Bevacizumab reduces tumor targeting of antiepidermal growth factor and anti‐insulin‐like growth factor 1 receptor antibodies

Bevacizumab (antivascular endothelial growth factor [anti‐VEGF]) and cetuximab (antiepidermal growth factor receptor [anti‐EGFR]) are approved antibodies for treatment of cancer. However, in advanced colorectal cancer, the combination fails to improve survival. As the reason for the lack of activity is unknown, our study aims to determine the effect of bevacizumab on targeting of anti‐EGFR and insulin‐like growth factor 1 receptor (IGF‐1R) antibodies in tumors with single‐photon emission computed tomography (SPECT)/CT imaging. Mice with subcutaneous EGFR and IGF‐1R‐expressing SUM149 xenografts received a single dose of bevacizumab (10 mg/kg) or saline. After 4 days, mice were injected with radiolabeled cetuximab or R1507, an anti‐IGF‐1R antibody. A control group received a radiolabeled irrelevant IgG (hLL2). Three days later, SPECT/CT images were acquired and mice were dissected to determine the concentration of antibodies in the tissues. Tumors were analyzed immunohistochemically to determine vascular density (CD34), VEGF, EGFR and IGF‐1R expression. SPECT/CT imaging revealed that bevacizumab treatment significantly reduced tumor targeting of radiolabeled cetuximab by 40% from 33.1 ± 1.1 %ID/g to 19.8 ± 5.7 %ID/g (p = 0.009) for untreated and bevacizumab‐treated tumors, respectively. A similar effect was found for ¹¹¹In‐R1507: tumor targeting of R1507 decreased by 35%. No significant differences in tumor uptake were observed in mice that received an irrelevant IgG. Uptake in normal organs was not altered by bevacizumab. Immunohistochemical analysis showed that vascular density decreased with 43%, whereas EGFR and IGF‐1R expression was unaltered. In conclusion, bevacizumab treatment significantly reduces tumor targeting of anti‐EGFR and anti‐IGF‐1R antibodies. This emphasizes the importance of timing and sequencing of bevacizumab in combination with other antibodies.     

Circulating tumor cells as a longitudinal biomarker in patients with advanced chemorefractory,RAS‐BRAF wild‐type colorectal cancer receiving cetuximab or panitumumab

A still relevant number of patients with RAS‐BRAF wild‐type colorectal cancer (CRC) do not respond to treatment with antiepidermal growth factor receptor (EGFR) monoclonal antibodies cetuximab and panitumumab, suggesting that additional biomarkers to guide patient selection are urgently needed. Circulating tumor cells (CTCs) may represent such a biomarker. In this prospective study, 38 patients with advanced RAS‐BRAF‐wild‐type CRC received third‐line therapy with cetuximab‐irinotecan or panitumumab. Peripheral blood samples for CTC status determination were collected at baseline, during treatment at early (2–4 weeks) and at later (8–10 weeks) times. CTC enrichment was done with the AdnaTest ColonCancerSelect kit, whereas CTC detection was done with the AdnaTest ColonCancerDetect kit. CTC status positivity was defined according to the kit manufacturer's thresholds. Fifty percent of patients were defined as CTC positive at baseline and the overall RECIST response rate was 26%. CTC baseline status was not associated with treatment response, whereas early CTC status and CTC status changes during treatment were significantly associated with tumor response. Kaplan‐Meier analysis showed a significantly shorter progression‐free survival (median, 2.0 versus 4.0 months, p = 0.004) and overall survival (4.7 versus11.4, p = 0.039) in patients with early CTC + status compared with CTC ‐ ones. In multivariable analysis including classical prognostic factors, the CTC status changes profile during treatment was an independent predictor of both progression‐free survival (p < 0.001) and overall‐survival (p = 0.001). CTC status assessed early during treatment with anti‐EGFR monoclonal antibodies may predict treatment failure in advance compared to imaging‐based tools.     

