FOLFOXIRI in combination with panitumumab as first-line treatment in quadruple wild-type (KRAS, NRAS, HRAS, BRAF) metastatic colorectal cancer patients: a phase II trial by the Gruppo Oncologico Nord Ovest (GONO)

The efficacy and safety of panitumumab plus irrinotecan-based chemotherapy in the treatment of metastatic colorectal cancer: A meta-analysis

BACKGROUND

Panitumumab, a fully human monoclonal antibody targeting epidermal growth factor receptor, is used in combination with chemotherapy for patients with metastatic colorectal cancer (mCRC). However, the effects of panitumumab in combination with irrinotecan-based chemotherapy remain uncertain. Therefore, we conducted this meta-analysis to assess the efficacy and safety of combination treatment of panitumumab plus chemotherapy in the treatment of mCRC.

METHODS

By searching electronic databases (PubMed, Embase, and Web of Science), all clinical trials which assessed the effects of panitumumab plus irrinotecan-based chemotherapy in mCRC would be included. Main outcome measures included progression-free survival (PFS), overall survival (OS), overall response rate (ORR), and adverse events. Pooled estimates were calculated by a fixed-effects model or random-effects model, according to the heterogeneity among the included studies.

RESULTS

Eleven trials with a total number of 1338 patients met the inclusion criteria and were included in this meta-analysis. The combination treatment of panitumumab and irrinotecan-based chemotherapy was associated with a median PFS of 5.83 months, OS of 11.15 months, and ORR of 33%. Subgroup analysis showed that, in the first-line and second-line treatment, the combination therapy for PFS was 9.27 and 5.01 months, for OS was 8.87 and 11.68 months, and for ORR was 61% and 26%, respectively. In the wild-type and mutant KRAS populations, the combination therapy for PFS was 5.76 and 5.27 months, for OS was 11.15 and 10.64 months, and for ORR was 37% and 18%, respectively. Moreover, combination therapy also induced an incidence of 56% treatment-related adverse events.

CONCLUSION

Panitumumab plus irrinotecan-based chemotherapy is effective and well-tolerated in the treatment of patients with mCRC, especially in those with wild-type KRAS tumors.

A comparative analysis and guidance for individualized chemotherapy of stage II and III colorectal cancer patients based on pathological markers

Adjuvant chemotherapy is considered the standard of care for patients with colorectal cancer after curative resection. Although current guidelines provide clear instructions for chemotherapy for stage II high-risk and stage III colorectal cancer, it is insufficient to individualize therapy. We analyzed the outcomes of 902 patients with colorectal cancer treated with or without chemotherapy in our hospital. We found Chinese survival benefit for chemotherapy was consistent with current guidelines. Moreover, our data added to the evidence that chemotherapy might be used for elderly patients with stage II high-risk colorectal cancer. Pathological markers could predict response to individualize therapy in a convenient, fast and inexpensive way. We compared survivals of patients with stage II high-risk and stage III colorectal cancer with chemotherapy in different pathological markers expression, and furthermore used 458 colon adenocarcinoma samples from The Cancer Genome Atlas to verify our preliminary results. We confirmed TOPIIα, EGFR and P170 may be sufficiently predictive markers to individualize chemotherapy. FOLFOX was the optimal adjuvant chemotherapy for patients with stage II high-risk and stage III colorectal cancer when TOPIIα was positive or EGFR or P170 was negative.

Novel therapeutics in metastatic colorectal cancer: molecular insights and pharmacogenomic implications

Although the survival of metastatic colorectal cancer (mCRC) patients has improved five-fold over the last century, CRC remains a significant global health burden. Impressive strides have been made in identifying new regimens, employing maintenance strategies to limit treatment toxicities, and combining multidisciplinary approaches to achieve cure in oligometastatic disease. Attempts at personalized integration of targeted agents have been limited by the ability to identify molecularly enriched patient populations most likely to benefit. In this review, we discuss novel therapeutics and regimens recently approved and in development for mCRC. In addition, we discuss using older agents in novel combination and maintenance strategies, and highlight evidence for implementing pharmacogenomic data and non-invasive monitoring into the personalized management of mCRC patients.

