Targeting the human epidermal growth factor receptor 2 (HER2) oncogene in colorectal cancer.

Human epidermal growth factor receptor 2 (HER2) is an oncogenic driver, and a well-established therapeutic target in breast and gastric cancers. Using functional and genomic analyses of patient-derived xenografts, we previously showed that a subset (approximately 5%) of metastatic colorectal cancer (CRC) tumors is driven by amplification or mutation of HER2. This paper reviews the role of HER2 amplification as an oncogenic driver, a prognostic and predictive biomarker, and a clinically actionable target in CRC, considering the specifics of HER2 testing in this tumor type. While the role of HER2 as a biomarker for prognosis in CRC remains uncertain, its relevance as a therapeutic target has been established. Indeed, independent studies documented substantial clinical benefit in patients treated with biomarker-driven HER2-targeted therapies, with an impact on response rates and duration of response that compared favorably with immunotherapy and other examples of precision oncology. HER2-targeted therapeutic strategies have the potential to change the treatment paradigm for a clinically relevant subgroup of metastatic CRC patients.

Phase I study of every 2- or 3-week dosing of ramucirumab, a human immunoglobulin G1 monoclonal antibody targeting the vascular endothelial growth factor receptor-2 in patients with advanced solid tumors.

BACKGROUND: Ramucirumab is a fully human immunoglobulin G1 monoclonal antibody receptor antagonist designed to block the ligand-binding site of vascular endothelial growth factor receptor-2 (VEGFR-2). An initial phase I study evaluated ramucirumab administered weekly in advanced cancer patients. This phase I study of ramucirumab [administered every 2 or 3 weeks (Q2W or Q3W)] examined safety, maximum tolerated dose, pharmacokinetics, immunogenicity, antitumor activity, and pharmacodynamics. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of ramucirumab i.v. over 1 h. Blood was sampled for pharmacokinetics studies throughout treatment; levels of circulating vascular endothelial growth factor-A (VEGF-A) and soluble VEGF receptors (R)-1 and -2 were assessed. RESULTS: Twenty-five patients were treated with ramucirumab: 13 with 6, 8, or 10 mg/kg Q2W, and 12 with 15 or 20 mg/kg Q3W. The median treatment duration was 12 weeks (range 2-81). No dose-limiting toxicities were observed. The most frequently reported adverse events (AEs) included proteinuria and hypertension (n = 6 each), and diarrhea, fatigue and headache (n = 4 each). Treatment-related grade 3/4 AEs were: two grade 3 hypertension (10 and 20 mg/kg), one each grade 3 vomiting, fatigue (20 mg/kg), atrial flutter (15 mg/kg), and one each grade 4 duodenal ulcer hemorrhage (6 mg/kg) and grade 4 pneumothorax (20 mg/kg). Pharmacokinetic analysis revealed low clearance and half-life of ∼110-160 h. Analysis of serum biomarkers indicated considerable patient-to-patient variability, but trends toward elevated VEGF-A and a transient decline in soluble VEGFR-2. Fifteen patients (60%) had best response of stable disease, with a median duration of 13 months (range 2-18 months) in tumor types including colorectal, renal, liver, and neuroendocrine cancers. CONCLUSION: Ramucirumab was well tolerated. Study results led to recommended phase II doses of 8 mg/kg Q2W and 10 mg/kg Q3W. Prolonged stable disease was observed, suggesting ramucirumab efficacy in various solid tumors. CLINICALTRIALSGOV: NCT00786383.

Understanding the mechanisms of action of antiangiogenic agents in metastatic colorectal cancer: a clinician's perspective.

Multiple clinical trials using bevacizumab, ziv-aflibercept, and regorafenib have recently demonstrated efficacy for patients with metastatic colorectal cancer. While the net clinical benefit of each of these therapies in the second-line and refractory disease setting appears to be similar, important distinctions exist between the agents at the pharmacodynamic, tumor microenvironment, and clinical levels. The purpose of this review is to survey the preclinical evidence regarding the mechanisms of action of these novel antiangiogenic agents and provide an overview of their respective clinical activity, while highlighting distinctions between therapies. Fundamental understanding of these distinctions may aid in clinical decisions and choice of antiangiogenic therapies.

