An open-label, single-arm study assessing safety and efficacy of panitumumab in patients with metastatic colorectal cancer refractory to standard chemotherapy

Translational research of new developments in targeted therapy of colorectal cancer

A severe global health concern is the rising incidence and mortality rate of colorectal cancer (CRC). Chemotherapy, which is typically used to treat CRC, is known to have limited specificity and can have noticeable side effects. A paradigm shift in cancer treatment has been brought about by the development of targeted therapies, which has led to the appearance of pharmacological agents with improved efficacy and decreased toxicity. Epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), and BRAF are among the molecular targets covered in this review that are used in targeted therapy for CRC. The current discussion also covers advancements in targeted therapeutic approaches, such as antibody-drug conjugates, immune checkpoint inhibitors, and chimeric antigen receptor (CAR) T-cell therapy. A review of the clinical trials and application of these particular therapies in treating CRC is also done. Despite the improvements in targeted therapy for CRC, problems such as drug resistance and patient selection remain to be solved. Despite this, targeted therapies have offered fresh possibilities for identifying and treating CRC, paving the way for the development of personalized medicine and extending the life expectancy and general well-being of CRC patients.

Progress of research on molecular targeted therapies for colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, accounting for approximately 10% of global cancer incidence and mortality. Approximately 20% of patients with CRC present metastatic disease (mCRC) at the time of diagnosis. Moreover, up to 50% of patients with localized disease eventually metastasize. mCRC encompasses a complex cascade of reactions involving multiple factors and processes, leading to a diverse array of molecular mechanisms. Improved comprehension of the pathways underlying cancer cell development and proliferation, coupled with the accessibility of relevant targeted agents, has propelled advancements in CRC treatment, ultimately leading to enhanced survival rates. Mutations in various pathways and location of the primary tumor in CRC influences the efficacy of targeted agents. This review summarizes available targeted agents for different CRC pathways, with a focus on recent advances in anti-angiogenic and anti-epidermal growth factor receptor agents, BRAF mutations, and human epidermal growth factor receptor 2-associated targeted agents.

Panitumumab-Induced Paronychia: A Case Report and a Brief Review of the Literature

Panitumumab is a recombinant, fully humanized IgG2 monoclonal antibody targeting the epidermal growth factor receptor (EGFR). Panitumumab is indicated for patients with metastatic colorectal cancer with progressive refractory disease. Targeted therapies are well known to be well tolerated; however, they may induce toxicities that are distinct from those of classical chemotherapeutic agents. For instance, EGFR inhibitors (EGFRIs) are associated with some specific dermatological adverse effects, one of which is nail toxicity. Since panitumumab is fully humanized, unlike most of the other EGFRIs, it has been reported to have reduced incidence of adverse reactions. Nail-related adverse effects are frequently observed with EGFRIs. A literature search has yielded a list of reviews describing panitumumab-induced nail toxicity. However, as far as we know, there is no case report detailing this adverse effect of panitumumab. Here, we present a case of panitumumab-induced paronychia in a 60-year-old woman with metastatic colon cancer. With this case report, we would like to review the literature and discuss the possible underlying mechanisms of this condition.

Targeted Cancer Therapy and Its Ophthalmic Side Effects: A Review

Targeted cancer therapy agents are the latest development in cancer therapeutics. Although the spectrum of their use continues to expand, ocular side effects are frequently encountered with the use of cancer therapeutics. This review describes the ocular side effects of targeted cancer therapy agents.

Successful rechallenge with cetuximab after an infusion related reaction to panitumumab in a patient with locally advanced rectal cancer

Incidence of infusion related reaction (IR) is more common with cetuximab (Cmab) than with panitumumab (Pmab). Although little is known about rechallenge IR with monoclonal antibodies, we experienced a successful rechallenge to Cmab after IR to Pmab. A 67-year-old female patient was scheduled for chemotherapy with mFOLFOX6 plus Pmab against unresectable advanced rectal cancer in the hope of tumor shrinkage. On the first administration of Pmab, she complained of dyspnea with shortness of breath and wheezing, even after premedication with steroids and antihistamines. Her reaction was judged as Grade 2 IR to Pmab. For the next course, we tried Cmab. No IRs were observed. Since then, she has undergone seven further courses of treatment, followed by surgical resection. The patient benefited from administration of Cmab after experiencing IR to Pmab, suggesting this treatment to be an option for patients of this type who experience IR to Pmab.

Current Development of Monoclonal Antibodies in Cancer Therapy

Exploiting the unique specificity of monoclonal antibodies has revolutionized the treatment and diagnosis of haematological and solid organ malignancies; bringing benefit to millions of patients over the past decades. Recent achievements include conjugating antibodies with toxic payloads resulting in superior efficacy and/or reduced toxicity, development of molecular imaging techniques targeting specific antigens for use as predictive and prognostic biomarkers, the development of novel bi- and tri-specific antibodies to enhance therapeutic benefit and abrogate resistance and the success of immunotherapy agents. In this chapter, we review an overview of antibody structure and function relevant to cancer therapy and provide an overview of pivotal clinical trials which have led to regulatory approval of monoclonal antibodies in cancer treatment. We further discuss resistance mechanisms and the unique side effects of each class of antibody and provide an overview of emerging therapeutic agents.

Clinical Pharmacokinetics and Pharmacodynamics of the Epidermal Growth Factor Receptor Inhibitor Panitumumab in the Treatment of Colorectal Cancer

Despite progress in the treatment of metastatic colorectal cancer (mCRC) in the last 15 years, it is still a condition with a relatively low 5-year survival rate. Panitumumab, a fully human monoclonal antibody directed against the epidermal growth factor receptor (EGFR), is able to prolong survival in patients with mCRC. Panitumumab is used in different lines of therapy in combination with chemotherapy, and as monotherapy for the treatment of wild-type (WT) RAS mCRC. It is administered as an intravenous infusion of 6 mg/kg every 2 weeks and has a t_½ of approximately 7.5 days. Elimination takes place via two different mechanisms, and immunogenicity rates are low. Only RAS mutations have been confirmed as a negative predictor of efficacy with anti-EGFR antibodies. Panitumumab is generally well tolerated and has a manageable toxicity profile, despite a very high prevalence of dermatologic side effects. This article presents an overview of the clinical pharmacokinetics and pharmacodynamics of panitumumab, including a description of the studies that led to its approval in the different lines of therapy of mCRC.

Monoclonal antibodies for the treatment of non-hematological tumors: a safety review

Introduction: The introduction of monoclonal antibodies (moAbs) into clinical practice revolutionized the treatment strategies in several solid tumors. These agents differ from cytotoxic chemotherapy for their mechanism of action and toxicity. By targeting specific antigens present on healthy cells and modulating immune system activity, these biological drugs are able to generate a wide spectrum of peculiar adverse events that can negatively impact on patients' quality of life. Areas covered: In this review, the main side effects associated with the use of moAbs have been described to show their incidence and current management strategies, which may drive clinicians in their daily practice. Expert opinion: The majority of these drugs represents an example of successful innovation, since they are able to induce a significant improvement of patients' survival and quality of life without any increase in related side effects as compared to standard cancer treatments. For this reason, they have become new milestones in personalized therapy for different non-hematological malignancies. With the increasing use of moAbs in treatment regimens, it is strongly recommended that clinicians are knowledgeable about the side effects associated with these agents, their management and monitoring, to optimize the clinical treatment of cancer patients.

