Jeremy David Shapiro

K-ras Mutations and Benefit from Cetuximab in Advanced Colorectal Cancer

BACKGROUND Treatment with cetuximab, a monoclonal antibody directed against the epidermal growth factor receptor, improves overall and progression-free survival and preserves the quality of life in patients with colorectal cancer that has not responded to chemotherapy. The mutation status of the K-ras gene in the tumor may affect the response to cetuximab and have treatment-independent prognostic value. METHODS We analyzed tumor samples, obtained from 394 of 572 patients (68.9%) with colorectal cancer who were randomly assigned to receive cetuximab plus best supportive care or best supportive care alone, to look for activating mutations in exon 2 of the K-ras gene. We assessed whether the mutation status of the K-ras gene was associated with survival in the cetuximab and supportive-care groups. RESULTS Of the tumors evaluated for K-ras mutations, 42.3% had at least one mutation in exon 2 of the gene. The effectiveness of cetuximab was significantly associated with K-ras mutation status (P=0.01 and P<0.001 for the interaction of K-ras mutation status with overall survival and progression-free survival, respectively). In patients with wild-type K-ras tumors, treatment with cetuximab as compared with supportive care alone significantly improved overall survival (median, 9.5 vs. 4.8 months; hazard ratio for death, 0.55; 95% confidence interval [CI], 0.41 to 0.74; P<0.001) and progression-free survival (median, 3.7 months vs. 1.9 months; hazard ratio for progression or death, 0.40; 95% CI, 0.30 to 0.54; P<0.001). Among patients with mutated K-ras tumors, there was no significant difference between those who were treated with cetuximab and those who received supportive care alone with respect to overall survival (hazard ratio, 0.98; P=0.89) or progression-free survival (hazard ratio, 0.99; P=0.96). In the group of patients receiving best supportive care alone, the mutation status of the K-ras gene was not significantly associated with overall survival (hazard ratio for death, 1.01; P=0.97). CONCLUSIONS Patients with a colorectal tumor bearing mutated K-ras did not benefit from cetuximab, whereas patients with a tumor bearing wild-type K-ras did benefit from cetuximab. The mutation status of the K-ras gene had no influence on survival among patients treated with best supportive care alone. (ClinicalTrials.gov number, NCT00079066.)

A prospective evaluation of treatment with Selective Internal Radiation Therapy (SIR-spheres) in patients with unresectable liver metastases from colorectal cancer previously treated with 5-FU based chemotherapy.

BackgroundTo prospectively evaluate the efficacy and safety of selective internal radiation (SIR) spheres in patients with inoperable liver metastases from colorectal cancer who have failed 5FU based chemotherapy.MethodsPatients were prospectively enrolled at three Australian centres. All patients had previously received 5-FU based chemotherapy for metastatic colorectal cancer. Patients were ECOG 0–2 and had liver dominant or liver only disease. Concurrent 5-FU was given at investigator discretion.ResultsThirty patients were treated between January 2002 and March 2004. As of July 2004 the median follow-up is 18.3 months. Median patient age was 61.7 years (range 36 – 77). Twenty-nine patients are evaluable for toxicity and response. There were 10 partial responses (33%), with the median duration of response being 8.3 months (range 2–18) and median time to progression of 5.3 mths. Response rates were lower (21%) and progression free survival shorter (3.9 mths) in patients that had received all standard chemotherapy options (n = 14). No responses were seen in patients with a poor performance status (n = 3) or extrahepatic disease (n = 6). Overall treatment related toxicity was acceptable, however significant late toxicity included 4 cases of gastric ulceration.ConclusionIn patients with metastatic colorectal cancer that have previously received treatment with 5-FU based chemotherapy, treatment with SIR-spheres has demonstrated encouraging activity. Further studies are required to better define the subsets of patients most likely to respond.

Health-Related Quality of Life in Patients With Advanced Colorectal Cancer Treated With Cetuximab: Overall and KRAS-Specific Results of the NCIC CTG and AGITG CO.17 Trial