Safety and effectiveness of bevacizumab treatment for metastatic colorectal cancer: final results from the Avastin(®) Registry - Investigation of Effectiveness and Safety (ARIES) observational cohort study.

AIMS: The Avastin(®) Registry - Investigation of Effectiveness and Safety (ARIES) observational cohort study (OCS) was designed to prospectively examine outcomes associated with bevacizumab-containing treatment for metastatic colorectal cancer (mCRC) in a community-based setting, where patient populations are less restricted than those in randomised trials. MATERIALS AND METHODS: Patients with mCRC who were eligible for bevacizumab in combination with chemotherapy in first- or second-line treatment were enrolled from November 2006 to September 2008. There were no protocol-specified treatment regimens; the dose and schedule of bevacizumab and chemotherapy were at the treating physician's discretion. The objectives in the ARIES OCS included analyses of progression-free survival (PFS), overall survival, treatment patterns and safety in each of the first- and second-line treatment cohorts. RESULTS: ARIES enrolled 1550 patients with mCRC receiving first-line therapy with bevacizumab. The median follow-up time was 20.6 months. The median PFS in this cohort was 10.2 months (95% confidence interval 9.8-10.6) and the median overall survival was 23.2 months (95% confidence interval 21.2-24.8). In a separate cohort of 482 patients with second-line mCRC, the median follow-up time was 16.9 months, the median PFS and overall survival from the start of second-line treatment to the end of follow-up was 7.9 months (95% confidence interval 7.2-8.3) and 17.8 months (95% confidence interval 16.5-20.7), respectively. Incidences of known bevacizumab-associated adverse events in ARIES were generally consistent with those previously reported in OCSs and randomised trials. CONCLUSION: Results from the prospective ARIES OCS add further evidence to support the effectiveness and safety of bevacizumab when added to first- and second-line treatment regimens for patients with mCRC in community treatment settings.

Clinical evaluation of ZD6474, an orally active inhibitor of VEGF and EGF receptor signaling, in patients with solid, malignant tumors.

BACKGROUND: ZD6474 selectively inhibits the tyrosine kinase activity of vascular endothelial growth factor receptor and epidermal growth factor receptor. The safety, tolerability and pharmacokinetics of ZD6474 were assessed in a phase I dose-escalation study of patients with advanced solid tumors. PATIENTS AND METHODS: Adult patients with tumors refractory to standard treatments received once-daily oral ZD6474 (50-600 mg) in 28-day cycles, until disease progression or unacceptable toxicity was observed. RESULTS: Seventy-seven patients were treated at doses of 50 mg (n=9), 100 mg (n=19), 200 mg (n=8), 300 mg (n=25), 500 mg (n=8), and 600 mg (n=8). Adverse events were generally mild, and the most common dose-limiting toxicities (DLT) were diarrhea (n=4), hypertension (n=4), and rash (n=3). The incidence of most adverse events appeared to be dose-dependant. In the 500 mg/day cohort, 3/8 patients experienced DLT and this dose was therefore considered to exceed the maximum tolerated dose. Pharmacokinetic analysis confirmed that ZD6474 was suitable for once-daily oral dosing. CONCLUSIONS: Once-daily oral dosing of ZD6474 at 300 mg/day is generally well tolerated in patients with advanced solid tumors, and this dose is being investigated in phase II trials.

Complications of pancreaticoduodenectomy after neoadjuvant chemoradiation in patients with and without preoperative biliary drainage.

BACKGROUND: It has been suggested that preoperative biliary drainage increases the risk of infectious complications of pancreaticoduodenectomy. AIMS: The aim of this study was to assess complications related to biliary stents/drains and postoperative morbidity in patients undergoing neoadjuvant chemoradiotherapy for periampullary cancer. PATIENTS: One hundred and eighty-four patients with periampullary neoplasms were prospectively selected for neoadjuvant external beam radiation therapy and 5-fluorouracil-based chemotherapy between 1995 and 2002. METHODS: The data were retrospectively completed and analysed with respect to biliary drainage, efficacy and complications of endoscopic biliary stents and postoperative morbidity. Patients who had undergone a surgical biliary bypass were excluded. RESULTS: Data were completed in 168 patients. One hundred and nineteen patients were treated with endoscopic biliary stents, 18 patients had a percutaneous biliary drain and 31 patients did not require biliary drainage. Hospitalisation for stent-related complications was necessary in 15% of the patients with endoscopic biliary stents. Seventy-two patients underwent pancreaticoduodenectomy. There was no significant difference in the rate of wound infections, intra-abdominal abscesses and overall complications between the groups with and without preoperative biliary drainage. CONCLUSIONS: Postoperative infectious complications are common in patients both with and without preoperative biliary drainage. A statistically significant difference in complication rates was not observed between these groups.