Conversion Chemotherapy for Technically Unresectable Colorectal Liver Metastases: A Retrospective, STROBE-Compliant, Single-Center Study Comparing Chemotherapy Alone and Combination Chemotherapy With Cetuximab or Bevacizumab

The response rate of patients with unresectable liver-limited metastases of colorectal cancer can be improved by converting inoperable disease to operable disease. However, the benefits of conversion chemotherapy for survival are still controversial.Patients considered to have technically inoperable disease by a multidisciplinary team were retrospectively analyzed. Patients were stratified based on the treatment they received, into the chemotherapy only (G1), chemotherapy plus bevacizumab (G2), or chemotherapy plus cetuximab (G3) groups. The primary endpoint was the resection rate. The secondary endpoint was the overall survival (OS), according to both the treatment received and liver surgery status.In total, 104 patients were included: 30 in the G1, 39 in the G2, and 35 in the G3 groups. All G3 patients had the wild-type KRAS exon 2. The surgical resection rates for patients in the G1, G2, and G3 groups were 43.3% (13/30), 30.7% (12/39), and 51.4% (18/35), respectively. Disease-free survival did not show significant differences among the 3 groups. The median OS was 35.2 months in the G1, 28.8 months in the G2, and 42.1 months in the G3 (P = 0.25) groups. The OS was significantly higher in patients who underwent surgical resection than those who did not. The median OS was 28.4 months in patients who did not undergo resection, whereas it had not been reached after a median follow-up period of 37.5 months for patients who underwent surgical resection (events: 21/43).Our data confirmed that the conversion of initially inoperable disease to operable disease conferred a survival benefit, even in patients who relapsed after surgery. The addition of cetuximab to chemotherapy improved the objective response and resection rates, conferring a potential survival benefit even in patients whose diseases were not converted to operable disease, compared to chemotherapy alone or in combination with bevacizumab.

A Phase II Study of FOLFOXIRI Plus Panitumumab Followed by Evaluation for Resection in Patients With Metastatic KRAS Wild-Type Colorectal Cancer With Liver Metastases Only

Lessons Learned

Background.

Patients with liver-only metastatic colorectal cancer (mCRC) who are not candidates for potentially curative resection may become resectable with more aggressive chemotherapy regimens. In this nonrandomized trial, we evaluated folinic acid, 5-fluorouracil (5-FU), oxaliplatin, and irinotecan (FOLFOXIRI) plus the epidermal growth factor receptor inhibitor panitumumab as first-line treatment for KRAS wild-type mCRC with liver-only metastasis.

Methods.

Patients received FOLFOXIRI (5-FU, 3,200 mg/m², 48-hour continuous intravenous (i.v.) infusion; leucovorin, 200 mg/m² i.v.; irinotecan, 125 mg/m²; oxaliplatin, 85 mg/m² i.v.) and panitumumab (6 mg/kg i.v.) on day 1 of 14-day cycles. Patients were restaged and evaluated for surgery every four cycles. Planned enrollment was originally 49 patients. The primary endpoint was objective response rate.

Results.

Fifteen patients (median age: 55 years; 87% male) received a median 6 cycles of treatment (range: 1–33 cycles); 10 patients (67%) were surgical candidates at baseline. Twelve patients were evaluable for clinical response; 9 (60%) achieved partial response. Ten patients underwent surgery; all had complete resections and pathologic partial response. Treatment-related grade 3 adverse events included diarrhea (33%) and rash (20%). Enrollment was halted because of emerging data on expanded KRAS/NRAS mutations beyond the region we initially examined, and the potential for negative interaction with oxaliplatin-based therapy. Eight patients underwent expanded KRAS/NRAS analysis outside exon 2; no additional mutations were found.

Conclusion.

KRAS/NRAS mutations outside the region tested in this study were recently shown to be associated with inferior survival on similar treatment regimens. Therefore, this trial was stopped early. This regimen remains a viable option for patients with liver-only mCRC in the KRAS/NRAS wild-type population. Enrollment criteria on future studies should include testing for the newly identified mutations.

Understanding the FOLFOXIRI-regimen to optimize treatment for metastatic colorectal cancer

The management of metastatic colorectal cancer substantially improved over the last 10 years and median overall survival of patients might exceed 30 months. The selection of an effective first-line treatment represents a crucial point in order to achieve good outcome results. In the last years, the intensive FOLFOXIRI regimen in combination with bevacizumab became a new standard option in this setting. In the present review we summarized the main steps of FOLFOXIRI regimen development from the first pilot study to the recent findings with biological agents, with a specific focus on practical aspects, such as patient's selection, adverse event management, treatment schedules and post-progression strategies. Possible predictive markers, open issues and ongoing clinical trials have been also deeply described.

