Pharmacogenetic profiling for cetuximab plus irinotecan therapy in patients with refractory advanced colorectal cancer

Evaluation of the additional prophylactic effect of topical steroid ointment to systemic minocycline against anti-epidermal growth factor antibody-induced skin toxicities in metastatic colorectal cancer treatment

BACKGROUND

Anti-epidermal growth factor receptor (EGFR) antibodies often cause skin toxicities. Preemptive skin treatments using systemic antibiotics with or without topical steroid are reportedly effective although the most suitable method remains unclear. This study aimed to determine whether combination prophylaxis using systemic minocycline and topical steroid is superior to minocycline alone in a real-world metastatic colorectal cancer (mCRC) treatment.

METHODS

Patients with mCRC (n = 87) who received anti-EGFR monoclonal antibodies were retrospectively assessed. The primary objective was to compare the incidence of grade ≥ 2 overall skin toxicities during all treatment periods between the control group receiving prophylactic minocycline 100 mg/day, and the combination prophylaxis group receiving minocycline 100 mg/day + topical steroid. The incidence of each skin symptom was also evaluated.

RESULTS

The incidence of grade ≥ 2 overall skin toxicities was 63.6% in the control and 56.9% in the combination groups, with no significant difference (P = 0.63). Similarly, the incidence of grade ≥ 2 dry skin, fissures, paronychia, and pruritus did not significantly differ. In addition, incidence of all-grade skin toxicities was not different. However, the incidence of grade ≥ 2 papulopustular rashes was significantly lower in the combination group (23.1% vs. 50.0%, P = 0.03). Propensity score-matched analysis supported these results. Multivariate logistic regression analysis showed no significant association between combination prophylaxis and grade ≥ 2 overall skin toxicities, but it did show a reduction in grade ≥ 2 papulopustular rashes.

CONCLUSION

Adding topical steroids to systemic minocycline did not mitigate grade ≥ 2 overall skin toxicities induced by anti-EGFR antibodies; however, it significantly improved papulopustular rashes.

Pharmacogenetics Role of Genetic Variants in Immune-Related Factors: A Systematic Review Focusing on mCRC

Pharmacogenetics plays a key role in personalized cancer treatment. Currently, the clinically available pharmacogenetic markers for metastatic colorectal cancer (mCRC) are in genes related to drug metabolism, such as DPYD for fluoropyrimidines and UGT1A1 for irinotecan. Recently, the impact of host variability in inflammatory and immune-response genes on treatment response has gained considerable attention, opening innovative perspectives for optimizing tailored mCRC therapy. A literature review was performed on the predictive role of immune-related germline genetic biomarkers on pharmacological outcomes in patients with mCRC. Particularly, that for efficacy and toxicity was reported and the potential role for clinical management of patients was discussed. Most of the available data regard therapy effectiveness, while the impact on toxicity remains limited. Several studies focused on the effects of polymorphisms in genes related to antibody-dependent cellular cytotoxicity (FCGR2A, FCGR3A) and yielded promising but inconclusive results on cetuximab efficacy. The remaining published data are sparse and mainly hypothesis-generating but suggest potentially interesting topics for future pharmacogenetic studies, including innovative gene-drug interactions in a clinical context. Besides the tumor immune escape pathway, genetic markers belonging to cytokines/interleukins (IL-8 and its receptors) and angiogenic mediators (IGF1) seem to be the best investigated and hopefully most promising to be translated into clinical practice after validation.

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

Association between miRNA signatures in serum samples from epidermal growth factor inhibitor treated patients and skin toxicity

Objective: Epidermal growth factor receptor inhibitors (EGFRI) are used as targeted cancer therapy. On average 70% of patients treated with EGFRIs suffer from skin toxicity. Studies showed a correlation between overall survival and the appearance of a skin rash, which is used as a biomarker for therapy efficacy. Micro RNAs (miRNA) as tumor or resistance biomarkers for cancer therapy are also highly investigated. In our study, we searched for associations of miRNA expression profiles in serum, with the severity of skin rash, in order to identify tentative therapy predictive biomarkers.

Materials and Methods: Five candidate miRNAs were selected, based on an earlier in vitro next-generation-sequencing-experiment and after literature search. MiR-21, miR-31, miR-17, miR-106b and miR-520e were investigated in serum samples from patients (n = 254) treated with EGFRI. The quantitative expression of miRNA was tested for association with the occurrence/severity of the rash.

Results: In our cohort of patients treated with EGFR inhibiting monoclonal antibodies, miR-21 and miR-520e serum concentrations were negatively correlated with severity of skin rash (p-value 0.000582 and 1.53e-07 linear-trend-test) whereas for miR-31, a positive correlation was observed (p-value 9.01e-06 linear-trend-test).

Conclusions: This suggests that miR-21, miR-31 and miR-520e expression might be a treatment dependent marker for EGFRI induced skin rash.

Is there any clinical or laboratory predictive factor for cetuximab-induced skin toxicity?

BACKGROUND: We aim to explore the predictive role of clinical and hematological parameters for cetuximab-induced skin toxicity (CI-ST) and survival outcomes in patients according to risk categories.RESEARCH DESIGN AND METHODS: The optimal cut-off values for hematological parameters were assessed by the Receiver Operating Characteristic (ROC) analysis. Patients were classified as High risk, Intermediate risk and Low risk subgroups with respect to platelet to lymphocyte ratio (PLR) and red blood cell count (RBC) values. Kaplan-Meier test was used for survival analysis, and outcomes were analyzed by Log-rank test. P-value <0.05 considered as statistically significant.RESULTS: Among hematological parameters, only PLR and RBC were statistically significant prognostic factors.Optimal cut-off value for PLR was 196.2 (82.9% sensitivity and 61.1% specificity), and 4.610x106/µL for RBC count (65.9% sensitivity and 81.1% specificity). Patients in high risk group had increased risk with an OR:69.34 (p<0.0001), and in the intermediate risk group had an OR:28.73 (p=0.002) for CI-ST. De novo metastatic patients had 9.11-fold increased risk for CI-ST compared to recurrent metastatic patients (p=0.028).CONCLUSION: Our study indicates that risk categories based on PLR and RBC can predict CI-ST and de novo metastatic patients had higher risk for CI-ST.

The association between adverse events and outcome under checkpoint inhibitors: Where is the deal?

•

A review which lays out different potential contributions which can help to understand the IRAEs-outcome link.

•

There is a possibility to compute a multifactorial index to characterise patients as ICI sensitive or ICI unsensitive.

•

Prospective trails with ICIs are now fesaible to shape patient care beyond high -dose steroids.

Recent reports have put into evidence the possibility of a link between immune-related adverse events (IRAEs) and treatment outcome, patients drawing a benefit from treatment being also exposed to the risk to develop toxicity.

A still unanswered question remains the biological origin(s) which can sustain and explain such a relationship.

The purpose of this review paper is to lay out different potential contributions which can help to understand the IRAEs-outcome link and to propose clinical perspectives taking advantage of this association.

In this respect, pharmacokinetics aspects, immunological and immunogenetics implications have been taken into consideration.