EGFR gene copy number predicts response to anti‐EGFR treatment in RAS wild type and RAS/BRAF/PIK3CA wild type metastatic colorectal cancer

Anti‐EGFR antibodies are used for the treatment of RAS wild type metastatic colorectal cancer. We previously showed that EGFR gene copy number (GCN) predicts response to anti‐EGFR therapy in KRAS exon 2 wild type metastatic colorectal cancer. The aim of our study was to analyse the predictive role of EGFR GCN in RAS/BRAF/PIK3CA wild type metastatic colorectal cancer. The material included 102 patients with KRAS exon 2 wild type metastatic colorectal cancer treated with anti‐EGFR ± cytotoxic therapy. Next generation sequencing was used for KRAS, NRAS, BRAF and PIK3CA gene mutation analyses. EGFR GCN was analysed by EGFR immunohistochemistry guided automated silver in situ hybridisation. Increased EGFR GCN (≥4.0) predicted a better response and prolonged progression free survival in anti‐EGFR treated RAS/BRAF/PIK3CA wild type patients (Log‐rank test, p = 0.0004). In contrast, survival of RAS/BRAF/PIK3CA wild type, EGFR GCN below 4.0 patients did not differ from patients with mutant RAS, BRAF or PIK3CA. Our study indicates that EGFR GCN predicts anti‐EGFR treatment efficacy in patients with RAS/BRAF/PIK3CA wt metastatic CRC. Tumours with EGFR GCN below 4.0 appear to be as refractory to anti‐EGFR treatment as tumours with mutation in any of the RAS/RAF/PIK3CA pathway genes.     

Dalotuzumab in chemorefractory KRAS exon 2 mutant colorectal cancer: Results from a randomised phase II/III trial

Limited data are available on the efficacy of anti‐IGF‐1R agents in KRAS mutant colorectal cancer (CRC). We analysed the outcome of 69 chemorefractory, KRAS exon 2 mutant CRC patients who were enrolled in a double‐blind, randomised, phase II/III study of irinotecan and cetuximab plus dalotuzumab 10 mg/kg once weekly (arm A), dalotuzumab 7.5 mg/kg every second week (arm B) or placebo (arm C). Objective response rate (5.6% vs. 3.1% vs. 4.8%), median progression‐free survival (2.7 vs. 2.6 vs. 1.4 months) and overall survival (7.8 vs. 10.3 vs. 7.8 months) were not statistically significantly different between treatment groups. Most common grade ≥3 treatment‐related toxicities included neutropenia, diarrhoea, hyperglycaemia, fatigue and dermatitis acneiform. Expression of IGF‐1R, IGF‐1, IGF‐2 and EREG by quantitative real‐time polymerase chain reaction was assessed in 351 patients from the same study with available data on KRAS exon 2 mutational status. Median cycle threshold values for all biomarkers were significantly lower (i.e., higher expression, p < 0.05) among patients with KRAS wild‐type compared to those with KRAS exon 2 mutant tumours. No significant changes were found according to location of the primary tumour with only a trend towards lower expression of IGF‐1 in colon compared to rectal cancers (p = 0.06). Albeit limited by the small sample size, this study does not appear to support a potential role for anti‐IGF‐1R agents in KRAS exon 2 mutant CRC. Data on IGF‐1R, IGF‐1 and IGF‐2 expression here reported may be useful for patient stratification in future trials with inhibitors of the IGF pathway.     

Additional value of EGFR downstream signaling phosphoprotein expression to KRAS status for response to anti‐EGFR antibodies in colorectal cancer

KRAS mutations are a strong predictive marker of resistance to anti‐epidermal growth factor receptor (EGFR) antibodies in advanced colorectal cancer (CRC) but only a subset of wild‐type (WT) KRAS patients are responders, suggesting the existence of additional markers of resistance to this treatment. The activation of EGFR downstream signaling pathways may be one of these ones. In a series of 42 patients with advanced CRC treated with cetuximab/panitumumab, for whom KRAS status was previously determined, we retrospectively analyzed the intratumor expression of EGFR downstream signaling phosphoproteins of the RAS/MAPK and PI3K/AKT pathways (pERK1/2, pMEK1, pAKT, pP70S6K and pGSK3β) using Bio‐Plex® phosphoprotein array. Association with tumor response, progression‐free survival (PFS) and overall survival (OS) was assessed. The expression of all the phosphoproteins was higher in KRAS mutated tumors than in WT tumors. The expression of pP70S6K was lower in responders than in nonresponder patients. In univariate analysis, patients with high pMEK1 or pP70S6K expression had a shorter PFS than those with low expression. Patients with high pP70S6K expression also had a shorter OS. In multivariate analysis, PFS was shorter for patients with high pMEK1 or pP70S6K expression, independently of KRAS status, as OS for patients with high pP70S6K expression. Therefore, WT KRAS patients with high pP70S6K expression had a shorter survival than those with low expression. Our results suggest the importance of EGFR downstream signaling phosphoproteins expression in addition to KRAS status to define the subgroup of patients who will not benefit from anti‐EGFR therapy.     