A plasma cytokine and angiogenic factor (CAF) analysis for selection of bevacizumab therapy in patients with metastatic colorectal cancer

This study intends to identify biomarkers that could refine the selection of patients with metastatic colorectal cancer (mCRC) for bevacizumab treatment. Pretreatment 36 plasma cytokines and angiogenic factors (CAFs) were first measured by protein microarray analysis in patients who received first-line bevacizumab-containing therapies (discovery cohort, n = 64), and further evaluated by enzyme-linked immunosorbent assay in patients treated on regimens with or without bevacizumab (validation cohort, n = 186). Factor levels were correlated with clinical outcomes, predictive values were assessed using a treatment by marker interaction term in the Cox model. Patients with lower pretreatment levels of hepatocyte growth factor (HGF) or VEGF-A¹²¹ gain much more benefit from bevacizumab treatment as measured by progression-free survival (PFS) and overall survival (OS), while angiopoietin-like 4 (ANGPTL4) levels negatively correlated with PFS and response rate following bevacizumab (all adjusted interaction P < 0.05). A baseline CAF signature combining these three markers has greater predictive ability than individual markers. Signature-negative patients showed impaired survival following bevacizumab treatment (PFS, 7.3 vs 7.0 months; hazard ratio [HR] 1.03; OS, 29.9 vs 21.1 months, HR 1.33) compared with signature-positive patients (PFS, 6.5 vs 11.9 months, HR 0.52; OS, 28.0 vs 55.3 months, HR 0.67). These promising results warrant further prospective studies.

Treatment-related gastrointestinal toxicities and advanced colorectal or pancreatic cancer: A critical update

Gastrointestinal toxicities (GIT), including oral mucositis, nausea and vomiting, and diarrhea, are common side effects of chemotherapy and targeted agents in patients with advanced colorectal cancer and pancreatic cancer. Being often underreported, it is still difficult to precisely establish their burden in terms of both patient’s quality of life and cancer care costs. Moreover, with the use of more intensive upfront combination regimens, the frequency of these toxicities is rapidly growing with a potential negative effect also on patient’s outcome, as a result of dose reductions, delays or even discontinuation of active treatments. Thus, identifying patients at higher risk of developing GIT as well as an optimal management are paramount in order to improve patient’s compliance and outcome. After the description of the main treatment-induced GIT, we discuss the current knowledge on the pathophysiology of these side effects and comment the scales commonly used to assess and grade them. We then provide a critical update on GIT incidence based on the results of key randomized trials conducted in patients with metastatic colorectal cancer and advanced pancreatic cancer.

Molecular markers predictive of chemotherapy response in colorectal cancer

Recognition of the molecular heterogeneity of colorectal cancer (CRC) has led to the classification of CRC based on a variety of clinical and molecular characteristics. Although the clinical significance of the majority of these molecular alterations is still being ascertained, it is widely anticipated that these characteristics will improve the accuracy of our ability to determine the prognosis and therapeutic response of CRC patients. A few of these markers, such as microsatellite instability and the CpG island methylator phenotype (CIMP), show promise as predictive markers for cytotoxic chemotherapy. KRAS is a validated biomarker for epidermal growth factor receptor (EGFR)-targeted therapy, while NRAS and PI3KCA are evolving markers for targeted therapies. Multiple new actionable drug targets and potential response biomarkers are being identified on a regular basis, but most are not ready for clinical use at this time. This review focuses on key molecular features of CRCs and the application of these molecular alterations as predictive biomarkers for CRC.

Upfront FOLFOXIRI+bevacizumab followed by fluoropyrimidin and bevacizumab maintenance in patients with molecularly unselected metastatic colorectal cancer

BACKGROUND

The addition of bevacizumab (BEV) to standard doublet chemotherapy improves outcomes compared with chemotherapy alone in patients with metastatic colorectal cancer (mCRC). The OPAL study examined the effect of BEV+FOLFOXIRI followed by 5FU/LV and BEV maintenance on progression-free survival (PFS) in patients with previously untreated unresectable mCRC.

