Cetuximab monotherapy and cetuximab plus irinotecan in irinotecan-refractory metastatic colorectal cancer

Phase I and pharmacokinetic study of gefitinib in children with refractory solid tumors: a Children's Oncology Group Study

PURPOSE

Epidermal growth factor receptor is expressed in pediatric malignant solid tumors. We conducted a phase I trial of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in children with refractory solid tumors.

PATIENTS AND METHODS

Gefitinib (150, 300, 400, or 500 mg/m2) was administered orally to cohorts of three to six patients once daily continuously until disease progression or significant toxicity. Pharmacokinetic studies were performed during course one (day 1 through 28).

RESULTS

Of the 25 enrolled patients, 19 (median age, 15 years) were fully evaluable for toxicity and received 54 courses. Dose-limiting toxicity was rash in two patients treated with 500 mg/m2 and elevated ALT and AST in one patient treated with 400 mg/m2. The maximum-tolerated dose was 400 mg/m2/d. The most frequent non-dose-limiting toxicities were grade 1 or 2 dry skin, anemia, diarrhea, nausea, and vomiting. One patient with Ewing's sarcoma had a partial response. Disease stabilized for 8 to > or = 60 weeks in two patients with Wilms' tumor and two with brainstem glioma (one exophytic). At 400 mg/m2, the median peak gefitinib plasma concentration was 2.2 microg/mL (range, 1.2 to 3.6 microg/mL) and occurred at a median of 2.3 hours (range, 2.0 to 8.3 hours) after drug administration. The median apparent clearance and median half-life were 14.8 L/h/m2 (range, 3.8 to 24.8 L/h/m2) and 11.7 hours (range, 5.6 to 22.8 hours), respectively. Gefitinib systemic exposures were comparable with those associated with antitumor activity in adults.

CONCLUSION

Oral gefitinib is well tolerated in children. Development of the drug in combination with cytotoxic chemotherapy will be pursued.

Treatment strategy for patients with colorectal cancer and synchronous irresectable liver metastases

BACKGROUND

The aim of this case-matched study was to determine the best treatment strategy for patients with asymptomatic colorectal cancer and irresectable synchronous liver metastases.

METHODS

Between 1997 and 2002, 27 patients with asymptomatic colorectal cancer and irresectable synchronous liver metastases were treated by chemotherapy without initial primary resection (chemotherapy group). These 27 patients were compared with 32 patients matched for age, sex, performance status, primary tumour location, number of liver metastases, nature of irresectable disease and type of chemotherapy, but who were treated initially by resection of primary tumour (resection group).

RESULTS

The 2-year actuarial survival rate was 41 per cent in the chemotherapy group and 44 per cent in the resection group (P = 0.753). In the latter group, the mortality and morbidity rates for primary resection were 0 and 19 per cent (six of 32 patients) respectively. In the chemotherapy group, intestinal obstruction related to the primary tumour occurred in four of 27 patients. The mean overall hospital stay was 11 days in the chemotherapy group and 22 days in the resection group (P = 0.003).

CONCLUSION

Systemic chemotherapy without resection of the bowel cancer is the option of choice because, for most patients, it is associated with a shorter hospital stay and avoids surgery without a detrimental effect on survival.

Preclinical Evaluation of ZD1839 Alone or in Combination with Oxaliplatin in a Panel of Human Tumor Cell Lines – Implications for Clinical Use

BACKGROUND

Preclinical studies have suggested antitumor activity of an epidermal growth factor (EGF)-receptor targeted therapy with selective tyrosine kinase inhibitors alone or in combination with conventional cytostatic drugs. However, in non-small cell lung cancer (NSCLC), addition of ZD1839 (Iressa) to combination chemotherapy did not improve the therapeutic outcome. Thus, further work is necessary to define factors predicting outcome of combination therapy.

MATERIALS AND METHODS

In the present study, the activity of ZD1839 alone or in combination with oxaliplatin (Eloxatin) was evaluated in 12 human cancer cell lines including colon, testicular, anaplastic thyroid and epidermoid carcinoma cells.

RESULTS

The EGF-receptor protein was overexpressed in line A431 (epidermoid carcinoma) and near the minimum detection limit in all other cell lines. The single agent activity of ZD1839 was highest in cell line A431. In the other cell lines, it was lower and appeared to be independent of EGF-receptor expression levels. The relative antitumor activity (RAA) was low (RAA = 1). Combined exposure to oxaliplatin and ZD1839 (IC30) resulted in significant synergy in 4 out of 6 colorectal cancer (CRC) cell lines and significant antagonism in 4 out of 6 non-colorectal cancer cell lines. Continuous exposure to ZD1839 (IC30) induced a marked G1-phase arrest and dephosphorylation of EGF-receptor in A431, whereas no significant cell cycle perturbation could be detected in the low-expression cell lines. Other factors than cell cycle perturbation seem to determine the mode of drug interaction between oxaliplatin and ZD1839.

CONCLUSION

Based on RAA, the single agent activity of ZD1839 in the investigated cell line panel appeared to be low. Combined exposure to ZD1839 and oxaliplatin exerted synergy in colorectal cancer cell lines, warranting further evaluation in this type of cancer. However, based on the observed antagonism in non-colorectal cancer cell lines, combined treatment with ZD1839 and oxaliplatin is not recommended for other types of cancer. Further research is necessary to identify factors which determine the nature of drug interaction in different tumor types including CRC and lung cancer.

