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

Prognostic value of Thymidylate Synthase, Epidermal Growth Factor Receptors and Vascular Endothelial Growth Factor in patients with stage III colon cancer

Purpose: We studied the prognostic value of thymidylate synthase (TS), Epidermal Growth Factor Receptors (EGFR) and Vascular Endothelial Growth Factor (VEGF) expression in primary colon cancer (CC). Patients and Methods : Those three markers were immunohistochemically assessed on tumor sections from 100 patients with CC Dukes C. All patients received the same adjuvant chemotherapy with FU/Leukovocin according to Mayo protocol. Considering the clinical course they were classified in two groups: bad in which all patients progressed and good in which neither progressed during the five year follow up period. Results: TS, EGFR and VEGF were an independent prognostic factor for time to progression (TTP) and overall survival (OS). Findings of at least two maximum expressed investigated markers, significantly increases the risk of progression which influences shorter five year survival, and the single maximum expression does not necessarily have to be a bad prognostic sign. Conclusion: Highest expression of TS, EGFR and VEGF carries prognostic significance with respect to TTP and OS for patients with Dukes C colon cancer.

Reg IV activates the epidermal growth factor receptor/Akt/AP-1 signaling pathway in colon adenocarcinomas

BACKGROUND & AIMS

Reg IV, a secreted protein and member of the Reg multigene family, is up-regulated in malignancies of the human gastrointestinal tract, including colorectal carcinoma (CRC). However, in vitro signal transduction pathway(s) utilized by Reg IV are not yet known.

METHODS

To determine the signaling pathway(s) responsive to Reg IV, we examined the effects of purified recombinant human Reg IV (rhR4) on HCT116 and HT29 colon adenocarcinoma cells.

RESULTS

Addition of rhR4 to cultures led to a dose-dependent increase in cell number similar to that observed after treatment with epidermal growth factor (EGF). In addition, rhR4 treatment resulted in rapid phosphorylation of EGF receptor at Tyr992 and Tyr1068 and Akt at Thr308 and Ser473. Using luciferase reporter gene assays, we demonstrated that Reg IV signaling through EGF receptor and Akt results in increased activator protein-1 (AP-1) transcription factor activity. Real-time reverse-transcription polymerase chain reaction and Western blot analyses revealed quantitative increases in c-Jun, JunB, JunD, and FosB expression associated with increased AP-1 activity. Electrophoretic mobility shift assay further revealed significant increases in AP-1 binding activity in rhR4-treated cells, with increased supershift in the presence of antibodies to JunB, JunD, and FosB. Furthermore, rhR4 treatments led to the increased expression of Bcl-2, Bcl-XL, survivin, and matrilysin, genes associated with a poor prognosis in advanced CRC.

CONCLUSIONS

Reg IV is a potent activator of the EGF receptor/Akt/AP-1 signaling pathway in CRC. Disruption of Reg signaling may have utility as a therapeutic intervention for human gastrointestinal adenocarcinomas.

Anthocyanidins modulate the activity of human DNA topoisomerases I and II and affect cellular DNA integrity

In the present study, we investigated the effect of anthocyanidins on human topoisomerases I and II and its relevance for DNA integrity within human cells. Anthocyanidins bearing vicinal hydroxy groups at the B-ring (delphinidin, DEL; cyanidin, CY) were found to potently inhibit the catalytic activity of human topoisomerases I and II, without discriminating between the IIalpha and the IIbeta isoforms. However, in contrast to topoisomerase poisons, DEL and CY did not stabilize the covalent DNA-topoisomerase intermediates (cleavable complex) of topoisomerase I or II. Using recombinant topoisomerase I, the presence of CY or DEL (> or = 1 microM) effectively prohibited the stabilization of the cleavable complex by the topoisomerase I poison camptothecin. We furthermore investigated whether the potential protective effect vs topoisomerase I poisons is reflected also on the cellular level, affecting the DNA damaging properties of camptothecin. Indeed, in HT29 cells, low micromolar concentrations of DEL (1-10 microM) significantly diminished the DNA strand breaking effect of camptothecin (100 microM). However, at concentrations > or = 50 microM, all anthocyanidins tested (delphinidin, cyanidin, malvidin, pelargonidin, and paeonidin), including those not interfering with topoisomerases, were found to induce DNA strand breaks in the comet assay. All of these analogues were able to compete with ethidium bromide for the intercalation into calf thymus DNA and to replace the minor groove binder Hoechst 33258. These data indicate substantial affinity to double-stranded DNA, which might contribute at least to the DNA strand breaking effect of anthocyanidins at higher concentrations (> or = 50 microM).

Maternal embryonic leucine zipper kinase/murine protein serine-threonine kinase 38 is a promising therapeutic target for multiple cancers

To identify genes that could serve as targets for novel cancer therapeutics, we used a bioinformatic analysis of microarray data comparing gene expression between normal and tumor-derived primary human tissues. From this approach, we have found that maternal embryonic leucine zipper kinase (Melk), a member of the AMP serine/threonine kinase family, exhibits multiple features consistent with the potential utility of this gene as an anticancer target. An oligonucleotide microarray analysis of multiple human tumor samples and cell lines suggests that Melk expression is frequently elevated in cancer relative to normal tissues, a pattern confirmed by quantitative reverse transcription-PCR and Western blotting of selected primary tumor samples. In situ hybridization localized Melk expression to malignant epithelial cells in 96%, 23%, and 13% of colorectal, lung, and ovarian tissue tumor samples, respectively. Expression of this gene is also elevated in spontaneous tumors derived from the ApcMin and Apc1638N murine models of intestinal tumorigenesis. To begin addressing whether Melk is relevant for tumorigenesis, RNA interference-mediated silencing within human and murine tumor cell lines was done. We show that Melk knockdown decreases proliferation and anchorage-independent growth in vitro as well as tumor growth in a xenograft model. Together, these results suggest that Melk may provide a growth advantage for neoplastic cells and, therefore, inactivation may be therapeutically beneficial.

