research with regards to the targeted therapy associated to these abnormalities.

Molecular targeted therapies for pancreatic cancer

BACKGROUND

Pancreatic cancer cells express different mutations that increase the aggressiveness and confer resistance to conventional chemotherapy and radiotherapy. Molecules that selectively bind and inhibit these mutations are effective in other solid tumors and are now emerging as a complementary therapy in pancreatic cancer. The objective of this review is to describe the effect of drugs that inhibit specific mutations present in pancreatic cancer with special emphasis on clinical trials.

DATA SOURCES

We reviewed the English-language literature (MedLine) addressing the role of drugs that target mutations present in pancreatic cancer. Both preclinical and clinical studies were included.

CONCLUSIONS

Preclinical evidence supports the combination of conventional approved therapies plus drugs that block epidermal growth factor receptor and vascular growth endothelial factor or induce apoptosis. However, most of the current clinical evidence is limited to small phase I trials evaluating the toxicity and safety of these regimens. The results of additional randomized trials that are still undergoing will clarify the role of these drugs in pancreatic cancer.

Biological approaches to therapy of pancreatic cancer

Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Improvement of our understanding of the disease has generated a large number of studies on biological approaches targeting the molecular abnormalities of pancreatic cancer, including gene therapy and signal transduction inhibition, antiangiogenic and matrix metalloproteinase inhibition, oncolytic viral therapy and immunotherapy. This article provides a review of these approaches, both investigated in the laboratories and in subsequent clinical trials.

Erlotinib: the first biologic in the management of pancreatic cancer

BACKGROUND

Pancreatic cancer remains a major therapeutic challenge largely characterized by chemotherapy-refractory disease and poor responses to currently available treatments. Pivotal studies of combination chemotherapeutic agents with gemcitabine showed that responses may exceed single-agent gemcitabine, but with added toxicities. The EGFR is known to be overexpressed in pancreatic cancer and data suggest that the presence of EGFR is associated with a poor prognosis.

OBJECTIVE

To analyze the current data on erlotinib and compare against other agents targeting against the EGFR pathway in pancreatic cancer.

METHODS

PubMed, Ovid, Cochran and the American Society of Clinical Oncology abstract database were searched using the terms 'erlotinib', 'EGFR', 'cetuximab', 'gemcitabine', 'fluorouracil', 'capecitabine' and 'pancreatic cancer' to identify relevant studies. Only studies using erlotinib in pancreatic cancer patients were reviewed and analyzed.

CONCLUSIONS

The combination of gemcitabine and erlotinib is the first combination therapy to demonstrate survival benefits in pancreatic cancer in a Phase III study albeit a modest one. Increased understanding of the EGFR pathway may permit the use of other targeted agents to either augment therapeutic efficacy or circumvent resistance. It is warranted to develop strategies to truly target our therapy with the EGFR agents by identifying those patients who are most likely to derive benefit and achieve meaningful responses.

Current situation of Panitumumab, Matuzumab, Nimotuzumab and Zalutumumab

EGFR overexpression usually correlates with a more advanced disease stage, a poorer prognosis and a worse chemotherapy response. EGFR expression increase has been observed in many tumours. For all the aforementioned reasons, EGFR inhibition can be considered an attractive approach in cancer treatment. One strategy has been receptor inhibition of extracellular domain using monoclonal antibodies. Cetuximab is the most developed one and there is plenty information on the literature about its current status. In this review we focus on other EGFR monoclonal antibodies under clinical development. The more developed one is Panitumumab. Its clinical development is taking place very quickly and it has mainly been studied in colorectal cancer showing promising results. There are also other interesting drugs such as Matuzumab, Nimotuzumab and Zalutumumab.