New drugs in cancer therapy, National Tumor Institute, Naples, 17-18 June 2004

An international meeting on 'New Drugs in Cancer Therapy' was held at the National Tumor Institute of Naples, on 17-18 June 2004. The first session of the meeting focused on analogs of conventional anti-cancer drugs, such as taxanes, platinum compounds, anthracyclines and topoisomerase I inhibitors. The data of a phase II trial of BMS-247550, an epothilone B analog, in patients with renal cell carcinoma were reported. Data were also presented on BBR-3464, a trinucleate platinum analog which was developed on the grounds of greater potency, a more rapid rate of DNA binding and the ability to induce apoptosis regardless of the p53 status of the cell. Pegylated-coated liposomal formulation doxorubicin (Caelyx) has shown efficacy in metastatic breast cancer and in advanced ovarian cancer; sabarubicin is a third-generation anthracycline with equal or superior potency to doxorubicin or idarubicin in a variety of human tumor cell lines of different histotypes. The main mechanisms of resistance to topoisomerase I inhibitors were discussed; data on diflomotecan were reported, showing a narrow therapeutic index of the drug. The second session of the meeting focused on the ErbB family as a target for anti-cancer therapy. Recent evidence of a correlation between epidermal growth factor receptor (EGFR) mutations at exons 18-21 and clinical response of advanced non-small cell lung cancer to gefitinib therapy was commented on. The issue of the association between ErbB2 expression and gefitinib activity was addressed, while clinical data of a phase II study of gefitinib in advanced breast cancer were presented. Monoclonal antibodies targeting EGFR represent another worthwhile way to interfere with EGFR-driven signal transduction. Cetuximab is reaching market registration in advanced colorectal cancer; in particular, due to the results of the BOND study. The recently presented results of the Bonner study strongly support the activity of this drug in head and neck cancer. A step forward in the research on anti-EGFR monoclonal antibodies may be represented by humanized monoclonal antibodies, such as EMD 72000 and ABX-EGF. Imatinib mesylate is probably the most outstanding example of an effective targeted therapy--its activity in gastrointestinal stromal tumors was so exciting that the drug reached the market without undergoing phase III evaluation. The third session of the meeting was on angiogenesis inhibitors. Drugs may interfere with the angiogenic process via different mechanisms and there is a sound rationale for combining anti-angiogenic agents with chemotherapy or multiple anti-angiogenic strategies. Clinical results obtained with direct anti-angiogenic agents have been negative up to now, but some exciting results have been seen with bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor (VEGF). A few VEGF-tyrosine kinase inhibiting small molecules, such as ZD6474, AZD2171 and PTK/ZK, are undergoing clinical trials. The fourth session of the meeting was on interference with intracellular signal transduction. Farnesyl transferase inhibitors exert their action by interfering with either pro-Ras or RhoB farnesylation. Several clinical studies of different phases with compounds belonging to this class have been carried out, either alone or in combination with chemotherapy; unfortunately, all of them have turned out to be negative. Cell cycle inhibitors, such as CYC-202 and BMS-387032, represent a class of interesting compounds which are in the early phase of development and whose clinical results are eagerly awaited. Another strategy to achieve cell cycle inhibition is to target heat shock protein 90, a molecular chaperone required for protein folding. Clinical data on depsipeptide, a histone deacetylase (HDAC) inhibitor with activity in T cell lymphoma, were presented. Suberoylanilide hydroxamic acid is another small molecular weight inhibitor of HDAC activity. Phase I/II clinical trials have shown low toxicity and evidence of anti-tumor activity; on the other hand, this compound has potential for synergism with radiotherapy, chemotherapy and biologicals.

Human antibodies from transgenic animals

Laboratory mice provide a ready source of diverse, high-affinity and high-specificity monoclonal antibodies (mAbs). However, development of rodent antibodies as therapeutic agents has been impaired by the inherent immunogenicity of these molecules. One technology that has been explored to generate low immunogenicity mAbs for in vivo therapy involves the use of transgenic mice expressing repertoires of human antibody gene sequences. This technology has now been exploited by over a dozen different pharmaceutical and biotechnology companies toward developing new therapeutic mAbs, and currently at least 33 different drugs in clinical testing--including several in pivotal trials--contain variable regions encoded by human sequences from transgenic mice. The emerging data from these trials provide an early glimpse of the safety and efficacy issues for these molecules. Nevertheless, actual product approval, the biggest challenge so far, is required to fully validate this technology as a drug discovery tool. In the future, it may be possible to extend this technology beyond rodents and use transgenic farm animals to directly generate and produce human sequence polyclonal sera.

Have we made progress in pharmacogenomics? The implementation of molecular markers in colon cancer

For the last 40 years, 5-fluorouracil (5-FU) has remained the treatment of choice in both the adjuvant and advanced treatment of colorectal cancer (CRC). However, 5-FU monotherapy produces response rates of only 10–20% in the advanced setting. 5-FU has been combined with newer agents, such as oxaliplatin and irinotecan, and this has significantly increased response rates to 40–50% in the advanced setting. More recently, novel biological agents, such as the monoclonal antibodies targeting either the epidermal growth factor receptor or vascular endothelial growth factor, have shown to provide additional clinical benefit for patients with metastatic CRC. A number of predictive markers have been identified for CRC to date. However, their usefulness as individual markers of response has led to somewhat inconclusive results. Therefore, there is a need to identify panels of predictive markers of response to therapy for advanced CRC, in order to improve these disappointing response rates. The advent of high-throughput methodologies, such as microarrays, enables tumor samples to be profiled on a global scale. This technology has been utilized to develop predictive markers for a wide range of tumor types to date, and hopefully this technology can be translated into the CRC setting with the hope of predicting the response of each individual tumor to chemotherapy.

Interferon-alpha promotes the anti-proliferative effect of gefitinib (ZD 1839) on human colon cancer cell lines

OBJECTIVE

Interferon-alpha (IFN alpha) treatment is associated with up-regulation of epidermal growth factor receptor (HER 1/EGFR) expression and marked growth inhibition of colon cancer cell lines in vitro. We aimed to determine the effect of combining IFN alpha and gefitinib on colon cancer cell line growth.

METHODS

A panel of nine colon cancer cell lines were characterised for expression of HER 1/EGFR and then treated with gefitinib alone, or IFN alpha alone, or IFN alpha plus gefitinib, following a pre-treatment using vehicle or IFN alpha. Crystal violet staining and flow cytometry were used to assess cell proliferation and expression of HER 1/EGFR. The indexes and statistical assays were used to evaluate significant differences between treatment groups against vehicle control.

RESULTS

All cell lines except SW 620 were HER 1/EGFR positive. IFN alpha treatment was associated with significant up-regulation of cell surface HER 1/EGFR expression in all HER 1/EGFR-positive cell lines except KM 12 SM. Concurrent treatment with IFN alpha and gefitinib, or IFN alpha pre-treatment followed by gefitinib, or IFN alpha pre-treatment followed by a combination of IFN alpha plus gefitinib, additively or supra-additively/synergistically enhanced the sensitivity of the seven HER 1/EGFR-up-regulated cell lines.