Metastatic colorectal cancer: treatment with panitumumab

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize producers to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and the clinical status of each patient.

Impact of Emergent Circulating Tumor DNA RAS Mutation in Panitumumab-Treated Chemoresistant Metastatic Colorectal Cancer

Purpose: The accumulation of emergent RAS mutations during anti-EGFR therapy is of interest as a mechanism for acquired resistance to anti-EGFR treatment. Plasma analysis of circulating tumor (ct) DNA is a minimally invasive and highly sensitive method to determine RAS mutational status.Experimental Design: This biomarker analysis of the global phase III ASPECCT study used next-generation sequencing to detect expanded RAS ctDNA mutations in panitumumab-treated patients. Plasma samples collected at baseline and posttreatment were analyzed categorically for the presence of RAS mutations by the PlasmaSelect-R 64-gene panel at 0.1% sensitivity.Results: Among panitumumab-treated patients with evaluable plasma samples at baseline (n = 238), 188 (79%) were wild-type (WT) RAS, and 50 (21%) were mutant RAS Of the 188 patients with baseline ctDNA WT RAS status, 164 had evaluable posttreatment results with a 32% rate of emergent RAS mutations. The median overall survival for WT and RAS mutant status by ctDNA at baseline was 13.7 (95% confidence interval, 11.5-15.4) and 7.9 months (6.4-9.6), respectively (P < 0.0001). Clinical outcomes were not significantly different between patients with and without emergent ctDNA RAS mutations.Conclusions: Although patients with baseline ctDNA RAS mutations had worse outcomes than patients who were WT RAS before initiating treatment, emergent ctDNA RAS mutations were not associated with less favorable patient outcomes in panitumumab-treated patients. Further research is needed to determine a clinically relevant threshold for baseline and emergent ctDNA RAS mutations. Clin Cancer Res; 24(22); 5602-9. ©2018 AACR.

Panitumumab in the treatment of metastatic colorectal cancer, including wild-type RAS, KRAS and NRAS mCRC

The humanized monoclonal antibody panitumumab, targeted against EGFR, plays an important role in patients with metastatic colorectal cancer. This article reviews the body of evidence for panitumumab which demonstrates significant benefits across multiple lines of therapy in those without an extended RAS mutation. The use of panitumumab with RAS mutations is not beneficial and possibly harmful. Panitumumab is well tolerated with manageable toxicities. The role of panitumumab continues to evolve as understanding of sequencing of therapies grows. There is evidence for use as maintenance therapy and conversion therapy for unresectable liver metastases. Future research is likely to focus on biomarkers for improved patient selection and the development of novel therapeutic strategies to overcome resistance.

Successful Treatment with the Fully Human Antibody Panitumumab after a Severe Infusion Reaction with Cetuximab

Aims and background

There are only limited data on the safety and efficacy of panitumumab in patients who experienced severe infusion reactions during cetuximab antibody therapy.

Case report

We report the case of a 69-year-old woman with chemotherapy-refractory metastatic colorectal cancer who received single-agent cetuximab treatment but experienced a severe reaction during the first infusion, despite premedication with corticosteroids/antihistamines. Cetuximab was discontinued and treatment with panitumumab initiated approximately 14 days later (without premedication); no infusion reactions occurred and there was a rapid improvement in her general condition. She experienced a partial response that was sustained for 7 months before progression.

Conclusions

This case supports the use of panitumumab in patients with chemotherapy-refractory metastatic colorectal cancer and suggests that panitumumab may be used in some patients with prior infusion reactions to cetuximab.

Exposure-response relationship of ramucirumab in patients with advanced second-line colorectal cancer: exploratory analysis of the RAISE trial

PURPOSE

To characterize ramucirumab exposure-response relationships for efficacy and safety in patients with metastatic colorectal cancer (mCRC) using data from the RAISE study.

METHODS

Sparse pharmacokinetic samples were collected; a population pharmacokinetic analysis was conducted. Univariate and multivariate Cox proportional hazards models analyzed the relationship between predicted ramucirumab minimum trough concentration at steady state (C min,ss) and survival. Kaplan-Meier analysis was used to evaluate survival from patients in the ramucirumab plus folinic acid, 5-fluorouracil, and irinotecan (FOLFIRI) treatment arm stratified by C min,ss quartiles (Q). An ordered categorical model analyzed the relationship between C min,ss and safety outcomes.

RESULTS

Pharmacokinetic samples from 906 patients were included in exposure-efficacy analyses; samples from 905 patients were included in exposure-safety analyses. A significant association was identified between C min,ss and overall survival (OS) and progression-free survival (PFS) (p < 0.0001 for both). This association remained significant after adjusting for baseline factors associated with OS or PFS (p < 0.0001 for both). Median OS was 11.5, 12.9, 16.4, and 16.7, and 12.4 months for ramucirumab C min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. Median PFS was 5.4, 4.6, 6.8, 8.5, and 5.2 months for ramucirumab C min,ss Q1, Q2, Q3, Q4, and placebo group, respectively. The risk of Grade ≥3 neutropenia was associated with an increase in ramucirumab exposure.

CONCLUSIONS

Exploratory exposure-response analyses suggested a positive relationship between efficacy and ramucirumab exposure with manageable toxicities in patients from the RAISE study with mCRC over the ranges of exposures achieved by a dose of 8 mg/kg every 2 weeks in combination with FOLFIRI.

An Update on Randomized Clinical Trials in Metastatic Colorectal Carcinoma

There have been remarkable advances in the treatment of metastatic colorectal cancer over the past 20 years, chiefly achieved by development of new active drugs and establishment of effective systemic therapy regimens. Multidisciplinary care of resectable liver disease with use of perioperative systemic therapy and superior liver resection has resulted in prolonged survival of select patients. Median overall survival has significantly improved with the modern multiagent regimens. This article reviews recent high-quality randomized clinical trials that were conducted to address optimal treatment of advanced and metastatic colorectal carcinoma, mainly focused on initially inoperable metastatic disease.

First-line panitumumab plus FOLFOX4 or FOLFIRI in colorectal cancer with multiple or unresectable liver metastases: A randomised, phase II trial (PLANET-TTD)

BACKGROUND

In first-line wild-type (WT)-Kirsten rat sarcoma viral oncogene homologue (KRAS) metastatic colorectal cancer (mCRC), panitumumab (Pmab) improves outcomes when added to FOLFOX [folinic acid, 5-fluorouracil, and oxaliplatin] or FOLFIRI [folinic acid, 5-fluorouracil, and irinotecan]. However no trial has directly compared these combinations.