Quantitative determination of nuclear and cytoplasmic epidermal growth factor receptor expression in oropharyngeal squamous cell cancer by using automated quantitative analysis

BACKGROUND

Several lines of evidence support the epidermal growth factor receptor (EGFR) as a molecular target for therapy in head and neck squamous cell carcinomas (HNSCC). Determination of tumor EGFR levels by conventional immunohistochemistry has not always predicted antitumor efficacy. Quantitative assays may provide more accurate assessment of the level of EGFR receptor in the tumor, which may thus provide more reliable prognostic and predictive information. We studied the prognostic value of quantitative assessment of EGFR in oropharyngeal squamous cell cancers treated with radiotherapy.

EXPERIMENTAL DESIGN

We studied EGFR protein expression on a tissue microarray composed of 95 oropharyngeal cancer cases using an in situ molecular-based method of quantitative assessment of protein expression (AQUA) and correlated those with clinical and pathologic data. Automated, quantitative analysis uses cytokeratin to define pixels as cancer (tumor mask) within the array spot and measures intensity of EGFR expression using a Cy5-conjugated antibody within the mask. A continuous index score is generated, which is directly proportional to the number of molecules per unit area, and cases were defined as high expressing if they were above the median expression level.

RESULTS

The mean follow-up time for survivors was 44.9 months, and for the entire cohort was 34.8 months. Patients with high tumor EGFR expression levels had a local recurrence rate of 58% compared with 17% for patients with low EGFR tumor expression (P < 0.01). Similarly, patients with high nuclear EGFR expression had a local recurrence rate of 54% compared with 21% for patients with low EGFR nuclear expression (P < 0.05). Additionally, patients with high tumor and nuclear EGFR levels had inferior disease-free survival compared with low expressors (19% versus 43% and 19% versus 45%, respectively. P < 0.05 for each). In multivariate analysis adjusting for well-characterized prognostic variables, high tumor and nuclear EGFR expression levels retained their prognostic significance.

CONCLUSION

The AQUA system provides a continuous measurement of EGFR on paraffin-embedded tissue and was able to reveal the association between EGFR expression and outcome expected from the biological role of EGFR. In the future, EGFR AQUA score may be useful in predicting response to EGFR-targeted therapies.

Effect of Epidermal Growth Factor Receptor Expression Level on Survival in Patients with Epithelial Ovarian Cancer

BACKGROUND

Several lines of laboratory evidence support the epidermal growth factor receptor (EGFR) as an adverse prognostic indicator in ovarian cancers. However, different methods of immunohistochemical assessment have yielded conflicting results. Here, we sought to determine the prognostic value of EGFR in ovarian cancer using a novel method of compartmentalized in situ protein analysis.

METHODS

A tissue array composed of 150 advanced-stage ovarian cancers uniformly treated, with surgical debulking followed by platinum-paclitaxel combination chemotherapy, was constructed. For evaluation of EGFR protein expression, we used an immunofluorescence-based method of automated in situ quantitative measurement of protein analysis (AQUA).

RESULTS

Mean follow-up time for the entire cohort was 34.4 months. Eighty-one of 150 cases had sufficient tissue for AQUA analysis. High tumor EGFR expression was associated with poor outcome for overall survival (P=0.0001) and disease-free survival (P=0.0005) at 3 years. In multivariable analysis, adjusting for well-characterized prognostic variables, EGFR expression status was the most significant prognostic factor for disease-free and overall survival.

CONCLUSION

The conflicting results in the literature regarding the prognostic value of EGFR may be due to the technical difficulties inherent in assessing EGFR with immunocytochemistry. In the present study, we show that measurement of EGFR protein levels in ovarian cancer using AQUA is feasible and can give important prognostic information.

Enhancing oxaliplatin-based regimens in colorectal cancer by inhibiting the epidermal growth factor receptor pathway

In the past several years, significant advances in the treatment of colorectal cancer (CRC) have been made. With the introduction of irinotecan and oxaliplatin combined with infusional 5-fluororuracil, survival times for patients with metastatic CRC have nearly doubled. With the incorporation of biologic agents that target the vascular endothelial growth factor and epidermal growth factor (EGF) pathways, additional improvements in response, progression-free survival, and overall survival have been seen in patients with advanced, metastatic disease. This article reviews the impact of EGF receptor inhibitors on improving survival in CRC when combined with oxaliplatin-containing regimens.

Analysis of prognostic factors and applicability of Kohne's prognostic groups in patients with metastatic colorectal cancer treated with first-line irinotecan or oxaliplatin-based chemotherapy

BACKGROUND

The objective of this study was to analyze prognostic factors for survival and to assess the applicability of Kohne's classification in patients treated with irinotecan- or oxaliplatin-based first-line chemotherapy.

PATIENTS AND METHODS

One hundred forty-two consecutive cases from a single center were retrospectively reviewed. Median patient age was 62 years. Sixty percent were men. Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0/1 in 88%. Primary tumor resection (PTR) was performed in 80.6% of patients who initially had stage IV disease. Chemotherapy consisted of fluoropyrimidines or raltitrexed plus irinotecan (50.5%), oxaliplatin (38.5%), or both (11%). Univariate and multivariate analyses for survival were performed using pretreatment patient characteristics.

RESULTS

Median follow-up was 33.9 months and median overall survival was 15.9 months. Significantly unfavorable prognostic factors were PTR not being performed, disease involvement of >1 organ, liver metastases, undifferentiated histology, EGOG PS>1, increased serum carcinoembryonic antigen and cancer antigen 19.9 levels, hypoalbuminemia, leucocytosis, and elevated alkaline phosphatase and lactate dehydrogenase (LDH) levels. Only ECOG PS, PTR, increased LDH level, no hypoalbuminemia, and number of organs involved retained prognostic value in the multivariate analysis. The incidence and median survival for Kohne's prognostic groups were as follows: good (54.2%; 20 months), intermediate (26.8%; 15.7 months), and poor (19%; 6.8 months). For patients with stage IV disease at presentation, PTR was associated with a significantly longer survival, mainly in patients with an ECOG PS of 0/1.

CONCLUSION

Eastern Cooperative Oncology Group PS, PTR, serum albumin, increased LDH levels, and organ involvement were the main prognostic indicators in our series. Kohne's prognostic groups, developed in the era of 5-fluorouracil treatment, also seem to be applicable to patients treated with combination chemotherapy. Primary tumor resection should always be considered, especially in patients with an ECOG PS of 0/1. However, the benefit of PTR and multiple-agent chemotherapy is questionable in patients with an ECOG PS of >1.