CONCLUSION

IFN alpha improves the anti-proliferative effect of EGFR inhibition in colorectal cancer cell lines. This approach may have clinical implications for improving treatment based on targeting of HER 1/EGFR.

Monoclonal antibodies targeting epidermal growth factor receptor and vascular endothelial growth factor with a focus on head and neck tumors

PURPOSE OF REVIEW

To provide an overview of recent clinical trials with monoclonal antibodies targeting epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) in head and neck cancer (HNC) and in other tumors. To discuss future therapeutic strategies.

RECENT FINDINGS

Cetuximab, a chimeric monoclonal antibody targeting EGFR, has induced improved locoregional control and survival in combination with radiotherapy in a phase III study in locally advanced inoperable HNC. The recent Bowel Oncology with Cetuximab Antibody (BOND) study has shown that the combination of irinotecan and cetuximab yields a better response rate and a longer time to progression with respect to cetuximab monotherapy in irinotecan-refractory metastatic colorectal cancer, pointing to both a cetuximab single-agent activity and a cetuximab potential for reversal of irinotecan resistance. Non-small cell lung cancer and pancreatic cancer represent further areas for cetuximab development. Bevacizumab is a humanized monoclonal antibody that targets VEGF. It is the first antiangiogenic drug to have induced a survival advantage in cancer therapy, within a randomized trial of irinotecan, 5-fluorouracil, leucovorin (IFL) combined with bevacizumab or placebo in metastatic colorectal cancer. The use of bevacizumab in HNC is supported by preclinical evidence of an angiogenic loop; a few clinical trials are exploring the feasibility and the therapeutic potential of a combination of bevacizumab and EGFR-targeted drugs.

SUMMARY

Monoclonal antibodies targeting EGFR and VEGF represent exciting therapeutic strategies that should be further evaluated both in combination with drugs acting on the same target at a different level and in combination with other antisignaling agents acting on different pathways.

Adjuvant regional chemotherapy and systemic chemotherapy versus systemic chemotherapy alone in patients with stage II-III colorectal cancer: a multicentre randomised controlled phase III trial

BACKGROUND

Systemic adjuvant chemotherapy can improve overall survival and reduce the incidence of distant metastases for patients with advanced colon cancer. This study aimed to investigate whether regional chemotherapy (given by intraperitoneal or intraportal methods) combined with systemic chemotherapy was more effective than was systemic chemotherapy alone in terms of survival and recurrence for patients with stage II-III colorectal cancer. The study also compared systemic chemotherapy with fluorouracil and folinic acid with that of fluorouracil and levamisole.

METHODS

During surgery, 753 patients with stage II-III colorectal cancer were randomly assigned to systemic chemotherapy alone (379 with fluorouracil and folinic acid, and 374 with fluorouracil and levamisole), and 748 to postoperative regional chemotherapy with fluorouracil followed by systemic chemotherapy with fluorouracil and folinic acid (n=368) or with fluorouracil and levamisole (n=380). Regional chemotherapy was given intraperitoneally (n=415) or intraportally (n=235) according to institution. The primary endpoint was 5-year overall survival. Secondary endpoints were 5-year disease-free survival and toxic effects. Analyses were by intention to treat.

FINDINGS

Median follow-up was 6.8 years (range 0.0-10.1). 5-year overall survival was 72.3% (95% CI 69.0-75.6) for patients assigned regional and systemic chemotherapy, compared with 72.0% (68.7-75.3) for those assigned systemic chemotherapy alone (hazard ratio [HR] 0.97 [0.81-1.15], p=0.69). 5-year overall survival for all patients assigned fluorouracil and levamisole was 72.0% (68.7-75.2) compared with 72.3% (69.0-75.6) for all those assigned fluorouracil and folinic acid (HR 0.98 [0.82-1.17], p=0.81). The hazard ratios for 5-year disease-free survival were 0.94 (0.80-1.10) for regional versus non-regional treatment, and 0.92 (0.79-1.08) for all fluorouracil and levamisole versus fluorouracil and folinic acid. Grade 3-4 toxic effects were low in all groups.

INTERPRETATION

Fluorouracil-based regional chemotherapy adds no further benefit to that obtained with systemic chemotherapy alone in patients with advanced colorectal cancer.

Cutaneous side-effects of kinase inhibitors and blocking antibodies

Although kinase inhibitors raise hope for people with cancer, patients and their clinicians are commonly confronted with the cutaneous side-effects that are associated with the use of these drugs. This review is the result of collaborations between dermatologists, medical oncologists, and pathologists, and discusses the cutaneous side-effects seen after treatment with the inhibitors of epidermal-growth-factor receptor (EGFR), imatinib, sorafenib, and sunitinib. Some of the side-effects caused by these agents are very distressing, partly because they are chronic owing to the long duration of treatment. Therefore, patients need early and appropriate dermatological management. Moreover, several studies have reported a link between the antitumour efficacy of EGFR inhibitors and cutaneous side-effects. Elucidation of this connection could lead to the identification of crucial predictive factors for tumour response.

Cetuximab therapy and symptomatic hypomagnesemia

We report that patients treated with cetuximab, a monoclonal antibody against the epithelial growth factor receptor (EGFR), occasionally develop a magnesium wasting syndrome with inappropriate urinary excretion. We first observed this phenomenon in a 34-year-old male patient with metastatic colorectal cancer who developed profound fatigue and symptomatic hypocalcemia and hypomagnesemia while on cetuximab plus irinotecan therapy. Other medications with the potential to cause magnesium wasting had not been administered. Intravenous magnesium supplementation was required for the duration of cetuximab therapy, but electrolyte abnormalities resolved after discontinuation of treatment. This case prompted review of serum chemistry reports for a consecutive case series of 154 colorectal cancer patients treated with cetuximab. Thirty-four patients (22%) had at least one serum magnesium measurement during cetuximab treatment, and six had grade 3 (< 0.9 mg/dL) and two had grade 4 (< 0.7 mg/dL) hypomagnesemia. Because EGFR is strongly expressed in the kidney, particularly in the ascending limb of the loop of Henle where 70% of filtered magnesium is reabsorbed, EGFR blockade may interfere with magnesium transport. Because symptoms may be rapidly ameliorated with supplementation, we suggest that, when fatigue or hypocalcemia is encountered during cetuximab therapy, serum magnesium level be measured and repleted as necessary.

