Marta Schirripa

FOLFOXIRI plus bevacizumab as first-line treatment in BRAF mutant metastatic colorectal cancer

BACKGROUND BRAF V600E mutation plays a negative prognostic role in metastatic colorectal cancer (mCRC), leading to a median Progression Free Survival (PFS) of 4-6months with first-line conventional treatments. Our group recently reported in a retrospective exploratory analysis of a phase II trial that FOLFOXIRI (5-FU/LV+Oxaliplatin+Irinotecan) plus bevacizumab might allow to achieve remarkable results in terms of PFS and Overall Survival (OS) also in this poor-prognosis subgroup. The aim of this work was to prospectively validate our retrospective finding. PATIENTS AND METHODS This phase II trial was designed to detect an increase in 6month-Progression Free Rate (6m-PFR) from 45% to 80% in a population of BRAF mutant mCRC patients treated with first-line FOLFOXIRI plus bevacizumab. Secondary end-points were PFS, OS, response rate (RR) and the analysis of outcome parameters in the pooled population consisting of both retrospectively and prospectively included patients. This trial is registered with ClinicalTrials.gov, number NCT01437618. RESULTS Two-hundred-fourteen potentially eligible mCRC patients were screened for BRAF mutational status. Fifteen BRAF mutant patients (7%) were included in the validation cohort. At a median follow up of 25.7months, 6m-PFR was 73%. Median PFS and OS were 9.2 and 24.1months, respectively. In the pooled population, at a median follow up of 40.4months, 6m-PFR was 84%. Median PFS and OS were 11.8 and 24.1months, respectively. Overall RR and disease control rate were 72% and 88%, respectively. CONCLUSION Lacking randomised trials in this specific molecular subgroup, FOLFOXIRI plus bevacizumab might be a reasonable option for the first-line treatment of BRAF mutant mCRC patients.

Pharmacodynamic and pharmacogenetic angiogenesis-related markers of first-line FOLFOXIRI plus bevacizumab schedule in metastatic colorectal cancer

Background:The identification of molecular and genetic markers to predict or monitor the efficacy of bevacizumab (BV) represents a key issue in the treatment of metastatic colorectal cancer (mCRC).Methods:Plasma levels of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble VEGF receptor 2 (sVEGFR-2) and thrombospondin-1 (TSP-1) were assessed by ELISA assay at different time points in a cohort of 25 patients enroled in a phase II trial of GONO-FOLFOXIRI plus BV as first-line treatment of mCRC. VEGF: −2578A/C, −1498C/T, −1154A/G, −634C/G and 936C/T; and VEGFR-2: −604A/G, +1192C/T and +1719A/T, polymorphisms were assessed in a total of 54 patients.Results:Treatment with GONO-FOLFOXIRI plus BV determined a prolonged and significant reduction in plasma free, biologically active VEGF concentration. Interestingly, VEGF concentrations remained lower than at baseline also at the time of PD. Conversely, PlGF levels increased during the treatment if compared with baseline, suggesting a possible role in tumour resistance; moreover, sVEGFR-2 increased at the time of PD, as well as TSP-1. No association of assessed polymorphisms with outcome was found.Conclusion:Our study suggested the possible mechanisms of resistance to combined therapy in those patients with a progressive disease to be tested in ongoing phase III randomised studies.

Retrospective exploratory analysis of VEGF polymorphisms in the prediction of benefit from first-line FOLFIRI plus bevacizumab in metastatic colorectal cancer

BackgroundMolecular predictors of bevacizumab efficacy in colorectal cancer have not been identified yet. Specific VEGF polymorphisms may affect gene transcription and therefore indirectly influence the efficacy of bevacizumab.MethodsGenomic DNA of 111 consecutive metastatic colorectal cancer patients treated with first-line FOLFIRI plus bevacizumab was obtained from blood samples. VEGF -2578 C/A, -1498 C/T, + 405 C/G, + 936 C/T polymorphisms were analyzed by means of PCR-RFLP. DNA samples from 107 patients treated with FOLFIRI alone served as historical control group. The relation of VEGF polymorphisms with PFS, evaluated through Kaplan-Meier method and log-rank test, was the primary end-point. An interaction test with a Cox model has been performed in order to demonstrate the heterogeneity of the effect of VEGF -1498 C/T polymorphism between bevacizumab-and control group.ResultsIn the bevacizumab-group median PFS and OS of patients carrying VEGF -1498 C/C, C/T and T/T allelic variants were, respectively, 12.8, 10.5, 7.5 months (p = 0.0046, log-rank test) and 27.3, 20.5, 18.6 months (p = 0.038, log-rank test). VEGF -1498 T/T genotype was associated with shorter PFS (HR = 2.13, [1.41-5.10], p = 0.0027). In the control group no significant association of VEGF -1498 C/T allelic variants and PFS or OS was found. Interaction between VEGF -1498 C/T variants and treatment effect suggested that the relation of VEGF -1498 T/T genotype with shorter PFS was caused by the effect of bevacizumab (p = 0.011). Other investigated polymorphisms did not affect the outcome.ConclusionsThese data suggest a possible role for VEGF -1498 C/T variants in predicting the efficacy of bevacizumab in the up-front treatment of metastatic colorectal cancer patients. A molecular tool for selecting subjects candidate to benefit from the anti-VEGF could be important for clinical practice. The retrospective and exploratory design of the present study, coupled with the non-randomized nature of the comparison between treated and untreated patients, imply that these results should be considered as hypothesis generators. A prospective validating trial is currently ongoing.