Treatment of colorectal cancer in the elderly: a review of the literature

Although major progress has been achieved in the treatment of colorectal cancer, there are still several questions open for discussion concerning the management of elderly colorectal cancer patients. We conducted a review of the available literature concerning the use of adjuvant chemotherapy, palliative chemotherapy and surgery in elderly patients with colorectal cancer, using data from meta-analyses, non-systematic reviews and individual trials. All report similar survival benefits with adjuvant and palliative chemotherapy in elderly patients in comparison with younger age groups. Data on treatment-related side effects did not reveal a different toxicity profile for elderly patients. Efficacy and safety data were similar but more difficult to interpret concerning surgery, so this review is inconclusive about the proper use of this treatment modality in the elderly population. It is demonstrated that there is significant gain from chemotherapy in the adjuvant and palliative management of colorectal cancer patients irrespective of age. We, therefore, conclude that all patients should receive the most intensive treatment thought to be effective and safe, according to their biological age and comorbidities.

The 41st Annual Meeting of the American Society of Clinical Oncology. Orlando, FL, USA, 13-17 May, 2005

Nearly 29,000 scientists from all over the world gathered at the 41st Annual Meeting of the American Society of Clinical Oncology (ASCO). The programme included the presentation of new data encompassing all the fields of cancer research, including cancer prevention, treatment and biology. Special sessions were added to summarise and discuss achievements in the field of translational research on biologically targeted therapies. Rational drug design based on tumour biology and genetics represents a promising strategy to overcome the limitations of conventional chemotherapy. Increased knowledge in the field of molecular oncology, genetics and progress in technology are revolutionising tumour classification, prognostication, prediction and therapy. However, at present, for most of the diseases, improvements brought about by the newer therapies are small, although clinically meaningful. This review will briefly address some of the most interesting data presented at ASCO 2005.

Demonstration of EGFR gene copy loss in colorectal carcinomas by fluorescence in situ hybridization (FISH): a surrogate marker for sensitivity to specific anti-EGFR therapy?

AIMS

To investigate EGFR gene copy number heterogeneity in colorectal carcinomas compared with copy number of chromosome 7 and immunohistochemical expression of the EGFR protein.

METHODS AND RESULTS

Fluorescence in situ hybridization of the EGFR gene and CEP7 was carried out on paraffin-embedded material from 48 rectal carcinomas combined with immunohistochemical detection of EGFR with a polymer detection kit. EGFR gene copy number had a range of 1.4-7.3 with a mean of 2.5. CEP7 copy number had a range of 1.5-6.1 with a mean of 2.5. The EGFR gene/CEP7 ratio ranged from 0.4 to 1.5 with a mean of 0.96. Most cases had a balanced EGFR gene/CEP7 ratio (37 cases = 77%). Copy gain was found in seven cases (15%) with a ratio of up to 1.5, consistent with gain of one EGFR gene copy in one chromosome. Copy loss was found in four cases (8%). All cases with EGFR gene copy loss were immunohistochemically positive.

CONCLUSIONS

Demonstration of EGFR gene copy loss might be a surrogate marker for EGFR mutation/deletion and could be used in a routine setting in pathology departments. Further studies are needed to determine whether this may be used to select patients that might benefit from specific anti-EGFR therapy.

Epidermal growth factor inhibition in solid tumours

The epidermal growth factor receptor (EGFR) plays an important role in the carcinogenesis of many human malignancies and is therefore an attractive target against which anticancer therapy may be effective. At present, there are two ways in which this may be achieved clinically: antibodies against EGFR and inhibitors of the EGFR tyrosine kinase. This review describes presently approved agents cetuximab (monoclonal EGFR antibody), gefitinib and erlotinib (EGFR tyrosine kinase inhibitors) in detail. Efficacy data for these agents in various human malignancies is presented. Various other agents that are in the early stages of development at present have also been mentioned.

Requirements for human antibody cocktails for oncology

Cancer patients receiving antibodies as monotherapy have benefited from these treatments. However, significant improvements can be made that should make the therapy more effective. Applying lessons learned from the natural oligoclonal antibody response that cancer patients mount to their own tumours suggests that cocktails of monoclonal antibodies could be formulated, which may be more effective in treating cancers. The next phase of antibody immunotherapy will include cocktails of monoclonal antibodies. Various requirements for human antibody cocktails are discussed, as well as potential limitations of this approach.

Colorectal cancer: what the clinician wants to know

Colorectal cancer is a common and lethal disease. The adenoma-carcinoma sequence offers a window of opportunity in which the precursor lesion or early carcinoma can be removed endoscopically to prevent systemic disease. New and advanced techniques to improve endoscopic detection of precursor lesions are being developed. Other, less invasive screening methods are currently being developed and may become of use for population-based screening in the near future. Recently, important developments in the treatment (both surgical and chemotherapeutic) of colorectal cancer have occurred. The extent of the disease (stage) forms the basis for therapeutic decisions and accurate imaging is crucial.

Phase I/II trial of gefitinib and oxaliplatin in patients with advanced colorectal cancer

Colorectal cancers frequently overexpress the epidermal growth factor receptor. Gefitinib (Iressa), an inhibitor of the epidermal growth factor receptor tyrosine kinase, is synergistic with oxaliplatin in preclinical colon cancer models. The authors conducted a phase I/II trial of gefitinib plus oxaliplatin in patients with previously treated metastatic colorectal cancer. In the phase I portion, 14 patients received oxaliplatin 130 mg/m2 intravenously every 21 days and gefitinib orally daily at 1 of 2 dose levels: 250 mg/day (8 patients), and 500 mg/day (6 patients). There were no objective responses. Three patients (38%) in the 250-mg cohort experienced disease stabilization for a median of 12 weeks, and 1 patient in the 500-mg cohort had stable disease for 18 weeks. Nausea/vomiting and rash were dose limiting. The randomized phase II part of the trial, in which patients were to receive oxaliplatin with or without gefitinib, was canceled due to the inactivity of single-agent gefitinib observed in the phase I portion, and emergent phase III data regarding the minimal activity of single-agent oxaliplatin. The authors conclude that the combination of gefitinib plus oxaliplatin is inactive in advanced colorectal cancer.