Phase 2 study of cetuximab (Erbitux) in patients with progressive or recurrent endometrial cancer

INTRODUCTION

Overexpression of the epidermal growth factor receptor (EGFR) found in common subtypes of endometrial cancer has been associated with advanced stage disease and a poor prognosis. The purpose of this phase 2 study was to evaluate the efficacy and safety of cetuximab in patients with recurrent endometrial cancer.

METHODS

The study was an open-label phase 2 clinical trial conducted at two institutions. Patients with recurrent or progressive endometrial cancer of any histologic type with the exception of uterine sarcoma received cetuximab at an initial dose of 400 mg/m² IV followed by weekly doses of 250 mg/m². One cycle was considered 4 weeks of treatment. The primary efficacy endpoint was clinical benefit response, defined as a complete or partial response or prolonged stable disease (>8 weeks) by RECIST 1.0 criteria.

RESULTS

A total of 30 patients were enrolled with a median age of 64 years (range 42-83). Of the 20 evaluable patients, three (15%) had clinical benefit response (one complete response, two stable disease). The patient with a clinical benefit response received a total of 27 cycles and the two patients with stable disease were taken off the study due to progression after four and six cycles, respectively. Of the 10 inevaluable patients, nine received ≤1 cycle due to clinical deterioration and one had an anaphylactic reaction. One patient had a grade 3 rash which resolved after a delay in treatment. No dose reduction was reported.

CONCLUSIONS

In this cohort, single agent therapy with cetuximab was well tolerated and had a 15% clinical benefit response. Further studies are required to better identify patients who may respond to this treatment.

Genetic Markers of the Host to Predict the Efficacy of Colorectal Cancer Targeted Therapy

The introduction of anti-EGFR (cetuximab and panitumumab) and antiangiogenic (bevacizumab, regorafeninb, ramucirumab, and aflibercept) agents in the therapeutic armamentarium of the metastatic colorectal cancer (CRC) has significantly improved the therapeutic efficacy and patients survival. However, despite the great improvements achieved in the patients life expectation, the high inter-individual heterogeneity in the response to the targeted agents still represent an issue for the management of advanced CRC patients. Even if the role of tumor genetic mutations as predictive markers of drug efficacy has been well-established, the contribution of the host genetic markers is still controversial. Promising results regard the germ-line immune-profile, inflammation and tumor microenvironment. Inherent variations in KRAS 3'UTR region as well as EGF/ EGFR genes were investigated as markers of cetuximab effectiveness. More recently interesting data in the field of anti- EGFR agents were generated also for germ-line variants in genes involved in inflammation (e.g. COX-2, LIFR, IGF1 signaling), immune system (e.g., FCGRs, IL-1RA), and other players of the RAS signaling, including the Hippo pathway related genes (e.g. Rassf, YAP, TAZ). Host genetic variants in VEGF-dependent (i.e., EGF, IGF-1, HIF1α, eNOS, iNOS) and -independent (i.e., EMT cascade, EGFL7) pathways, with specific attention on inflammation and immune system-related factors (e.g., IL-8, CXCR-1/2, CXCR4-CXCL12 axis, TLRs, GADD34, PPP1R15A, ANXA11, MKNK1), were investigated as predictive markers of bevacizumab outcome, generating some promising results. In this review, we aimed to summarize the most recent literature data regarding the potential role of common and rare inhered variants in predicting which CRC patients will benefit more from a specifically targeted drug administration.

Fc-gamma receptor polymorphisms, cetuximab therapy, and overall survival in the CCTG CO.20 trial of metastatic colorectal cancer

Background

Two germ line Fc‐γ receptor (FCGR) polymorphisms, rs1801274 [FCGR2A; His(H)131Arg(R)] and rs396991 [FCGR3A; Phe(F)158Val(V)], produce altered proteins through amino acid substitutions. We previously reported that the FCGR2A H/H genotype was associated with longer overall survival (OS) in cetuximab‐treated chemotherapy‐refractory patients with metastatic colorectal cancer. Here, we aimed to replicate and extend this finding in the Canadian Clinical Trials Group CO.20 trial.

Methods

After germ line DNA genotyping, polymorphic relationships with survival were assessed using log‐rank tests and hazard ratios (HR) from Cox proportional hazard models, adjusting for known prognostic factors. The dominant genetic inheritance model was used for the main analysis.

Results

Of 592 wild‐type KRAS patients treated with cetuximab, those with the FCGR2A H/H genotype (n = 165, 28%) had improved OS (HR: 0.66, P < 0.001; median absolute benefit, 1.3 months) compared to those with R/‐ genotype (n = 427, 72%). Patients with H/R had intermediate results under a codominant genetic inheritance model (HR: 0.72, P = 0.003). No significant associations were found between FCGR3A genotype and OS. In an exploratory analysis, patients with the combination of FCGR2A H/H + FCGR3A F/F genotype had significantly better OS (HR: 0.33, P = 0.003; median absolute benefit, 12.5 months) than patients with the combination of double‐variant R/R + V/V genotype. Progression‐free survival results were similar to OS. Toxicity rates were not associated with either polymorphism.

Conclusions

The FCGR2A genotype was associated with efficacy but not with toxicity in wild‐type KRAS, cetuximab‐treated colorectal cancer patients. FCGR3A genotype may modulate the relationship between FCGR2A polymorphism and outcome. FCGR2A is a promising biomarker for clinical management for these patients.

Associations between skin rash, treatment outcome, and single nucleotide polymorphisms in head and neck cancer patients receiving the EGFR-inhibitor zalutumumab: results from the DAHANCA 19 trial

PURPOSE

To study the associations between development of moderate to severe skin rash, clinical outcome, and single nucleotide polymorphisms (SNPs) in candidate genes in head and neck cancer patients from the DAHANCA 19 trial receiving the EGFR-inhibitor zalutumumab concurrently with radiation treatment.

MATERIAL AND METHODS

310 patients were included from the zalutumumab-arm of the DAHANCA 19 study. Nine SNPs in the candidate genes EGFR, EGF, AREG, FCGR2A, FCGR3A, and CCND1 were successfully determined in 294 patients. Clinical endpoints were moderate to severe skin rash within the first 3 weeks of treatment, loco-regional failure (LRF), disease-specific survival (DSS), and overall survival (OS).

RESULTS

During the first 3 weeks of treatment, 86% of the patients experienced any grade of rash and 17% experienced a moderate to severe rash. Development of moderate to severe rash was not associated with LRF or DSS but was associated with improved OS, HR 0.40 (95% CI: 0.19-0.82). The effect was similar for patients with p16-negative or p16-positive tumors (p = .90). After adjustment for comorbidity and performance status, the minor alleles of SNPs rs9996584 and rs13104811 located near the AREG gene were significantly associated with increased risk of moderate to severe rash with per-allele odds ratios of 1.61 (1.01-2.54) and 1.56 (1.00-2.44). SNP rs11942466 located close to rs9996584 had a borderline significant association, and none of the other SNPS were significantly associated with risk of skin rash.

CONCLUSIONS

Moderate to severe skin rash after zalutumumab during radiation treatment was associated with improved OS, independent of HPV/p16-status. Genetic variants in AREG (member of the EGF family) may be associated with increased risk of skin rash.