Staging of pancreatic cancer before and after neoadjuvant chemoradiation.

Neoadjuvant chemoradiation therapy is used at many institutions for treatment of localized adenocarcinoma of the pancreas. Accurate staging before neoadjuvant therapy identifies patients with distant metastatic disease, and restaging after neoadjuvant therapy selects patients for laparotomy and attempted resection. The aims of this study were to (1) determine the utility of staging laparoscopy in candidates for neoadjuvant therapy and (2) evaluate the accuracy of restaging CT following chemoradiation. Staging laparoscopy was performed in 98 patients with radiographically potentially resectable (no evidence of arterial abutment or venous occlusion) or locally advanced (arterial abutment or venous occlusion) adenocarcinoma of the pancreas. Unsuspected distant metastasis was identified in 8 (18%) of 45 patients with potentially resectable tumors and 13 (24%) of 55 patients with locally advanced tumors by CT. Neoadjuvant chemoradiation therapy and restaging CT were completed in a total of 103 patients. Thirty-three patients with potentially resectable tumors by restaging CT underwent surgical exploration and resections were performed in 27 (82%). Eleven (22%) of 49 patients with locally advanced tumors by restaging CT were resected, with negative margins in 55%; the tumors in these 11 patients had been considered locally advanced because of arterial involvement on restaging CT. Staging laparoscopy is useful for the exclusion of patients with unsuspected metastatic disease from aggressive neoadjuvant chemoradiation protocols. Following neoadjuvant chemoradiation, restaging CT guides the selection of patients for laparotomy but may overestimate unresectability to a greater extent than does prechemoradiation CT.

Neoadjuvant chemoradiation for localized adenocarcinoma of the pancreas.

BACKGROUND: The use of neoadjuvant (preoperative) chemoradiotherapy (CRT) for pancreatic cancer has been advocated for its potential ability to optimize patient selection for surgical resection and to downstage locally advanced tumors. This article reports our experience with neoadjuvant CRT for localized pancreatic cancer. METHODS: Since 1995, 111 patients with radiographically localized, pathologically confirmed pancreatic adenocarcinoma have received neoadjuvant external beam radiation therapy (EBRT; median, 4500 cGy) with 5-flourouracil-based chemotherapy. Tumors were defined as potentially resectable (PR, n = 53) in the absence of arterial involvement and venous occlusion and locally advanced (LA, n = 58) with arterial involvement or venous occlusion by CT. RESULTS: Five patients (4.5%) were not restaged due to death (n = 3) or intolerance of therapy (n = 2). Twenty-one patients (19%) manifested distant metastatic disease on restaging CT. Twenty-eight patients with initially PR tumors (53%) and 11 patients with initially LA tumors (19%) were resected after CRT. Histologic examination revealed significant fibrosis in all resected specimens and two complete responses. Surgical margins were negative in 72%, and lymph nodes were negative in 70% of resected patients. Median survival in resected patients has not been reached at a median follow-up of 16 months. CONCLUSIONS: Neoadjuvant CRT provided an opportunity for patients with occult metastatic disease to avoid the morbidity of resection and resulted in tumor downstaging in a minority of patients with LA tumors. Survival after neoadjuvant CRT and resection appears to be at least comparable to survival after resection and adjuvant (postoperative) CRT.

Pharmacokinetics and bioequivalence of a combined oral formulation of eniluracil, an inactivator of dihydropyrimidine dehydrogenase, and 5-fluorouracil in patients with advanced solid malignancies.