METHODS

Multicentre, open-label study in untreated patients ≥ 18 years with (WT)-KRAS mCRC and multiple or unresectable liver-limited disease (LLD) randomised to either Pmab-FOLFOX4 or Pmab-FOLFIRI. The primary end-point was objective response rate (ORR). Secondary end-points included liver metastases resection rate (R0 + R1), progression-free survival (PFS), overall survival (OS), adverse events and perioperative safety. Exploratory end-points were: response by RAS status, early tumour shrinkage (ETS) and depth of response (DpR) in WT-RAS patients.

RESULTS

Data on 77 patients were analysed (38 Pmab-FOLFOX4; 39 Pmab-FOLFIRI; WT-RAS: 27/26, respectively). ORR was 74% with Pmab-FOLFOX4 and 67% with Pmab-FOLFIRI (WT-RAS: 78%/73%). Out of the above, 45% and 59% underwent surgical resection, respectively (WT-RAS: 37%/69%). The R0-R1 resection rate was 34%/46% (WT-RAS:26%/54%). Median PFS was 13/14 months (hazard ratio [HR] Pmab-FOLFIRI versus Pmab-FOLFOX4: 0.9; 95% confidence interval: [0.6-1.5]; WT-RAS:13/15; HR: 0.7 [0.4-1.3]). Median OS was 37/41 months (HR:1.0 [0.6-1.8]; WT-RAS: 39/49; HR:0.9 [0.4-1.9]). In WT-RAS patients with confirmed response, median DpR was 71%/66%, and 65%/77% of patients showed ETS ≥ 30%/ ≥ 20% at week 8, without significant differences between arms; these patients had longer median PFS and OS and higher resectability rates. Surgery was associated with longer survival. Perioperative and overall safety were similar, except for higher grade 3/4 neutropenia (40%/10%; p = 0.003) and neuropathy (13%/0%; p = 0.025) in the Pmab-FOLFOX4 arm.

CONCLUSIONS

In patients with WT-KRAS mCRC and LLD, both first-line Pmab-FOLFOX4 and Pmab-FOLFIRI resulted in high ORR and ETS, allowing potentially curative resection. No significant differences in efficacy were observed between the two regimens. (clinicaltrials.gov:NCT00885885).

Biological agents in gastrointestinal cancers: adverse effects and their management

Biological therapy comprises agents that by virtue of their unique mechanisms of action, are able to specifically incite a response against or target malignant cells. They differ from conventional chemotherapy with regard to mechanisms of action, indications and side effect profile. Biologic agents have revolutionized therapy for a number of malignancies. In the setting of gastrointestinal (GI) malignancies, agents targeting vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (Her2/Neu) and epidermal growth factor receptor (EGFR) have proven to be invaluable additions to chemotherapy. However, these agents bring with them a set of side effects attributable to their unique mechanisms of action. The anti VEGF agents-bevacizumab, aflibercept and ramucirumab, can result in renal and vascular complications such as hypertension, arterial thrombotic events (ATE), proteinuria and GI perforations. The anti EGFR agents classically cause dermatological toxicities, in addition to hypomagnesemia, which can be dose limiting for patients. Trastuzumab, a monoclonal antibody that targets Her2/Neu, is known to cause cardiotoxicity, especially when used with anthracyclines. Use of immunotherapy agents such as nivolumab is associated with the development immune related adverse events (irAEs). The use of these agents is expected to increase over the next few years and it is crucial that patients and practitioners are aware of their adverse effects and current management strategies. This review highlights the adverse events associated with the use of biologic and immunologic therapies in GI cancers, their incidence and current management strategies.

Cost-effectiveness analysis in the Spanish setting of the PEAK trial of panitumumab plus mFOLFOX6 compared with bevacizumab plus mFOLFOX6 for first-line treatment of patients with wild-type RAS metastatic colorectal cancer

OBJECTIVE

To assess the cost-effectiveness of panitumumab in combination with mFOLFOX6 (oxaliplatin, 5-fluorouracil, and leucovorin) vs bevacizumab in combination with mFOLFOX6 as first-line treatment of patients with wild-type RAS metastatic colorectal cancer (mCRC) in Spain.

METHODS

A semi-Markov model was developed including the following health states: Progression free; Progressive disease: Treat with best supportive care; Progressive disease: Treat with subsequent active therapy; Attempted resection of metastases; Disease free after metastases resection; Progressive disease: after resection and relapse; and Death. Parametric survival analyses of patient-level progression free survival and overall survival data from the PEAK Phase II clinical trial were used to estimate health state transitions. Additional data from the PEAK trial were considered for the dose and duration of therapy, the use of subsequent therapy, the occurrence of adverse events, and the incidence and probability of time to metastasis resection. Utility weightings were calculated from patient-level data from panitumumab trials evaluating first-, second-, and third-line treatments. The study was performed from the Spanish National Health System (NHS) perspective including only direct costs. A life-time horizon was applied. Probabilistic sensitivity analyses and scenario sensitivity analyses were performed to assess the robustness of the model.

RESULTS

Based on the PEAK trial, which demonstrated greater efficacy of panitumumab vs bevacizumab, both in combination with mFOLFOX6 first-line in wild-type RAS mCRC patients, the estimated incremental cost per life-year gained was €16,567 and the estimated incremental cost per quality-adjusted life year gained was €22,794. The sensitivity analyses showed the model was robust to alternative parameters and assumptions.

LIMITATIONS

The analysis was based on a simulation model and, therefore, the results should be interpreted cautiously.

CONCLUSIONS

Based on the PEAK Phase II clinical trial and taking into account Spanish costs, the results of the analysis showed that first-line treatment of mCRC with panitumumab + mFOLFOX6 could be considered a cost-effective option compared with bevacizumab + mFOLFOX6 for the Spanish NHS.

Final results and outcomes by prior bevacizumab exposure, skin toxicity, and hypomagnesaemia from ASPECCT: randomized phase 3 non-inferiority study of panitumumab versus cetuximab in chemorefractory wild-type KRAS exon 2 metastatic colorectal cancer

PURPOSE

The primary analysis of the ASPECCT study demonstrated that panitumumab was non-inferior to cetuximab for overall survival (OS) in patients with chemotherapy-refractory wild-type KRAS exon 2 metastatic colorectal cancer (mCRC). Here, we report the final analysis results of ASPECCT.

PATIENTS AND METHODS

Patients with wild-type KRAS exon 2 mCRC who progressed on or were intolerant to irinotecan- or oxaliplatin-based chemotherapy were randomised to receive panitumumab 6 mg/kg once every 2 weeks or cetuximab (400 mg/m²) followed by 250 mg/m² weekly. The primary end-point was OS assessed for non-inferiority. Patients were followed for survival for 24 months after the last patient was randomised and a final analysis was conducted. No formal hypothesis testing was done. Post hoc analyses of outcomes by prior bevacizumab exposure, worst-grade skin toxicity (0-1 versus 2-4) and worst-grade hypomagnesaemia (0 versus 1-4) were conducted.

