Niall C. Tebbutt

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.)

Neoadjuvant Capecitabine and Oxaliplatin Followed by Synchronous Chemoradiation and Total Mesorectal Excision in Magnetic Resonance Imaging–Defined Poor-Risk Rectal Cancer

PURPOSE To evaluate neoadjuvant capecitabine/oxaliplatin before chemoradiotherapy (CRT) and total mesorectal excision (TME) in newly diagnosed patients with magnetic resonance imaging (MRI) -defined poor-risk rectal cancer. PATIENTS AND METHODS MRI criteria for poor-risk rectal cancer were tumors within 1 mm of mesorectal fascia (ie, circumferential resection margin threatened), T3 tumors at or below levators, tumors extending > or = 5 mm into perirectal fat, T4 tumors, and T1-4N2 tumors. Patients received 12 weeks of neoadjuvant capecitabine/oxaliplatin followed by concomitant capecitabine and radiotherapy. TME was planned 6 weeks after CRT. Postoperatively, patients received another 12 weeks of capecitabine. RESULTS Between November 2001 and August 2004, 77 eligible patients were recruited. After neoadjuvant capecitabine/oxaliplatin, the radiologic response rate was 88%. In addition, 86% of patients had symptomatic responses in a median of 32 days (ie, just over one cycle of capecitabine/oxaliplatin). After CRT, the tumor response rate was increased to 97%. Three patients remained inoperable. Sixty-seven patients proceeded to TME, and all but one patient had R0 resection. Pathologic complete response was observed in 16 patients (24%; 95% CI, 14% to 36%), and in an additional 32 patients (48%), only microscopic tumor foci were found on surgical specimens. Four deaths occurred during neoadjuvant capecitabine/oxaliplatin therapy as a result of pulmonary embolism, ischemic heart disease, sudden death with history of chest pain, and neutropenic colitis. CONCLUSION Capecitabine/oxaliplatin before synchronous CRT and TME results in substantial tumor regression, rapid symptomatic response, and achievement of R0 resection.

Bevacizumab in Combination With Chemotherapy as First-Line Therapy in Advanced Gastric Cancer: A Biomarker Evaluation From the AVAGAST Randomized Phase III Trial

PURPOSE The AVAGAST study showed that adding bevacizumab to chemotherapy in patients with advanced gastric cancer improves progression-free survival and tumor response rate but not overall survival. To examine the hypothesis that angiogenic markers may have predictive value for bevacizumab efficacy in gastric cancer, AVAGAST included a prospective, mandatory biomarker program. PATIENTS AND METHODS Patients with previously untreated, locally advanced or metastatic gastric cancer were randomly assigned to bevacizumab (n = 387) or placebo (n = 387) in combination with chemotherapy. Blood and tumor tissue samples were collected at baseline. Prespecified biomarkers included plasma vascular endothelial growth factor-A (VEGF-A), protein expression of neuropilin-1, and VEGF receptors-1 and -2 (VEGFR-1 and VEGFR-2). Correlations between biomarkers and clinical outcomes were assessed by using a Cox proportional hazards model. RESULTS Plasma was available from 712 patients (92%), and tumor samples were available from 727 patients (94%). Baseline plasma VEGF-A levels and tumor neuropilin-1 expression were identified as potential predictors of bevacizumab efficacy. Patients with high baseline plasma VEGF-A levels showed a trend toward improved overall survival (hazard ratio [HR], 0.72; 95% CI, 0.57 to 0.93) versus patients with low VEGF-A levels (HR, 1.01; 95% CI, 0.77 to 1.31; interaction P = .07). Patients with low baseline expression of neuropilin-1 also showed a trend toward improved overall survival (HR, 0.75; 95% CI, 0.59 to 0.97) versus patients with high neuropilin-1 expression (HR, 1.07; 95% CI, 0.81 to 1.40; interaction P = .06). For both biomarkers, subgroup analyses demonstrated significance only in patients from non-Asian regions. CONCLUSION Plasma VEGF-A and tumor neuropilin-1 are strong biomarker candidates for predicting clinical outcome in patients with advanced gastric cancer treated with bevacizumab.