METHODS

Eligible patients had histologically confirmed mCRC, ECOG performance status ⩽1 and were 18-70 years old. Patients received up to 12 cycles of FOLFOXIRI+BEV q2w (induction phase) followed by up to ⩽40 cycles of 5FU/LV+BEV q2w (maintenance phase). Median PFS was the primary end point; secondary end points included response, OS, secondary resection rate, safety and prognostic value of pharmacogenetic profiling.

RESULTS

Ninety-seven patients were enrolled. Of these, 90 received study medication and formed the safety population: 64 males; median age 58 (range 28-71) years; ECOG performance status 0/1 in 54%/46% patients; and liver only disease in 35 patients. Relative dose intensities were 79-85% for all four drugs. The incidence of adverse events (AEs) was as previously reported and there were no new safety signals. In total, 87 serious AEs occurred in 39 patients (43%). Median PFS was 11.1 months (95% CI 9.4-12.0) and did thus not meet the primary objective of 12 months. Median OS was 32.2 months (95% CI 22.6-36.9). Fifty-two patients were pharmacogenetically profiled.

CONCLUSIONS

FOLFOXIRI+BEV was feasible in this molecularly unselected mCRC patient population, showing a high efficacy in terms of survival, overall response and secondary resection rate. Pharmacogenomic profiling revealed no clinically relevant marker.

Phase II Trial of S-1 and Oxaliplatin Plus Cetuximab for Colorectal Cancer Patients with Initially Unresectable or Not Optimally Resectable Liver Metastases (KSCC1002)

BACKGROUND

The Kyushu Study Group of Clinical Cancer (KSCC) conducted phase II trials of KSCC1002 (UMIN000001308) concerning liver resectability after first-line treatment of initially unresectable or not optimally resectable colorectal liver metastases in a prospective, multicenter study.

METHODS

Patients with wild-type KRAS received 4-6 cycles of S-1 and oxaliplatin (SOX) plus cetuximab. Liver resectability was evaluated subsequently with the liver resection rate as the primary endpoint.

RESULTS

Of the 33 patients enrolled between March 2010 and July 2013, the median number of administration cycles was 4 (range 0-10). The overall response rate was 63.6 % (95 % confidence interval [CI] 45.1-79.6 %). Liver resection was possible in 16 of 33 (48.5 %) patients, and there were 13 R0 cases (39.4 %). We conducted a central review of liver resectability evaluated by five liver surgeons, and the resectability increased from 18.2 to 66.7 % after chemotherapy, based on imaging. The median overall survival for all 33 cases was 31.6 months (95 % CI 14.8-not reached). The median progression-free survival was 9.7 months (95 % CI 6.2-11.8).

CONCLUSIONS

SOX plus cetuximab is safe and effective for advanced colorectal cancer with limited liver metastasis, and may lead to high liver resectability.

FOLFOXIRI plus bevacizumab versus FOLFIRI plus bevacizumab as first-line treatment of patients with metastatic colorectal cancer: updated overall survival and molecular subgroup analyses of the open-label, phase 3 TRIBE study

BACKGROUND

In the TRIBE study, FOLFOXIRI (fluorouracil, leucovorin, oxaliplatin, and irinotecan) plus bevacizumab significantly improved progression-free survival of patients with metastatic colorectal cancer compared with FOLFIRI (fluorouracil, leucovorin, and irinotecan) plus bevacizumab. In this updated analysis, we aimed to provide mature results for overall survival-a secondary endpoint-and report treatment efficacy in RAS and BRAF molecular subgroups.

METHODS

TRIBE was an open-label, multicentre, phase 3 randomised study of patients (aged 18-70 years with Eastern Cooperative Oncology Group [ECOG] performance status of 2 or less and aged 71-75 years with an ECOG performance status of 0) with unresectable metastatic colorectal cancer who were recruited from 34 Italian oncology units. Patients were randomly assigned (1:1) via a web-based procedure to receive FOLFIRI plus bevacizumab or FOLFOXIRI plus bevacizumab. Bevacizumab was given as a 5 mg/kg intravenous dose. FOLFIRI consisted of a 180 mg/m(2) intravenous infusion of irinotecan for 60 min followed by a 200 mg/m(2) intravenous infusion of leucovorin for 120 min, a 400 mg/m(2) intravenous bolus of fluorouracil, and a 2400 mg/m(2) continuous infusion of fluorouracil for 46 h. FOLFOXIRI consisted of a 165 mg/m(2) intravenous infusion of irinotecan for 60 min, followed by an 85 mg/m(2) intravenous infusion of oxaliplatin given concurrently with 200 mg/m(2) leucovorin for 120 min, followed by a 3200 mg/m(2) continuous infusion of fluorouracil for 48 h. Tissue samples for RAS and BRAF mutational status analyses were centrally collected. In this updated analysis, we assessed the secondary endpoint of overall survival in the main cohort and treatment efficacy in RAS and BRAF molecular subgroups. All analyses were by intention to treat. TRIBE was concluded on Nov 30, 2014. The trial is registered with ClinicalTrials.gov, number NCT00719797.