A randomized,placebo‐controlled,phase 1/2 study of tivantinib (ARQ 197) in combination with irinotecan and cetuximab in patients with metastatic colorectal cancer with wild‐type KRAS who have received first‐line systemic therapy

Cetuximab in combination with an irinotecan‐containing regimen is a standard treatment in patients with KRAS wild‐type (KRAS WT), metastatic colorectal cancer (mCRC). We investigated the addition of the oral MET inhibitor tivantinib to cetuximab + irinotecan (CETIRI) based on preclinical evidence that activation of the MET pathway may confer resistance to anti‐EGFR therapy. Previously treated patients with KRAS WT advanced or mCRC were enrolled. The phase 1, open‐label 3 + 3, dose‐escalation study evaluated the safety and maximally tolerated dose of tivantinib plus CETIRI. The phase 2, randomized, double‐blinded, placebo‐controlled study of biweekly CETIRI plus tivantinib or placebo was restricted to patients who had received only one prior line of chemotherapy. The phase 2 primary endpoint was progression‐free survival (PFS). The recommended phase 2 dose was tivantinib (360 mg/m² twice daily) with biweekly cetuximab (500 mg/m²) and irinotecan (180 mg/m²). Among 117 patients evaluable for phase 2 analysis, no statistically significant PFS difference was observed: 8.3 months on tivantinib vs. 7.3 months on placebo (HR, 0.85; 95% confidence interval, 0.55–1.33; P = 0.38). Subgroup analyses trended in favor of tivantinib in patients with MET‐High tumors by immunohistochemistry, PTEN‐Low tumors, or those pretreated with oxaliplatin, but subgroups were too small to draw conclusions. Neutropenia, diarrhea, nausea and rash were the most frequent severe adverse events in tivantinib‐treated patients. The combination of tivantinib and CETIRI was well tolerated but did not significantly improve PFS in previously treated KRAS WT mCRC. Tivantinib may be more active in specific subgroups.     

Relevance of liver‐limited disease in metastatic colorectal cancer: Subgroup findings of the FIRE‐3/AIO KRK0306 trial

In metastatic colorectal cancer (mCRC), liver‐limited disease (LLD) is associated with a higher chance of metastectomy leading to long‐term survival. However, limited data describes the prognostic and predictive relevance of initially unresectable LLD with regard to targeted first‐line therapy. The present analysis investigated the relevance of initially unresectable LLD in mCRC patients treated with targeted therapy against either the epidermal growth factor receptor (EGFR) or vascular epithelial growth factor (VEGF). The analysis was performed based on FIRE‐3, a randomized phase III trial comparing first‐line chemotherapy with FOLFIRI plus either cetuximab (anti‐EGFR) or bevacizumab (anti‐VEGF) in RAS wild‐type (WT) mCRC. Of 400 patients, 133 (33.3%) had LLD and 267 (66.8%) had non‐LLD. Median overall survival (OS) was significantly longer in LLD compared to non‐LLD patients (36.0 vs. 25.4 months; hazard ratio [HR] = 0.66; 95% confidence interval [CI]: 0.51–0.87; p = 0.002). In a multivariate analysis also including secondary hepatic resection as time‐dependent variable, LLD status was independently prognostic for OS (HR = 0.67; 95% CI: 0.50–0.91; p = 0.01). As assessed by interaction tests, treatment benefit from FOLFIRI plus cetuximab compared to FOLFIRI plus bevacizumab was independent of LLD status with regard to objective response rate (ORR), early tumour shrinkage ≥20% (ETS), depth of response (DpR) and OS (all p > 0.05). In conclusion, LLD could be identified as a prognostic factor in RAS‐WT mCRC, which was independent of hepatic resection in patients treated with targeted therapy. LLD had no predictive relevance since benefit from FOLFIRI plus cetuximab over bevacizumab was independent of LLD status.     