BACKGROUND: This study was performed to evaluate the pharmacokinetics, bioequivalence, and feasibility of a combined oral formulation of 5-flurouracil (5-FU) and eniluracil (Glaxo Wellcome Inc., Research Triangle Park, North Carolina), an inactivator of dihydropyrimidine dehydrogenase (DPD). The rationale for developing a combined eniluracil/5-FU formulation oral dosing form is to simplify treatment with these agents, which has been performed using separate dosing forms, and decrease the probability of severe toxicity and/or suboptimal therapeutic results caused by inadvertently high or conversely insufficient 5-FU dosing. PATIENTS AND METHODS: The trial was a randomized, three-way crossover bioequivalence study of three oral dosing forms of eniluracil/5-FU tablets in adults with solid malignancies. Each period consisted of two days of treatment and a five- to seven-day washout phase. Eniluracil at a dose of 20 mg, which results in maximal DPD inactivation, was administered twice daily on the first day and in the evening on the second day of each of the three treatments. On the morning of the second day, all patients received a total eniluracil dose of 20 mg orally and a total 5-FU dose of 2 mg orally as either separate tablets (treatment A) or combined eniluracil/5-FU tablets in two different strengths (2 tablets of eniluracil/5-FU at a strength (mg/mg) of 10/1 (treatment B) or 8 tablets at a strength of 2.5/0.25 (treatment C)). The pharmacokinetics of plasma 5-FU, eniluracil, and uracil, and the urinary excretion of eniluracil, 5-FU, uracil, and alpha-fluoro-beta-alanine (FBAL), were studied. To determine the bioequivalence of the combined eniluracil/5-FU dosing forms compared to the separate tablets, an analysis of variance on pharmacokinetic parameters reflecting eniluracil and 5-FU exposure was performed. RESULTS: Thirty-nine patients with advanced solid malignancies had complete pharmacokinetic studies performed during treatments A, B, and C. The pharmacokinetics of eniluracil and 5-FU were similar among the three types of treatment. Both strengths of the combined eniluracil/5-FU dosing form and the separate dosing forms were bioequivalent. Mean values for terminal half-life, systemic clearance, and apparent volume of distribution for oral 5-FU during treatments A/B/C were 5.5/5.6/5.6 hours, 6.6/6.6/6.5 liters/hour, and 50.7/51.5/50.0 liters, respectively. The intersubject coefficient of variation for pharmacokinetic variables reflecting 5-FU exposure and clearance in treatments ranged from 23% to 33%. The urinary excretion of unchanged 5-FU over 24 hours following treatments A, B, and C averaged 52.2%, 56.1%, and 50.8'%, of the administered dose of 5-FU, respectively. Parameters reflecting DPD inhibition, including plasma uracil and urinary FBAL excretion following treatments A, B, and C were similar. Toxicity was generally mild and similar following all three types of treatments. CONCLUSIONS: The pharmacokinetics of 5-FU and eniluracil were similar and met bioequivalence criteria following treatment with the separate oral formulations of 5-FU and eniluracil and two strengths of the combined formulation. The availability of a combined eniluracil/5-FU oral dosing form will likely simplify dosing and decrease the probability of severe toxicity or suboptimal therapeutic results caused by an inadvertent 5-FU overdose or insufficient 5-FU dosing in the case of separate oral formulations, thereby enhancing the overall feasibility and 0therapeutic index of oral 5-FU therapy.

Primary chemotherapy in epithelial ovarian cancer.

Ovarian cancer is an important disease due to its occurrence in women in the prime of life (40-70) and its responsiveness to therapy but generally poor outcome due to the emergence of drug-resistant cells. In early-stage disease, adjuvant therapies may improve outcome, but previous studies have concentrated more on the reduction of toxicity of therapy than on improved survival, although modern approaches are evaluating more aggressive intervention in these patients with good survival rates (40%-90% cure with surgery). In advanced disease, the most common presentation, it appears that more aggressive staging and surgical debulking as well as new classes of drugs for treatment have altered, albeit modestly, the outcome in this disease. Future approaches will evaluate taxol, a new active agent, as well as more dose-intense therapy and a continued search will be made for new active drugs and methods to overcome intrinsic and acquired drug resistance.