FINDINGS

Between July 17, 2008, and May 31, 2011, 508 patients were randomly assigned. At a median follow-up of 48·1 months (IQR 41·7-55·6), median overall survival was 29·8 months (95% CI 26·0-34·3) in the FOLFOXIRI plus bevacizumab group compared with 25·8 months (22·5-29·1) in the FOLFIRI plus bevacizumab group (hazard ratio [HR] 0·80, 95% CI 0·65-0·98; p=0·03). Median overall survival was 37·1 months (95% CI 29·7-42·7) in the RAS and BRAF wild-type subgroup compared with 25·6 months (22·4-28·6) in the RAS-mutation-positive subgroup (HR 1·49, 95% CI 1·11-1·99) and 13·4 months (8·2-24·1) in the BRAF-mutation-positive subgroup (HR 2·79, 95% CI 1·75-4·46; likelihood-ratio test p<0·0001). Treatment effect was not significantly different across molecular subgroups (pinteraction=0·52).

INTERPRETATION

FOLFOXIRI plus bevacizumab is a feasible treatment option for those patients who meet the inclusion criteria of the present study, irrespective of baseline clinical characteristics and RAS or BRAF mutational status.

Panitumumab for the treatment of metastatic colorectal cancer: a review

In recent years, the treatment of metastatic colorectal cancer (mCRC) has evolved significantly with the increase of new therapeutic options, leading to an improved median survival for these patients. In particular, the identification of molecular targets in tumor cells has led to the introduction of biological drugs for the treatment of mCRC. Panitumumab is a fully human monoclonal antibody that binds the EGF receptor of tumor cells and inhibits downstream cell signaling with antitumor effect on inhibition of tumor growth. Its use has been approved by randomized clinical trials as monotherapy in chemorefractory patients or combined with chemotherapy in the treatment of RAS wild-type mCRC, where it demonstrated a significant improvement in survival and response rate. The purpose of this review is to analyze the use and efficacy profile of panitumumab, particularly focusing on recently reported data on its use, and future perspectives in patients with mCRC.

Is more not better?: combination therapies in colorectal cancer treatment

The treatment of colorectal cancer has evolved dramatically in recent years with the availability of new chemotherapeutic agents and inhibitors of the vascular endothelial growth factor- and epidermal growth factor-signaling pathways. The incremental benefit of each individual line of therapy for advanced disease is relatively small. Advances in our ability to select patients should improve the cost-effectiveness of our treatment strategies (avoiding unnecessary toxicity in the patients who are unlikely to benefit and accepting the potential for adverse events in the patients who stand to benefit the most from a given regimen).

First-line chemotherapy for mCRC—a review and evidence-based algorithm

The response to first-line therapy is a primary determinant of outcome in patients with metastatic colorectal cancer (mCRC), for three main reasons: effective upfront therapy provides a unique opportunity to cure some patients; can be crucial in delaying disease progression and achieving symptom relief; and can improve patient eligibility for, and the effectiveness of, further treatments. In the past decade, decision-making regarding the choice of first-line therapy for mCRC has been complicated by the availability of many different options without a definitive consensus on a specific standard of care (despite major advances in categorizing predictive molecular disease subtypes). Most of the efforts of the scientific community have been directed at establishing the best biologic agent to be combined with a chemotherapy doublet, although a different branch of research has produced new data that underscore the importance of defining the optimal chemotherapy backbone. Herein, we review the key clinical trials completed in the past 10 years that have investigated and compared the use of chemotherapy doublets, triplets, and monotherapies, with or without molecularly targeted biologic agents, in the first-line treatment of patients with mCRC. Our examination of the literature led us to propose a new patient-oriented algorithm to guide clinicians' decisions on the best choice of upfront therapy for mCRC.