Capecitabine, bevacizumab, and mitomycin in first-line treatment of metastatic colorectal cancer: Results of the Australasian Gastrointestinal Trials Group randomized phase III MAX study

PURPOSE To determine whether adding bevacizumab, with or without mitomycin, to capecitabine monotherapy improves progression-free survival (PFS) in patients with metastatic colorectal cancer (mCRC) in an open-label, three-arm randomized trial. PATIENTS AND METHODS Overall, 471 patients in Australia, New Zealand, and the United Kingdom with previously untreated, unresectable mCRC were randomly assigned to the following: capecitabine; capecitabine plus bevacizumab (CB); or capecitabine, bevacizumab, and mitomycin (CBM). We compared CB with capecitabine and CBM with capecitabine for progression-free survival (PFS). Secondary end points included overall survival (OS), toxicity, response rate (RR), and quality of life (QOL). RESULTS Median PFS was 5.7 months for capecitabine, 8.5 months for CB, and 8.4 months for CBM (capecitabine v CB: hazard ratio [HR], 0.63; 95% CI, 0.50 to 0.79; P < .001; C v CBM: HR, 0.59; 95% CI, 0.47 to 0.75; P < .001). After a median follow-up of 31 months, median OS was 18.9 months for capecitabine and was 16.4 months for CBM; these data were not significantly different. Toxicity rates were acceptable, and all treatment regimens well tolerated. Bevacizumab toxicities were similar to those in previous studies. Measures of overall QOL were similar in all groups. CONCLUSION Adding bevacizumab to capecitabine, with or without mitomycin, significantly improves PFS without major additional toxicity or impairment of QOL.

Everolimus for Previously Treated Advanced Gastric Cancer: Results of the Randomized, Double-Blind, Phase III GRANITE-1 Study

PURPOSE The oral mammalian target of rapamycin inhibitor everolimus demonstrated promising efficacy in a phase II study of pretreated advanced gastric cancer. This international, double-blind, phase III study compared everolimus efficacy and safety with that of best supportive care (BSC) in previously treated advanced gastric cancer. PATIENTS AND METHODS Patients with advanced gastric cancer that progressed after one or two lines of systemic chemotherapy were randomly assigned to everolimus 10 mg/d (assignment schedule: 2:1) or matching placebo, both given with BSC. Randomization was stratified by previous chemotherapy lines (one v two) and region (Asia v rest of the world [ROW]). Treatment continued until disease progression or intolerable toxicity. Primary end point was overall survival (OS). Secondary end points included progression-free survival (PFS), overall response rate, and safety. RESULTS Six hundred fifty-six patients (median age, 62.0 years; 73.6% male) were enrolled. Median OS was 5.4 months with everolimus and 4.3 months with placebo (hazard ratio, 0.90; 95% CI, 0.75 to 1.08; P = .124). Median PFS was 1.7 months and 1.4 months in the everolimus and placebo arms, respectively (hazard ratio, 0.66; 95% CI, 0.56 to 0.78). Common grade 3/4 adverse events included anemia, decreased appetite, and fatigue. The safety profile was similar in patients enrolled in Asia versus ROW. CONCLUSION Compared with BSC, everolimus did not significantly improve overall survival for advanced gastric cancer that progressed after one or two lines of previous systemic chemotherapy. The safety profile observed for everolimus was consistent with that observed for everolimus in other cancers.

Effect of Adjuvant Chemotherapy With Fluorouracil Plus Folinic Acid or Gemcitabine vs Observation on Survival in Patients With Resected Periampullary Adenocarcinoma: The ESPAC-3 Periampullary Cancer Randomized Trial

CONTEXT Patients with periampullary adenocarcinomas undergo the same resectional surgery as that of patients with pancreatic ductal adenocarcinoma. Although adjuvant chemotherapy has been shown to have a survival benefit for pancreatic cancer, there have been no randomized trials for periampullary adenocarcinomas. OBJECTIVE To determine whether adjuvant chemotherapy (fluorouracil or gemcitabine) provides improved overall survival following resection. DESIGN, SETTING, AND PATIENTS The European Study Group for Pancreatic Cancer (ESPAC)-3 periampullary trial, an open-label, phase 3, randomized controlled trial (July 2000-May 2008) in 100 centers in Europe, Australia, Japan, and Canada. Of the 428 patients included in the primary analysis, 297 had ampullary, 96 had bile duct, and 35 had other cancers. INTERVENTIONS One hundred forty-four patients were assigned to the observation group, 143 patients to receive 20 mg/m2 of folinic acid via intravenous bolus injection followed by 425 mg/m2 of fluorouracil via intravenous bolus injection administered 1 to 5 days every 28 days, and 141 patients to receive 1000 mg/m2 of intravenous infusion of gemcitabine once a week for 3 of every 4 weeks for 6 months. MAIN OUTCOME MEASURES The primary outcome measure was overall survival with chemotherapy vs no chemotherapy; secondary measures were chemotherapy type, toxic effects, progression-free survival, and quality of life. RESULTS Eighty-eight patients (61%) in the observation group, 83 (58%) in the fluorouracil plus folinic acid group, and 73 (52%) in the gemcitabine group died. In the observation group, the median survival was 35.2 months (95%% CI, 27.2-43.0 months) and was 43.1 (95%, CI, 34.0-56.0) in the 2 chemotherapy groups (hazard ratio, 0.86; (95% CI, 0.66-1.11; χ2 = 1.33; P = .25). After adjusting for independent prognostic variables of age, bile duct cancer, poor tumor differentiation, and positive lymph nodes and after conducting multiple regression analysis, the hazard ratio for chemotherapy compared with observation was 0.75 (95% CI, 0.57-0.98; Wald χ2 = 4.53, P = .03). CONCLUSIONS Among patients with resected periampullary adenocarcinoma, adjuvant chemotherapy, compared with observation, was not associated with a significant survival benefit in the primary analysis; however, multivariable analysis adjusting for prognostic variables demonstrated a statistically significant survival benefit associated with adjuvant chemotherapy. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00058201.