The DNA-polymorphism rs849142 is associated with skin toxicity induced by targeted anti-EGFR therapy using cetuximab

Skin toxicity (ST) is a frequent adverse effect (AE) in anti-epidermal growth factor receptor (EGFR)-targeted treatment of metastatic colorectal cancer (mCRC) resulting in decreased quality of life and problems in clinical management. We wanted to identify biomarkers predicting ST in this setting and focused on 70 DNA polymorphisms associated with acne, the (immunoglobulin fragment crystallizable region) Fcγ-receptor pathway, and systemic lupus erythematosus (SLE) applying next-generation-sequencing (NGS). For the analysis patients with mCRC treated with cetuximab were selected from the FIRE-3 study. A training group consisting of the phenotypes low (1) - and high-grade (3) ST (n = 16) and a validation group (n = 55) representing also the intermediate grade (2) were genotyped and investigated in a genotype-phenotype association analysis. The single nucleotide polymorphism (SNP) rs849142 significantly associated with ST in both the training- (p < 0.01) and validation-group (p = 0.04). rs849142 is located in an intron of the juxtaposed with another zinc finger protein 1 (JAZF1) gene. Haplotype analysis demonstrated significant linkage disequilibrium of rs849142 with JAZF1. Thus, rs849142 might be a predictive biomarker for ST in anti-EGFR treated mCRC patients. Its value in the clinical management of AE has to be validated in larger cohorts.

Host genetic profiling to increase drug safety in colorectal cancer from discovery to implementation

Adverse events affect the pharmacological treatment of approximately 90% of colorectal cancer (CRC) patients at any stage of the disease. Chemotherapy including fluoropyrimidines, irinotecan, and oxaliplatin is the cornerstone of the pharmacological treatment of CRC. The introduction of novel targeted agents, as anti-EGFR (i.e. cetuximab, panitumumab) and antiangiogenic (i.e. bevacizumab, ziv-aflibercept, regorafenib, and ramucirumab) molecules, into the oncologist's toolbox has led to significant improvements in the life expectancy of advanced CRC patients, but with a substantial increase in toxicity burden. In this respect, pharmacogenomics has largely been applied to the personalization of CRC chemotherapy, focusing mainly on the study of inhered polymorphisms in genes encoding phase I and II enzymes, ATP-binding cassette (ABC)/solute carrier (SLC) membrane transporters, proteins involved in DNA repair, folate pathway and immune response. These research efforts have led to the identification of some validated genetic markers of chemotherapy toxicity, for fluoropyrimidines and irinotecan. No validated genetic determinants of oxaliplatin-specific toxicity, as peripheral neuropathy, has thus far been established. The contribution of host genetic markers in predicting the toxicity associated with novel targeted agents' administration is still controversial due to the heterogeneity of published data. Pharmacogenomics guidelines have been published by some international scientific consortia such as the Clinical Pharmacogenomics Implementation Consortium (CPIC) and the Dutch Pharmacogenetics Working Group (DPWG) strongly suggesting a pre-treatment dose adjustment of irinotecan based on UGT1A1*28 genotype and of fluoropyrimidines based on some DPYD genetic variants, to increase treatment safety. However, these recommendations are still poorly applied at the patient's bedside. Several ongoing projects in the U.S. and Europe are currently evaluating how pharmacogenomics can be implemented successfully in daily clinical practice. The majority of drug-related adverse events are still unexplained, and a great deal of ongoing research is aimed at improving knowledge of the role of pharmacogenomics in increasing treatment safety. In this review, the issue of pre-treatment identification of CRC patients at risk of toxicity via the analysis of patients' genetic profiles is addressed. Available pharmacogenomics guidelines with ongoing efforts to implement them in clinical practice and new exploratory markers for clinical validation are described.

Germline polymorphisms as biomarkers of tumor response in colorectal cancer patients treated with anti-EGFR monoclonal antibodies: a systematic review and meta-analysis

Studies of germline polymorphisms as predictors of tumor response to anti-epidermal growth factor receptor (EGFR) monoclonal antibody agents in metastatic colorectal cancer have reported inconsistent results. We performed a systematic review of studies from 1990 to September 2015, followed by random-effects meta-analyses for polymorphisms examined in at least three studies. Of 87 studies, 40 passed the criteria for systematic review and 23 for meta-analysis. The polymorphisms suitable for meta-analysis were CCND1 (rs17852153), COX2 (rs20417), EGF (rs4444903), EGFR (rs712829, rs11543848, 3'UTR CA repeat), FCGR2A (rs1801274), FCGR3A (rs396991), IL8 (rs4073), KRAS (rs61764370) and VEGFA (rs3025039). Meta-analysis yielded nominal significance (at α=0.05) for rs4444903 and rs11543848, but showed no significant results after multiple testing correction; this was unchanged by sensitivity analyses to address subgroups, funnel-plot asymmetries, and study quality. This highlights a tendency for lack of replication in the face of initial positive results, and possibly the unsuitability of relying on tumor response as a surrogate marker in this setting.

Comprehensive pharmacogenetic profiling of the epidermal growth factor receptor pathway for biomarkers of response to, and toxicity from, cetuximab

BACKGROUND

Somatic mutations in the epidermal growth factor receptor (EGFR) intracellular signalling pathways predict non-response to cetuximab in the treatment of advanced colorectal cancer (aCRC). We hypothesised that common germline variants within these pathways may also play similar roles.

METHODS

We analysed 54 potentially functional, common, inherited EGFR pathway variants in 815 patients with aCRC treated with oxaliplatin-fluoropyrimidine chemotherapy plus cetuximab. Primary endpoints were response and skin rash (SR). We had >85% power to detect ORs=1.6 for variants with minor allele frequencies >20%.

RESULTS

We identified five potential biomarkers for response and four for SR, although none remained significant after correction for multiple testing. Our initial data supported a role for Ser313Pro in PIK3R2 in modulating response to cetuximab-in patients with KRAS wild-type CRCs, 36.4% with one allele encoding proline responded, as compared with 71.2% homozygous for allele encoding serine (OR 0.23, 95% CI 0.09 to 0.56, p=0.0014), and this association was predictive for cetuximab (pinteraction=0.017); however, independent replication failed to validate this association. No previously proposed predictive biomarkers were validated.

CONCLUSIONS

Our study highlights the need to validate potential pharmacogenetic biomarkers. We did not find strong evidence for common germline biomarkers of cetuximab response and toxicity.

Hypomagnesemia is a reliable predictor for efficacy of anti-EGFR monoclonal antibody used in combination with first-line chemotherapy for metastatic colorectal cancer

PURPOSE

Anti-EGFR monoclonal antibody is effective for KRAS wild-type metastatic colorectal cancer (mCRC), but frequently causes several adverse reactions, including hypomagnesemia and skin disorders. The present study was designed to investigate the relationship between the incidence of adverse reactions and therapeutic effects in mCRC patients receiving anti-EGFR monoclonal antibody in combination with first-line chemotherapy.