Systematic review and meta‐analysis of the risk of severe and life‐threatening thromboembolism in cancer patients receiving anti‐EGFR monoclonal antibodies (cetuximab or panitumumab)

Cancer‐associated thromboembolism is a substantial problem in clinical practice. An increase in the level of fibrinopeptide A (a substance associated with hypercoagulable states) has been observed in humans exposed to fluorouracil. Anti‐EGFR monoclonal antibodies cetuximab and panitumumab, which are now widely used in patients with metastatic colorectal cancer, could prolong the uncovering of endothelial structures resulting from flouorouracil or other co‐administered agents, thus favouring several factors leading to thromboembolism. We performed a systematic review and meta‐analysis of randomised, controlled trials assessing whether cancer patients receiving anti‐EGFR monoclonal antibodies cetuximab and panitumumab are at increased risk of thromboembolic events. We searched electronic databases (Medline, Embase, Web of Science, Central) and reference lists. Phase II/III randomised, controlled trials comparing standard anti‐cancer regimens with or without anti‐EGFR monoclonal antibodies and reporting serious venous thromboembolic events were included in the analysis. Seventeen studies (12,870 patients) were considered for quantitative analysis. The relative risk (RR) for venous thromboembolism (18 comparisons) was 1.46 (95% CI 1.26 to 1.69); the RR of pulmonary embolism, on the basis of eight studies providing nine comparisons, was 1.55 (1.20 to 2.00). Cancer patients receiving anti‐EGFR monoclonal antibodies‐containing regimens are approximately 1.5 times more likely to experience venous or pulmonary embolism, compared to those treated with the same regimens without anti‐EGFR monoclonal antibodies. Clinicians should consider patient's baseline thromboembolic risk when selecting regimens that include cetuximab or panitumumab. Potential non‐reporting of these important adverse events remains a concern. PROSPERO registration number is CRD42014009165.     

Anti–Epidermal Growth Factor Receptor Monotherapy in the Treatment of Metastatic Colorectal Cancer: Where Are We Today?

Over the past 10 years there has been a significant increase in the armamentarium of agents available for use in the treatment of advanced colorectal cancer (CRC). Among these new agents are two monoclonal antibodies targeting the epidermal growth factor receptor (EGFR): cetuximab, a mouse–human chimeric monoclonal antibody, and panitumumab, a fully human monoclonal antibody. Both are approved as monotherapy for the treatment of chemotherapy‐refractory advanced CRC. Cetuximab is also indicated for use in combination with irinotecan. Here, we review 10 reports of phase II and III clinical studies of patients treated with panitumumab or cetuximab monotherapy. The clinical trials demonstrate similar efficacy profiles for advanced CRC patients treated with panitumumab and cetuximab monotherapy, with some differences in their adverse event profiles. In addition, the recent results of retrospective tumor KRAS gene mutational analyses in CRC patients treated with anti‐EGFR monotherapy are reviewed. Data from the clinical trials reviewed here clearly demonstrate that anti‐EGFR monotherapy is an effective treatment modality for patients with chemotherapy‐refractory advanced CRC.     

Assessment of K‐ras mutation

Some of the most significant therapeutic advances in the treatment of cancer have occurred in the management of colorectal metastases. The introduction of new cytotoxic chemotherapeutic and biologic agents has changed the approach to these patients from both an oncologic and a surgical perspective. In addition, an understanding of the molecular mechanisms by which these agents affect tumors is developing. This molecular information will be critical in the future in designing therapeutic regimens based on an individual tumor's genetic profile rather than treatment for a specific tumor type. The rapidly evolving treatment of colon cancer has provided several interesting genetic biomarkers/pathways/genes‐/kinases that have been targeted or seem to play an important role. Of particular interest is the blockade of epidermal growth factor receptor (EGFR) with monoclonal antibodies. This treatment is efficacious when used alone or combined with chemotherapy. However, recent data revealed that patients with tumors positive for the K‐ras mutation do not benefit from EGFR blockade. Compelling evidence has indicated that mutated K‐ras is an important oncogene involved at the early stage of the development of colorectal cancer. Furthermore, mutations in the K‐ras gene have been associated with aggressive tumor biology. K‐ras mutational analysis is an important step in the overarching goal of developing personalized medicine. New treatment strategies are needed to more effectively treat patients with the K‐ras mutation. Cancer 2009. © 2009 American Cancer Society.     