Pancreatic cancer hENT1 expression and survival from gemcitabine in patients from the ESPAC-3 trial

BACKGROUND Human equilibrative nucleoside transporter 1 (hENT1) levels in pancreatic adenocarcinoma may predict survival in patients who receive adjuvant gemcitabine after resection. METHODS Microarrays from 434 patients randomized to chemotherapy in the ESPAC-3 trial (plus controls from ESPAC-1/3) were stained with the 10D7G2 anti-hENT1 antibody. Patients were classified as having high hENT1 expression if the mean H score for their cores was above the overall median H score (48). High and low hENT1-expressing groups were compared using Kaplan-Meier curves, log-rank tests, and Cox proportional hazards models. All statistical tests were two-sided. RESULTS Three hundred eighty patients (87.6%) and 1808 cores were suitable and included in the final analysis. Median overall survival for gemcitabine-treated patients (n = 176) was 23.4 (95% confidence interval [CI] = 18.3 to 26.0) months vs 23.5 (95% CI = 19.8 to 27.3) months for 176 patients treated with 5-fluorouracil/folinic acid (χ(2) 1=0.24; P = .62). Median survival for patients treated with gemcitabine was 17.1 (95% CI = 14.3 to 23.8) months for those with low hENT1 expression vs 26.2 (95% CI = 21.2 to 31.4) months for those with high hENT1 expression (χ(2)₁= 9.87; P = .002). For the 5-fluorouracil group, median survival was 25.6 (95% CI = 20.1 to 27.9) and 21.9 (95% CI = 16.0 to 28.3) months for those with low and high hENT1 expression, respectively (χ(2)₁ = 0.83; P = .36). hENT1 levels were not predictive of survival for the 28 patients of the observation group (χ(2)₁ = 0.37; P = .54). Multivariable analysis confirmed hENT1 expression as a predictive marker in gemcitabine-treated (Wald χ(2) = 9.16; P = .003) but not 5-fluorouracil-treated (Wald χ(2) = 1.22; P = .27) patients. CONCLUSIONS Subject to prospective validation, gemcitabine should not be used for patients with low tumor hENT1 expression.

Neoadjuvant capecitabine and oxaliplatin before chemoradiotherapy and total mesorectal excision in MRI-defined poor-risk rectal cancer: a phase 2 trial