METHODS

Forty-three mCRC patients who received cetuximab or panitumumab between April 2012 and December 2015 were the subjects of the present study. All patients were pretreated with oral minocycline in combination with skin treatment using moisturizer for prevention of skin rash. Hypomagnesemia and acneiform rash were graded according to the Common Terminology Criteria for Adverse Events, version 3.0. Overall response rate (ORR) and time to treatment failure (TTF) were compared between patients with and without these adverse events.

RESULTS

The incidence rates of hypomagnesemia and acneiform rash were 32.6 % (grade 1: 20.9 %, grade 2: 11.6 %) and 93.0 % (grade 1: 41.9 %, grade 2: 41.9 %, grade 3: 9.3 %), respectively. ORR was significantly higher in patients with hypomagnesemia than in those without it (71.4 vs 34.5 %, P = 0.048). Median TTF tended to be longer, though not significantly, in patients with hypomagnesemia than in those without it. However, no significant difference in both ORR and median TTF was observed between patients with and without acneiform rash.

CONCLUSION

Hypomagnesemia may become a predicting factor for therapeutic effects of anti-EGFR monoclonal antibody in mCRC patients.

Combined assessment of EGFR-related molecules to predict outcome of 1st-line cetuximab-containing chemotherapy for metastatic colorectal cancer

Several studies have reported that epidermal growth factor receptor (EGFR)-related molecules may serve as predictors of cetuximab treatment for metastatic colorectal cancer (mCRC), such as EGFR gene copy number (GCN), expression of 2 ligands of EGFR, amphiregulin (AREG) and epiregulin (EREG), and EGFR CA simple sequence repeat 1 (CA-SSR1) polymorphism; however, these biomarkers still remain not useful in clinical practice since they have been evaluated using cohorts with patients treated in various settings of chemotherapy. We therefore analyzed associations of mRNA expression of AREG and EREG, EGFR GCN, and CA-SSR1 polymorphism [short (S;≤ 19) / long (L; ≥ 20)] with clinical outcomes in 77 Japanese patients with KRAS exon 2 wild-type mCRC enrolled in phase II trials of FOLFOX (n = 28/57, UMIN000004197) or SOX (n = 49/67, UMIN000007022) plus cetuximab as first-line therapy. High AREG expression correlated with significantly better progression-free survival (median 11.6 vs. 66 months, HR 0.52, P = 0.037); moreover, it remained statistically significant in multivariate analysis (HR: 0.48, P = 0.027). S/S genotype of CA-SSR1 predicted severe skin toxicity (P = 0.040). Patients with both AREG-low and EGFR low-GCN had significantly shorter overall survival than the others (median 22.2 vs. 42.8 months, HR 2.34, P = 0.042). The multivariate analysis showed that molecular status with both AREG-low and EGFR low-GCN was a predictor of worse survival (P = 0.006). In conclusion, AREG mRNA expression and EGFR CA-SSR1 polymorphism predict survival and skin toxicity, respectively, of initial chemotherapy with cetuximab. Our results also suggest potential prognostic value of the combined assessment of AREG and EGFR GCN for first-line cetuximab treatment.

Cost-Effectiveness of Cetuximab for Advanced Esophageal Squamous Cell Carcinoma

Background

Costly biologicals in palliative oncology are emerging at a rapid pace. For example, in patients with advanced esophageal squamous cell carcinoma addition of cetuximab to a palliative chemotherapy regimen appears to improve survival. However, it simultaneously results in higher costs. We aimed to determine the incremental cost-effectiveness ratio of adding cetuximab to first-line chemotherapeutic treatment of patients with advanced esophageal squamous cell carcinoma, based on data from a randomized controlled phase II trial.

Methods

A cost effectiveness analysis model was applied based on individual patient data. It included only direct medical costs from the health-care perspective. Quality-adjusted life-years and incremental cost-effectiveness ratios were calculated. Sensitivity analysis was performed by a Monte Carlo analysis.

Results

Adding cetuximab to a cisplatin-5-fluorouracil first-line regimen for advanced esophageal squamous cell carcinoma resulted in an the incremental cost-effectiveness ratio of €252,203 per quality-adjusted life-year. Sensitivity analysis shows that there is a chance of less than 0.001 that the incremental cost-effectiveness ratio will be less than a maximum willingness to pay threshold of €40,000 per quality-adjusted life-year, which is representative for the threshold used in The Netherlands and other developed countries.

Conclusions

Addition of cetuximab to a cisplatin-5-fluorouracil first-line regimen for advanced esophageal squamous cell carcinoma is not cost-effective when appraised according to currently accepted criteria. Cost-effectiveness analyses using outcome data from early clinical trials (i.c. a phase II trial) enable pharmaceutical companies and policy makers to gain early insight into whether a new drug meets the current eligibility standards for reimbursement and thereby potential admittance for use in regular clinical practice.

CA-SSR1 Polymorphism in Intron 1 of the EGFR Gene in Patients with Malignant Tumors Who Develop Acneiform Rash Associated with the Use of Cetuximab

Background and Objective

Epidermal growth factor receptor (EGFR) inhibitors are not equally effective in all cancer patients. One potential clinical factor that could help in selecting patients who may benefit from treatment with cetuximab is acneiform rash, which correlates with the clinical response to EGFR inhibitors. Some previous studies have suggested that the tendency to develop rash may depend on polymorphisms in the EGFR gene. In this investigation, the association of degree of CA dinucleotide polymorphism with skin rash and cetuximab therapy outcome was examined.

Methods

The study included 60 patients treated with cetuximab. For each patient, the severity of acneiform rash was assessed, and the type of polymorphism was determined by genotyping. Associations between genotypes, the acneiform rash, and response to treatment were determined by using the chi-square test and Spearman’s rank correlation. The cutoffs S ≤ 17(CA), L > 17(CA), n(CA) ≤ 35, and n(CA) > 35 were tested, as well as the sum of the two allele repetitions.

Results

A correlation was found between body surface area covered by rash and the sum of the two allele repetitions (p = 0.030). No statistically significant relationship between genotype and response to treatment was observed. However, in patients who have had partial remission, we noticed a higher incidence of polymorphism, with less CA dinucleotide repetitions and early onset of rash.

Conclusion

A correlation between genotype and severity of rash was observed. That is, the severity of rash decreased with an increased number of CA repetitions.

Biomarkers of skin toxicity induced by anti-epidermal growth factor receptor antibody treatment in colorectal cancer

Skin toxicity is a common symptom of anti-epidermal growth factor receptor (EGFR) antibody treatment and is also a predictive marker of its efficacy in colorectal cancer patients. However, severe skin disorders induced by such antibodies negatively impact on the quality of life of patients and decreases drug compliance during treatment. If we can predict the high-risk group susceptible to severe skin toxicity before treatment, we can undertake the early management of any arising skin disorders and formulate a more accurate prognosis for anti-EGFR antibody treatment. Previous studies have identified molecular markers of skin toxicity induced by anti-EGFR antibody, such as EGFR polymorphisms, the expression of inflammatory chemokines and serum levels of EGFR ligands. A clinical trial was undertaken involving the escalation of cetuximab doses, guided by the grade of skin toxicity observed, such as no or low-grade, in metastatic colorectal cancer (the EVEREST study). The dose escalation of cetuximab was confirmed by a safety profile and had the tendency to achieve a higher response rate in KRAS wild-type patients. A large, prospective randomized trial is now ongoing (EVEREST 2) and the results of this trial may contribute to personalized medicine in KRAS wild-type colorectal cancer patients.