[Biotherapy in colorectal cancer]

Strategies for the treatment of metastatic colorectal cancer must take into account the contribution of monoclonal antibodies. A group of new efficient tools in oncology, these drugs target tumor antigens. Bevacizumab recognizes VEGF. Vascular endothelial growth factor (VEGF) is a key mediator in angiogenesis. This antibody combined with chemotherapy increases the survival of patients treated for metastatic colorectal cancer. Median survival of patients treated with antibodies and chemotherapy is 20 months, compared with only 15 months for patients treated with chemotherapy alone. Cetuximab is a monoclonal antibody that binds competitively and with high affinity to the EGF receptor. Cetuximab is currently approved for use in patients with pretreated colorectal cancer. EGF is a major cell growth factor. The side effects of these new biotherapies are different from chemotherapy: bevacizumab affects vascular elements and the most common side effect of anti-EGFR treatment is acneiform skin rash.

Pulmonary toxicity from novel antineoplastic agents

BACKGROUND

The pulmonary side-effects induced by novel antineoplastic agents have not been well characterized.

METHODS

To further investigate this topic, relevant English and non-English language studies were identified through Medline. For our search we used the generic names of novel cytotoxic or non-cytotoxic antineoplastic agents and the key phrases pulmonary/lung toxicity, dyspnea, pneumonitis, acute lung injury, acute respiratory distress syndrome and alveolar damage. The references from the articles identified were reviewed for additional sources. Abstracts from International Meetings were also included. Furthermore, information was obtained from the Pneumotox website, which provides updated knowledge on drug-induced respiratory disease as well as from pharmaceutical websites.

RESULTS

Most novel antineoplastic drugs may induce pulmonary toxicity, which involves mainly the parenchyma, and less frequently the airways, pleura or the pulmonary circulation. Furthermore, a subset of these agents impairs pulmonary function tests. The exact incidence of lung toxicity remains unclear. The most common patterns consist of dyspnea without further details and infiltrative lung disease (ILD), denoting changes in the interstitium or alveoli. The diagnosis is one of exclusion. ILD is usually benign and responds to appropriate treatment; however, fatalities have been reported.

CONCLUSIONS

Clinicians should be aware of the potential of most novel antineoplastic agents to cause lung toxicity. A high index of suspicion is required if these are combined with other cytotoxic drugs or radiation.

Molecular alterations in tumors and response to combination chemotherapy with gefitinib for advanced colorectal cancer

PURPOSE

Recently, activating mutations of the epidermal growth factor receptor (EGFR) gene were discovered in non-small cell lung cancers sensitive to gefitinib (ZD1839, an EGFR tyrosine kinase inhibitor) but not in gefitinib-resistant cancers. Abnormalities of EGFR and related pathways may have an effect on responsiveness of advanced colorectal cancer to combination chemotherapy with gefitinib.

EXPERIMENTAL DESIGN

We examined patients with previously untreated metastatic colorectal cancer, who were enrolled into two phase I/II trials of combination chemotherapy (irinotecan, leucovorin, and 5-fluorouracil) and daily oral gefitinib. We obtained paraffin tissue blocks of primary tumors from 31 patients, sequenced the EGFR, KRAS, and BRAF genes, and did immunohistochemistry for EGFR, phosphorylated AKT1, p53, p21, and p27.

RESULTS

Twelve (39%) of the 31 patients experienced a partial objective response to the therapy. A novel EGFR mutation in exon 18 (c.2170G>A, p.Gly724Ser) was identified in only one patient who did not experience an objective tumor response. EGFR immunohistochemistry was not predictive of responsiveness. In contrast, loss of p21 was associated with a higher response rate to therapy (P = 0.05). Moreover, the response rate among patients whose tumors maintained p21 expression and possessed a mutation in p53 was only 9% (1 of 11, P = 0.005). Overexpression of phosphorylated AKT1 also seemed to predict a trend towards resistance to the therapy.

CONCLUSIONS

p21 expression in colorectal cancer, especially in combination with p53 mutation, is a predictor of resistance to the combination chemotherapy with gefitinib. Activating EGFR mutations are rare in colorectal cancer and do not seem to confer sensitivity to gefitinib and chemotherapy.

Up-regulated expression of ADAM17 in human colon carcinoma: co-expression with EGFR in neoplastic and endothelial cells

The ADAM17 metalloproteinase (a disintegrin and metalloprotease 17) controls epidermal growth factor receptor (EGFR) activation through regulated shedding of EGFR ligands. With the advent of new therapeutic options targeting EGFR signalling in colon carcinoma, it was decided to determine ADAM17 status in relation to clinico-pathological parameters and EGFR status. To this end, a series of 39 colon carcinomas were analysed. Immunohistochemistry and immunofluorescence were used to localize ADAM17, EGFR, and the activated forms of EGFR. The activated form of ADAM17 was assessed in primary cancers and colon cell lines by immunoblotting. ADAM17 and EGFR mRNA levels were assessed by quantitative RT-PCR. Chromogenic in situ hybridization (CISH) was used to quantify the HER1 gene. ADAM17 was strongly expressed in all tumours, by both neoplastic and endothelial cells. It was expressed both as a pro- and as an active form in tumours and colonic cancer cell lines. ADAM17 mRNA was up-regulated in 90% of colon carcinomas relative to the paired normal mucosa, whatever the tumour grade or stage. When present, activated EGFR was co-expressed with ADAM17 by colon carcinomas, although at a variable level among tumour cells, and by endothelial cells. EGFR mRNA was overexpressed in 77% of colon carcinomas compared with the paired normal mucosa. One case showed high-level amplification of HER1. In conclusion, this study is the first demonstration that ADAM17 is overexpressed in human primary colon carcinoma, whatever the tumour stage and differentiation and whatever the level of EGFR expression. Its co-expression with EGFR, in both neoplastic and endothelial cells, suggests a role for ADAM17 in tumour growth and angiogenesis.