Circulating Tumor Cell Enumeration in a Phase II Trial of a Four-Drug Regimen in Advanced Colorectal Cancer

BACKGROUND

Multidrug regimens are active against advanced colorectal cancer (ACRC). However, the increased toxicity requires the use of biomarkers to select the patients who will derive the most benefit. We assessed circulating tumor cells (CTCs) as a prognostic biomarker in patients treated with a 4-drug regimen.

PATIENTS AND METHODS

A single-arm phase II trial (Erbitux Study of CPT11, Oxaliplatin, UFToral Targeted-therapy [eSCOUT]) was undertaken in patients with previously untreated KRAS wild-type ACRC using a regimen of irinotecan, oxaliplatin, and tegafur-uracil with leucovorin and cetuximab. Baseline CTCs were enumerated using CellSearch. The endpoints were an objective response rate (ORR) and overall survival (OS). We modeled our results and compared them with those modeled for the capecitabine, oxaliplatin, bevacizumab +/- cetuximab (CAIRO2) trial, stratifying patients a priori into low (< 3) and high (≥ 3) CTC groups.

RESULTS

For 48 eligible patients, the best ORR from the 4-drug regimen was 71%, with a disease control rate of 98%. The median OS for patients with a high and low CTC count was 18.7 and 22.3 months (log-rank test, P = .038), respectively. In our modeled data, for patients with a low CTC count, no differences were found between the median OS in the eSCOUT trial and that in the CAIRO2 trial (22.2 vs. 22.0 months). However, for the high CTC group, a clinically relevant improvement was seen in median OS (eSCOUT vs. CAIRO2, 18.7 vs. 13.7 months; P = .001).

CONCLUSION

These data are hypothesis generating-for patients with ACRC, stratification by CTC count can identify those who might benefit the most from an intensive 4-drug regimen, avoiding high-toxicity regimens in low CTC groups. This hypothesis warrants validation in a phase III biomarker-driven trial.

How can we determine the best neoadjuvant chemoradiotherapy regimen for rectal cancer?

SUMMARY 

The current management of patients with clinically defined ‘locally advanced rectal cancer’ often involves fluoropyrimidine-based preoperative chemoradiotherapy (CRT) followed by total mesorectal excision. The focus remains primarily on reducing local recurrence, and improving survival, with organ preservation an increasing target. The best neoadjuvant CRT is the most effective regimen, balanced against the tolerability and late functional consequences, which should be selected for the individual according to their individual risk of local and distant recurrence. Hence, what makes the best neoadjuvant treatment depends on the activity and toxicity of the particular schedule, the aims of treatment, the individual disease characteristics and the individual patient pharmacogenomics. Current research efforts focus on enhancing the efficacy of CRT by integrating additional cytotoxics and biologically targeted agents.

Cost estimates and economic implications of expanded RAS testing in metastatic colorectal cancer

BACKGROUND

In colorectal cancer (CRC), evidence shows that expanding RAS testing to analyze more mutations may better predict benefit from anti-EGFR therapy. The economic implications of expanding RAS testing for metastatic CRC were analyzed.

MATERIALS AND METHODS

Estimates of standard KRAS exon 2 testing were based on the Centers for Medicare and Medicaid Services (CMS) 2014 Diagnostic Laboratory Fee Schedule, and expanded RAS testing was estimated using a sensitivity analysis done with various potential cost scenarios (1, 2, 10, and 30 times the cost of the standard KRAS test). The cost estimates for cetuximab and panitumumab were based on the CMS payment allowance limits for Medicare Part B.

RESULTS

A total of 28,692 patients with metastatic CRC were estimated to be eligible annually for RAS testing. For cetuximab, the societal cost of standard KRAS testing plus the drug versus expanded testing plus the drug would be $1.16 billion versus $816 million if the cost of the tests were the same. If the cost of the expanded RAS test were 30 times the cost of the standard test, then the societal cost of standard KRAS testing plus the drug versus expanded testing plus the drug would be $1.16 billion versus $980 million, a continued savings of more than $184 million annually. Similar savings were seen with panitumumab.

CONCLUSION

The increased societal cost of expanded RAS testing versus standard approved KRAS exon 2 testing was inconsequential when compared with the amount of money saved by not treating the additional 18% of patients who harbor additional RAS mutations (beyond exon 2) with anti-EGFR therapy.