Continuation or reintroduction of bevacizumab beyond progression to first-line therapy in metastatic colorectal cancer: final results of the randomized BEBYP trial

BACKGROUND The combination of bevacizumab with fluorouracil-based chemotherapy is a standard first-line treatment option in metastatic colorectal cancer (mCRC). We studied the efficacy of continuing or reintroducing bevacizumab in combination with second-line chemotherapy after progression to bevacizumab-based first-line therapy. PATIENTS AND METHODS In this phase III study, patients with mCRC treated with fluoropyrimidine-based first-line chemotherapy plus bevacizumab were randomized to receive in second-line mFOLFOX-6 or FOLFIRI (depending on first-line regimen) with or without bevacizumab. The primary end point was progression-free survival. To detect a hazard ratio (HR) for progression of 0.70 with an α and β error of 0.05 and 0.20, respectively, 262 patients were required. RESULTS In consideration of the results of the ML18147 trial, the study was prematurely stopped. Between April 2008 and May 2012, a total of 185 patients were randomized. Bevacizumab-free interval was longer than 3 months in 43% of patients in chemotherapy alone arm and in 50% of patients in the bevacizumab arm. At a median follow-up of 45.3 months, the median progression-free survival was 5.0 months in the chemotherapy group and 6.8 months in the bevacizumab group [adjusted HR = 0.70; 95% confidence interval (CI) 0.52-0.95; stratified log-rank P = 0.010]. Subgroup analyses showed a consistent benefit in all subgroups analyzed and in particular in patients who had continued or reintroduced bevacizumab. An improved overall survival was also observed in the bevacizumab arm (adjusted HR = 0.77; 95% CI 0.56-1.06; stratified log-rank P = 0.043). Responses (RECIST 1.0) were similar in the chemotherapy and bevacizumab groups (17% and 21%; P = 0.573). Toxicity profile was consistent with previously reported data. CONCLUSIONS This study demonstrates that the continuation or the reintroduction of bevacizumab with second-line chemotherapy beyond first progression improves the outcome and supports the use of this strategy in the treatment of mCRC. ClinicalTrials.gov number: NCT00720512.

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

BACKGROUND The FOLFOXIRI regimen developed by the Gruppo Oncologico Nord Ovest (GONO) demonstrated higher activity and efficacy compared with FOLFIRI in metastatic colorectal cancer (mCRC). Panitumumab is effective in some patients with KRAS codon 12-13 wild-type mCRC. KRAS codon 61, HRAS, NRAS, and BRAF V600E mutations might predict resistance to anti-epidermal growth factor receptor antibodies. PATIENTS AND METHODS We conducted a phase II study evaluating the combination of panitumumab (6 mg/kg on day 1) with a slightly modified GONO-FOLFOXIRI (irinotecan 150 mg/m², oxaliplatin 85 mg/m², and folinate 200 mg/m² on day 1, followed by fluorouracil 3000 mg/m² as a 48-h continuous infusion starting on day 1) repeated every 2 weeks as first-line treatment of wild-type KRAS, HRAS, NRAS (codon 12-13-61), and BRAF unresectable mCRC patients. Fluorouracil dose was reduced to 2400 mg/m² after two of the first three patients reported grade 3-4 diarrhoea (in one case with febrile neutropenia). Induction treatment was scheduled for a maximum of 12 cycles, followed by panitumumab ± fluorouracil/folinate maintenance until progression. Primary end point was overall response rate (ORR). RESULTS Eighty-seven patients were screened and 37 were enrolled. Thirty-three patients achieved an objective response (ORR: 89%; 95% CI 75% to 96%). Sixteen patients (43%) underwent secondary surgery of metastases, and R0 resection was achieved in 13 cases (35%). At a median follow-up of 17.7 months, median progression-free survival was 11.3 months (95% CI 9.7-12.9 months). After amendment, most common grade 3-4 adverse events reported during induction treatment were neutropenia (48%; febrile neutropenia: 5%), diarrhoea (35%), asthenia (27%), stomatitis (14%), and skin toxic effect (14%). One treatment-related death was registered. CONCLUSIONS Adding panitumumab to FOLFOXIRI is feasible decreasing the dose of fluorouracil and irinotecan to reduce the risk of diarrhoea. Activity and secondary resectability of metastases among Ras-BRAF wild-type patients are promising.