RESULTS

Nine hundred ninety-nine patients were randomised and received ≥1 treatment dose (panitumumab, n = 499; cetuximab, n = 500). Median OS was 10.2 months with panitumumab versus 9.9 months with cetuximab (hazard ratio = 0.94; 95% confidence interval = 0.82-1.07). Median progression-free survival was 4.2 months with panitumumab and 4.4 months with cetuximab (hazard ratio = 0.98; 95% confidence interval = 0.87-1.12). Longer OS was observed for patients with increased skin toxicity and with hypomagnesaemia in both arms. Furthermore, OS was longer for patients with prior bevacizumab exposure treated with panitumumab than with cetuximab. The observed safety profiles were consistent with previous studies.

CONCLUSION

Consistent with the primary analysis, the final analysis of ASPECCT showed panitumumab was non-inferior to cetuximab for OS for patients with chemotherapy-refractory, wild-type KRAS exon 2 mCRC.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01001377.

Y90 Radioembolization in chemo-refractory metastastic, liver dominant colorectal cancer patients: outcome assessment applying a predictive scoring system

BACKGROUND

In treatment-refractory liver dominant metastatic colorectal cancer, the role of liver directed therapies still is unclear. We sought to determine a prognostic score for Y90 radioembolization in these patients.

METHODS

We analyzed 106 patients with refractory liver dominant mCRC who had undergone a total of 178 Y90 radioembolizations with resin microspheres was collected. Potential factors influencing survival were analyzed using a Cox regression. The Log rank test served to establish prognostic factors and to form a clinical score for outcome prediction after Y90 radioembolization.

RESULTS

Median survival of all patients was 6.7 months. Neither age nor prior surgical or systemic therapy nor metastatic spread had an effect on survival. In contrast, hepatic tumor load, Karnofsky index as well as CEA and CA19-9 serums level had a significant influence (p < 0.001, p = 0.037, p = 0.023 and p < 0.001, respectively). These three factors formed a score with 1 point each for tumor load >20 %, CEA >130 ng/ml or CA19-9 > 200U/ml and Karnofsky index <80 %. Patients with a score of 0 and 1 displayed a median OS of 10.4 months. Patients with a score of 2 and 3 demonstrated a median OS of 5.1 months only (p < 0.001).

CONCLUSION

Overaggressive patient selection for Y90 radioembolization of liver dominant chemorefractory mCRC is of questionable benefit. A scoring system comprising hepatic tumor load, CEA and CA19-9 serum levels and Karnofsky index (TuCK-score) may support an improved patient selection. In our cohort of liver only versus liver dominant disease, extrahepatic lung or lymphatic metastases did not significantly alter the prognosis.

New findings on primary and acquired resistance to anti-EGFR therapy in metastatic colorectal cancer: do all roads lead to RAS?

Anti-epidermal growth factor receptor therapy with the monoclonal antibodies cetuximab and panitumumab is the main targeted treatment to combine with standard chemotherapy for metastatic colorectal cancer. Many clinical studies have shown the benefit of the addition of these agents for patients without mutations in the EGFR pathway. Many biomarkers, including KRAS and NRAS mutations, BRAF mutations, PIK3CA mutations, PTEN loss, AREG and EREG expression, and HER-2 amplification have already been identified to select responders to anti-EGFR agents. Among these alterations KRAS and NRAS mutations are currently recognized as the best predictive factors for primary resistance. Liquid biopsy, which helps to isolate circulating tumor DNA, is an innovative method to study both primary and acquired resistance to anti-EGFR monoclonal antibodies. However, high-sensitivity techniques should be used to enable the identification of a wide set of gene mutations related to resistance.

Immunogenicity of Biotherapeutics: Causes and Association with Posttranslational Modifications

Today, potential immunogenicity can be better evaluated during the drug development process, and we have rational approaches to manage the clinical consequences of immunogenicity. The focus of the scientific community should be on developing sensitive diagnostics that can predict immunogenicity-mediated adverse events in the small fraction of subjects that develop clinically relevant anti-drug antibodies. Here, we discuss the causes of immunogenicity which could be product-related (inherent property of the product or might be picked up during the manufacturing process), patient-related (genetic profile or eating habits), or linked to the route of administration. We describe various posttranslational modifications (PTMs) and how they may influence immunogenicity. Over the last three decades, we have significantly improved our understanding about the types of PTMs of biotherapeutic proteins and their association with immunogenicity. It is also now clear that all PTMs do not lead to clinical immunogenicity. We also discuss the mechanisms of immunogenicity (which include T cell-dependent and T cell-independent responses) and immunological tolerance. We further elaborate on the management of immunogenicity in preclinical and clinical setting and the unique challenges raised by biosimilars, which may have different immunogenic potential from their parent biotherapeutics.

Evidence-based medical oncology and interventional radiology paradigms for liver-dominant colorectal cancer metastases

Colorectal cancer metastasizes predictably, with liver predominance in most cases. Because liver involvement has been shown to be a major determinant of survival in this population, liver-directed therapies are increasingly considered even in cases where there is (limited) extrahepatic disease. Unfortunately, these patients carry a known risk of recurrence in the liver regardless of initial therapy choice. Therefore, there is a demand for minimally invasive, non-surgical, personalized cancer treatments to preserve quality of life in the induction, consolidation, and maintenance phases of cancer therapy. This report aims to review evidence-based conceptual, pharmacological, and technological paradigm shifts in parenteral and percutaneous treatment strategies as well as forthcoming evidence regarding next-generation systemic, locoregional, and local treatment approaches for this patient population.

Management of Epidermal Growth Factor Receptor Inhibitor-Induced Hypomagnesemia: A Systematic Review

BACKGROUND

Despite occurring in 30% of patients, there are no evidence-based guidelines on the management of epidermal growth factor receptor inhibitor (EGFRI)-induced hypomagnesemia. Based on expert opinion, severe hypomagnesemia should be treated by intravenous magnesium replacement. A systematic review of published data of intervention on EGFRI-induced hypomagnesemia was performed.

METHODS

Articles from 1960 to March 2015 were identified from Medline, Embase, Cochrane Central Register of Controlled Trials, and PubMed using a peer-reviewed systematic search strategy. Eligible studies included randomized controlled trials or observational studies that evaluated management of hypomagnesemia in adult patients treated with EGFRIs. Risk factors for severe hypomagnesemia were also assessed. The quality of included studies was rated using Jadad scores.

RESULTS

A total of 1327 references were identified, and 6 studies, involving 486 patients, met inclusion criteria for analysis. There were no randomized controlled trials, and all included studies were of poor quality. From the studies included in this review, severity of EGFRI-induced hypomagnesemia was associated with length of EGFRI treatment, concomitant platinum chemotherapy, increasing age, and baseline magnesium concentration. In most patients with grade 3 or 4 hypomagnesemia, high-dose intravenous magnesium replacement did not achieve sustainable magnesium repletion beyond 72 hours. Oral magnesium supplementation was not effective or tolerable. Severe hypomagnesemia has been associated with tachycardia and mental alteration. After discontinuation of EGFRI therapy, hypomagnesemia generally resolves within weeks to months.