Management of Rash and Other Toxicities in Patients Treated with Epidermal Growth Factor Receptor—Targeted Agents

Inhibition of the epidermal growth factor receptor (EGFR) represents one of the most important avenues for research and development in the field of cancer therapy. The EGFR is a member of the ErbB receptor tyrosine kinase (TK) family, which also includes ErbB-2 (HER2/neu), ErbB-3 (HER3), and ErbB-4 (HER4). Current EGFR therapies available for use include monoclonal antibodies, such as cetuximab, and small-molecule EGFR TK inhibition by agents such as erlotinib. Side effects of these agents include dermatologic manifestations without the bone marrow suppressive properties of chemotherapy. Understanding of rash and how it relates to EGFR inhibitor toxicity and, perhaps more importantly, EGFR inhibitor response must be more clearly defined with clinical trials. The optimum management of rash in patients receiving anti-EGFR therapy remains somewhat controversial; this is secondary to imprecise classification of rash as well as the lack of clinical trials to determine the most appropriate treatment algorithm for these patients. We propose a treatment strategy to help aggressively treat dermatologic side effects allowing patients to continue receiving therapy without dose interruption or drug discontinuation.

First-line therapy for advanced colorectal cancer

First-line therapy for advanced colorectal cancer is rapidly moving from modulation and infusional administration of fluoropyrimidines in the past decades to more complex and more active regimens, with new chemotherapy drugs, oxaliplatin and irinotecan, and modulated targeted drugs inhibiting angiogenesis or the epidermal growth factor receptor (EGFR). The choice of first-line therapy is becoming more complex and is part of a global strategy also integrating individual prognostic factors, salvage surgery, and second-line therapy. Furthermore, we fear that limited financial resources will also influence the management of this disease.

Current Status of Small-Molecule Tyrosine Kinase Inhibitors Targeting Epidermal Growth Factor Receptor in Colorectal Cancer

The epidermal growth factor receptor (EGFR) is expressed in the majority of colorectal cancers (CRCs) and is associated with poor clinical outcome. Ample evidence suggests that inhibition of this pathway by monoclonal antibodies directed against EGFR leads to antitumor activity in CRC. Small-molecule tyrosine kinase inhibitors (TKIs) provide distinct advantages over monoclonal antibodies by virtue of lower production costs, ease of oral administration, and ability to target multiple cellular survival pathways. Despite theoretical advantages, multiple early-phase trials of EGFR TKIs fail to demonstrate single-agent activity in CRC. However, the unusually high response rates observed when gefitinib, an EGFR TKI, is combined with chemotherapy for patients with metastatic CRC suggest a possible synergistic effect. This effect is not seen in non-small-cell lung cancer (NSCLC), for which larger phase III trials have been conducted. The differences between NSCLC and CRC with respect to EGFR expression and mutation status do not completely explain this dichotomy, and further investigation into the pharmacogenomics of EGFR tyrosine kinase inhibition in CRC is under way. Significant effort is directed toward newer strategies targeted at the EGFR in CRC. A new generation of small-molecule TKIs is emerging in which multiple receptor pathways, including ErbB2 and vascular endothelial growth factor receptor, can be simultaneously targeted with EGFR. These agents are still in early-phase clinical trials, and specific data for patients with CRC are forthcoming.

Phase II study of Erlotinib (OSI-774) in patients with advanced hepatocellular cancer

PURPOSE

Epidermal growth factor receptor/human epidermal growth factor receptor 1 (EGFR/HER1) and ligand expression is frequently seen in hepatocellular cancers (HCCs). Erlotinib (Tarceva, OSI-774; OSI Pharmaceuticals, Melville, NY) is a receptor tyrosine kinase inhibitor with specificity for the EGFR/HER1.

METHODS

The primary objective of this study was to determine the proportion of patients with advanced HCC who were progression-free at 6 months. Patients with either unresectable or metastatic disease were studied. Only one prior systemic or locoregional therapy was allowed. Erlotinib was given continuously at a dose of 150 mg per day orally.

RESULTS

Thirty-eight patients with HCC were enrolled. Median age of the patients was 69 years (range, 27 to 83 years). A majority of patients (63%) had an Eastern Cooperative Oncology Group performance status of 1. Forty-seven percent of patients had received prior chemotherapy for advanced HCC. EGFR/HER1 expression was detected in 88% of the patients. Median number of cycles per patient was two (range, 1 to 26). Twelve (32%; CI 95%, 18 to 49) of the 38 patients with HCC were progression-free at 6 months. Three patients had partial radiologic responses of duration of 2, 10, and 11 months, respectively. Disease control was seen in 59% of the patients. Median overall survival time was 13 months. Ten patients (26%) had toxicity-related dose reductions of erlotinib. Grade 3/4 skin toxicity or diarrhea was encountered in five and three patients, respectively.

CONCLUSION

Results of this trial suggest a benefit for EGFR/HER1 blockade with erlotinib in patients with HCC manifested by disease control. Additional studies with erlotinib as a single agent or in combination with other agents are warranted.

Multicenter phase I/II study of cetuximab with paclitaxel and carboplatin in untreated patients with stage IV non-small-cell lung cancer

PURPOSE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have demonstrated antitumor activity in patients with non-small-cell lung cancer (NSCLC). This study examined the safety profile of the monoclonal antibody EGFR inhibitor, cetuximab, when added to paclitaxel and carboplatin in untreated patients with stage IV NSCLC. Secondary objectives included efficacy and paclitaxel and carboplatin pharmacokinetics during cetuximab treatment.

PATIENTS AND METHODS

Patients with tumor evidence of EGFR by immunohistochemistry, performance status of 0 to 2, and measurable disease received paclitaxel 225 mg/m2 with carboplatin area under the curve = 6 on day 1 every 3 weeks. Cetuximab was administered at 400 mg/m2, 1 week before paclitaxel and carboplatin, then weekly at 250 mg/m2. The regimen continued until disease progression or intolerable toxicity.

RESULTS

Thirty-one of 32 enrolled patients were treated. The most common cetuximab toxicity was rash in 84% of patients (grade 3 in 13%). Pharmacokinetic sampling did not reveal an interaction between carboplatin, paclitaxel, and cetuximab. An objective response was observed in eight patients (26%). With a median follow-up of 19 months, the median time to progression was 5 months, median survival was 11 months, and the 1- and 2-year survival rates were 40% and 16%, respectively.