Cyclophosphamide Inhibition of Anti-CD40 Monoclonal Antibody–Based Therapy of B Cell Lymphoma Is Dependent on CD11b+ Cells

Monoclonal antibody (mAb)-based immunotherapy is now established as an important option for treating some cancers. The antitumor effects may be further enhanced by combining mAb with conventional chemotherapy. Certain novel immunomodulatory mAbs such as anti-CD40 have shown significant activity in preclinical models. We therefore assessed the efficacy of combining anti-CD40 mAb, known to elicit CTL responses against murine lymphoma models with the commonly used cytotoxic drug, cyclophosphamide. Using the syngeneic tumor model, BCL1, we have shown that timing of cyclophosphamide relative to mAb is critical to therapeutic outcome. Pretreatment with cyclophosphamide 7 to 10 days prior to mAb results in markedly reduced survival levels, similar to that achieved with cyclophosphamide alone. Conversely, when anti-CD40 is given before cyclophosphamide, the level of tumor protection was moderately increased. In vivo tracking experiments reveal that pretreatment with cyclophosphamide leads to diminished CTL expansion, as well as an increased number of CD11b+ cells that display an activated phenotype. These latter cells are able to inhibit T-cell proliferation, at least in part via production of nitric oxide, but do not induce T-cell apoptosis. Furthermore, adoptive transfer of the induced CD11b+ cells is sufficient to inhibit anti-CD40 therapy in tumor-bearing recipients. We have shown that the timing of cyclophosphamide relative to mAb administration is critical to the therapeutic outcome, and although the combination can improve survival, cyclophosphamide given prior to immunotherapy may generate a population of myeloid cells that can interfere with CTL responses and compromise the therapeutic outcome.

HER1/EGFR inhibitor-associated rash: future directions for management and investigation outcomes from the HER1/EGFR inhibitor rash management forum

Skin rash associated with HER1/epidermal growth factor receptor (EGFR) inhibitors is common. The lack of clinical and patient guidance for this often chronic and sometimes distressing side effect makes rash management and etiology investigation high priorities. To address this, oncologists and dermatologists with experience with HER1/EGFR inhibitors attended the HER1/EGFR Inhibitor Rash Management Forum. Recommendations include continued analysis of the correlation between rash and clinical outcome and improving the accuracy and reproducibility of terminology and grading systems. Because acne vulgaris has a unique pathology, and the pathology and etiology of rash are unclear yet distinct from acne vulgaris, using such terms as acne, acne-like, or acneiform should be avoided. Until there is a specific dermatological definition, rash is best described using phenotypic terms for its appearance and location. It is currently unknown which agents are best for treating rash. Clinical trials of rash treatments are urgently required, and suggestions for agents to consider are made based on current knowledge. The effect of dose reduction or interruption on rash should also be investigated. Secondarily infected rash may be more frequent than has been previously recognized, and some investigators favor empiric use of an oral antibiotic if this appears to be the case. Suggestions for patients include makeup to camouflage the rash and an emollient to prevent and alleviate skin dryness. The increasing use of HER1/EGFR-targeted agents makes managing rash important. We hope the outcomes from this Forum provide background for future studies.

Conventional surgery and systemic chemotherapy for peritoneal carcinomatosis of colorectal origin: a prospective study

AIMS

To report the results of standard therapy for peritoneal carcinomatosis of colorectal origin, which consists of conventional surgery and systemic chemotherapy.

METHOD

In a prospective study 50 patients with proven peritoneal carcinomatosis of colorectal origin were treated with conventional surgery combined with 5-fluorouracil and leucovorin, or irinotecan in patients treated by 5-fluorouracil within 12 months prior to entry. Survival and progression-free survival were studied and prognostic factors were analysed.

RESULTS

The median survival time was 12.6 months. The median time to progression was 7.6 months. Location of primary tumour and result of conventional surgery and systemic chemotherapy were prognostic factors related to survival.

CONCLUSION

The survival time of patients with peritoneal carcinomatosis of colorectal origin seems to be increased in patients treated by conventional surgery and systemic chemotherapy when compared to minimal treatment.

Benefit-risk assessment of irinotecan in advanced colorectal cancer

Irinotecan exerts its cytotoxic activity through inhibition of the nuclear enzyme topoisomerase I. It has been approved in most countries worldwide for treatment of patients with advanced colorectal cancer (CRC). Activity is seen in previously untreated patients and in patients refractory to fluorouracil treatment, whether it is given alone or in combination with other cytotoxic drugs. Irinotecan was first developed in patients refractory to fluorouracil. Activity in terms of tumour responses and patient benefit was seen in several phase II trials that used either a weekly or a three-weekly schedule. In two randomised trials (irinotecan vs best supportive care, and irinotecan vs an infused fluorouracil-based regimen), irinotecan prolonged median survival by approximately 2.5 months without any deterioration in quality-of-life. It was later studied in previously untreated patients with advanced CRC in combination with fluorouracil/folinic acid (leucovorin). In three large randomised trials, median time to tumour progression was prolonged by approximately 2.5 months and overall survival by about 2.5 months compared with fluorouracil/folinic acid alone. Tumour responses were also seen more frequently in the irinotecan arm (35-40% vs 20%). Again, quality-of-life scores were not deteriorated by the addition of irinotecan. Irinotecan has many acute adverse effects. The most prominent and dose limiting being diarrhoea and neutropenia. With irinotecan monotherapy, diarrhoea was seen in 80% of patients and severe grade 3 to 4 diarrhoea occurred in 30-40% of the patients. The severity of diarrhoea can be diminished by preventive actions. Less risk of diarrhoea is generally seen when irinotecan is combined with fluorouracil. Neutropenia is generally short-lived, but may be severe if diarrhoea is also present. This has been noticed particularly when irinotecan has been given in combination with a bolus fluorouracil/folinic acid regimen. Other toxicities include acute cholinergic-like symptoms, nausea and vomiting, and alopecia. In spite of these adverse effects, irinotecan has been accepted as an important first-line treatment for patients with advanced CRC, in combination with, preferably, an infused fluorouracil-based regimen, and has been approved for use as monotherapy in the second-line indication.