A synonymous EGFR polymorphism predicting responsiveness to anti-EGFR therapy in metastatic colorectal cancer patients

Genetic factors are known to affect the efficiency of therapy with monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor (EGFR) in patients with metastatic colorectal cancer (mCRC). At present, the only accepted molecular marker predictive of the response to anti-EGFR mAbs is the somatic mutation of KRAS and NRAS as a marker of resistance to anti-EGFR. However, only a fraction of KRAS wild-type patients benefit from that treatment. In this study, we show that the EGFR gene polymorphism rs1050171 defines, independently of RAS mutational status, a sub-population of 11 % of patients with a better clinical outcome after anti-EGFR treatment. Median PFS for patients with the GG genotype was 10.17 months compared to 5.37 of those with AG + AA genotypes. Taken together, our findings could be used to better define CRC populations responding to anti-EGFR therapy. Further studies in larger independent cohorts are necessary to validate the present observation that a synonymous polymorphism in EGFR gene impacts on clinical responsiveness.

Pharmacogenomics of cetuximab in metastatic colorectal carcinoma

Cetuximab is a chimeric monoclonal antibody that has revolutionized the treatment of metastatic colorectal cancer. Knowledge of the mechanisms that underlie its effectiveness, as well as the primary and secondary resistance mechanisms, have led to important developments in the understanding of cetuximab biology. In light of knowledge gained from recent trials, the efficacy of cetuximab has been clearly demonstrated to depend upon RAS mutational status, moreover cetuximab should only be used in a subset of patients who may benefit. In this article, we critically review clinical and pharmacogenetic issues of cetuximab, focusing on the cost-effectiveness involved with the use of the drug.

FcγR and EGFR polymorphisms as predictive markers of cetuximab efficacy in metastatic colorectal cancer

BACKGROUND AND OBJECTIVES

Cetuximab shows activity in KRAS (Kirsten rat sarcoma viral oncogene homolog) wild-type metastatic colorectal cancer (mCRC). Recent studies have demonstrated that cetuximab induces antibody-dependent cell-mediated cytotoxicity (ADCC) in mCRC. We investigated the associations of FcγR (fragment C γ receptor) and EGFR (epidermal growth factor receptor) polymorphisms with the outcome of mCRC patients treated with cetuximab and FOLFIRI (folic acid/5-fluorouracil/irinotecan) as second-line therapy in the FLIER (Cetuximab Plus Folinic Acid/5-Fluorouracil/Irinotecan in KRAS Wild-Type Metastatic Colorectal Cancer as a Second-Line Treatment) study.

METHODS

A total of 57 patients were evaluated in this study. The association of each polymorphism with the response rate, progression-free survival, and overall survival was analyzed.

RESULTS

A tendency for longer overall survival was observed in patients with the EGFR CA repeat ≥36 genotype than in those with the ≤35 genotype (600 versus 483 days, P = 0.051). The haplotype containing the 131H and 158V alleles was associated with a lower response rate than the other haplotypes (P = 0.018). These results are contrary to previously published results.

CONCLUSION

Our data suggest that FcγR and EGFR CA repeat polymorphisms may be associated with the outcome of mCRC patients treated with cetuximab and FOLFIRI, although further investigations will be needed to confirm the association of FcγR and EGFR polymorphisms with the efficacy of cetuximab.

Methods: for studying pharmacogenetic profiles of combination chemotherapeutic drugs

INTRODUCTION

Molecular and genetic analysis of tumors and individuals has led to patient-centered therapies, through the discovery and identification of genetic markers predictive of drug efficacy and tolerability. Present therapies often include a combination of synergic drugs, each of them directed against different targets. Therefore, the pharmacogenetic profiling of tumor masses and patients is becoming a challenge, and several questions may arise when planning a translational study.

AREAS COVERED

The review presents the different techniques used to stratify oncology patients and to tailor antineoplastic treatments according to individual pharmacogenetic profiling. The advantages of these methodologies are discussed as well as current limits.

EXPERT OPINION

Facing the rapid technological evolution for genetic analyses, the most pressing issues are the choice of appropriate strategies (i.e., from gene candidate up to next-generation sequencing) and the possibility to replicate study results for their final validation. It is likely that the latter will be the major obstacle in the future. However, the present landscape is opening up new possibilities, overcoming those hurdles that have limited result translation into clinical settings for years.

FCGR polymorphisms and cetuximab efficacy in chemorefractory metastatic colorectal cancer: an international consortium study

OBJECTIVE

We aimed to better clarify the role of germline variants of the FCG2 receptor, FCGR2A-H131R and FCGR3A-V158F, on the therapeutic efficacy of cetuximab in metastatic colorectal cancer (mCRC). A large cohort with sufficient statistical power was assembled.

DESIGN

To show a HR advantage of 0.6 in progression-free survival (PFS) for FCGR2A-HH versus the rest and FCGR3A-VV versus the rest, with an 80% power, 80 Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) wild-type (KRAS-WT) and 52 KRAS-WT patients are required, respectively. This leads to a total sample size of 952 and 619 patients, respectively. Samples were collected from 1123 mCRC patients from 15 European centres treated with cetuximab alone or in combination with chemotherapy. Fc gamma receptor (FCGR) status was centrally genotyped. Two additional externally genotyped series were included.

RESULTS

Incidences of FCGR2A-HH and FCGR3A-VV in KRAS-WT patients were 220/660 (33%) and 109/676 (16.1%) respectively. There was no difference in median PFS (mPFS) for KRAS-WT patients with FCGR2A-HH (22.0 weeks; 95% CI18.8 to 25.2) versus non-HH (22.0 weeks; 95% CI 19.4 to 24.6) or for FCGR3A-VV (16.4 weeks; 95% CI 13.0 to 19.8) versus non-VV (23 weeks; 95% CI 21.1 to 24.9) (p=0.06). Median overall survival, response rate and disease control rate assessments showed no benefit for either HH or VV.

CONCLUSIONS

No differences in mPFS were found between the FCGR polymorphisms HH and the others and VV versus the others in KRAS-WT mCRC patients refractory to irinotecan, oxaliplatin and 5-fluorouracil treated with cetuximab. We cannot confirm the effects of other IgG1 antibodies, which may be weaker than previously suggested. Other markers may be needed to study the actual host antibody response to cetuximab.

EGF and EGFR genetic polymorphisms predict prognosis in locally advanced pharyngolaryngeal squamous cell carcinoma patients receiving postoperative concurrent chemoradiotherapy

Background

Epidermal growth factor (EGF) and its receptor (EGFR) are part of an important signaling pathway that is involved in the pathogenesis of squamous cell carcinoma of the head and neck (SCCHN). We hypothesized that EGF/EGFR genetic polymorphisms might have a prognostic impact on disease-free survival and overall survival (OS) in locally advanced SCCHN.