CONCLUSION

The combination of cetuximab, paclitaxel, and carboplatin was safe and well tolerated in this population of stage IV patients. The response rate, time to progression, and median survival were slightly superior to historical controls treated with paclitaxel and carboplatin alone. A randomized phase II trial has completed accrual.

Pharmacokinetic profile of cetuximab (Erbitux) alone and in combination with irinotecan in patients with advanced EGFR-positive adenocarcinoma

This trial assessed pharmacokinetic interactions between cetuximab and irinotecan. Patients were placed in either in group A (irinotecan 350 mg/m2/3 weeks and 400 mg/m2 cetuximab at week 2 then 250 mg/m2/week) or group B (cetuximab weekly starting week 1 then irinotecan starting week 4). Patient plasma or serum samples from each treatment arm were analysed using HPLC and ELISA. Among 14 patients, compartmental model showed no significant differences in mean plasma AUC at week 1 versus week 4 for irinotecan (44,388 versus 39,800 microg/ml/h) and cetuximab (20,441 versus 23,363 microg/ml/h), respectively. Half-lifes (standard deviations) for irinotecan were 16.02 (+/-8.41) h at week 1 and 13.99 (+/-2.14) h at week 4, and for cetuximab 106 (+/-32) at week 3 and 111 (+/-30) h at week 4. Mean concentration-versus-time profiles either alone or in combination were superimposable for cetuximab and irinotecan. From this study, we conclude that there is no evidence of pharmacokinetic interaction between irinotecan and cetuximab.

[Which role do new therapeutic options play in palliative care of colorectal cancer?]

Therapeutic options in the treatment of metastatic colorectal cancer have recently been expanded by the introduction of two new monoclonal antibodies: bevacizumab and cetuximab. These antibodies were the proof of principle of two exciting new antitumor strategies: antiangiogenesis and inhibition of epidermal growth factor (EGF) receptor. Bevacizumab binds to vascular endothelial growth factor and thus blocks its angiogenic effects. In a randomized phase III trial bevacizumab in combination with irinotecan + 5-fluorouracil/leucovorin (IFL) was compared to chemotherapy alone as first-line treatment. The combination showed a superior response rate, a prolonged progression-free and overall survival. Cetuximab binds to the EGF receptor and thus inhibits its activation by its natural ligand. In a randomized phase II trial irinotecan refractory patients were treated with cetuximab alone or cetuximab plus irinotecan. The combination showed a response rate of 22,5% and a prolonged progression-free survival identifying cetuximab as an important new option for this patient group.

Capecitabine and mitomycin C as third-line therapy for patients with metastatic colorectal cancer resistant to fluorouracil and irinotecan

Protracted venous infusion 5-fluorouracil (5FU) combined with mitomycin C (MMC) has demonstrated significant activity against metastatic colorectal cancer. Owing to potential synergy based upon upregulation of thymidine phosphorylase by MMC, the combination of capecitabine and MMC may improve outcomes in irinotecan-refractory disease. Eligible patients with progressive disease during or within 6 months of second-line chemotherapy were treated with capecitabine (1250 mg m⁻² twice daily) days 1–14 every 3 weeks and MMC (7 mg m⁻² IV bolus) once every 6 weeks. A total of 36 patients were recruited, with a median age of 64 years (range 40–77), and 23 patients (78%) were performance status 0–1. The objective response rate was 15.2%. In all, 48.5% of patients had stable disease. Median failure-free survival was 5.4 months (95% CI 4.6–6.2). Median overall survival was 9.3 months (95% CI: 6.9–11.7). Grade 3 toxicities were palmar-plantar erythema 16.7%, vomiting 8.3%, diarrhoea 2.8%, anaemia 8.3%, and neutropenia 2.8%. No patients developed haemolytic uraemic syndrome. Symptomatic improvement occurred for pain, bowel symptoms, and dyspnoea. Capecitabine in combination with MMC is an effective regimen for metastatic colorectal cancer resistant to 5FU and irinotecan with an acceptable toxicity profile and a convenient administration schedule.

A prospective evaluation of treatment with Selective Internal Radiation Therapy (SIR-spheres) in patients with unresectable liver metastases from colorectal cancer previously treated with 5-FU based chemotherapy

BACKGROUND

To prospectively evaluate the efficacy and safety of Selective Internal Radiation (SIR) spheres in patients with inoperable liver metastases from colorectal cancer who have failed 5FU based chemotherapy.

METHODS

Patients were prospectively enrolled at three Australian centres. All patients had previously received 5-FU based chemotherapy for metastatic colorectal cancer. Patients were ECOG 0-2 and had liver dominant or liver only disease. Concurrent 5-FU was given at investigator discretion.

RESULTS

Thirty patients were treated between January 2002 and March 2004. As of July 2004 the median follow-up is 18.3 months. Median patient age was 61.7 years (range 36-77). Twenty-nine patients are evaluable for toxicity and response. There were 10 partial responses (33%), with the median duration of response being 8.3 months (range 2-18) and median time to progression of 5.3 mths. Response rates were lower (21%) and progression free survival shorter (3.9 mths) in patients that had received all standard chemotherapy options (n = 14). No responses were seen in patients with a poor performance status (n = 3) or extrahepatic disease (n = 6). Overall treatment related toxicity was acceptable, however significant late toxicity included 4 cases of gastric ulceration.

CONCLUSION

In patients with metastatic colorectal cancer that have previously received treatment with 5-FU based chemotherapy, treatment with SIR-spheres has demonstrated encouraging activity. Further studies are required to better define the subsets of patients most likely to respond.

Targeted therapy: for kids, too

Innovative hypothesis-driven clinical trials have achieved major successes over the past several decades in treating children and adolescents with cancer. DNA-damaging cytotoxic agents have cured children with cancer. While the mission is not yet accomplished, chemotherapy has been validated. None of these drugs were designed specifically for a pediatric disease. Continued progress will require new strategies. Now being tested for adult cancers, these strategies include gene therapy, immunotherapy, cancer prevention, and signal transduction inhibitor (STI) therapy. Of these, the most promising is STI therapy, also known as molecular therapeutics or targeted therapy. For this therapy to succeed, components of signal transduction (i.e., candidate drug targets) must be identified, the targets relevant to cancers, and the drugs available for trial. Because STI therapy is biologically driven and because therapy will be tailored depending on the molecular profile of a specific patient's tumor, clinical pediatric oncologists will need to acquire greater understanding of signaling pathways and their therapeutic relevance. With examples drawn from pediatric oncology, the critical steps in the pre-clinical development of targeted therapy are reviewed here.