Colorectal cancer with liver metastases: Neoadjuvant chemotherapy, surgical resection first or palliation alone?

Colorectal cancer (CRC) is one of the commonest cancers with 1.2 million new cases diagnosed each year in the world. It remains the fourth most common cause of cancer-related mortality in the world and accounts for > 600000 cancer-related deaths each year. There have been significant advances in treatment of metastatic CRC in last decade or so, due to availability of new active targeted agents and more aggressive approach towards the management of CRC, particularly with liver-only-metastases; however, these drugs work best when combined with conventional chemotherapy agents. Despite these advances, there is a lack of biomarkers to inform us about the accurate management of the patients with metastatic CRC. It is therefore imperative to carefully select the patients with comprehensive multi-disciplinary team input in order to optimise the management of these patients. In this review we will discuss various treatment options available in management of colorectal liver metastases with potential guidance on how and when to choose these options along with consideration on future directions in management of this disease.

Next-generation sequencing analysis of lung and colon carcinomas reveals a variety of genetic alterations

The development of targeted therapies in cancer has accelerated the development of molecular diagnosis. This new cancer discipline is booming, with an increasing number of gene alterations to analyze in a growing number of patients. To deal with this fast-developing activity, current analysis techniques (Sanger sequencing, allelic discrimination and high resolution melting) take more and more time. In recent years, next generation sequencing (NGS) technologies have appeared and given new perspectives in oncology. In this study, we analyzed FFPE lung and colon carcinomas using the Truseq Cancer Panel, which analyzes the mutation hotspots of 48 genes. We also tested the use of whole-genome amplification before NGS analysis. NGS results were compared with the data obtained from routine diagnosis. All of the alterations routinely observed were identified by NGS. Moreover, NGS revealed mutations in the KRAS and EGFR genes in patients diagnosed as wild-type by routine techniques. NGS also identified concomitant mutations in EGFR and KRAS or BRAF mutations, and a 15-nt deletion in exon 19 of EGFR in colon carcinomas. The study of the other genes sequenced in the Panel revealed 14 genes altered by 27 different mutations and three SNP with a possible role in cancer susceptibility or in the response to treatment. In conclusion, this study showed that NGS analysis could be used for the analysis of gDNA extracted from FFPE tissues. However, given the high sensitivity of this technology, high-throughput clinical trials are needed to confirm its reliability for the molecular diagnosis of cancer.

Potentially resectable metastatic colorectal cancer: an individualized approach to conversion therapy

Colorectal cancer is one of the most common cancers worldwide. In recent years, the survival of patients with metastatic disease has improved due to the developments in both medical and surgical care. Patients with technically unresectable metastatic disease could benefit from a multidisciplinary approach for their possible shift toward a technically resectable condition; the choice of the most effective systemic treatment is then crucial to allow conversion to resectability. Systemic conversion therapy may include chemotherapy agents' combinations (fluoropyrimidine, irinotecan and oxaliplatin), with or without targeted agents (cetuximab, panitumumab, bevacizumab). The choice of the best treatment option has to be evaluated by taking into account each patient's baseline characteristics, biological and pathological information and surgical strategy. In particular, the role of some biologic characteristics of the disease, namely the mutational status of EGFR-pathway oncogenes, is emerging as an important predictive factor of response to anti-EGFR targeted agents. Patients presenting with colorectal cancer metastases should be evaluated for multimodal management with curative intent as the appropriate chemotherapy regimen may induce tumor shrinkage, conversion to resectability and improved survival.

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.

Clinicopathological characteristics and prognostic impact of colorectal cancers with NRAS mutations

At present, molecular markers of colorectal cancer (CRC), including KRAS, NRAS and BRAF mutations, and the microsatellite status are evaluated for the development of personalized treatments. However, clinicopathological and molecular characteristics and the prognostic role of NRAS mutations remain unclear. In the present study, a total of 1,304 consecutive stage 0-IV CRC tumor samples were analyzed for KRAS (exon 2, 3 and 4), NRAS (exon 2 and 3) and BRAF (exon 15) mutations. Multivariate analysis was performed to assess the prognostic impact of NRAS mutations. KRAS, NRAS and BRAF mutations were identified in 553 (42.4%), 35 (2.7%), and 59 (4.5%) of 1,304 CRC cases, respectively. Tumors with NRAS mutations were more frequently located in the distal colorectum compared with those with KRAS or BRAF mutations. Multivariate analysis indicated that KRAS and BRAF mutations were found to be associated with poor prognosis [hazard ratio (HR)=1.44, 95% confidence interval (CI), 1.18-1.76 and HR=2.09; 95% CI, 1.33-3.28, respectively], whereas NRAS mutations were associated with a trend toward favorable prognosis (HR=0.53; 95% CI, 0.27-1.03). Characteristics and prognosis of CRC with NRAS mutations are different from those with KRAS or BRAF mutations.