CONCLUSIONS

There is an absence of high-quality evidence for the management of EGFRI-induced hypomagnesemia. As hypomagnesemia is often refractory to frequent intravenous or oral replacement, there is a need for prospective trials of new interventions for this common toxicity.

Profile of panitumumab as first-line treatment in patients with wild-type KRAS metastatic colorectal cancer

Targeted therapies against EGFR, vascular endothelial growth factor, and vascular endothelial growth factor receptor have expanded treatment options for patients with metastatic colorectal cancer (mCRC). Unfortunately, biomarkers to identify patients that are most likely to derive benefit from targeted therapies in this disease are still needed. Indeed, only RAS mutations have been identified as predictive of lack of benefit from monoclonal antibodies against EGFR in patients with mCRC. Panitumumab is a fully humanized monoclonal antibody against EGFR. In this study, we review data to support the use of panitumumab in combination with a chemotherapy backbone, in the first line setting in patients with RAS wild-type mCRC. Ongoing efforts are aimed at identifying smaller subsets of patients within the RAS wild-type group that will derive the largest benefit from anti-EGFR therapy. In the meantime, treatment with anti-EGFR therapy should be reserved for patients with RAS wild-type mCRC.

Effectiveness and safety of monoclonal antibodies for metastatic colorectal cancer treatment: systematic review and meta-analysis

BACKGROUND

The effectiveness of chemotherapy (CT) for select cases of metastatic colorectal cancer (MCRC) has been well established in the literature, however, it provides limited benefits and in many cases constitutes a treatment with high toxicity. The use of specific molecular biological treatments with monoclonal antibodies (MA) has been shown to be relevant, particularly for its potential for increasing the response rate of the host to the tumour, as these have molecular targets present in the cancerous cells and their microenvironment thereby blocking their development. The combination of MA and CT can bring a significant increase in the rate of resectability of metastases, the progression-free survival (PFS), and the global survival (GS) in MCRC patients.

OBJECTIVE

To assess the effectiveness and safety of MA in the treatment of MCRC.

METHODS

A systematic review was carried out with a meta-analysis of randomised clinical trials comparing the use of cetuximab, bevacizumab, and panitumumab in the treatment of MCRC.

RESULTS

Sixteen randomised clinical trials were selected. The quality of the evidence on the question was considered moderate and data from eight randomised clinical trials were included in this meta-analysis. The GS and PFS were greater in the groups which received the MA associated with CT, however, the differences were not statistically significant between the groups (mean of 17.7 months versus 17.1 months; mean difference of 1.09 (CI: 0.10-2.07); p = 0.84; and 7.4 versus 6.9 months. mean difference of 0.76 (CI: 0.08-1.44); p = 0.14 respectively). The meta-analysis was not done for any of the secondary outcomes.

CONCLUSION

The addition of MA to CT for patients with metastatic colorectal cancer does not prolong GS and PFS.

The efficacy and safety of panitumumab in the treatment of patients with metastatic colorectal cancer: a meta-analysis from five randomized controlled trials

Background

The efficacy of adding panitumumab to chemotherapy remains controversial in the treatment of metastatic colorectal cancer (mCRC). Thus, we conducted this meta-analysis to assess the efficacy and safety of this combination regimen in patients with mCRC.

Methods

The PubMed, Embase, and Web of Science databases were comprehensively searched. Eligible studies included randomized controlled trials (RCTs) that estimated the efficacy of panitumumab with or without chemotherapy in the treatment of patients with mCRC. Hazard ratio (HR), risk ratio (RR), and 95% confidence intervals (CIs) were calculated, and heterogeneity was tested using I² statistics.

Results

Four studies involving a total of 3,066 patients were included in this meta-analysis. The addition of panitumumab to chemotherapy significantly improved progression-free survival (PFS) (HR =0.84, 95% CI =0.78–0.91, P=0.000) and the objective response rate (ORR) (RR =2.18, 95% CI =1.13–4.22, P=0.021) compared to chemotherapy alone, but no effect was noted on overall survival (OS) (HR =0.97, 95% CI =0.89–1.05, P=0.402). Subgroup analysis based on KRAS gene status revealed that the combined therapy significantly improved PFS (HR =0.71, 95% CI =0.57–0.88, P=0.002) and ORR (RR =2.43, 95% CI =1.21–4.90, P=0.013) in patients with wild-type KRAS tumors. Irinotecan-based chemotherapy plus panitumumab significantly prolonged PFS in patients with mCRC (HR =0.84, 95% CI =0.76–0.94, P=0.002). The combined treatment also increased the incidence of grade 3/4 adverse events.

Conclusion

This meta-analysis indicates that the combination of panitumumab and chemotherapy effectively improved PFS and ORR, but it did not prolong OS. However, as the number of studies in the meta-analysis was limited, more large-scale, better-designed RCTs are needed to assess the combination of panitumumab and chemotherapy.

First-line single-agent panitumumab in frail elderly patients with wild-type KRAS metastatic colorectal cancer and poor prognostic factors: A phase II study of the Spanish Cooperative Group for the Treatment of Digestive Tumours

BACKGROUND

Frail elderly patients with metastatic colorectal cancer (mCRC) are not candidates for chemotherapy. Monotherapy with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies may be an option for these patients with few systemic toxic effects.

PATIENTS AND METHODS

Single-arm, multicentre, phase II trial including patients ⩾ 70y ears with wild-type (WT) KRAS (exon 2) mCRC, Eastern Cooperative Oncology Group (ECOG) status ⩽ 3, KPC (Köhne Prognostic Classification)--defined intermediate or high risk status, frailty and/or ineligibility for chemotherapy. Patients received panitumumab until progression or unacceptable toxicity. The primary end-point was progression free survival (PFS) rate at 6 months.

RESULTS

The study included 33 patients (intention-to-treat (ITT) population). Median age: 81 years; sex: 66.7% male; high-risk KPC status: 45.4%. Median treatment duration was 14 weeks and 6-month PFS rate was 36.4% (95% confidence interval (CI): 20.0-52.8). The objective response rate: 9.1% (95% CI: 0-18.9) (all partial responses), and there were 18 stable diseases (54.5%). Median PFS was 4.3 months (95% CI: 2.8-6.4) and median overall survival (OS) was 7.1 months (95% CI: 5.0-12.3). There were no deaths or grade 4-5 adverse events (AEs) related to panitumumab and the most common grade 3-related AE was rash acneiform (15.2%). A significant association between clinical response and RAS status was observed (P=0.037). In the WT RAS subgroup (WT exons 2, 3, and 4 of KRAS and NRAS, N = 15), 6-month PFS rate was 53.3% (95% CI: 30.1-75.2) and median PFS and OS were 7.9 and 12.3 months, respectively.