Novel therapeutics in colorectal cancer

Colorectal cancer is an excellent tumor model for evaluating novel therapeutic strategies. Development of a mechanistic understanding of how this cancer develops, spreads, and grows allows a tailored approach to all stages of treatment: prevention, adjuvant treatment, and therapy of advanced disease. We focus on therapy in the advanced disease setting, although progress in this area could lend itself to treatment of early or premalignant disease. In the last 20 years, information has been generated about the intracellular pathways of tumor formation, invasion, and metastasis. As a result, specific molecular processes have been targeted for therapeutic intervention, including cell surface growth factor receptors, proliferation signaling, cell cycling, apo-ptosis, angiogenesis, and matrix metalloproteinases. We review the scientific rationale for recently developed novel therapeutics in colorectal cancer, and the results of clinical trials to date. We also suggest appropriate clinical settings for specific targets and outline future directions of research.

FLT3 Antibody-Based Therapeutics for Leukemia Therapy

Antibodies represent a unique class of therapeutics because of their high specificity toward a defined target antigen. Recent clinical success with antibody-based cancer therapeutics has led to an upsurge in the development of these agents. Antibodies directed against FLT3 represent a promising approach for the treatment of human leukemia. We discuss some basic aspects of antibody-based cancer therapeutics, including their mechanisms of action, with a focus on recent progress in the generation and development of anti-FLT3 antibodies as well as their therapeutic potentials in the treatment of human hematologic malignancies.

Molekulare Zielstrukturen in der Onkologie

Substantial progress has been made in recent years in understanding the molecular pathogenesis of malignant disorders, especially in identification of molecular targets for therapeutic interventions ("targeted therapies"). An important group of therapeutical targets are signaling cascades, e.g. protein tyrosine kinases (PTK) that are activated by mutations, translocations or overexpression. Small molecule inhibitors that compete with ATP and inhibit kinase activity have produced clinical impressive responses in chronic myeloid leukemia, gastrointestinal stroma tumors and non-small cell lung cancer. Another group of cellular targets is represented by tumor-selective cell surface proteins that can serve as target structures for antibodies. Therapeutical concepts using monoclonal antibodies have substantially improved response rates in patients with malignant lymphomas and are currently evaluated in other types of cancer. The definition of molecular target structures critical for the malignant phenotype is driving a new era of integrated diagnostics and therapeutics in the field of oncology.

Molekulare Therapie in der Gastroenterologie und Hepatologie

During recent years, molecular techniques have significantly impacted our understanding and therapeutic concepts in gastrointestinal and liver disease. In a number of diseases, diagnostic work-up includes molecular data that supplements the phenotypical evaluation. This includes monogenic diseases as well as the identification of genetic risk factors (e. g. NOD2/CARD15 mutation in Crohn's disease) and viral disease. Attempts to replace liver transplantation in hereditary liver disease by targeted molecular interventions (e. g. via viral vectors) are still experimental, but the associated techniques have improved considerably. The molecular identification of therapeutic targets was followed by the development of specifically tailored therapeutics. These agents are mainly used in the treatment of chronic inflammatory bowel disease and gastrointestinal tumors.

Promises and pitfalls in the prediction of antiepidermal growth factor receptor activity

There is a constant examination of the features that may anticipate or predict the likelihood of the clinical benefit that a patient may experience from a given therapy. This is especially true in the case of novel targeted therapies, as proof-of-principle experimental or pilot analyses are increasingly being embedded into clinical protocols. An unprecedented number of significant developments in the field of epidermal growth factor receptor-targeted therapy have occurred in recent months. This is exemplified by the discovery of activating mutations in the catalytic domain of the epidermal growth factor receptor that increase sensitivity to antiepidermal growth factor receptor small-molecule inhibitors. This review discusses the recent advances and controversies of the different approaches to predict the efficacy of antiepidermal growth factor receptor agents and the effectiveness of the tools that we are using to evaluate and predict the efficacy of epidermal growth factor receptor-targeted drugs and their potential pitfalls.

The management of skin reactions in cancer patients receiving epidermal growth factor receptor targeted therapies. Behandlung der Hautreaktionen bei EGFR-spezifischer Tumortherapie (Epidermaler Wachstumsfaktor Rezeptor)

The use of epidermal growth factor receptor (EGFR) inhibitors for the treatment of solid tumours is increasing. However, the tolerability profile for EGFR-inhibitors, such as the monoclonal antibody cetuximab and the tyrosine kinase inhibitor erlotinib, is characterised by a unique group of skin reactions dominated by an acneiform eruption, xerosis, eczema and changes in the hair and nails. The possibility that this skin toxicity correlates with anti-tumour activity offers the potential to titrate dosing on a case-by-case basis. These skin effects may constitute a significant obstacle to treatment compliance. Accordingly, there is a need for consistent, multi-disciplinary management strategies that will allow patients to receive the recommended dosages of such targeted therapies. The eruption responds well to some acne therapies and xerosis can be controlled by standard emollients. Here we present an overview of the treatment options for skin reactions that are available today, and evaluate some of the ways in which the treatment of such EGFR-inhibitor-related skin reactions may be improved in the future. Evidence-based studies are needed to determine the best way to manage these effects.

Somatic mutations of epidermal growth factor receptor in colorectal carcinoma

PURPOSE

Somatic mutations of the epidermal growth factor receptor (EGFR) gene may predict the sensitivity of non-small cell lung carcinoma to gefitinib. However, no mutations have been reported for colorectal carcinoma. We therefore analyzed EGFR mutations in colorectal adenocarcinomas by the combined use of laser microdissection and sequencing of genomic DNA.

EXPERIMENTAL DESIGN

We examined 11 representative colorectal adenocarcinoma cell lines and 33 clinical samples of colorectal carcinoma. In the clinical cases, we carefully dissected only carcinoma cells from frozen sections by laser microdissection. After DNA extraction and PCR, we examined EGFR mutations by sequencing genomic DNA.

RESULTS

None of 11 colorectal carcinoma cell lines exhibited somatic mutations, but 4 of 33 clinical tumors (12%) exhibited mutations in the EGFR kinase domain. This may be the first report of somatic mutations in colorectal adenocarcinoma.