Panitumumab safety for treating colorectal cancer

INTRODUCTION

Panitumumab is a human IgG2 mAb against the EGFR, inhibiting tumor cell proliferation, survival and angiogenesis. It has demonstrated clinical efficacy in metastatic colorectal cancer (CRC) in combination with chemotherapy in first- and second-line settings and as monotherapy in third-line setting. Recently, mutations in the RAS genes have been shown to be predictive of lack of efficacy, panitumumab should be restricted to patients with RAS wild-type (wt) tumors.

AREAS COVERED

This review focuses on main efficacy results of panitumumab in metastatic CRC in first-, second- and third-line settings in combination with chemotherapy or as monotherapy. Additionally, we have covered safety aspects of this agent in these indications, especially in K-RAS and all RAS wt patients. These safety aspects refer to the most common toxicities (i.e., acne-like skin rash, diarrhea and hypomagnesaemia).

EXPERT OPINION

Panitumumab adds to the armamentarium of effective agents in the treatment of metastatic CRC. Due to its human origin, panitumumab is a well-tolerated agent with low rates of infusional reactions. Skin toxicity is frequent and should be pre-emptively treated. Other common toxicities related to panitumumab treatment, such as diarrhea and hypomagnesaemia, should be closely monitored to ensure early treatment or substitution.

Conversion therapy for colorectal cancer patients with potentially resectable liver metastases

Conversion therapy brings hope of a cure for colorectal cancer patients with potentially resectable liver metastases. Recent studies demonstrated that conversion therapy could achieve shrinkage of liver metastases and thus render some for resection and offer the chance of long-term survival. Besides preoperative systemic chemotherapy, oncosurgical modalities are also available, primarily including liver resection following portal vein ligation/embolization and two-stage liver resection. In this article, we will review recent advances in conversion therapy for these patients.

How to select the optimal treatment for first line metastatic colorectal cancer

Choice of first line treatment for patients with metastatic colorectal cancer (mCRC) is based on tumour and patient related factors and molecular information for determination of individual treatment aim and thus treatment intensity. Recent advances (e.g., extended RAS testing) enable tailored patient assignment to the most beneficial treatment approach. Besides fluoropyrimidines, irinotecan and oxaliplatin, a broad variety of molecular targeting agents are currently available, e.g., anti-angiogenic agents (bevacizumab) and epidermal growth factor receptor (EGFR) antibodies (cetuximab, panitumumab) for first line treatment of mCRC. Although some combinations should be avoided (e.g., oral or bolus fluoropyrimidines, oxaliplatin and EGFR antibodies), treatment options range from single agent to highly effective four-drug regimen. Preliminary data comparing EGFR antibodies and bevacizumab, both with chemotherapy, seem to favour EGFR antibodies in RAS wildtype disease. However, choosing the most appropriate treatment approach for mCRC patients remains a complex issue, with numerous open questions.

Evidence-based appraisal of the upfront treatment for unresectable metastatic colorectal cancer patients

Colorectal cancer (CRC) is a significant health problem, with around 1 million new cases and 500000 deaths every year worldwide. Over the last two decades, the use of novel therapies and more complex treatment strategies have contributed to progressively increase the median survival of patients with unresectable advanced CRC up to approximately 30 mo. The availability of additional therapeutic options, however, has created new challenges and generated more complicated treatment algorithms. Moreover, several clinically important points are still in debate in first-line, such as the optimal treatment intensity, the most appropriate maintenance strategy, the preferred biologic to be used upfront in patients with KRAS wild-type CRC, and the need for more detailed information on tumor biology. In this moving landscape, this review analyses why the first-line treatment decision is crucial and how the choice may impact on further treatment lines. In addition, it focuses on results of major phase III randomized trials.