Materials and methods

The patient group included a consecutive cohort of 180 patients with locally advanced SCCHN who underwent postoperative concurrent chemoradiotherapy between 2002 and 2010. DNA from formalin-fixed, paraffin-embedded tumor tissues was genotyped for the single nucleotide polymorphism (SNP) of EGF A61G A>G, EGFR R521K G>A and G-216T. The log-rank test was applied to evaluate the impact of SNPs on the outcomes. Survival was estimated using the Kaplan–Meier statistical method.

Results

We demonstrated that EGF/EGFR SNPs might predict prognosis in patients with primary pharyngolaryngeal tumors, but not in those with oral cavity tumors. In pharyngolaryngeal tumor subgroup, EGF61 G/G genotype led to worse 5 year OS rate when compared to G/A or A/A genotypes (13.3% versus 34.3% versus 50.0%, P=0.017). The 5 year OS of patients with EGFR R521K G/G (11.1%) and G/A (15.9%) were lower than the A/A (62.5%) genotype (P=0.054). Patients carrying one or two unfavorable alleles had worse 5 year OS than those without unfavorable allele (not available versus 20% versus 71.4%, P=0.002). Multivariate analysis revealed that the highest risk of death was associated with the coexistence of two unfavorable genotypes (hazard ratio 25.7, 95% confidence interval =3.4–193.4; P=0.002).

Conclusion

In this study, we were able to demonstrate that the EGF A61G and EGFR R521K genetic polymorphisms might be important prognostic factors in patients with locally advanced primary pharyngolaryngeal squamous cell carcinoma who underwent postoperative concurrent chemoradiotherapy.

Association of EGF and p53 gene polymorphisms and colorectal cancer risk in the Slovak population

During the transformation process single nucleotide polymorphisms (SNPs) of key genes, such as p53 Arg72Pro or EGF A61G, may mediate various cellular processes. These variants may be associated with colorectal cancer risk (CRC), but conflicting findings have been reported. The purpose of this study was to determine the association of the SNPs in 5′ UTR of EGF A61G and p53 Arg72Pro and CRC in the Slovak population. The present case-control study was carried out in 173 confirmed CRC patients and 303 healthy subjects. Genotyping was performed by PCR-RFLP methods. Significant association was observed between age and CRC risk (p=0.001). Lower CRC risk was seen in younger patients carrying genotype p53 Arg72Pro (0.14; 95% CI 0.02–0.99, p=0.049). Gender-stratified analysis showed a significant inverse association of the polymorphism EGF G61G with CRC risk (0.48; 95% CI 0.2–0.9, p=0.04) only in male patients. Tumour site genotype distribution revealed that female patients with localized colon cancer were significantly associated with p53 Pro72Pro genotype (4.0; 95% CI 1.27–12.7, p=0.04) whereas the cancer of rectosigmoid junction was associated with the EGF G61G genotype (4.5; 95% CI 1.2–16.97, p=0.02). Combination of p53 Arg72Pro or EGF A61G polymorphisms were not associated with CRC risk by using logistic regression.

FCGR2A and FCGR3A polymorphisms and clinical outcome in metastatic colorectal cancer patients treated with first-line 5-fluorouracil/folinic acid and oxaliplatin +/- cetuximab

Background

Polymorphisms of genes encoding the Fcy receptors (Fc fragment of IgG receptor 2A (FCGR2A) and 3A (FCGR3A)), which influence their affinity for the Fc fragment, have been linked to the pharmacodynamics of monoclonal antibodies. Most studies have been limited by small samples sizes and have reported inconsistent associations between the FCGR2A and the FCGR3A polymorphisms and clinical outcome in metastatic colorectal cancer (mCRC) patients treated with cetuximab. We investigated the association of these polymorphisms and clinical outcome in a large cohort of mCRC patients treated with first-line 5-fluorouracil/folinic acid and oxaliplatin (Nordic FLOX) +/- cetuximab in the NORDIC-VII study (NCT00145314).

Methods

504 and 497 mCRC patients were evaluable for the FCGR2A and FCGR3A genotyping, respectively. Genotyping was performed on TaqMan ABI HT 7900 (Applied Biosystems, Foster City, CA, USA) with pre-designed SNP genotyping assays for FCGR2A (rs1801274) and FCGR3A (rs396991).

Results

The response rate for patients with the FCGR2A R/R genotype was significantly increased when cetuximab was added to Nordic FLOX (31% versus 53%, interaction P = 0.03), but was not significantly different compared to the response rate of patients with the FCGR2A H/H or H/R genotypes given the same treatment. A larger increase in response rate with the addition of cetuximab to Nordic FLOX in patients with KRAS mutated tumors and the FCGR2A R/R genotype was observed (19% versus 50%, interaction P = 0.04). None of the FCGR3A polymorphisms were associated with altered response when cetuximab was added to Nordic FLOX (interaction P = 0.63). Neither of the FCGR polymorphisms showed any significant associations with progression-free survival or overall survival.

Conclusion

Patients with KRAS mutated tumors and the FCGR2A R/R polymorphism responded poorly when treated with chemotherapy only, and experienced the most benefit of the addition of cetuximab in terms of response rate.

Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms

Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.

Digging up the human genome: current progress in deciphering adverse drug reactions

Adverse drug reactions (ADRs) are a major clinical problem. In addition to their clinical impact on human health, there is an enormous cost associated with ADRs in health care and pharmaceutical industry. Increasing studies revealed that genetic variants can determine the susceptibility of individuals to ADRs. The development of modern genomic technologies has led to a tremendous advancement of improving the drug safety and efficacy and minimizing the ADRs. This review will discuss the pharmacogenomic techniques used to unveil the determinants of ADRs and summarize the current progresses concerning the identification of biomarkers for ADRs, with a focus on genetic variants for genes encoding drug-metabolizing enzymes, drug-transporter proteins, and human leukocyte antigen (HLA). The knowledge gained from these cutting-edge findings will form the basis for better prediction and management for ADRs, ultimately making the medicine personalized.

Genetic and immune factors underlying the efficacy of cetuximab and panitumumab in the treatment of patients with metastatic colorectal cancer

Efficacy of monoclonal anti-EGFR antibodies (cetuximab, panitumumab) used in combination with chemotherapy or alone has been demonstrated in clinical trials of patients with mCRC. Both drugs block signaling EGFR pathway in malignant cells (blocking ligand binding and EGFR dimerization). Obtaining treatment responses with anti-EGFR agents is possible only in a selected subgroup of patients with mCRC. Successful treatment with cetuximab and panitumab is possible almost exclusively in patients without RAS mutations. Research on predictive value of EGFR gene copy number, PI3KCA gene mutations, P53 and PTEN, and EGFR their ligands concentrations is ongoing. Cetuximab, as IgG1 class antibody, can cause antibody dependent cellular cytotoxicity against neoplasm cells, while panitumumab, as IgG2 class antibody, does not induce such effect. Therefore a potential predictor cetuximab therapy may be the presence of different polymorphic forms of the genes for receptor immunoglobulin Fc fragments: FcγRIIa and FcγRIII subclasses.