BACKGROUND Patients with poor-risk rectal cancer defined by MRI can be at high risk of disease recurrence despite standard chemoradiotherapy and optimum surgery. We aimed to assess the safety and long-term efficacy of neoadjuvant chemotherapy with capecitabine and oxaliplatin before chemoradiotherapy and total mesorectal excision, a treatment strategy developed to enhance the outcome of this population. METHODS Between November, 2001, and August, 2005, we enrolled eligible patients with poor-risk rectal cancer defined by high-resolution MRI and without metastatic disease. The protocol was amended in January, 2004, following clinically significant cardiotoxic events (nine events in eight of 77 patients), to exclude patients with a recent history of clinically significant cardiac problems. Patients received 12 weeks of neoadjuvant capecitabine and oxaliplatin (oxaliplatin 130 mg/m2 on day 1 with capecitabine 1000 mg/m2 twice daily for 14 days every 3 weeks) followed by chemoradiotherapy (54 Gy over 6 weeks) with capecitabine (825 mg/m2 twice daily), total mesorectal excision, and 12 weeks of postoperative adjuvant capecitabine (1250 mg/m2 twice daily for 14 days every 3 weeks). The primary endpoint was pathological complete response rate. We followed up patients for a median of 55 months (IQR 47-67). Efficacy analyses were undertaken for the intention-to-treat population, unless otherwise specified. This study is registered with ClinicalTrials.gov, number NCT00220051. FINDINGS 105 eligible patients were enrolled. Radiological response rates after neoadjuvant chemotherapy and chemoradiotherapy were 74% (78/105) and 89% (93/105), respectively. 97 patients underwent surgery, of whom 95 underwent total mesorectal excision, of whom 93 had microscopically clear resection margins and 21 had pathological complete response (21/105 [20%]). 3-year progression-free and overall survival were 68% (95% CI 59-77) and 83% (76-91), respectively. 3-year relapse-free survival for patients who had complete resection was 74% (65-83). Following the protocol amendment for cardiovascular safety, only one further thromboembolic event was reported (fatal pulmonary embolism). INTERPRETATION Intensification of systemic therapy with neoadjuvant combination chemotherapy before standard treatment is feasible in poor-risk potentially operable rectal cancer, with acceptable safety and promising long-term outcomes. Future development of this multidisciplinary treatment strategy in randomised trials is warranted. FUNDING UK National Health Service, Sanofi-Aventis.

A phase I clinical trial with monoclonal antibody ch806 targeting transitional state and mutant epidermal growth factor receptors

An array of cell-surface antigens expressed by human cancers have been identified as targets for antibody-based therapies. The great majority of these antibodies do not have specificity for cancer but recognize antigens expressed on a range of normal cell types (differentiation antigens). Over the past two decades, our group has analyzed thousands of mouse monoclonal antibodies for cancer specificity and identified a battery of antibodies with limited representation on normal human cells. The most tumor-specific of these antibodies is 806, an antibody that detects a unique epitope on the epidermal growth factor receptor (EGFR) that is exposed only on overexpressed, mutant, or ligand-activated forms of the receptor in cancer. In vitro immunohistochemical specificity analysis shows little or no detectable 806 reactivity with normal tissues, even those with high levels of wild-type (wt)EGFR expression. Preclinical studies have demonstrated that 806 specifically targets a subset of EGFR expressed on tumor cells, and has significant anti-tumor effects on human tumor xenografts, primarily through abrogation of signaling pathways. The present clinical study was designed to examine the in vivo specificity of a chimeric form of mAb 806 (ch806) in a tumor targeting/biodistribution/pharmacokinetic analysis in patients with diverse tumor types. ch806 showed excellent targeting of tumor sites in all patients, no evidence of normal tissue uptake, and no significant toxicity. These in vitro and in vivo characteristics of ch806 distinguish it from all other antibodies targeting EGFR.

Intestinal complications after chemotherapy for patients with unresected primary colorectal cancer and synchronous metastases

Background: The role of palliative resection of the primary tumour in patients who present with metastatic colorectal cancer is unclear. Aims: This study compared the incidence of major intestinal complications in such patients who received chemotherapy treatment with or without prior palliative resection of the primary tumour. Patients: The incidence of intestinal obstruction, perforation, fistula formation, and gastrointestinal haemorrhage, and the requirement for abdominal radiotherapy in patients with metastatic colorectal cancer treated at a single institution over a 10 year period was determined. Results: Eighty two patients received initial treatment with chemotherapy without resection of the primary tumour (unresected group) and 280 patients had undergone prior resection (resected group). In the unresected group, the incidence of peritonitis, fistula formation, and intestinal haemorrhage was 2.4% (95% confidence interval (CI) 0.3–8.5%), 3.7% (95% CI 0.8–10.3%), and 3.7% (95% CI 0.8–10.3%), respectively, and was not significantly different from the resected group. Intestinal obstruction affected 13.4% (95% CI 6.9–22.7%) of patients in the unresected group and 13.2% (95% CI 9.2–17.2%) of patients in the resected group. More patients in the unresected group required ⩾3 blood transfusions (14.6% v 7.5%; p=0.048) and abdominal radiotherapy (18.3% v 9.6%; p=0.03) than the resected group. Conclusions: The incidence of major intestinal complications in patients with unresected colorectal cancer and synchronous metastases who receive initial treatment with chemotherapy is low. Chemotherapy may be successfully used as initial treatment for such patients with no increased risk of most major intestinal complications compared with patients who have undergone initial resection of the primary tumour.