Jordan Berlin

The molecular evolution of acquired resistance to targeted EGFR blockade in colorectal cancers

Colorectal tumours that are wild type for KRAS are often sensitive to EGFR blockade, but almost always develop resistance within several months of initiating therapy. The mechanisms underlying this acquired resistance to anti-EGFR antibodies are largely unknown. This situation is in marked contrast to that of small-molecule targeted agents, such as inhibitors of ABL, EGFR, BRAF and MEK, in which mutations in the genes encoding the protein targets render the tumours resistant to the effects of the drugs. The simplest hypothesis to account for the development of resistance to EGFR blockade is that rare cells with KRAS mutations pre-exist at low levels in tumours with ostensibly wild-type KRAS genes. Although this hypothesis would seem readily testable, there is no evidence in pre-clinical models to support it, nor is there data from patients. To test this hypothesis, we determined whether mutant KRAS DNA could be detected in the circulation of 28 patients receiving monotherapy with panitumumab, a therapeutic anti-EGFR antibody. We found that 9 out of 24 (38%) patients whose tumours were initially KRAS wild type developed detectable mutations in KRAS in their sera, three of which developed multiple different KRAS mutations. The appearance of these mutations was very consistent, generally occurring between 5 and 6 months following treatment. Mathematical modelling indicated that the mutations were present in expanded subclones before the initiation of panitumumab treatment. These results suggest that the emergence of KRAS mutations is a mediator of acquired resistance to EGFR blockade and that these mutations can be detected in a non-invasive manner. They explain why solid tumours develop resistance to targeted therapies in a highly reproducible fashion.

Cetuximab-Induced Anaphylaxis and IgE Specific for Galactose-α-1,3-Galactose

BACKGROUND Cetuximab, a chimeric mouse-human IgG1 monoclonal antibody against the epidermal growth factor receptor, is approved for use in colorectal cancer and squamous-cell carcinoma of the head and neck. A high prevalence of hypersensitivity reactions to cetuximab has been reported in some areas of the United States. METHODS We analyzed serum samples from four groups of subjects for IgE antibodies against cetuximab: pretreatment samples from 76 case subjects who had been treated with cetuximab at multiple centers, predominantly in Tennessee, Arkansas, and North Carolina; samples from 72 control subjects in Tennessee; samples from 49 control subjects with cancer in northern California; and samples from 341 female control subjects in Boston. RESULTS Among 76 cetuximab-treated subjects, 25 had a hypersensitivity reaction to the drug. IgE antibodies against cetuximab were found in pretreatment samples from 17 of these subjects; only 1 of 51 subjects who did not have a hypersensitivity reaction had such antibodies (P<0.001). IgE antibodies against cetuximab were found in 15 of 72 samples (20.8%) from control subjects in Tennessee, in 3 of 49 samples (6.1%) from northern California, and in 2 of 341 samples (0.6%) from Boston. The IgE antibodies were shown to be specific for an oligosaccharide, galactose-alpha-1,3-galactose, which is present on the Fab portion of the cetuximab heavy chain. CONCLUSIONS In most subjects who had a hypersensitivity reaction to cetuximab, IgE antibodies against cetuximab were present in serum before therapy. The antibodies were specific for galactose-alpha-1,3-galactose.

Phase III Study of Gemcitabine in Combination With Fluorouracil Versus Gemcitabine Alone in Patients With Advanced Pancreatic Carcinoma: Eastern Cooperative Oncology Group Trial E2297

PURPOSE Gemcitabine is generally considered to constitute first-line therapy for pancreatic cancer. To determine whether the addition of fluorouracil (5-FU) improves on the results from single-agent gemcitabine, the Eastern Cooperative Oncology Group (ECOG) compared gemcitabine plus bolus 5-FU with gemcitabine alone for patients with advanced pancreatic carcinoma. PATIENTS AND METHODS This trial involved patients with biopsy-proven, advanced carcinoma of the pancreas not amenable to surgical resection. Patients were randomized to receive either gemcitabine alone (1,000 mg/m(2)/wk) weekly for 3 weeks of every 4 or to receive gemcitabine (1,000 mg/m(2)/wk) followed by 5-FU (600 mg/m(2)/wk) weekly on the same schedule. The primary end point of the trial was survival, with secondary end points of time to progression and response rate. RESULTS Of 327 patients enrolled over 18 months, 322 were eligible. Overall, the median survival was 5.4 months for gemcitabine alone and 6.7 months for gemcitabine plus 5-FU (P =.09). Progression-free survival for gemcitabine alone was 2.2 months, compared with 3.4 months for gemcitabine plus 5-FU (P =.022). Objective responses were uncommon and were observed in only 5.6% of patients treated with gemcitabine and 6.9% of patients treated with gemcitabine plus 5-FU. Most toxicities were hematologic or gastrointestinal; no significant differences were noted between the two treatment arms. CONCLUSION 5-FU, administered in conjunction with gemcitabine, did not improve the median survival of patients with advanced pancreatic carcinoma compared with single-agent gemcitabine. Further studies with other combinations of gemcitabine and 5-FU are not compelling, and clinical trial resources should address other combinations and novel agents.