Intergenic polymorphisms in the amphiregulin gene region as biomarkers in metastatic colorectal cancer patients treated with anti-EGFR plus irinotecan

In the epidermal growth factor receptor (EGFR) pathway, polymorphisms in EGFR and its ligand EGF have been studied as biomarkers for anti-EGFR treatment. However, the potential pharmacogenetic role of other EGFR ligands such as amphiregulin (AREG) and epiregulin (EREG) has not been elucidated. We studied 74 KRAS and BRAF wild-type metastatic colorectal cancer patients treated with anti-EGFR plus irinotecan. Twenty-two genetic variants in EGFR, EGF, AREG and EREG genes were selected using HapMap database and literature resources. Three tagging single-nucleotide polymorphisms in the AREG gene region (rs11942466 C>A, rs13104811 A>G, and rs9996584 C>T) predicted disease control in the multivariate analyses. AREG rs11942466 C>A and rs9996584 C>T were also associated with overall survival (OS). The functional polymorphism, EGFR rs712829 G>T, was associated with progression-free and OS. Our findings support that intergenic polymorphisms in the AREG gene region might help to identify colorectal cancer patients that will benefit from irinotecan plus anti-EGFR therapy.

Individualized therapy for metastatic colorectal cancer

Systemic therapeutic efficacy is central to determining the outcome of patients with metastatic colorectal cancer (CRC). In these patients, there is a critical need for predictive biomarkers to optimize efficacy whilst minimizing toxicity. The integration of a new generation of molecularly targeted drugs into the treatment of CRC, coupled with the development of sophisticated technologies for individual tumours as well as patient molecular profiling, underlines the potential for personalized medicine. In this review, we focus on the latest progress made within the genomic and proteomic fields, concerning predictive biomarkers for individualized therapy in metastatic CRC.

Pharmacogenetic markers of toxicity for chemotherapy in colorectal cancer patients

Chemotherapeutic agents used in colorectal cancer are frequently associated with severe adverse reactions that compromise the efficacy of treatment. Predicting toxicity could enable therapy to be tailored. Genetic variations have been associated with toxicity in patients treated with fluoropyrimidines (5-fluorouracil, capecitabine and tegafur), oxaliplatin, irinotecan and cetuximab. Complexity of treatment and variability in toxicity classifications make it difficult to compare studies. This article analyzes the association between toxicity and polymorphisms in DPYD, TYMS, MTHFR, ABCB1, UGT1A1, ERCC1, ERCC2, XRCC1, GSTT1 and GSTM1. In addition, the state-of-the-art and future perspectives are discussed.

Polymorphisms in XPD and ERCC1 Associated with Colorectal Cancer Outcome

Using the comprehensive approach to selecting polymorphisms to date, we sought to examine whether recurrence in colorectal cancer was associated with inherited variation in three genes involved in DNA repair and cell proliferation. Three polymorphisms, which are excision repair cross-complementation 1 (ERCC1), xeroderma pigmentosum group D (XPD) and epidermal growth factor receptor (EGFR), were assessed in 257 postoperative stage II/III CRC patients with 5-fluorouracial chemotherapy in Taiwan. In addition, the correlations between genetic polymorphisms and patients’ clinicopathological features were investigated. Genotypes of XPD codon751 A/A and ERCC1 codon118 T/T were associated with regional recurrence in a statistically significant way (p = 0.018). Patients who carried XPD AA and ERCC1 TT genotypes demonstrated a significantly greater regional recurrence risk (OR = 5.625, 95% CI, 1.557–20.32). Inherited variation in XPD and ERCC1 was associated with outcome in patients with colorectal cancer in Taiwan. As the significant association of single-nucleotide polymorphisms has not been studied previously in colorectal cancer, these findings suggest novel sites of variation, in part explaining the range of treatment responses seen in this disease.

Targeted therapies in colorectal cancer-an integrative view by PPPM

In developed countries, colorectal cancer (CRC) is the third most common malignancy, but it is the second most frequent cause of cancer-related death. Clinicians are still faced with numerous challenges in the treatment of this disease, and future approaches which target the molecular features of the disorder will be critical for success in this disease setting. Genetic analyses of many solid tumours have shown that up to 100 protein-encoding genes are mutated. Within CRC, numerous genetic alterations have been identified in a number of pathways. Therefore, understanding the molecular pathology of CRC may present information on potential routes for treatment and may also provide valuable prognostic information. This will be particularly pertinent for molecularly targeted treatments, such as anti-vascular endothelial growth factor therapies and anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapy. KRAS and BRAF mutations have been shown to predict response to anti-EGFR therapy. As EGFR can also signal via the phosphatidylinositol 3-kinase (PI3K) kinase pathway, there is considerable interest in the potential roles of members of this pathway (such as PI3K and PTEN) in predicting treatment response. Therefore, a combined approach of new techniques that allow identification of these biomarkers alongside interdisciplinary approaches to the treatment of advanced CRC will aid in the treatment decision-making process and may also serve to guide future therapeutic approaches.

Role of immunoglobulin G fragment C receptor polymorphism-mediated antibody-dependant cellular cytotoxicity in colorectal cancer treated with cetuximab therapy

Antibody-dependent cellular cytotoxicity (ADCC), which is activated by effector cells via immunoglobulin G (IgG) fragment C receptors (FcRs), was proposed as a mechanism of cetuximab efficacy. Peripheral blood mononuclear cells (PBMCs) from 23 healthy donors and 13 patients with metastatic colorectal cancer (mCRC) treated with cetuximab were tested for FcγR polymorphisms and cetuximab-mediated ADCC. ADCC was measured by chromium-51 release on a epidermal growth factor receptor (EGFR)-positive human colon cancer cell line. Overall, 86 mCRC patients were genotyped for study purposes. PBMCs harbouring the FcγRIIIa 158 V/V genotype had a significantly higher cetuximab-mediated ADCC. No correlation was found between FcγR polymorphisms and response rate or time to progression after cetuximab-based therapy. Despite the in vitro analysis showing that the FcγRIIIa 158 V/V genotype is associated with higher ADCC, clinical data do not support a predictive role of FcγRIIIa polymorphisms in mCRC treated with cetuximab.

Predictors of EGF receptor monoclonal antibody activity in metastatic colorectal cancer: current status

SUMMARY In the treatment of metastatic colorectal cancer, the cytostatic drugs 5-fluorouracil, irinotecan and oxaliplatin, as well as the VEGF antibody bevacizumab, are applied without the use of predictive biomarkers. To date, KRAS mutational status is the only accepted predictive biomarker, limiting the use of the EGF receptor (EGFR) monoclonal antibodies cetuximab and panitumumab to patients with KRAS wild-type tumors. The different KRAS mutations on codons 12 and 13 represent a negative predictive biomarker with poor positive predictive power. The negative predictive value of KRAS mutations has been questioned by several retrospective analyses of clinical trials, hypothesizing variable efficacies of EGFR antibodies associated with the diverse range of mutations. While the BRAF mutation is associated with a negative prognosis, its predictive value in the context of EGFR monoclonal antibody therapy is not fully understood. The present review aims to outline possible clinical and molecular biomarkers of EGFR monoclonal antibodies in metastatic colorectal cancer.

Multifactorial pharmacogenetic analysis in colorectal cancer patients receiving 5-fluorouracil-based therapy together with cetuximab-irinotecan

AIM

To examine the predictive value of gene polymorphisms potentially linked to toxicity, clinical response, time to progression and overall survival, following cetuximab-tegafur-uracil (UFT)-irinotecan therapy.