CONCLUSIONS

Single-agent panitumumab is active and well tolerated and may be a therapeutic option for high-risk frail elderly patients with WT RAS tumours considered not candidates for chemotherapy (clinicaltrials.gov identifier NCT01126112).

Panitumumab in Metastatic Colorectal Cancer: The Importance of Tumour RAS Status

Tumour biomarker status is being used more and more frequently to guide treatment decisions in patients with metastatic colorectal cancer (mCRC). Continued cycles of hypothesis generation and biomarker testing in retrospective, prospective-retrospective and prospective analyses from studies of the epidermal growth factor (EGFR)-targeted monoclonal antibodies (mAbs), panitumumab and cetuximab, have resulted in improved patient selection in mCRC. Initial data suggested EGFR-targeted mAb treatment should be limited to patients with KRAS exon 2 wild-type (WT) tumours, but the availability of tumour samples from large phase III studies permitted evaluation of additional potential biomarkers of activity for these agents. Subsequent analyses further refined the target population to those patients whose tumours were WT for KRAS and NRAS exons 2, 3 and 4 (i.e., those with RAS WT status). Here, we review key clinical data for panitumumab in mCRC across the lines of treatment, assessing in detail the impact of more comprehensive RAS selection on patient outcomes. Panitumumab data across first- to third-line therapy consistently demonstrate that by testing tumour RAS status, it is possible to select patients more likely to benefit from treatment.

Genetic evidence that intratumoral T-cell proliferation and activation are associated with recurrence and survival in patients with resected colorectal liver metastases

Though immune responses correlate with prognosis in primary colorectal cancer, the role of tumor immunity in metastatic disease is less clear. We hypothesized that patient survival and tumor recurrence correlate with transcriptional evidence of lymphocyte proliferation/activation in resected colorectal cancer liver metastases (CRLM). Microarray gene analysis was performed on liver tumor specimens from 96 patients who underwent resection for CRLM. A Cox proportional hazards model identified genes associated with overall survival (OS) and recurrence-free survival (RFS). Conventional gene ontology (GO) enrichment analysis ranked biologically relevant processes. Survival probabilities of prioritized processes were assessed. Protein expression was validated with immunohistochemistry in an independent set of patients. GO analysis identified and ranked unique biologic processes that correlated with survival. Genes that specifically functioned in the biologic process of "T-cell proliferation" were significant predictors of OS (P = 0.01), and both "T-cell proliferation" and "activation" were highly associated with RFS (P ≤ 0.01). Analysis of genes in these GO categories identified increased TNFSF14/LIGHT expression to be most associated with improved OS and RFS (P ≤ 0.0006). Immunohistochemistry of an independent validation set of CRLM confirmed that both increased tumor-infiltrating lymphocytes (TIL) and higher LIGHT expression on TILs were associated with improved OS and RFS. Differential expression of genes involved in T-cell proliferation/activation was associated with survival outcomes in a large number of surgical patients who underwent resection of CRLM. These biologic functions determined by GO analysis of the tumor microenvironment have identified specific immune-related genes that may be involved in an antitumor immune response.

ERCC1 Induction after Oxaliplatin Exposure May Depend on KRAS Mutational Status in Colorectal Cancer Cell Line: In Vitro Veritas

Introduction: Oxaliplatin (Oxa) is widely used in metastatic colorectal cancer (mCRC), but currently there are not valid predictors of response to this drug. In the control arms both of OPUS and PRIME studies Oxa seems more active in patients with mCRC with mutated (mt) KRAS than in those with wild type (wt) KRAS. Recently we have retrospectively confirmed this suggestion, therefore we have hypothesized that the mutational status of KRAS could influence the expression of ERCC1, one of the main mechanisms of Oxa resistance.

Material and Methods: We used four cell lines of colorectal cancer: two KRAS wild type (wt) (HCT-8 and HT-29) and two KRAS mt (SW620 and SW480). We evaluated the sensitivity of these cell lines to Oxa by MTT-test as well the ERCC1 levels before and after 24 h exposure to Oxa by Real-Time PCR. We silenced KRAS in a KRAS mt cell line (SW620LV) to evaluate the impact on Oxa sensitivity and ERCC1 levels. Lastly, ERCC1 was also silenced in order to confirm the importance of this protein as an Oxa resistance factor.

Results: The KRAS mt cell lines resulted more sensitive to Oxa (OR 2.68; IC 95% 1.511-4.757 p<0.001). The basal levels of ERCC1 did not show significant differences between KRAS mt and wt cell lines, however, after 24 h exposure to Oxa, only the wt KRAS lines showed the ability to induce ERCC1, with a statistically significant difference (OR 42.9 IC 95% 17.260-106.972 p<0.0005). By silencing KRAS, sensitivity to Oxa was reduced in mt KRAS cell lines and this effect was associated with the acquisition of ability to induce ERCC1. Silencing of ERCC1, in turn, enhanced the sensitivity to Oxa in wt KRAS cell lines and restored sensitivity to Oxa in SW620LV cell line.

Conclusion: KRAS mutated cell lines were more sensitive to Oxa. This feature seems secondary to the inability of these cells to induce ERCC1 after exposure to Oxa. Thus, KRAS mutational status might be a predictor of response to Oxa in CRC surrogating the cell ability to induce ERCC1.

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.

A systematic review of salvage therapy to patients with metastatic colorectal cancer previously treated with fluorouracil, oxaliplatin and irinotecan +/- targeted therapy

Oxaliplatin, irinotecan and 5-fluorouracil in combination with or without targeted therapies are well-documented treatment options for first- and second-line treatments of metastatic colorectal cancer. However, there are much less data on the beneficial effect on systemic therapy in the third-line setting. We therefore performed a systematic review of the current literature on third or later lines of treatment to patients with metastatic colorectal cancer after the use of approved drugs or combinations.

METHODS

A computer-based literature search was carried out using Pubmed and data reported at international meetings. Original studies reporting ≥15 patients who had previously received 5-fluorouracil, oxaliplatin and irinotecan were included. Furthermore, patients with KRAS wild type tumours should had received EGFR-directed therapy.

RESULTS

Conventional chemotherapeutic agents as capecitabine, mitomycin C, and gemcitabine have limited or no activity. Retreatment with oxaliplatin might be an option in selected patients. In addition, rechallenge with EGFR-directed therapy might be a valuable strategy. Data also suggest that angiogenetic drugs may postpone further progression and prolong survival. Lately, regorafinib has been approved. In conclusion, our current knowledge is based on many retrospective studies, some phase II studies and very few randomized clinical trials. Further prospective phase III trials comparing an investigational drug or combination with best supportive care in third- or later lines of treatment in metastatic colorectal cancer are highly warranted. Identification of predictive biomarkers and improvement of our understanding of molecular mechanisms is crucial.