CONCLUSIONS

Our findings suggest that a distinct minority of colorectal adenocarcinomas exhibit somatic mutations of EGFR, and these tumors may be susceptible to gefitinib treatment.

Critical evaluation of current treatments in metastatic colorectal cancer

Fluorouracil (FU) has been the mainstay of treatment for metastatic colorectal cancer (mCRC) for many years. However, in recent years, newer chemotherapeutic agents, particularly irinotecan (Campostar; Pfizer Pharmaceuticals, New York, NY, http://www.pfizer.com) and more recently oxaliplatin (Eloxatin; Sanofi-Aventis Inc., New York, NY, http://www.sanofi-aventis.com), have been shown to improve survival in combination with FU-based therapies. These agents were therefore incorporated into first- and second-line treatment strategies. The development of targeted agents that are tumor specific with better toxicity profiles than chemotherapeutic agents has widened the spectrum of therapies for this disease. The U.S. Food and Drug Administration (FDA) recently approved two targeted agents for treating mCRC: an antivascular endothelial growth factor monoclonal antibody (mAb), bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA, http://www.gene.com), in combination with first-line 5-FU-based chemotherapy regimens and the human epidermal growth factor receptor (HER-1/EGFR)-targeted mAb cetuximab (Erbitux; ImClone Systems, Inc., New York, NY, http://www.imclone.com) as monotherapy or in combination with irinotecan as second-line therapy in refractory cancer. These newer, more effective agents are improving clinical outcome for patients with mCRC. However, as the number of agents has increased, choosing the most effective treatment strategy has become increasingly complex. This review discusses the role of the individual agents in the treatment of mCRC and identifies the most effective regimens.

Phase I study of gefitinib, oxaliplatin, 5-fluorouracil, and leucovorin (IFOX) in patients with advanced solid malignancies

PURPOSE

Aphase 1 study of gefitinib in combination with oxaliplatin, 5-fluorouracil and leucovorin (IFOX)was conducted to evaluate the safety and feasibility of this regimen.

PATIENTS AND METHODS

Patients with advanced solid malignancies were treated with escalating doses of gefitinib (250 mg or 500 mg once daily) in combination with FOLFOX (oxaliplatin, 5-fluorouracil, and leucovorin). The initial dose of oxaliplatin was 70 mg/m2 with sequential dose escalation to 85 mg/m2.

RESULTS

Sixteen patients received a total of 138 14-day courses of daily gefitinib in combination with FOLFOX. Escalation of gefitinib from 250 mg/d to 500 mg/d with FOLFOX was well-tolerated. In addition, no severe toxicities precluded subsequent dose escalation of oxaliplatin from 70 mg/m2 to 85 mg/m2 at which no dose-limiting toxicity was seen. No further dose escalation was performed as this represented the oxaliplatin dose administered in the standard FOLFOX-4 regimen. The most predominant toxicity was diarrhea, which was well controlled with oral antidiarrheal agents. Four partial remissions occurred in patients with metastatic colorectal cancer.

CONCLUSIONS

Gefitinib as a 500 mg daily continuous dose was well tolerated in combination with full doses of FOLFOX-4.

Oxaliplatin, folinic acid and 5-fluorouracil (FOLFOX-4) combination chemotherapy as second-line treatment in advanced colorectal cancer patients with irinotecan failure: a Korean single-center experience

OBJECTIVE

This study was designed to determine the effectiveness and tolerance of oxaliplatin, folinic acid (FA) and infusional 5-fluorouracil (5-FU) (FOLFOX-4) chemotherapy when used as a second-line treatment in patients with advanced colorectal cancer for whom an irinotecan-containing regimen failed.

METHODS

Thirty-eight patients with measurable colorectal cancer, progressive after previous irinotecan-containing chemotherapy for metastatic disease, were registered in this trial. Oxaliplatin was administered on day 1 at the dose of 85 mg/m(2) as a 2 h infusion, concurrently with FA 200 mg/m(2)/day, followed by bolus 5-FU 400 mg/m(2) and a 22 h infusion of 5-FU 600 mg/m(2) for two consecutive days. The treatment was repeated every 2 weeks until disease progression or unacceptable toxicity occurred or until a patient chose to discontinue the treatment.

RESULTS

For 34 patients treated, a total of 183 chemotherapy cycles were administered. In an intent-to-treat analysis, six patients (16%) achieved a partial response that they maintained for 5.4 months. The median progression-free and overall survivals were 2 and 5 months, respectively. Frequently encountered toxicities were peripheral neuropathy and gastrointestinal side effects including diarrhea. Although there was one early death, toxicity profiles were generally predictable and manageable.

CONCLUSION

Second-line FOLFOX-4 is a feasible regimen with modest activity for colorectal cancer patients with irinotecan failure. Further clinical trials incorporating novel biological agents are warranted.

The antiepidermal growth factor receptor monoclonal antibody cetuximab/C225 reduces hypoxia-inducible factor-1 alpha, leading to transcriptional inhibition of vascular endothelial growth factor expression

We have previously shown that the antiepidermal growth factor receptor monoclonal antibody cetuximab (C225; Erbitux), which was recently approved for the treatment of metastatic colorectal cancer, has antiangiogenic properties, inhibiting vascular endothelial growth factor (VEGF) secretion in culture and in animal models. Here, we have furthered the study by demonstrating that cetuximab reduces cellular levels of hypoxia-inducible factor-1 alpha (HIF-1alpha), a transcriptional regulator of VEGF expression, in A431 epidermoid carcinoma cells under both normoxic and hypoxic culture conditions. Expression of a constitutively active Ras in A431 cells rendered cellular resistance to the cetuximab-mediated reduction of the HIF-1alpha level. Cell lines with naturally occurring phosphatase and tensin homologue deleted on chromosome 10 mutations or deletions were also resistant to cetuximab-mediated reduction of the HIF-1alpha level. Pharmacologic inhibition of phosphatidylinositol 3-kinase with LY294002 reduced the HIF-1alpha level in both normoxic and hypoxic A431 cells, whereas inhibition of the mitogen-activated protein kinase kinase by PD98059 reduced the level of HIF-1alpha only in normoxic A431 cells. In addition, cetuximab reduced the cellular level of HIF-1alpha in the presence of a proteasome inhibitor, lactacystin, indicating that cetuximab acts mainly at the level of protein synthesis. The reduction of HIF-1alpha in response to cetuximab treatment was accompanied by transcriptional inhibition of VEGF expression, measured by a luciferase assay in A431 cells transfected with a vector containing the VEGF hypoxia response element. Taken together, our results indicate that the previously demonstrated inhibition of VEGF by cetuximab occurs at the level of transcription in response to a reduced level of HIF-1alpha and justify further testing of therapeutic strategies that combine cetuximab with approaches inhibiting the function of VEGF or the VEGF receptor.