Targeted therapy for colorectal cancer: mapping the way

In spite of the significant advances in conventional therapeutic approaches to colorectal cancer (CRC), most patients ultimately die of their disease. Dissecting the molecular mechanisms underlying CRC progression will not only accelerate the development of novel cancer-selective drugs but will also enable the therapeutic regimen to be personalized according to the molecular features of individual patients and tumors. Here, we report on the novel insights into CRC biology that are paving the way to the development of molecular therapies and summarize the results from recent clinical trials demonstrating that agents targeting tumor-specific molecular derangements can significantly improve the therapeutic efficacy of conventional chemotherapy. Only a broader clinical implementation of these concepts will provide patients with CRC the best chance of a cure.

Epidermal growth factor receptor expression and gene amplification in colorectal carcinoma: an immunohistochemical and chromogenic in situ hybridization study

Recent data suggest that detection of epidermal growth factor receptor protein by immunohistochemistry (IHC) does not predict response to the antiepidermal growth factor receptor drug, cetuximab, in patients with colorectal carcinoma. In searching for foundation for further investigation to optimize patient selection for cetuximab therapy, this study sought to exploit the tissue microarray and chromogenic in situ hybridization techniques to evaluate the status of epidermal growth factor receptor gene amplification in colorectal cancer and its relationship with protein expression by IHC. The study included 158 primary or metastatic colorectal adenocarcinomas. Immunohistochemical results were scored as 0-3+ based on the intensity of membrane staining. The in situ hybridization signals were counted in 30 nuclei per tissue core. Overall, the rate of tissue loss was 7%, yielding 147 analyzable cases: 123 primary, 24 metastatic. Positive immunohistochemical staining of any intensity was detected in 85% (105/123) of primary and 79% (19/24) of metastatic tumors, whereas gene amplification (>5 gene copies/nucleus) was only seen in 12% (15/123) of primary and 8% (2/24) of metastatic tumors. Only 2/15 primary and 1/2 metastatic tumors that showed gene amplification were amplified at a high level (>10 gene copies/nucleus). Although a positive correlation was detected between the intensity of protein expression and the likelihood of gene amplification in both the primary (P = 0.01) and the metastatic (P = 0.05) tumors, IHC had a low specificity (17% in primary, 23% in metastatic) in predicting gene amplification. Conversely, all tumors that did not express the protein by IHC lacked gene amplification. Thus, this study shows that only a small fraction of epidermal growth factor receptor- positive colorectal carcinomas detected by IHC are associated with gene amplification. Additional studies are needed to determine whether epidermal growth factor receptor gene amplification bears any informative value in predicting response to cetuximab-based therapy.

Pharmacogenetics and pharmacogenomics in oncology therapeutic antibody development

Pharmacogenetics and pharmacogenomics are keys to the success of personalized medicine, prescribing drugs based on a patien's individual genetic and biological profile. In this review, we will focus on the application of pharmacogenetics and pharmacogenomics in developing monoclonal antibody (MAb) therapeutics in oncology. The significance of pharmacogenomics in MAb therapeutics is highlighted by the association between polymorphisms in Fc receptors and clinical response to anti-CD20 MAb rituximab (Rituxan®) or anti-ganglioside GD2 MAb 3F8, as well as the potential link between polymorphisms in HER2 and cardiac toxicity in patients treated with the anti-HER2 MAb trastuzumab (Herceptin®). The dependence on gene copy number or expression levels ofHER2 and epidermal growth factor receptor (EGFR) for therapeutic efficacy of trastuzumab and cetuximab (Erbitux®), respectively, supports the importance of selecting suitable patient populations based on their pharmacogenetic profile. In addition, a better understanding of target mutation status and biological consequences will benefit MAb development and may guide clinical development and use of these innovative therapeutics. The application of pharmacogenetics and pharmacogenomics in developing MAb therapeutics will be largely dependent on the discovery of novel surrogate biomarkers and identification of disease- and therapeutics-relevant polymorphisms. Challenges and opportunities in biomarker discovery and validation, and in implementing clinical pharmacogenetics and pharmacogenomics in oncology MAb development and clinical practice will also be discussed.

A Phase I/II Study of Trimetrexate and Capecitabine in Patients With Advanced Refractory Colorectal Cancer

OBJECTIVE

We tested the hypothesis that the combination of trimetrexate (TMTX) and capecitabine (CAP) would be active in patients with previously treated metastatic colorectal cancer (CRC). Because the optimum dose of this combination was unknown, we used a phase I/II design.

METHODS

In the phase I cohort, patients received 110 mg/m2 TMTX intravenously weekly x6 and CAP starting at 750 mg/m2 orally twice daily from days 2 to 15 and 23 to 36 (one cycle). Cycles were repeated every 8 weeks. The phase II doses were 110 mg/m2 TMTX and 1000 mg/m2 CAP orally twice daily.

RESULTS

Thirty-two patients were entered. All patients had prior 5-fluorouracil therapy and 94% had prior exposure to irinotecan. Grade 3/4 toxicities included abdominal pain in 4 patients (12.5%) and vomiting in 3 patients (9.4%). Twenty-seven patients were evaluable for response: one patient each had a complete response and a partial response for an overall response rate of 7.4%. The median time to progression was 3.3 months (95% confidence interval [CI], 1.6-3.7 months) and the median overall survival was 5.9 months (95% CI, 5.2-10.2 months).

CONCLUSIONS

The combination of TMTX and CAP is well tolerated. However, recent studies have shown more active regimens in the second- and third-line metastatic setting.

Monoclonal antibodies and fusion proteins in medicine

Humanized antibodies and decoy receptors have been introduced in clinical practice to treat malignancies and systemic autoimmune disease because they ablate specific cells or disrupt pathogenic processes at distinct points. Reported clinical responses offer hope to treatment-resistant patients, particularly those with lymphomas and rheumatic diseases. Side effects from the use of biologic agents include lymphokine release syndrome, reactivation of tuberculosis, and immunosuppression. Further insights are needed regarding limitation of adverse effects, correct use in conjunction with existing drugs, and treatment of patients in whom resistance develops.