Genetically designing a more potent antipancreatic cancer agent by simultaneously co-targeting human IL13 and EGF receptors in a mouse xenograft model

OBJECTIVE

Investigators are currently interested in the epidermal growth factor receptor (EGFR) and interleukin 13 receptor (IL13R) as potential targets in the development of new biologicals for pancreatic cancer. Attempts to develop successful agents have met with difficulty. The novel approach used here was to target these receptors simultaneously with EGF and IL13 cloned on the same bispecific single-chain molecule with truncated diphtheria toxin (DT(390)) to determine if co-targeting with DTEGF13 had any advantages.

DESIGN

Proliferation experiments were performed to measure the potency and selectivity of bispecific DTEGF13 and its monospecific counterparts against pancreatic cancer cell lines PANC-1 and MiaPaCa-2 in vitro. DTEGF13 was then administered intratumourally to nude mice with MiaPaCa-2 flank tumours to measure efficacy and toxicity (weight loss).

RESULTS

In vitro, bispecific DTEGF13 was 2800-fold more toxic than monospecific DTEGF or DTIL13 against PANC-1. A similar enhancement was observed in vitro when MiaPaCa-2 pancreatic cancer cells or H2981-T3 lung adenocarcinoma cells were studied. DTEGF13 activity was blockable with recombinant EGF13. DTEGF13 was potent (IC(50) = 0.00017 nM) against MiaPaCa-2, receptor specific and significantly inhibited MiaPaCa-2 tumours in nude mice (p<0.008).

CONCLUSIONS

In vitro studies show that the presence of both ligands on the same bispecific molecule is responsible for the superior activity of DTEGF13. Intratumoural administration showed that DTEGF13 was highly effective in checking aggressive tumour progression in mice. Lack of weight loss in these mice indicated that the drug was tolerated and a therapeutic index exists in an "on target" model in which DTEGF13 is cross-reactive with native mouse receptors.

Pancreatic cancer: from molecular signature to target therapy

Pancreatic adenocarcinoma is a leading cause of cancer death in western countries. The treatment of advanced disease with gemcitabine has only a modest activity on survival with a favourable impact on quality of life. However, recent data support the evidence that the combination of gemcitabine with erlotinib, capecitabine or platinum compounds could be more active than gemcitabine alone in advanced pancreatic cancer. New therapeutic strategies, particularly using molecular target agents, are under evaluation. A number of molecular mechanisms responsible of transformation and progression of pancreatic cancer have been identified, opening the possibility to identify also possible pharmacological targets. A promising approach is the pharmacological inhibition of tumor angiogenesis with anti-vascular endothelial growth factor (VEGF) agents, such as bevacizumab, cyclooxygenase-2 inhibitors (celecoxib), thalidomide and others. Also epidermal growth factor receptor (EGFR) plays an important role in progression of pancreatic cancer. Erlotinib, an oral available anti-EGFR compound, was the first agent capable to significantly improve overall survival in a phase III trial, leading to its approval by Food and Drug Administration (FDA) in combination with gemcitabine as first-line therapy. Ongoing studies are exploring the role of targeted therapy in the adjuvant setting. However, despite these promising results, several questions remain to be resolved, including the rational selection of the patients who are more likely to obtain benefit of target therapy, the choice of the optimal therapeutic schedule of therapy, the clinical setting of choice, and the management of the toxicity.

Matuzumab binding to EGFR prevents the conformational rearrangement required for dimerization

An increasing number of therapeutic antibodies targeting tumors that express the epidermal growth factor receptor (EGFR) are in clinical use or late stages of clinical development. Here we investigate the molecular basis for inhibition of EGFR activation by the therapeutic antibody matuzumab (EMD72000). We describe the X-ray crystal structure of the Fab fragment of matuzumab (Fab72000) in complex with isolated domain III from the extracellular region of EGFR. Fab72000 interacts with an epitope on EGFR that is distinct from the ligand-binding region on domain III and from the cetuximab/Erbitux epitope. Matuzumab blocks ligand-induced receptor activation indirectly by sterically preventing the domain rearrangement and local conformational changes that must occur for high-affinity ligand binding and receptor dimerization.