Cetuximab in previously treated colorectal cancer

Within the past decade, there have been considerable advances in the first- and second-line treatment of colorectal cancer (CRC). For many years, 5-fluorouracil was the only therapeutic option for the first-line treatment of CRC, and virtually no effective salvage therapies were available. However, the advent of oxaliplatin and irinotecan has improved outcomes for advanced CRC, providing increased therapeutic choice in the first-line setting and effective salvage therapies. Many patients are now receiving multiple lines of therapy, and it is in the setting of previously treated CRC that cetuximab, a monoclonal antibody to the epidermal growth factor receptor, has been successfully developed based on sound scientific principles. The ability to integrate new biologic therapies with conventional cytotoxic agents marks a new treatment era for this disease. This review discusses the development of cetuximab in pretreated CRC to date and future directions with this novel therapy.

Clinical signs, pathophysiology and management of skin toxicity during therapy with epidermal growth factor receptor inhibitors

The last few years, new therapies targeting the epidermal growth factor receptor (EGFR) have shown their efficacy in the treatment of several types of cancer. Monoclonal antibodies against the EGFR (e.g. cetuximab, panitumumab) or EGFR tyrosine kinase inhibitors (e.g. gefitinib, erlotinib) are generally well tolerated and do not have the severe systemic side-effects usually seen with cytotoxic drugs. A considerable number of patients treated with these EGFR inhibitors, however, develop dermatological side-effects, most frequently an acneiform eruption but also xerosis, eczema, fissures, telangiectasia, hyperpigmentation, hair changes and paronychia with pyogenic granuloma. These skin effects appear to be mechanism-based linked to the inhibition of EGFR action but the exact pathophysiology remains elusive. Left untreated these dermatological side-effects could represent a threat to patient compliance. Therefore effective management is mandatory. Mild cases of acneiform eruption respond well to topical anti-inflammatory acne therapy, whereas tetracyclines are needed to treat moderate to severe cases. This review outlines the broad spectrum of cutaneous side-effects of EGFR inhibitors, discusses possible underlying mechanisms and provides practical guidelines for the management based on literature data and on personal experience.

Epidermal growth factor receptor signaling in colorectal cancer: preclinical data and therapeutic perspectives

Epidermal growth factor receptor (EGFR) belongs to a family of receptors known as the ErbB family (ErbB tyrosine kinase receptors) which comprises four proteins encoded by the c-erbB proto-oncogene. EGFR is known to activate a cascade of multiple signaling pathways that facilitate tumor growth process. EGFR has been shown to be overexpressed in colorectal cancer patient populations but its prognostic value in colorectal cancer progression remains unclear. The development of a panel of EGFR inhibitors could reduce the proliferation of tumor cells when used alone or in combination with cytotoxic drugs or radiation. This review focuses on the potential role of EGFR signaling in the survival of colorectal tumor cells and the possible modulation of such signaling pathways by EGFR inhibitors so as to increase tumor control or render tumor cells more sensitive to conventional therapy.

Role of novel targeted therapies in the clinic

The number and variety of novel, molecular-targeted agents offers realistic hope for significant advances in cancer treatment. The potential of these new treatment approaches is unquestionable, but the reality is something that only thorough clinical evaluation and experience can reveal. Clinical experience of targeted therapies is at an early stage but it is likely that we will have an increasing number of treatment options available to us in the near future. This manuscript explores our current understanding of molecular-targeted therapies and considers: What approach should be used? (single vs multitarget agents); When should they be administered? (identifying the optimal point for intervention); How should they be used? (monotherapy or combination therapy regimens); and Who should we be giving them to? (acknowledging the need for patient selection).

Phase II multicenter study of the antiepidermal growth factor receptor monoclonal antibody cetuximab in combination with platinum-based chemotherapy in patients with platinum-refractory metastatic and/or recurrent squamous cell carcinoma of the head and neck

PURPOSE

To evaluate the efficacy and safety of the antiepidermal growth factor receptor monoclonal antibody cetuximab in combination with platinum-based chemotherapy in patients with platinum-refractory recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Ninety-six eligible patients received cetuximab (initial dose of 400 mg/m2 followed by subsequent weekly doses of 250 mg/m2) followed by platinum chemotherapy at the same dose and schedule at which progressive disease was documented before entry onto the study.

RESULTS

The response rate, based on an independently read assessment, in the intent-to-treat population was 10%, with a disease control rate (complete response, partial response [PR], and stable disease) of 53%. The median time to progression and overall survival were 85 and 183 days, respectively; both were longest in patients achieving a PR (median, 203.5 and 294 days, respectively). Treatment was well tolerated. The most common cetuximab-related adverse events were skin reactions, particularly an acne-like rash.

CONCLUSION

The combination of cetuximab and platinum chemotherapy is an active and well-tolerated approach to the treatment of this poor-prognosis patient population with platinum-refractory recurrent or metastatic SCCHN for whom there are no recommended standard therapeutic options.