BRAF and RAS mutations as prognostic factors in metastatic colorectal cancer patients undergoing liver resection

Background:Despite major advances in the management of metastatic colorectal cancer (mCRC) with liver-only involvement, relapse rates are high and reliable prognostic markers are needed.Methods:To assess the prognostic impact of BRAF and RAS mutations in a large series of liver-resected patients, medical records of 3024 mCRC patients were reviewed. Eligible cases undergoing potentially curative liver resection were selected. BRAF and RAS mutational status was tested on primary and/or metastases by means of pyrosequencing and mass spectrometry genotyping assay. Primary endpoint was relapse-free survival (RFS).Results:In the final study population (N=309) BRAF mutant, RAS mutant and all wild-type (wt) patients were 12(4%), 160(52%) and 137(44%), respectively. Median RFS was 5.7, 11.0 and 14.4 months respectively and differed significantly (Log-rank, P=0.043). At multivariate analyses, BRAF mutant had a higher risk of relapse in comparison to all wt (multivariate hazard ratio (HR)=2.31; 95% CI, 1.09–4.87; P=0.029) and to RAS mutant (multivariate HR=2.06; 95% CI, 1.02–4.14; P=0.044). Similar results were obtained in terms of overall survival. Compared with all wt patients, RAS mutant showed a higher risk of death (HR=1.47; 95% CI, 1.05–2.07; P=0.025), but such effect was lost at multivariate analyses.Conclusions:BRAF mutation is associated with an extremely poor median RFS after liver resection and with higher probability of relapse and death. Knowledge of BRAF mutational status may optimise clinical decision making in mCRC patients potentially candidate to hepatic surgery. RAS status as useful marker in this setting might require further studies.

An EZH2 polymorphism is associated with clinical outcome in metastatic colorectal cancer patients.

BACKGROUND Despite therapeutic innovations, metastatic colorectal cancer (mCRC) is still characterized by poor prognosis and few molecular markers predict the risk of progression. Polycomb group genes (PcGs) are epigenetic modifiers involved in tumor suppressor gene silencing. PcG member EZH2 mediates gene silencing through histone-H3 lysine-27 methylation. In colorectal cancer (CRC), EZH2 overexpression predicts shorter survival. Recently, four EZH2 single-nucleotide polymorphisms (SNPs) have been described. The present study was aimed at evaluating the correlation between EZH2 SNPs and outcome parameters in mCRC patients. PATIENTS AND METHODS DNA was extracted from blood samples of 110 mCRC patients treated with first-line 5-fluorouracil, folinic acid, irinotecan (FOLFIRI) and bevacizumab. Genotyping was carried out by real-time PCR. Genotype was used to predict objective response, progression-free survival (PFS) and overall survival (OS). EZH2 messenger RNA levels were evaluated on lymphocytes of a parallel cohort of 50 CRC patients. RESULTS One allelic variant (rs3757441 C/C versus C/T or T/T) was significantly associated with shorter PFS and OS (P < 0.01 and P < 0.05, respectively). At multivariate analysis, the same variant resulted an independent predictor of PFS and OS (P < 0.05). The C/C variant was associated with significantly higher EZH2 expression (P < 0.05). CONCLUSION An EZH2 SNP may be useful to predict clinical outcome in mCRC patients.BACKGROUND Despite therapeutic innovations, metastatic colorectal cancer (mCRC) is still characterized by poor prognosis and few molecular markers predict the risk of progression. Polycomb group genes (PcGs) are epigenetic modifiers involved in tumor suppressor gene silencing. PcG member EZH2 mediates gene silencing through histone-H3 lysine-27 methylation. In colorectal cancer (CRC), EZH2 overexpression predicts shorter survival. Recently, four EZH2 single-nucleotide polymorphisms (SNPs) have been described. The present study was aimed at evaluating the correlation between EZH2 SNPs and outcome parameters in mCRC patients. PATIENTS AND METHODS DNA was extracted from blood samples of 110 mCRC patients treated with first-line 5-fluorouracil, folinic acid, irinotecan (FOLFIRI) and bevacizumab. Genotyping was carried out by real-time PCR. Genotype was used to predict objective response, progression-free survival (PFS) and overall survival (OS). EZH2 messenger RNA levels were evaluated on lymphocytes of a parallel cohort of 50 CRC patients. RESULTS One allelic variant (rs3757441 C/C versus C/T or T/T) was significantly associated with shorter PFS and OS (P < 0.01 and P < 0.05, respectively). At multivariate analysis, the same variant resulted an independent predictor of PFS and OS (P < 0.05). The C/C variant was associated with significantly higher EZH2 expression (P < 0.05). CONCLUSION An EZH2 SNP may be useful to predict clinical outcome in mCRC patients.