Panitumumab in the management of patients with KRAS wild-type metastatic colorectal cancer

The past 15 years has seen a marked increase in available therapeutic options for patients with metastatic colorectal cancer resulting in improvements in median survival from 12 to 24 months. One of these new options is panitumumab, which is a fully humanized monoclonal antibody that binds to the epidermal growth factor receptor of tumor cells and inhibits downstream cell signaling with antitumor effects of inhibition of tumor growth, induction of apoptosis and inhibition of angiogenesis. Large randomized clinical trials have demonstrated significant improvements in tumor response rates and progression-free survival when panitumumab is combined with chemotherapy and as monotherapy in chemorefractory metastatic colorectal cancer. Clinical benefit with panitumumab is limited to patients with nonmutated KRAS tumors. Rash is a common toxicity of panitumumab treatment but can potentially be ameliorated with the use of prophylactic strategies. The role of panitumumab in the overall treatment of metastatic colorectal cancer is evolving and future clinical trials will focus on improved patient selection through use of novel predictive biomarkers, and the optimal timing of treatment.

Targeted therapy-induced diarrhea: A review of the literature

PURPOSE OF RESEARCH

Revision of the literature on targeted therapy-induced diarrhea (TT-ID).

PRINCIPAL RESULTS

TT-ID is frequent; the mechanisms are mainly secretive, followed by ischemic or autoimmune ones. The duration of TT-ID is protracted over time. Its intensity is of grade G1-G3 but may be fatal in patients with diffuse colitis or on ipilimumab. However, no specific guidelines are available on management of different grades of TT-ID. Preventive measures with antibiotics, probiotics or activated charcoal should be further investigated. Loperamide is the first choice drug followed by octreotide. The role of corticosteroids is controversial.

CONCLUSION

Early assessment and management of TT-ID is essential to prevent the worsening of this side-effect, patients' hospitalization and dose reduction or oncological treatment discontinuation. Future research is needed to better understand the pathophysiological mechanisms of TT-ID and it should also be investigated whether a specific pharmacological and/or non pharmachological approach is indicated.

Management of advanced colorectal cancer, Part 2

PURPOSE

Important developments in chemotherapy for advanced colorectal cancer over the past 15 years are reviewed, with an emphasis on the most recently published data from clinical trials of newer multidrug regimens, administration techniques, and dosing schedules.

SUMMARY

Eight agents are approved by the Food and Drug Administration (FDA) for use in treating patients with advanced colorectal cancer. Fluorouracil and leucovorin still constitute the foundation of most chemotherapy regimens for this population; combination fluorouracil-leucovorin therapy plus either irinotecan (the FOLFIRI regimen) or oxaliplatin (the FOLFOX regimen) are two firmly established first-line treatments shown to produce similar outcomes. In Phase III trials conducted over the past six to seven years, regimens of capecitabine plus oxaliplatin (CapeOx) were demonstrated to have clinical effectiveness comparable to that of FOLFOX therapy. Response rates of 35-55% and median overall survival of ≥20 months have been documented with some of the newer regimens. Research to define the optimal role of the three monoclonal antibody agents approved by FDA for use in managing advanced colorectal cancer is ongoing; bevacizumab has been shown to confer significant survival benefits when added to certain chemotherapy regimens, and other monoclonal antibodies (cetuximab and panitumumab) also appear to offer significant benefits in select patients as first- or second-line therapies.

CONCLUSION

Over the past 15 years, a shift toward multiagent treatment strategies including a variety of chemotherapy agents and monoclonal antibodies has yielded improved rates of response and prolonged survival among patients with advanced colorectal cancer. The CapeOx, FOLFOX, and FOLFIRI regimens are currently among the most widely used first-line treatments.

Gene expression profiles can predict panitumumab monotherapy responsiveness in human tumor xenograft models

BACKGROUND

Epidermal growth factor receptor (EGFR)-targeted agents have demonstrated clinical benefit in patients with cancer. Identifying tissue-of-origin-independent predictive biomarkers is important to optimally treat patients. We sought to identify a gene array profile that could predict responsiveness to panitumumab, a fully human EGFR-binding antibody, using preclinical models of human cancer.

METHODS

Mice bearing 25 different xenograft models were treated twice weekly with panitumumab or immunoglobulin G2 control to determine their responsiveness to panitumumab. Samples from these xenografts and untreated xenografts were arrayed on the Affymetrix human U133A gene chip to identify gene sets predicting responsiveness to panitumumab using univariate and multivariate analyses. The predictive models were validated using the leave-one-group-out (LOO) method.

RESULTS

Of the 25 xenograft models tested, 12 were responsive and 13 were resistant to panitumumab. Unsupervised analysis demonstrated that the xenograft models clustered by tissue type rather than responsiveness to panitumumab. After normalizing for tissue effects, samples clustered by responsiveness using an unsupervised multidimensional scaling. A multivariate selection algorithm was used to select 13 genes that could stratify xenograft models based on responsiveness after adjustment for tissue effects. The method was validated using the LOO method on a training set of 22 models and confirmed independently on three new models. In contrast, a univariate gene selection method resulted in higher misclassification rates.

CONCLUSION

A model was constructed from microarray data that prospectively predict responsiveness to panitumumab in xenograft models. This approach may help identify patients, independent of disease origin, likely to benefit from panitumumab.

Pruritus in patients treated with targeted cancer therapies: systematic review and meta-analysis

BACKGROUND

Pruritus has been anecdotally described in association with targeted cancer therapies. The risk of pruritus has not been systematically ascertained.

OBJECTIVE

A systematic review and meta-analysis of the literature was conducted for axitinib, cetuximab, dasatinib, erlotinib, everolimus, gefitinib, imatinib, ipilimumab, lapatinib, nilotinib, panitumumab, pazopanib, rituximab, sorafenib, temsirolimus, tositumomab, vandetanib, and vemurafenib.

METHODS

Databases from PubMed, Web of Science (January 1998 through July 2012), and American Society of Clinical Oncology abstracts (2004 through 2012) were searched. Incidence and relative risk of pruritus were calculated using random- or fixed-effects model.

RESULTS

The incidences of all-grade and high-grade pruritus were 17.4% (95% confidence interval 16.0%-19.0%) and 1.4% (95% confidence interval 1.2%-1.6%), respectively. There was an increased risk of all-grade pruritus (relative risk 2.90 [95% confidence interval 1.76-4.77, P < .001]) and variation among different drugs (P < .001).

LIMITATIONS

The reporting of pruritus may vary, resulting from concomitant medications, comorbidities, and underlying malignancies. We found a higher incidence of pruritus in patients with solid tumors, concordant with those targeted therapies with the highest pruritus incidences.

CONCLUSION

There is a significant risk of developing pruritus in patients receiving targeted therapies. To prevent suboptimal dosing and decreased quality of life, patients should be counseled and treated against this untoward symptom.