METHODS

Fifty-two patients with advanced colorectal cancer were enrolled in an ancillary pharmacogenetic study of the phase II CETUFTIRI trial. Treatment consisted of 21 day cycles of cetuximab (day 1-day 8-day 15, 250 mg m(-2) week(-1) following a 400 mg m(-2) initial dose) together with irinotecan (day 1, 250 mg m(-2)) and UFT-folinic acid (days 1-14, 250 mg m(-2) day(-1) UFT, 90 mg day(-1) folinic acid). Analysed gene polymorphisms (blood DNA) were as follows: EGFR (CA repeats in intron 1, -216G>T, -191C>A), EGF (61A>G), FCGR2A (131Arg>His), FCGR3A (158Phe>Val), UDP-glycosyltransferase1-polypeptide A1 (TA repeats), TYMS (28 bp repeats, including the G>C mutation on the 3R allele, 6 bp deletion in 3' UTR) and MTHFR (677C>T, 1298A>C).

RESULTS

Maximum toxicity grade was linked to EGFR-191C>A polymorphism, with 71.1% grade 3-4 toxicity in CC patients vs. 28.6% in other patients (P= 0.010). A tendency to a better response was observed in patients bearing the TYMS 3RG allele (P= 0.029) and those bearing the FCGR3A 158Val genotype (P= 0.020). The greater the score of favourable TYMS and FCGR3A genotypes, the better the response rate (P= 0.009) and the longer the overall survival (P= 0.007). In multivariate analysis, the score of favourable genotypes was a stronger survival predictor than the performance status.

CONCLUSIONS

Present data suggest the importance of FCGR3A 158Phe>Val and TYMS 5' UTR polymorphisms in responsiveness and survival of patients receiving cetuximab-fluoropyrimidine-based therapy.

Selecting the best targeted agent in first-line treatment of unresectable liver metastases from colorectal cancer: does the bench have the answers?

For physicians facing patients with organ-limited metastases from colorectal cancer, tumor shrinkage and sterilization of micrometastatic disease is the main goal, giving the opportunity for secondary surgical resection. At the same time, for the majority of patients who will not achieve a sufficient tumor response, disease control remains the predominant objective. Since FOLFOX or FOLFIRI have similar efficacies, the challenge is to define which could be the most effective targeted agent (anti-EGFR or anti-VEGF) to reach these goals. Therefore, a priori molecular identification of patients that could benefit from anti-EGFR or anti-VEGF monoclonal antibodies (i.e. the currently approved targeted therapies for metastatic colorectal cancer) is of critical importance. In this setting, the KRAS mutation status was the first identified predictive marker of response to anti-EGFR therapy. Since it has been demonstrated that tumors with KRAS mutation do not respond to anti-EGFR therapy, KRAS status must be determined prior to treatment. Thus, for KRAS wild-type patients, the choices that remain are either anti-VEGF or anti-EGFR. In this review, we present the most updated data from translational research programs dealing with the identification of biomarkers for response to targeted therapies.

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

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

Prognostic and predictive biomarkers for epidermal growth factor receptor-targeted therapy in colorectal cancer: beyond KRAS mutations

The advent of the epidermal growth factor receptor (EGFR)-targeted monoclonal antibodies (mAbs), cetuximab and panitumumab has expanded the range of treatment options for metastatic colorectal cancer (CRC). Despite these agents have paved the way to individualized therapy, our understanding why some patients respond to treatment whereas others do not remain poor. The realization that detection of positive EGFR expression by IHC does not reliably predict clinical outcome of EGFR-targeted treatment has led to an intense search for alternative predictive biomarkers. Data derived from multiple phase III trials have indicated that KRAS mutations can be considered a highly specific negative biomarker of benefit to anti-EGFR mAbs. Oncologists are now facing emerging issues in the treatment of metastatic CRC, including the identification of additional genetic determinants of primary resistance to EGFR-targeted therapy for further improving selection of patients, the explanation of rare cases of patients carrying KRAS-mutated tumours who have been reported to respond to cetuximab and panitumumab and the discovery of mechanisms of secondary resistance to EGFR-targeted therapy. Current data suggest that, together with KRAS mutations, the evaluation of EGFR gene copy number (GCN), BRAF, NRAS, PIK3CA mutations or loss of PTEN expression could also be useful for selecting patients with reduced chance to benefit from anti-EGFR mAbs. This review aims to provide an updated of the most recent data on predictive and prognostic biomarkers within the EGFR pathway, the challenges this emerging field presents and the future role of these molecular markers in CRC treatment.

Pharmacogenomics and metastatic colorectal cancer: current knowledge and perspectives

The pharmacogenomics field is crucial for optimizing the selection of which chemotherapy regimen to use according to the patient's genomic profile. Indeed, the individual's inherited genome accounts for a large proportion of the variation in his or her response to chemotherapeutic agents both in terms of efficiency and toxicity. Patients with metastatic disease are more likely to receive different lines of chemotherapy with variable efficacy and experience some related complications. It is therefore critical to tailor the best therapeutic arsenal to improve the efficacy and avoid as much as possible related complications that are susceptible to interrupt the treatment. The pharmacogenomics approach investigates for each drug the implicated metabolic pathway and the potential personal variations in gene function. The aim of this review is to present a clear overview of the most accurate polymorphisms that have been identified as related to drug response in patients with mCRC.

Correlation between gene expression of IGF-1R pathway markers and cetuximab benefit in metastatic colorectal cancer

PURPOSE

This study examined potential correlations between markers related to the insulin-like growth factor-1 receptor (IGF-1R) pathway and clinical benefit from the anti-epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab in metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

Gene expression profiles for 70 pretreatment specimens from metastatic lesions of patients with chemorefractory mCRC receiving cetuximab monotherapy were analyzed using 74 predefined Gene-Chip probesets representing 33 unique IGF-1R pathway markers to determine correlations with progression-free survival (PFS) and disease control rate.

RESULTS

Higher IGF-1R, higher GRB(7), and lower INSIG(2) expression were associated with longer PFS with cetuximab in univariate analyses, particularly in patients with wild-type K-Ras tumors: median, 122 versus 60 days (P = 0.01), 122 versus 57 days (P = 0.011), and 57 versus 156 days (P < 0.0001), favoring higher IGF-1R, higher GRB(7), and lower INSIG(2) expression, respectively. Lower IGF-1 expression was associated with a PFS benefit with cetuximab, whereas lower IGFBP(3) and INSR expression levels showed trends for a PFS benefit. Lower INSIG(2) expression (vs. higher expression) was associated with greater PFS in the high epiregulin-expressing group (P = 0.001), but not in the low-expressing cohort suggesting an effect independent from the previously reported effect of epiregulin expression. Lower INSIG(2) expression was also associated with higher disease control rate in the overall population (51.4% vs. 11.4%; P = 0.001) and wild-type K-Ras subset (76.2% vs. 18.2%; P < 0.0001).

CONCLUSIONS

These results suggest that markers of the IGF-1R pathway may play a role in predicting benefit from cetuximab therapy in mCRC. Additional clinical studies are warranted to validate these findings.