Bevacizumab in combination with fluorouracil and leucovorin: an active regimen for first-line metastatic colorectal cancer.

PURPOSE In a phase III trial, combining bevacizumab (BV)--a recombinant, humanized, monoclonal antibody targeting vascular endothelial growth factor--with irinotecan, bolus fluorouracil (FU), and leucovorin (LV; IFL) increased survival compared with IFL alone in first-line treatment of patients with metastatic colorectal cancer (CRC). Results for the parent study of IFL/BV versus IFL/placebo are reported elsewhere. Here, we describe efficacy and safety results for the third patient cohort in this trial, who received BV combined with FU/LV, and compare them with results for concurrently enrolled patients who received IFL. METHODS Patients (N = 923) were randomly assigned to receive IFL/placebo (control), IFL/BV, or FU/LV/BV. Bevacizumab (Avastin; Genentech Inc, South San Francisco, CA) 5 mg/kg was administered intravenously every 2 weeks. Before an interim analysis confirmed acceptable safety for IFL/BV, 313 patients were concurrently randomly assigned to these three arms; after this analysis, the FU/LV/BV arm was discontinued. RESULTS Median overall survivals were 18.3 and 15.1 months with FU/LV/BV (n = 110) and IFL/placebo (n = 100), respectively. Median progression-free survivals were 8.8 and 6.8 months, respectively. Overall response rates were 40.0% and 37.0%, and median response durations were 8.5 and 7.2 months, respectively. Adverse events consistent with those expected from FU/leucovorin- or IFL-based regimens were seen, as were modest increases in hypertension and bleeding in the bevacizumab arm, which were generally easily managed. CONCLUSION The FU/LV/BV regimen seems as effective as IFL and has an acceptable safety profile. FU/LV/BV is an active alternative treatment regimen for patients with previously untreated metastatic CRC.

Superiority of oxaliplatin and fluorouracil-leucovorin compared with either therapy alone in Patients with progressive colorectal cancer after irinotecan and fluorouracil-leucovorin: Interim results of a phase III trial

PURPOSE In North America, no effective therapy has been available for patients with progressive metastatic colorectal cancer after front-line treatment with irinotecan, bolus fluorouracil (FU), and leucovorin (IFL). PATIENTS AND METHODS Patients with metastatic colorectal cancer who progressed after IFL therapy were randomly assigned to bolus and infusional FU and leucovorin (LV5FU2), single-agent oxaliplatin, or the combination (FOLFOX4). This planned interim analysis evaluated objective response rate (RR), time to tumor progression (TTP), and alleviation of tumor-related symptoms (TRS) in an initial cohort of patients. RESULTS Between November 2000 and September 2001, 463 patients from 120 sites in North America were randomly assigned to treatment. FOLFOX4 proved superior to LV5FU2 in all measures of clinical efficacy. Objective RRs determined by an independent radiology panel were 9.9% for FOLFOX4 versus 0% for LV5FU2 (Fishers exact test, P <.0001). Median TTP was 4.6 months for FOLFOX4 versus 2.7 months for LV5FU2 (two-sided, stratified log-rank test, P <.0001). Relief of TRS occurred in 33% of patients treated with FOLFOX4 versus 12% of patients treated with LVFU2 (chi2 test, P <.001). Single-agent oxaliplatin was not superior to LV5FU2 in any measure of efficacy. Patients treated with FOLFOX4 experienced a higher incidence of clinically significant toxicities than patients treated with LV5FU2, but these toxicities were predictable and did not result in a higher rate of treatment discontinuation or 60-day mortality rate. CONCLUSION For patients with metastatic colorectal cancer, second-line treatment with FOLFOX4 is superior to treatment with LVFU2 in terms of RR, TTP, and relief of TRS.

Phase III, Randomized Study of Gemcitabine and Oxaliplatin Versus Gemcitabine (fixed-dose rate infusion) Compared With Gemcitabine (30-minute infusion) in Patients With Pancreatic Carcinoma E6201: A Trial of the Eastern Cooperative Oncology Group

PURPOSE Single-agent gemcitabine (GEM) is standard treatment of metastatic pancreatic cancer. Fixed-dose rate (FDR) GEM and GEM plus oxaliplatin have shown promise in early clinical trials. E6201 was designed to compare overall survival (OS) of standard weekly GEM 1,000 mg/m(2)/30 minutes versus GEM FDR 1,500 mg/m(2)/150 minutes or GEM 1,000 mg/m(2)/100 minutes/day 1 plus oxaliplatin 100 mg/m(2)/day 2 every 14 days (GEMOX). METHODS This trial included patients with metastatic or locally advanced pancreatic cancer, normal organ function, and performance status of 0 to 2. The study was designed to detect a 33% difference in median survival (hazard ratio [HR] < or = 0.75 for either of the experimental arms) with 81% power while maintaining a significance level of 2.5% in a two-sided test for each of the two primary comparisons. RESULTS Eight hundred thirty-two patients were enrolled. The median survival and 1-year survival were 4.9 months (95% CI, 4.5 to 5.6) and 16% for GEM, 6.2 months (95% CI, 5.4 to 6.9), and 21% for GEM FDR (HR, 0.83; stratified log-rank P = .04), and 5.7 months (95% CI, 4.9 to 6.5) and 21% for GEMOX (HR, 0.88; stratified log-rank P = .22). Neither of these differences met the prespecified criteria for significance. Survival was 9.2 months for patients with locally advanced disease, and 5.4 months for those with metastatic disease. Grade 3/4 neutropenia and thrombocytopenia were greatest with GEM FDR. GEMOX caused higher rates of nausea, vomiting, and neuropathy. CONCLUSION Neither GEM FDR nor GEMOX resulted in substantially improved survival or symptom benefit over standard GEM in patients with advanced pancreatic cancer.

Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors

Background Patients with advanced midgut neuroendocrine tumors who have had disease progression during first‐line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium‐177 (177Lu)–Dotatate in patients with advanced, progressive, somatostatin‐receptor–positive midgut neuroendocrine tumors. Methods We randomly assigned 229 patients who had well‐differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu‐Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long‐acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu‐Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression‐free survival. Secondary end points included the objective response rate, overall survival, safety, and the side‐effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here. Results At the data‐cutoff date for the primary analysis, the estimated rate of progression‐free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu‐Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu‐Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu‐Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu‐Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame. Conclusions Treatment with 177Lu‐Dotatate resulted in markedly longer progression‐free survival and a significantly higher response rate than high‐dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu‐Dotatate group. (Funded by Advanced Accelerator Applications; NETTER‐1 ClinicalTrials.gov number, NCT01578239; EudraCT number 2011‐005049‐11.)

Protocol for the Examination of Specimens From Patients With Primary Carcinoma of the Colon and Rectum

The College of American Pathologists offers these protocols to assist pathologists in providing clinically useful and relevant information when reporting results of surgical specimen examinations. The College regards the reporting elements in the “Surgical Pathology Cancer Case Summary (Checklist)” portion of the protocols as essential elements of the pathology report. However, the manner in which these elements are reported is at the discretion of each specific pathologist, taking into account clinician preferences, institutional policies, and individual practice. The College developed these protocols as an educational tool to assist pathologists in the useful reporting of relevant information. It did not issue the protocols for use in litigation, reimbursement, or other contexts. Nevertheless, the College recognizes that the protocols might be used by hospitals, attorneys, payers, and others. Indeed, effective January 1, 2004, the Commission on Cancer of the American College of Surgeons mandated the use of the checklist elements of the protocols as part of its Cancer Program Standards for Approved Cancer Programs. Therefore, it becomes even more important for pathologists to familiarize themselves with these documents. At the same time, the College cautions that use of the protocols other than for their intended educational purpose may involve additional considerations that are beyond the scope of this document.

American Society of Clinical Oncology Perspective: Raising the Bar for Clinical Trials by Defining Clinically Meaningful Outcomes

See accompanying editorial on page 1186 Lee M. Ellis, University of Texas MD Anderson Cancer Center, Houston, TX; David S. Bernstein and Richard L. Schilsky, American Society of Clinical Oncology, Alexandria, VA; Emile E. Voest, University Medical Center Utrecht, Utrecht, the Netherlands; Jordan D. Berlin, Vanderbilt-Ingram Cancer Center, Nashville, TN; Daniel Sargent, Mayo Clinic, Rochester, MN; Patricia Cortazar, US Food and Drug Administration, Silver Spring, MD; Elizabeth Garrett-Mayer, Medical University of South Carolina, Charleston, SC; Roy S. Herbst and Rogerio C. Lilenbaum, Yale Cancer Center, New Haven, CT; Camelia Sima and Mithat Gonen, Memorial Sloan-Kettering Cancer Center, New York, NY; Alan P. Venook, Helen Diller Family Comprehensive Cancer Center at University of California San Francisco, San Francisco, CA; Neal J. Meropol, University Hospitals Seidman Cancer Center, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH; Lowell E. Schnipper, Beth Israel Deaconess Medical Center, Boston, MA.

Consensus report of the national cancer institute clinical trials planning meeting on pancreas cancer treatment

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer mortality, despite significant improvements in diagnostic imaging and operative mortality rates. The 5-year survival rate remains less than 5% because of microscopic or gross metastatic disease at time of diagnosis. The Clinical Trials Planning Meeting in pancreatic cancer was convened by the National Cancer Institutes Gastrointestinal Cancer Steering Committee to discuss the integration of basic and clinical knowledge in the design of clinical trials in PDAC. Major emphasis was placed on the enhancement of research to identify and validate the relevant targets and molecular pathways in PDAC, cancer stem cells, and the microenvironment. Emphasis was also placed on developing rational combinations of targeted agents and the development of predictive biomarkers to assist selection of patient subsets. The development of preclinical tumor models that are better predictive of human PDAC must be supported with wider availability to the research community. Phase III clinical trials should be implemented only if there is a meaningful clinical signal of efficacy and safety in the phase II setting. The emphasis must therefore be on performing well-designed phase II studies with uniform sets of basic entry and evaluation criteria with survival as a primary endpoint. Patients with either metastatic or locally advanced PDAC must be studied separately.