Changes in mutational status during third‐line treatment for metastatic colorectal cancer—Results of consecutive measurement of cell free DNA,KRAS and BRAF in the plasma

KRAS and BRAF mutations are responsible for primary resistance to epidermal growth factor receptor (EGFR) MoAbs in metastatic colorectal cancer (mCRC), but it is unknown what causes wildtype (wt) patients to develop resistance during treatment. We measured circulating free DNA (cfDNA), KRAS and BRAF in plasma and report the changes during third line treatment with cetuximab and irinotecan. One‐hundred‐and‐eight patients received irinotecan 350 mg/m² q3w and weekly cetuximab (250 mg/m²) until progression (RECIST) or unacceptable toxicity. cfDNA and number of mutated KRAS/BRAF alleles in plasma at baseline and before each cycle was analyzed by an in‐house qPCR. cfDNA and pKRAS levels decreased from baseline to cycle three and increased at time of progression (p = 0.008). The decrease was larger in responding patients than in non‐responding (p < 0.05). Two patients with primary mutant disease had different types of mutations detected in the plasma, including synchronous KRAS and BRAF. Twelve patients had a primary KRAS mutant tumor, but wild‐type disease according to baseline plasma analysis, eight of these obtained stabilization of disease. In five patients with primary wt disease a mutation appeared in plasma before radiological evidence of progression. Loss of mutations may explain observed benefit of treatment in primary mutant disease, whereas appearance of mutations during therapy may be responsible for acquired resistance in primary wt disease. Benefit from EGFR MoAbs may be influenced by the quantitative level of mutational alleles rather than by mutational status alone, and plasma levels of cfDNA, KRAS and BRAF could be used to monitor patients during treatment.     

Comparison of <i>UGT1A1</i> Polymorphism as Guidance of Irinotecan Dose Escalation in RAS Wild-Type Metastatic Colorectal Cancer Patients Treated With Cetuximab or Bevacizumab Plus FOLFIRI as the First-Line Therapy

Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) polymorphism plays a crucial role in the increased susceptibility and toxicity of patients to irinotecan. This retrospective, observational study compared the clinical outcomes and adverse events (AEs) in RAS wild-type metastatic colorectal cancer (mCRC) patients treated with cetuximab or bevacizumab plus FOLFIRI with UGT1A1 genotyping and irinotecan dose escalation as the first-line therapy. In total, 173 patients with mCRC with RAS wild-type were enrolled. Among them, 98 patients were treated with cetuximab, whereas 75 patients were treated with bevacizumab. All patients received irinotecan dose escalation based on UGT1A1 genotyping. We compared the progression-free survival (PFS), overall survival (OS), objective response rates (ORRs), disease control rates (DCRs), metastatectomy, and severe adverse events (SAEs) between the two groups. The clinical effects of primary tumor sidedness and target therapy crossover were further analyzed. Over a median follow-up of 23.0 months [interquartile range (IQR), 15.0–32.5 months], no significant differences were observed between the cetuximab and bevacizumab groups in PFS [18.0 months vs. 14.0 months; 95% confidence interval (CI), 0.517–1.027; hazard ratio (HR), 0.729; p = 0.071], OS (40.0 months vs. 30.0 months; 95% CI, 0.410–1.008; HR, 0.643; p = 0.054), ORR (65.3% vs. 62.7%; p = 0.720), DCR (92.8% vs. 86.7%; p = 0.175), metastatectomy (36.7% vs. 29.3%; p = 0.307), and SAEs (p = 0.685). Regardless of primary tumor sidedness and target therapy crossover, no significant differences were noted in efficacy and safety between the two groups (all p > 0.05). Our results revealed that patients with wild-type RAS mCRC, regardless of biologics, with UGT1A1 genotyping can tolerate escalated doses of irinotecan and potentially achieve a more favorable clinical outcome without significantly increased toxicity.     

Influence of mRNA expression of epiregulin and amphiregulin on outcome of patients with metastatic colorectal cancer treated with 5‐FU/LV plus irinotecan or irinotecan plus oxaliplatin as first‐line treatment (FIRE 1‐trial)