PURPOSE National Cancer Institute of Canada Clinical Trials Group CO.17 demonstrated the antiepidermal growth factor receptor (anti-EGFR) monoclonal antibody cetuximab improves overall and progression-free survival in patients with advanced, chemotherapy-refractory colorectal cancer (CRC), particularly in patients with wild-type KRAS tumors. This article reports the health-related quality-of-life (HRQL) outcomes from CO.17. PATIENTS AND METHODS Patients (N = 572) with pretreated EGFR-detectable advanced CRC were randomly assigned to cetuximab and best supportive care (BSC) or to BSC alone. HRQL primary end points assessed by the EORTC QLQ-C30 were physical function (PF) and global health status (GHS); mean changes from baseline to 8 and 16 weeks were assessed. Post hoc analysis by KRAS mutation status was performed. RESULTS Questionnaire compliance was 94% at baseline, but it declined differentially (67% v 47% for cetuximab v BSC at 16 weeks). PF change scores were -3.9 for cetuximab and -8.6 for BSC (P = .046) at 8 weeks and were -5.9 and -12.5 for cetuximab and BSC, respectively, (P = .027) at 16 weeks. GHS change scores were -0.5 and -7.1 (P = .008) at 8 weeks and were -3.6 and -15.2 (P = .008) at 16 weeks for cetuximab and BSC, respectively. In patients who had tumors with wild-type KRAS status, cetuximab resulted in less PF deterioration at 8 weeks (-0.7 v -7.2; P = .11) and 16 weeks (-3.4 v -13.8; P = .008) compared with BSC. Patients with wild-type status who received cetuximab experienced improved GHS at 8 weeks, whereas patients who received BSC alone deteriorated (3.2 v -7.7; P = .002). Cetuximab preserved GHS at 16 weeks (-0.2 v -18.1; P < .001). No significant differences were noted between study arms for patients with mutated KRAS tumors. CONCLUSION Cetuximab offers important HRQL and survival benefits for pretreated patients with advanced, wild-type KRAS CRC.

PIK3CA, BRAF and PTEN status and benefit from cetuximab in the treatment of advanced colorectal cancer - results from NCIC CTG / AGITG CO.17

Purpose: Cetuximab improves survival in patients with K-ras wild-type advanced colorectal cancer. We examined the predictive and prognostic significance of additional biomarkers in this setting, in particular BRAF, PIK3CA, and PTEN. Experimental Design: Available colorectal tumor samples were analyzed from the CO.17 study. BRAF mutations were identified in tumor-derived DNA by direct sequencing and PIK3CA mutations were identified using a high-resolution melting screen with confirmation by sequencing. PTEN expression by immunohistochemistry (IHC) was performed on tissue microarrays. For each biomarker, prognostic and predictive effects were examined using a Cox model with tests for treatment–biomarker interaction. Results: A total of 572 patients with pretreated colorectal cancer were randomly assigned to receive cetuximab or best supportive care (BSC). Of 401 patients assessed for BRAF status, 13 (3.2%) had mutations. Of 407 patients assessed for PIK3CA status, 61 (15%) had mutations. Of 205 patients assessed for PTEN, 148 (72%) were negative for IHC expression. None of BRAF, PIK3CA, or PTEN was prognostic for overall or progression-free survival in the BSC arm. None was predictive of benefit from cetuximab, either in the whole study population or the K-ras wild-type subset. In the K-ras wild-type subgroup, the overall survival adjusted HR according to BRAF mutation status was 1.39 (interaction P = 0.69), PIK3CA mutation status HR = 0.79 (interaction P = 0.63), and PTEN expression HR = 0.75 (interaction P = 0.61). Conclusions: In chemotherapy-refractory colorectal cancer, neither PIK3CA mutation status nor PTEN expression were prognostic, nor were they predictive of benefit from cetuximab. Evaluation of predictive significance of BRAF mutations requires a larger sample size. Clin Cancer Res; 20(3); 744–53. ©2013 AACR.

Phase III Randomized, Placebo-Controlled Study of Cetuximab Plus Brivanib Alaninate Versus Cetuximab Plus Placebo in Patients With Metastatic, Chemotherapy-Refractory, Wild-Type K-RAS Colorectal Carcinoma: The NCIC Clinical Trials Group and AGITG CO.20 Trial

PURPOSE The antiepidermal growth factor receptor monoclonal antibody cetuximab has improved survival in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer. The addition of brivanib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor and fibroblast growth factor receptor, to cetuximab has shown encouraging early clinical activity. PATIENTS AND METHODS Patients with metastatic colorectal cancer previously treated with combination chemotherapy were randomly assigned 1:1 to receive cetuximab 400 mg/m(2) intravenous loading dose followed by weekly maintenance of 250 mg/m(2) plus either brivanib 800 mg orally daily (arm A) or placebo (arm B). The primary end point was overall survival (OS). RESULTS A total of 750 patients were randomly assigned (376 in arm A and 374 in arm B). Median OS in the intent-to-treat population was 8.8 months in arm A and 8.1 months in arm B (hazard ratio [HR], 0.88; 95% CI, 0.74 to 1.03; P = .12). Median progression-free survival (PFS) was 5.0 months in arm A and 3.4 months in arm B (HR, 0.72; 95% CI, 0.62 to 0.84; P < .001). Partial responses observed (13.6% v 7.2%; P = .004) were higher in arm A. Incidence of any grade ≥ 3 adverse events was 78% in arm A and 53% in arm B. Fewer patients received ≥ 90% dose-intensity of both cetuximab (57% v 83%) and brivanib/placebo (48% v 87%) in arm A versus arm B, respectively. CONCLUSION Despite positive effects on PFS and objective response, cetuximab plus brivanib increased toxicity and did not significantly improve OS in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer.

Prospective study of treatment with selective internal radiation therapy spheres in patients with unresectable primary or secondary hepatic malignancies.