Prospective Validation of Candidate SNPs of VEGF/VEGFR Pathway in Metastatic Colorectal Cancer Patients Treated with First-Line FOLFIRI Plus Bevacizumab

Purpose The potential impact of different SNPs of VEGF/VEGFR pathway on the clinical outcome of mCRC patients receiving bev-containing regimens has been investigated in retrospective experiences with contrasting results. We previously reported the association of VEGFA rs833061 C/T variants with PFS in metastatic colorectal cancer patients treated with first-line FOLFIRI plus bevacizumab. The primary objective of this work was to prospectively validate that retrospective finding. A confirmatory analysis of other SNPs of VEGF/VEGFR pathway genes was included. Experimental design To detect a HR for PFS of 1.7 for VEGFA rs833061 T/T compared to C- variants in metastatic colorectal cancer patients treated with first-line FOLFIRI plus bevacizumab, setting two-sided α = 0.05 and β = 0.20, 199 events were required. VEGFA rs699946 A/G, rs699947 A/C, VEGFR1 rs9582036 A/C and rs7993418 A/G, VEGFR2 rs11133360 C/T, rs12505758 C/T and rs2305948 C/T and EPAS1 rs4145836 A/G were also tested. Germ-line DNA was extracted from peripheral blood. SNPs were analyzed by PCR and sequencing. Results Four-hundred-twenty-four pts were included. At the univariate analysis, no differences according to VEGFA rs833061 C/T variants were observed in PFS (p = 0.38) or OS (p = 0.95). Among analyzed SNPs, only VEGFR2 rs12505758 C- variants, compared to T/T, were associated to shorter PFS (HR: 1.36 [1.05–1.75], p = 0.015, dominant genetic model) and OS, with a trend toward significance (HR: 1.34 [0.95–1.88], p = 0.088). In the multivariate model, this association retained significance (HR: 1.405 [1.082–1.825], p = 0.012) in PFS, that was lost by applying multiple testing correction (p = 0.14). Conclusion This prospective experience failed to validate the hypothesized predictive impact of VEGFA rs833061 variants. Retrospective findings on different candidate SNPs were not confirmed. Only VEGFR2 rs12505758 variants, whose prognostic and not predictive impact was previously reported, correlated with PFS. Given the complexity of angiogenesis, it is rather unlike that a single germ-line SNP might be a good predictor of benefit from bevacizumab.

Histopathologic evaluation of liver metastases from colorectal cancer in patients treated with FOLFOXIRI plus bevacizumab.

Background:The FOLFOXIRI regimen produces a high rate of radiological and histopathological responses. Bevacizumab added to chemotherapy showed an improvement in pathological response and necrosis of colorectal liver metastases (CLMs). FOLFOXIRI plus bevacizumab produced promising early clinical results and is under investigation in several randomised trials, although no data are currently available on its effects on response of CLMs and on liver toxicities.Methods:Starting from 499 patients enrolled in first-line phase II/III trials, we selected on the basis of tissue sample availability 18 patients treated with FOLFOXIRI/XELOXIRI and 24 patients treated with FOLFOXIRI plus bevacizumab who underwent secondary resection of CLMs. The 28 untreated patients who underwent primary resection of CLMs were included as control group. Responses of CLMs and chemotherapy-induced toxicities were assessed.Results:Among the patients, 63% of those treated with FOLFOXIRI plus bevacizumab, as compared with 28% of those treated with only FOLFOXIRI/XELOXIRI, showed a histopathological response (P=0.033). In the two groups, 52% and 12.5%, respectively, showed necrosis ⩾50% (P=0.017). The incidence of liver toxicities was not significantly increased in patients treated with FOLFOXIRI plus bevacizumab.Conclusion:The addition of bevacizumab to FOLFOXIRI produces high rates of pathologic responses and necrosis of CLM without increasing liver toxicity.

Clinical impact of anti-epidermal growth factor receptor monoclonal antibodies in first-line treatment of metastatic colorectal cancer: meta-analytical estimation and implications for therapeutic strategies.

Antiepidermal growth factor receptor (anti‐EGFR) monoclonal antibodies (MoAbs) are indicated for the treatment of metastatic colorectal cancer patients, but some scientific issues concerning their efficacy are currently unsolved.