Our aim was to investigate the impact of EREG and AREG mRNA expression (by RT‐qPCR) in patients with metastatic colorectal cancer (mCRC). In addition, epidermal growth factor receptor (EGFR) expression (by immunohistochemistry) as well as RAS‐and PIK3CA‐mutations (by pyrosequencing) were assessed. Tumors of 208 mCRC patients receiving 5‐fluorouracil/leucovorin plus irinotecan (FUFIRI) or irinotecan plus oxaliplatin (mIROX) within the FIRE‐1 trial were analyzed for mutations. Molecular characteristics were correlated with response, progression‐free survival (PFS), overall survival (OS). mRNA expression was evaluated using ROC‐analysis in 192 tumors (AREG high n = 31 vs. low n = 161; EREG high n = 89 vs. low n = 103). High versus low AREG expression was associated with PFS of 10.0 versus 8.0 months (HR = 0.62, 95% CI: 0.402–0.940, p = 0.03) and OS of 24.6 versus 18.7 months (HR = 0.72, 95% CI: 0.476–1.078, p = 0.11). High versus low EREG expression correlated with prolonged PFS (9.4 vs. 6.8 months, HR = 0.62, 95% CI: 0.460–0.846, p = 0.002) and OS (25.8 vs. 15.5 months, HR = 0.48, 95% CI: 0.351–0.657, p < 0.001). The positive prognostic effect of high EREG expression was confirmed in a multivariate analysis and was neither affected by EGFR expression nor by mutations of RAS‐ and PIK3CA‐genes. EREG expression appears as an independent prognostic marker in patients with mCRC receiving first‐line irinotecan‐based chemotherapy.     

The role of HER-3 expression in the prediction of clinical outcome for advanced colorectal cancer patients receiving irinotecan and cetuximab

Preclinical data suggested that, in the presence of human epidermal growth factor receptor (HER)-3-altered activation, colorectal cancer cells may escape anti-epidermal growth factor receptor (EGFR)-mediated cell death. HER-3 overexpression may then represent a key factor for resistance to anti-EGFR antibodies in colorectal cancer. The aim of our analysis was to investigate a possible correlation between HER-3 expression and clinical outcome in wild-type K-RAS advanced colorectal cancer patients receiving cetuximab and irinotecan. We retrospectively analyzed immunoreactivity for HER-3 in wild-type K-RAS advanced colorectal cancer patients receiving irinotecan and cetuximab. Eighty-four advanced wild-type K-RAS colorectal cancer patients were available for HER-3 analysis. Forty patients (48%) had a HER-3(-) colorectal tumor, whereas the remaining 44 cases (52%) were deemed HER-3(+). In patients with HER-3(-) and HER-3(+) tumors, we observed a partial response in 17 (42%) and eight (18%) patients respectively; progressive disease occurred in 11 (35%) and 26 (53%) patients with HER-3(-) and HER-3(+) tumors, respectively (p = .003). The median progression-free survival time was 6.3 months in patients with HER-3(-) tumors and 2.8 months for those who had HER-3-overexpressing tumors (p < .0001). The median overall survival time was 13.6 months in patients showing HER-3(-) tumors and 10.5 months for those who had HER-3-expressing tumors (p = .01). HER-3 proved to be a predictive factor for clinical outcome in wild-type K-RAS colorectal cancer patients treated with cetuximab. Combined HER-3 and K-RAS analysis may represent an effective strategy for better selection of responding colorectal cancer patients.     

Chemotherapy with Targeted Agents for the Treatment of Metastatic Colorectal Cancer

The introduction of novel agents targeted to specific molecular features of cancer cells promises more options and marked improvements in efficacy for treatment of colon cancer. This overview of clinical studies describes the effects of administering the targeted agents bevacizumab, cetuximab, and panitumumab, also known as monoclonal antibodies, to treat metastatic colorectal cancer (mCRC) patients. All three targeted agents have been approved for use by the U.S. Food and Drug Administration and the European Agency for the Evaluation of Medicinal Products. Bevacizumab has been shown to extend survival when used in combination with irinotecan and 5‐fluorouracil–based chemotherapy, and the addition of cetuximab to irinotecan and 5‐fluorouracil–based chemotherapy overcomes irinotecan resistance. Cetuximab and panitumumab are both efficacious among refractory mCRC patients with wild‐type KRAS tumors. Other targeted agents, for example, the tyrosine kinase inhibitors erlotinib, gefitinib, sunitinib, and vatalanib (PTK787/ZK 222584), are currently in various stages of clinical development.     