Systemic Therapy for Metastatic Colorectal Cancer: Current Options, Current Evidence

Combination chemotherapy regimens including irinotecan and oxaliplatin markedly improve response rate and prolong median survival over fluorouracil with leucovorin (FU/LV), and have supplanted FU/LV as the standard systemic approach for metastatic colorectal cancer. The recent availability of five active chemotherapeutic agents has doubled the median overall survival for metastatic colorectal cancer from 10 to 20 months, and though the optimal strategy for incorporation of all drugs is still unclear, current data support the use of chemotherapy doublets in first-line rather than sequential single-agent therapy. Multidrug regimens increase both response rate and the proportion of patients able to undergo potentially curative resection. In addition, as many as 20% to 30% of patients never receive second-line chemotherapy. When used as single agents, bolus and infusional FU/LV and capecitabine are similarly effective but have differing toxicity. Chemotherapy combinations that incorporate infusion of FU are less toxic and more effective than those using bolus FU dosing. Capecitabine is under study as an alternative dosing method for use in combination regimens; however, the optimal dose has not been defined and final safety and efficacy outcomes are being addressed in ongoing phase II and III investigations. Three combinations have shown excellent first-line efficacy in phase III trials—IFL with bevacizumab, FOLFOX, and FOLFIRI—but neither of these combinations is clearly superior. Sound clinical judgment must continue to guide treatment decisions while we await data regarding the optimal combination and sequence of fluorouracil, irinotecan, oxaliplatin, bevacizumab, and cetuximab.

Targeting signal transduction pathways in colorectal cancer--more than skin deep

Colorectal cancer is the second leading cause of cancer death in the United States. The nihilism that previously often characterized the treatment of patients with this disease has been replaced by a measure of excitement, given recent therapeutic advances. These advances have been stimulated in part through identification of cellular processes characteristic of colorectal cancers that permit therapeutic targeting with favorable therapeutic index. Inhibition of the epidermal growth factor receptor in the clinic has provided proof of principle that interruption of signal transduction cascades in patients with colorectal cancer has therapeutic potential. This experience has also taught us that resistance to such rationally developed targeted therapeutic strategies is common. In this article, we review the role of signal transduction in colorectal cancer, introduce promising molecular targets, and outline therapeutic approaches under development. We will describe the barriers to success, and highlight paradigms to facilitate rapid and successful evaluation of new agents, in a clinical context that has (by virtue of recent clinical successes) become a somewhat crowded playing field.

Colorectal cancer and antiangiogenic therapy: What can be expected in clinical practice?

Angiogenesis is a strongly regulated process, which is dependent upon a complex interplay between inhibitory and stimulatory angiogenic factors. It is essential for tumor growth and metastasis: increased angiogenesis is correlated with poor prognosis in cancer patients. Many novel compounds that potently inhibit formation of neoplastic blood vessels have been recently developed. Major categories of angiogenesis antagonists include protease inhibitors, direct inhibitors of endothelial cell proliferation and migration, angiogenic growth factor suppressors, inhibitors of endothelial-specific integrin/survival signalling, copper chelators, and inhibitors with other specific mechanisms. There is increasing interest in developing angio-suppressive agents for colorectal cancer treatment. Some 20 direct and indirect antiangiogenesis drugs are currently being evaluated in clinical trials in colorectal cancer (CRC). Promising results have been reported. These include an increase in overall survival and reduction in the risk of death (Bevacizumab), reversal of cellular resistance (Cetuximab) and activity as second-line therapy in patients who have exhausted other available treatment options (Cetuximab, ABX-EGF, PTK-787, Gefitinib, Erlotinib). This review will outline the mechanisms of action of the principal antiangiogenic drugs, summarize the available data on the use of these new drugs in colorectal cancer, discuss their impact in clinical practice and offer a glimpse into how antiangiogenetic therapy will be integrated into the future care of patients with gastrointestinal cancers.

Assessing epidermal growth factor receptor expression in tumours: What is the value of current test methods?

Over-expression of the epidermal growth factor receptor (EGFR) in tumours is associated with aggressive disease and poor clinical prognosis. In theory, the EGFR status of a tumour provides an indication of the likelihood of response to EGFR-targeted therapy. However, the clinical data do not support a relationship between EGFR expression and response to EGFR-targeted therapies cetuximab, gefitinib and erlotinib. Recently, patients who appear to lack EGFR expression have been shown to respond to cetuximab. Possible causes for this paradox include false negative results due to a lack of sensitivity in the detection system, heterogeneity of EGFR expression within the tumour and specific mutations that mediate response to the tyrosine kinase inhibitors. Immunohistochemistry is the most reliable assay for EGFR expression but its interpretation is confounded by the lack of non-standard techniques. Other approaches for measuring EGFR expression can be considered at best exploratory at this point. Further work is needed to identify how EGFR contributes to carcinogenic and metastatic processes. As tumours that appear to be EGFR negative can respond to cetuximab, there is some doubt as to the usefulness of immunohistochemistry as a screen to select patients for treatment. Histopathology will continue to be essential for unravelling the role of this enigmatic molecule and refining its status as a legitimate target in cancer therapy.

Chronic treatment of Ménétrier's disease with Erbitux: clinical efficacy and insight into pathophysiology

BACKGROUND & AIMS

Ménétrier's disease is a rare premalignant hypertrophic gastropathy characterized by large rugal folds, foveolar hyperplasia with glandular atrophy, hypochlorhydria, and hypoalbuminemia. Patients with severe disease often exhibit refractory nausea and vomiting and require gastrectomy. Evidence from both mice and human beings suggests a critical role for epidermal growth factor receptor (EGFR) signaling in the pathogenesis of this disease. We previously reported significant clinical and biochemical improvement of a single patient treated for 1 month with Erbitux, a monoclonal antibody that blocks ligand binding to EGFR.

METHODS/RESULTS

We describe 2 patients who were given longer-term treatment with Erbitux as an alternative to gastrectomy. The first patient presented with nausea, hypoalbuminemia, and peripheral edema that required total parenteral nutrition (TPN) and infusions of albumin. On institution of Erbitux, there was rapid improvement in nausea and vomiting and stabilization of serum albumin with discontinuation of TPN and albumin infusions. Serum albumin remained stable during a 1-year course of Erbitux without supplemental protein. Application before and after Erbitux of the radiopaque dye ruthenium red to biopsies of the gastric oxyntic gland mucosa demonstrated prompt and persistent closure of tight junctions by electron microscopy. The second patient presented with chronic gastric bleeding that required bimonthly blood transfusions. During a 4-month course of Erbitux, his hematocrit stabilized, and transfusion requirements were eliminated.

CONCLUSIONS

The present report demonstrates the efficacy of prolonged Erbitux therapy in patients with different presentations of severe Ménétrier's disease and also provides insight into the pathophysiology of the protein-losing gastropathy.