Abstract

Management of advanced gastric cancer

The management of advanced gastric cancer has only evolved a little over the last 15 years: platinum and fluoropyrimidine chemotherapy remains the backbone of therapy with ongoing debate as to the benefit of triplet therapy with either an anthracycline or taxane. Recently published trials of biological agents, in particular those targeting the Her2 receptor, have provided some signs of improvement. This article summarizes the relevant literature, discusses the role of these agents, as well as geographical variations in use, and provides recommendations regarding both ‘standard chemotherapy’ and the role of biological agents in advanced gastric cancer. Given the relative lack of progress for gastric cancer over the last 15 years, the focus for the next 5 years should be on an improved understanding of the molecular basis of gastric cancer, thus allowing rational integration of new molecular agents.

Epiregulin gene expression as a biomarker of benefit from cetuximab in the treatment of advanced colorectal cancer.

Background:Anti-EGFR antibody, cetuximab, improves overall survival (OS) in K-ras wild-type chemotherapy–refractory colorectal cancer. Epidermal growth factor receptor ligand epiregulin (EREG) gene expression may further predict cetuximab benefit.Methods:Tumour samples from a phase III clinical trial of cetuximab plus best supportive care (BSC) vs BSC alone (CO.17) were analysed for EREG mRNA gene expression. Predictive effects of high vs low EREG on OS and progression-free survival (PFS) were examined for treatment–biomarker interaction.Results:Both EREG and K-ras status were ascertained in 385 (193 cetuximab, 192 BSC) tumour samples. Within the high EREG and K-ras wild-type status (‘co-biomarker’)-positive group (n=139, 36%), median PFS was 5.4 vs 1.9 months (hazard ratio (HR) 0.31; P<0.0001), and median OS was 9.8 vs 5.1 months (HR 0.43; P<0.001) for cetuximab vs BSC, respectively. In the rest (n=246, 64%), PFS (HR 0.82; P=0.12) and OS (HR 0.90; P=0.45) were not significantly different. Test for treatment interaction showed a larger cetuximab effect on OS (HR 0.52; P=0.007) and PFS (HR 0.49; P=0.001) in the co-biomarker-positive group.Conclusion:In pre-treated K-ras wild-type status colorectal cancer, patients with high EREG gene expression appear to benefit more from cetuximab therapy compared with low expression. Epiregulin as a selective biomarker requires further evaluation.

Measurement of plasma uracil using gas chromatography–mass spectrometry in normal individuals and in patients receiving inhibitors of dihydropyrimidine dehydrogenase

A sensitive gas chromatographic-mass spectrometric method is described for reliably measuring endogenous uracil in 100 microl of human plasma. Validation of this assay over a wide concentration range, 0.025 microM to 250 microM (0.0028 microg/ml to 28 microg/ml), allowed for the determination of plasma uracil in patients treated with agents such as eniluracil, an inhibitor of the pyrimidine catabolic enzyme, dihydropyrimidine dehydrogenase. Calibration standards were prepared in human plasma using the stable isotope, [15N2]uracil, to avoid interference from endogenous uracil and 10 microM 5-chlorouracil was added as the internal standard.

Fc-γ Receptor Polymorphisms, Cetuximab Therapy, and Survival in the NCIC CTG CO.17 Trial of Colorectal Cancer.

Purpose: Two germline 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; both are reported to be associated with cetuximab-related outcomes. We performed a validation of these polymorphisms in NCIC CTG CO.17, a randomized trial of cetuximab monotherapy in refractory, metastatic colorectal cancer expressing EGFR. Experimental Design: DNA extracted from formalin-fixed paraffin-embedded tissue was genotyped. In addition to log-rank tests, Cox proportional hazard models assessed their relationships with overall (OS) and progression-free survival (PFS), adjusting for clinically important prognostic factors, along with a polymorphism–treatment arm interaction term. Results: Somatic KRAS status was wild-type for exon 2 in 153 (52%) of 293 patients, from whom tumor DNA was available. For FCGR2A H/H, a genotype–treatment interaction for KRAS wild-type patients was observed for OS (P = 0.03). In KRAS wild-type patients carrying FCGR2A H/H, cetuximab (vs. no cetuximab) improved survival substantially, with adjusted HRs (aHR) of 0.36 (OS) and 0.19 (PFS) and absolute benefits of 5.5 months (OS; P = 0.003) and 3.7 months (PFS; P = 0.02). In contrast, patients carrying FCGR2A R alleles (H/R or R/R) had aHRs of only 0.78 (OS; 2.8-month benefit) and 0.53 (PFS; 1.6-month benefit). No relationships were found for rs396991 (FCGR3A). Conclusions: In the CO.17 trial, cetuximab worked best for patients with KRAS wild-type colorectal cancers carrying FCGR2A H/H genotypes. Significantly lower benefits were observed in patients carrying germline FCGR2A R alleles. Clin Cancer Res; 22(10); 2435–44. ©2016 AACR.