Promising biomarkers for predicting the outcomes of patients with KRAS wild‐type metastatic colorectal cancer treated with anti‐epidermal growth factor receptor monoclonal antibodies: A systematic review with meta‐analysis

KRAS mutations have been established as a major predictive biomarker for resistance to the treatment of metastatic colorectal cancer (mCRC) with anti‐epidermal growth factor receptor monoclonal antibodies (anti‐EGFR MoAbs). However, many patients with KRAS wild‐type tumors still do not respond to the treatment. We conducted a systematic review with meta‐analysis to assess whether BRAF mutations, PIK3CA mutations and PTEN loss can predict the outcomes of patients with KRAS wild‐type mCRC treated with anti‐EGFR MoAbs. Studies that explored the association of one or more of the three biomarkers with progression‐free survival (PFS), overall survival (OS) and/or objective response rate (ORR) were identified through August 2012. Summary hazard ratios (HRs) and rate differences (RDs) and corresponding 95% confidence intervals (CIs) were calculated by using the random‐effects model. BRAF mutations, PIK3CA exon 20 mutations and PTEN loss were all associated with shorter PFS (HR = 2.59, 95% CI 1.67–4.03; HR = 2.52, 95% CI 1.33–4.78 and HR = 1.75, 95% CI 1.19–2.56, respectively), shorter OS (HR = 2.74, 95% CI 1.79–4.19; HR = 3.29, 95% CI 1.60–6.75 and HR = 1.85, 95% CI 1.30–2.64, respectively) and lower ORR (RD = ?36%, 95% CI ?44 to ?28%; RD = ?38%, 95% CI ?51 to ?24% and RD = ?41%, 95% CI ?68 to ?14%, respectively). PIK3CA exon 9 mutations were associated with none of the outcomes. Studies with relevant data consistently demonstrated a stronger predictive power of combined multiple biomarkers as compared to one alteration alone. These results suggest that BRAF mutations, PIK3CA exon 20 mutations and PTEN loss are predictive of better outcomes in KRAS wild‐type mCRC treated with anti‐EGFR MoAbs. However, the quality of included studies varied, and some of the meta‐analyses were limited by significant between‐study heterogeneity. In the future, well‐designed large randomized controlled trials conducted in KRAS wild‐type mCRC patients with subgroup analysis according to BRAF, PIK3CA exon 20 and PTEN status are essential to fully assess the clinical relevance of these biomarkers.     

DNA methylation status as a biomarker of anti‐epidermal growth factor receptor treatment for metastatic colorectal cancer

Anti‐epidermal growth factor receptor (EGFR) treatment is an effective option for metastatic colorectal cancer (CRC) treatment. However, there are few reliable biomarkers to predict the clinical response to anti‐EGFR treatment. We investigated the genome‐wide DNA methylation status in metastatic colorectal cancer to identify associations between the methylation status and clinical response to anti‐EGFR antibody. We retrospectively reviewed the medical records of 97 patients (45 patients for the first cohort and 52 patients for the second cohort) who received anti‐EGFR treatment for KRAS wild‐type metastatic CRC. Then we analyzed the associations between genome‐wide DNA methylation status and clinical response to anti‐EGFR treatment, and evaluated the predictive power and value of the methylation status statistically. As a result, each cohort was classified into highly methylated CRC and low methylated CRC subgroups by unsupervised clustering analyses. In the first cohort, clinical outcomes were significantly better in the low methylated CRC subgroup than in the highly methylated CRC subgroup (response rate, 35.7% vs 6.3%, P = 0.03; disease control rate, 75% vs 31.3%, P = 0.005; hazard ratio for progression‐free survival, 0.27; 95% confidence interval, 0.13–0.57, P < 0.001; overall survival, 0.19; 95% confidence interval, 0.06–0.54, P < 0.001). These results were reproducible in the second cohort. The genome‐wide methylation status was a predictive factor of progression‐free survival and overall survival independently of RAS mutation status. In conclusion, we found that the genome‐wide DNA methylation status is a powerful epigenetic predictor of anti‐EGFR treatment in patients with KRAS wild‐type metastatic colorectal cancer (UMIN000005490).     

Prognostic value of cetuximab‐related skin toxicity in metastatic colorectal cancer patients and its correlation with parameters of the epidermal growth factor receptor signal transduction pathway: Results from a randomized trial of the GERMAN AIO CRC Study Group