Identification of a KRAS mutation in a patient with non-small cell lung cancer treated with chemoradiotherapy and panitumumab

RTOG 0839 is a Phase II study of pre-operative chemoradiotherapy with or without panitumumab in potentially operable locally advanced non-small cell lung cancer (NSCLC). The investigational agent, panitumumab, is an anti-epithelial growth factor receptor (EGFR) antibody that improves progression-free survival in chemorefractory metastatic colorectal cancer (mCRC). Recently, both KRAS mutational status (i.e., mutated or not) and subtype (i.e., activating or inactivating) have been shown to be predictive of response to anti-EGFR therapy in mCRC. However, in NSCLC, it is unknown if KRAS mutational status or subtype predict benefit to anti-EGFR therapies because of unique genetic and epigenetic factors unique to each cancer. We present a patient with stage III NSCLC containing a KRAS G12D activating mutation who had a partial pathologic response, with disappearance of a minor KRAS mutant clone. This case suggests possible eradication of the G12D KRAS lung cancer clones by concurrent chemoradiation with panitumumab.

Immunotherapy for gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) cancers are the most common human tumors encountered worldwide. The majority of GI cancers are unresectable at the time of diagnosis, and in the subset of patients undergoing resection, few are cured. There is only a modest improvement in survival with the addition of modalities such as chemotherapy and radiation therapy. Due to an increasing global cancer burden, it is imperative to integrate alternative strategies to improve outcomes. It is well known that cancers possess diverse strategies to evade immune detection and destruction. This has led to the incorporation of various immunotherapeutic strategies, which enable reprogramming of the immune system to allow effective recognition and killing of GI tumors.

METHODS

A review was conducted of the results of published clinical trials employing immunotherapy for esophageal, gastroesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers.

RESULTS

Monoclonal antibody therapy has come to the forefront in the past decade for the treatment of colorectal cancer. Immunotherapeutic successes in solid cancers such as melanoma and prostate cancer have led to the active investigation of immunotherapy for GI malignancies, with some promising results.

CONCLUSIONS

To date, monoclonal antibody therapy is the only immunotherapy approved by the US Food and Drug Administration for GI cancers. Initial trials validating new immunotherapeutic approaches, including vaccination-based and adoptive cell therapy strategies, for GI malignancies have demonstrated safety and the induction of antitumor immune responses. Therefore, immunotherapy is at the forefront of neoadjuvant as well as adjuvant therapies for the treatment and eradication of GI malignancies.

Systemic cancer therapy: achievements and challenges that lie ahead

In the last half of the century, advances in the systemic therapy of cancer, including chemotherapy, hormonal therapy, targeted therapy, and immunotherapy have been responsible for improvements in cancer related mortality in developed countries even as the population continues to age. Although such advancements have yet to benefit all cancer types, systemic therapies have led to an improvement in overall survival in both the adjuvant and metastatic setting for many cancers. With the pressure to make therapies available as soon as possible, the side-effects of systemic therapies, in particular long-term side-effects are not very well characterized and understood. Increasingly, a number of cancer types are requiring long-term and even lifelong systemic therapy. This is true for both younger and older patients with cancer and has important implications for each subset. Younger patients have an overall greater expected life-span, and as a result may suffer a greater variety of treatment related complications in the long-term, whereas older patients may develop earlier side-effects as a result of their frailty. Because the incidence of cancer in the world will increase over the next several decades and there will be more people living with cancer, it is important to have an understanding of the potential side-effects of new systemic therapies. As an introductory article, in this review series, we begin by describing some of the major advances made in systemic cancer therapy along with some of their known side-effects and we also make an attempt to describe the future of systemic cancer therapy.

New and potential clinical applications of KRAS as a cancer biomarker

IMPORTANCE OF THE FIELD

KRAS mutation is the most common oncogenic alteration in various human cancers. Recently, KRAS has emerged as an important predictive biomarker in common malignancies such as metastatic colorectal cancer (mCRC) and non-small cell lung cancer (NSCLC). This work aims to discuss the clinical impact of the KRAS mutation status on state-of-the-art treatment approaches, including epidermal growth factor receptor (EGFR)-targeted therapies.

AREAS COVERED IN THIS REVIEW

This review considers the potential of KRAS to serve as a diagnostic, prognostic or predictive biomarker in various cancers, including those of the lung, colon/rectum, pancreas, ovary and endometrium.

WHAT THE READER WILL GAIN

KRAS mutations in mCRC and NSCLC primary tumors predict resistance to EGFR-targeted therapy. In pancreatic cancer, KRAS may prove useful as a diagnostic biomarker to screen for early neoplasia. Furthermore, quantitative KRAS mutation analysis could have the potential to distinguish pancreatic cancer from other conditions such as chronic pancreatitis. With respect to ovarian and endometrial cancer, further studies should focus on determining reliable biomarkers for predicting response to EGFR-targeted therapy. Besides EGFR inhibition, KRAS may also serve as a diagnostic and predictive biomarker for evolving therapies directed against mutant RAS proteins.

TAKE HOME MESSAGE

KRAS has been recognized as an outstanding predictive biomarker to select mCRC and NSCLC patients for EGFR-targeted therapies; however, multi-determinant approaches including other molecular markers should facilitate the identification of patients likely to respond to such therapies.

EGFR gene copy number as a prognostic marker in colorectal cancer patients treated with cetuximab or panitumumab: a systematic review and meta analysis

Background

The epidermal growth factor receptor (EGFR) gene copy number (GCN) has been previously demonstrated to correlate with the clinical outcome of colorectal cancer (CRC) treated with anti-EGFR monoclonal antibodies (mAbs), although it remains controversial. We conducted a systematic review and meta-analysis to assess EGFR GCN as a potential biomarker of survival for patients with advanced CRC receiving treatment with anti-EGFR mAbs.

Methods

We systematically identified articles investigating EGFR GCN by fluorescent or chromogenic in situ hybridization or other detection techniques in patients with metastatic CRC treated with panitumumab or cetuximab, (last search: 10 August 2012). Eligible studies had to report on overall survival (OS), progression-free survival (PFS) or time-toprogression (TTP), stratified by EGFR GCN. Summary hazard ratios (HRs) were calculated using random-effects models.

Results

Among 13 identified studies, 10 (776 patients, 302 with increased GCN), 8 (893 patients, 282 with increased GCN) and 3 (149 patients, 66 with increased GCN) were eligible for the OS, PFS and TTP meta-analyses, respectively. Increased EGFR GCN was associated with increased OS (HR = 0.62; 95% CI 0.50–0.77; P<0.001), PFS (HR = 0.65; 95% CI 0.47–0.89; P = 0.008) but not TTP (HR = 0.71; 95% CI 0.44–1.14; P = 0.157). It was also shown that EGFR GCN is independent of other factors such as KRAS status. Among those populations received second-line or higher treatment, increased EGFR GCN was strongly associated with improved survival (for OS, HR = 0.60; 95% CI 0.47–0.75; P<0.001; for PFS, HR = 0.59; 95% CI 0.47–0.75; P<0.001), whereas it did not influence survival in patients that received first-line therapy.

Conclusion

Among the anti-EGFR-treated patients, increased EGFR GCN appears to be associated with improved survival outcomes. The effect on survival appears to be related to patients receiving the line of treatment.