Selenium supplementation may increase the efficacy of cetuximab in metastatic colorectal cancer patients

Recently, cyclooxygenase-2 (COX-2) inhibitor therapy has emerged as a possible new approach to the prevention and treatment of colorectal cancer (CRC). The COX enzymes (COX-1 and COX-2) are key enzymes of prostaglandin (PG) biosynthesis and are overexpressed in approximately 80% of human CRCs. Presumably, bioactive lipid products of COX, such as PGE(2), are responsible for some of the pro-neoplastic effects mediated by this enzyme. The early effects of COX-2-derived PGE(2) are in part mediated by the epidermal growth factor receptor (EGFR). Selenomethionine decreases COX-2 protein and PGE(2) levels. Cetuximab is a chimeric IgG1 monoclonal antibody that binds to EGFR with high specificity thus blocking ligand-induced phosphorylation of EGFR. Cetuximab has clinically significant activity when given alone or in combination with irinotecan in patients with irinotecan-refractory CRC. We suggest that selenium supplementation by decreasing the COX-2 protein and PGE-2 levels in cancer cells may increase efficacy of cetuximab in advanced CRC patients.

Lysophosphatidic acid transactivates both c-Met and epidermal growth factor receptor, and induces cyclooxygenase-2 expression in human colon cancer LoVo cells

AIM: To examine whether lysophosphatidic acid (LPA) induces phosphorylation of c-Met and epidermal growth factor receptor (EGFR), both of which have been proposed as prognostic markers of colorectal cancer, and whether LPA induces cyclooxygenase-2 (COX-2) expression in human colon cancer cells.

METHODS: Using a human colon cancer cell line, LoVo cells, we performed immunoprecipitation analysis, followed by Western blot analysis. We also examined whether LPA induced COX-2 expression, by Western blot analysis.

RESULTS: Immunoprecipitation analysis revealed that 10 µmol/L LPA induced tyrosine phosphorylation of c-Met and EGFR in LoVo cells within a few minutes. We found that c-Met tyrosine phosphorylation induced by LPA was not attenuated by pertussis toxin or a matrix metalloproteinase inhibitor, in marked contrast to the results for EGFR. In addition, 0.2-40 µmol/L LPA induced COX-2 expression in a dose-dependent manner.

CONCLUSION: Our results suggest that LPA acts upstream of various receptor tyrosine kinases (RTKs) and COX-2, and thus may act as a potent stimulator of colorectal cancer.

Integration of novel therapeutics into combined modality therapy of locally advanced non-small cell lung cancer

Novel therapeutic agents (NTA) directed against a wide array of newly described molecular targets are now entering clinical investigation, many in the treatment of non-small cell lung cancer (NSCLC). The great majority of these clinical trials have been directed toward patients with advanced stage (metastatic) disease. More recently, study of NTAs has turned toward earlier-stage disease. Locally advanced, or stage III, NSCLC represents a large and heterogeneous group of patients and several clinically distinct substages. During the last 15 years, randomized clinical trials have shown improved survival with sequential chemoradiation compared with radiation alone and, more recently, the superiority of concurrent versus sequential chemoradiation. As NTAs have increasingly shown clinical activity against NSCLC, questions of how to incorporate them into clinical trials in stage III disease, whether they should be given together with radiotherapy, substituting for chemotherapy, or whether they should be added to current chemoradiation strategies, all remain as issues. Here, we describe conceptual issues, preclinical rationale, and ongoing or planned clinical trials incorporating NTAs into current treatment paradigms for unresectable stage III NSCLC.

Phase II study of gefitinib, fluorouracil, leucovorin, and oxaliplatin therapy in previously treated patients with metastatic colorectal cancer

PURPOSE

To investigate the gefitinib, fluorouracil (FU), leucovorin, and oxaliplatin regimen (IFOX) in previously treated patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Eligible patients had stage IV colorectal adenocarcinoma and had demonstrated progression or intolerance to a prior chemotherapy regimen not including oxaliplatin. Each cycle consisted of 14 days. Cycle 1 consisted of oxaliplatin 85 mg/m2 intravenously (IV) during 2 hours on day 1, hours 0 to 2; leucovorin 200 mg/m2 IV on days 1 and 2, hours 0 to 2; FU 400 mg/m2 IV push on days 1 and 2; and FU 600 mg/m2 IV on days 1 and 2, hours 2 to 24 (FOLFOX-4). All subsequent cycles consisted of FOLFOX-4 with gefitinib at 500 mg/d administered orally throughout the 14-day cycle.

RESULTS

Twenty-seven patients were enrolled onto the study. The median number of prior chemotherapy regimens was two, and 74% of all patients received prior irinotecan. Nine of the 27 patients (33%) and six of the 20 patients (30%) who had prior FU and irinotecan had a partial response by Response Evaluation Criteria in Solid Tumors Group criteria. Median overall survival was 12.0 months. Median event-free survival was 5.4 months. Grade 3 to 4 toxicities included neutropenia (48%), diarrhea (48%), nausea (22%), and vomiting (15%).

CONCLUSION

IFOX is an active regimen in patients with previously treated metastatic colorectal adenocarcinoma, demonstrating higher response rates than those reported with FOLFOX-4 alone in a similar patient population.

Blockade of epidermal growth factor receptor (EGFR) activity

The rapidly expanding knowledge of the pathogenesis of cancer at the molecular level is providing new targets for drug discovery and development. The key role that EGFR plays in the intracellular transduction of environmental variations and the maintenance of cellular homeostasis explains the dependence that many tumor types have on this pathway, and the pivotal role that it plays in the development of malignant features such as uncontrolled proliferation, augmented invasion, and the ability to escape apoptosis. An enormous body of knowledge has been gathered in the past 20 years that has enabled the development of rationally designed EGFR-targeted therapies, and the results of their clinical evaluation are now becoming available. The lack of positive results of some of these trials has highlighted the need for a robust preclinical knowledge in order to efficiently select patients for therapy, and have prompted the implementation of novel trial designs with rational endpoints.