Skin toxicity is a frequent adverse event of epidermal growth factor receptor (EGFR) targeting agents. Occurrence of cetuximab‐induced skin toxicity (Cet‐ST) correlates with better treatment response and longer survival times. Molecular markers predicting Cet‐ST are still missing. This investigation analyzed the value of Cet‐ST for treatment efficacy in a randomized trial comparing cetuximab plus capecitabine/irinotecan to cetuximab plus capecitabine/oxaliplatin as first‐line treatment of metastatic colorectal cancer. Patient characteristics and molecular parameters (KRAS mutation, EGFR‐FISH, EGFR‐IHC and EGFR intron‐1 polymorphism) of the tumour were correlated with response and Cet‐ST. Cet‐ST grade 0–1 was observed in 31%, grade 2–3 in 69% of patients. Outcome favoured patients with grade 2–3 Cet‐ST with regard to overall response rate (62 vs. 41%), PFS (7.8 vs. 5.2 months) and overall survival (OS) (30.3 vs. 18.0 months). First‐cycle rash was observed in 66% of patients and corresponded with longer survival (30.7 vs. 20.2 months, p = 0.007). Patients without Cet‐ST had a poor outcome (PFS, 1.9 months; OS, 11 months). The correlation of Cet‐ST with survival was specifically evident in patients with KRAS codon‐12‐mutated tumours assumed to be cetuximab resistant. In multivariate analysis of patient characteristics, male gender and younger age were significantly correlated with Cet‐ST. Among molecular parameters, no significant correlation with Cet‐ST was found. Cet‐ST is an early predictor of treatment efficacy in cetuximab‐treated patients. This effect of Cet‐ST is independent of the KRAS mutation status, suggesting that Cet‐ST rather relates to constitutional factors of the patient than alterations of the EGFR pathway in the tumour.     

Overexpression of WWP1 is associated with the estrogen receptor and insulin‐like growth factor receptor 1 in breast carcinoma

WWP1, a HECT type E3 ubiquitin ligase frequently amplified and overexpressed in breast cancer, has the potential to become a useful clinical biomarker and therapeutic target in breast cancer. Here, we performed immunohistochemical staining in formalin‐fixed and paraffin‐embedded tissue sections from 187 cases of primary invasive mammary carcinoma [137 ductal carcinomas (IDC) and 50 lobular carcinomas (ILC)] by using a monoclonal anti‐WWP1 antibody. The normal breast epithelium and adjacent benign epithelium are essentially negative for WWP1. Cytoplasmic WWP1 immunoreactivity was observed in 76/187 (40.6%) tumors and showed a positive correlation with ERα (p = 0.05) and IGF‐1R proteins (p = 0.001) in this cohort. The positive correlations between WWP1 and ER/IGF‐1R were also observed in a panel of 12 breast cancer cell lines by Western blot. Interestingly, the ER levels are decreased when WWP1 is silenced in ER positive MCF7 and T47D breast cancer cell lines. Finally, WWP1 ablation collectively inhibits cell proliferation with tamoxifen in MCF7 and T47D, as measured by ³H‐thymidine incorporation assays. These findings suggest that WWP1 may play an important role in ER positive breast cancer. © 2009 UICC     

Role of NRAS mutations as prognostic and predictive markers in metastatic colorectal cancer

NRAS mutations occur in 3–5% of colorectal cancer. Differently from KRAS and BRAF mutations, the role of NRAS mutations as prognostic and predictive markers in metastatic colorectal cancer (mCRC) has been investigated to a lesser extent. A retrospective series suggested the role of NRAS mutations as predictors of resistance to anti‐EGFR monoclonal antibodies (MoAbs) in chemo‐refractory patients with mCRC. In our study, KRAS codons 12, 13, 61 and BRAF codon 600 mutational status were evaluated in mCRCs referred to our Institution from 2009 to 2012. NRAS codons 12, 13 and 61 mutational status was analyzed in KRAS/BRAF wt patients. We collected pathological and clinical features in the overall population and outcome data in a subset of NRAS mutated chemo‐refractory patients treated with anti‐EGFR MoAbs in advanced lines. NRAS was mutated in 47/786 (6%) mCRCs. NRAS and KRAS mutated tumors did not show significant differences in terms of clinical and pathological characteristics, except for a lower prevalence of mucinous histology (p = 0.012) and lung metastases (p = 0.012) among NRAS mutated tumors. In the uni‐ and multivariate model, NRAS mutations were associated with shorter overall survival (OS) compared to all wt patients (median OS 25.6 vs 42.7 months; univ: HR = 1.91, 95% CI 1.39–3.86, p = 0.0013; multiv: HR = 1.75, 95% CI 1.1.3–2.72, p = 0.013). None of the chemo‐refractory NRAS mutated patients evaluable for response to anti‐EGFRs achieved response. In conclusion, NRAS mutations have a relevant incidence in patients with mCRC and showed an association with specific clinical and pathological features. NRAS mutations affect mCRC patients' prognosis and predict lack of response to anti‐EGFRs.