Current progress in targeted therapy for colorectal cancer.

BACKGROUND: Several molecular targeting agents are available and being used in patients with colorectal cancer, and many others are being tested clinically. METHODS: The authors review and present the biology and use, including predictive testing, of the agents currently approved for use in colorectal cancer as well as current data on several newer tyrosine kinase inhibitors that are undergoing clinical trials. RESULTS: The angiogenesis inhibitor bevacizumab and the two EGFR inhibitors cetuximab and panitumumab are currently the three targeted agents approved in colorectal cancer. Recent studies show that the combined use of bevacizumab and EGFR inhibitors may lead to increased toxicity and inferior outcome. Much remains to be understood regarding these drugs and other targeted therapies as well as the underlying mechanism of tumor resistance or responsiveness to treatment. Their optimal use and sequencing with other treatment modalities such as surgery need to be further refined. CONCLUSIONS: There is a crucial need for identification of predictive markers of response and identification of possible negative interactions between targeted agents so that we can better select patients likely to respond to treatment.

Efficacy of gemcitabine plus axitinib compared with gemcitabine alone in patients with advanced pancreatic cancer: an open-label randomised phase II study.

BACKGROUND: Axitinib (AG-013736) is a potent and selective oral inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, which have an important role in pancreatic cancer. The aim of this study was to assess the safety and efficacy of gemcitabine plus axitinib versus gemcitabine alone. METHODS: Between January and August, 2006, 103 patients with unresectable, locally advanced, or metastatic pancreatic cancer were randomly assigned in a two to one ratio to receive gemcitabine (1000 mg/m(2)) plus axitinib 5 mg twice daily (n=69) or gemcitabine (1000 mg/m(2)) alone (n=34) by a centralised registration system. The primary endpoint was overall survival. Analyses were done by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00219557. FINDINGS: All randomised patients were included in the efficacy analyses. Median overall survival was longer with gemcitabine plus axitinib than with gemcitabine alone (6.9 [95% CI 5.3-10.1] months vs 5.6 [3.9-8.8] months). The hazard ratio for survival with gemcitabine plus axitinib versus with gemcitabine alone, adjusted for stratification factors, was 0.71 (95% CI 0.44-1.13). The most common grade 3 or worse adverse events were fatigue (15 [22%] patients in the gemcitabine plus axitinib group vs one [3%] in the gemcitabine alone group), abdominal pain (eight [12%] vs five [16%]), and asthenia (eight [12%] vs one [3%]). INTERPRETATION: Gemcitabine plus axitinib showed a similar safety profile to gemcitabine alone; the small, non-statistically significant gain in overall survival needs to be assessed in a randomised phase III trial.

A phase 1 escalating single-dose and weekly fixed-dose study of cetuximab: pharmacokinetic and pharmacodynamic rationale for dosing.

PURPOSE: This phase 1 study evaluated the pharmacokinetic and pharmacodynamic effects of cetuximab on patients with epithelial malignancies. EXPERIMENTAL DESIGN: Following a skin and tumor biopsy, patients with advanced epithelial malignancies were randomized to receive a single dose of cetuximab at 50, 100, 250, 400, or 500 mg/m2 i.v. Repeat skin (days 2, 8, 15, and 22) and tumor (day 8) biopsies were obtained. Immunohistochemical expression of epidermal growth factor receptor (EGFR) and its pathway members was done on biopsies. Blood samples were obtained over 22 days for pharmacokinetic analyses. After day 22, all patients received weekly 250 mg/m2 cetuximab until disease progression or unacceptable toxicity. RESULTS: Thirty-nine patients enrolled. Rash was noted in 26 (67%) patients. Three patients (two with colon cancer and one with laryngeal cancer) achieved a partial response and 13 patients had stable disease. Pharmacokinetic data revealed mean maximum observed cetuximab concentrations and mean area under the concentration-time curve from time zero to infinity increased in a dose-dependent manner up to 400 mg/m2 cetuximab. Mean clearance was similar at cetuximab doses>or=100 mg/m2, supporting saturation of EGFR binding at 250 mg/m2. Pharmacodynamic evaluation revealed that patients with partial response/stable disease had a higher-grade rash and higher cetuximab trough levels than those with progressive disease (P=0.032 and 0.002, respectively). Administration of single doses (250-500 mg/m2) of cetuximab resulted in a dose-dependent decrease in EGFR protein expression levels in skin over time, supporting a minimal dose of cetuximab at 250 mg/m2 for a pharmacodynamic effect. CONCLUSION: This study provides a pharmacokinetic and pharmacodynamic rationale for the dosing of cetuximab.

A case of primary squamous cell colon cancer.

Carcinomas of the colon are a common cancer seen in both inpatient and outpatient settings with approximately 145,000 new cases being diagnosed every year in the USA. Despite the frequency of these cancers being seen, it continues to be a rarity to see a primary squamous cell cancer of the colon. In this article, such a case is presented. While the exact aetiology of this rare tumour is currently still not completely understood, various aetiologies include chronic irritation leading to squamous differentiation, embryonic migration of ectodermal cells to the colon, or adenomas undergoing squamous transformation.

Gliomatosis cerebri: a review of 296 cases from the ANOCEF database and the literature.

Gliomatosis cerebri (GC) is a rare disease, defined as a diffuse neoplastic glial cell infiltration of the brain. Diagnosis and management of GC are difficult. This study analyzed 296 individual cases (90 patients followed through the ANOCEF network, and 206 cases from the literature), aged 1 month to 85 years (median 42), sex ratio=1.31. Median survival was 14.5 months. It was higher for patients younger than 42 years (17 months vs. 13 months), with performance status>or=80 (27 months vs. 9 months), low grade gliomatosis (grade 2=20 months, grade 3=11.5 months, grade 4=8.5 months), oligodendroglial subtype (36 months compared to 14 months for mixed GC and 11 months for astrocytic GC). Male population was younger (median 39 years vs. 45), had a higher incidence of oligodendroglial GC (22% vs. 13%), which may explain their better prognosis (median survival 17 months vs. 11.5 months) than female population. Despite a high rate of stabilization, the impact on survival of whole brain radiotherapy, which carries the risk of severe toxicity, is still unclear. Up-front chemotherapy benefit to some patients and may be preferred to whole brain radiotherapy. However, the many bias of such retrospective heterogeneous data claim for multicentric clinical trials in this rare disease.

Leptomeningeal metastases from solid malignancy: a review.

Leptomeningeal metastases (LMM) consist of diffuse involvement of the leptomeninges by infiltrating cancer cells. In solid tumors, the most frequent primary sites are lung and breast cancers, two tumors where the incidence of LMM is apparently increasing. Careful neurological examination is required to demonstrate multifocal involvement of the central nervous system (CNS), cranial nerves, and spinal roots, which constitute the clinical hallmark of the disease. Cerebro-spinal fluid (CSF) analysis is almost always abnormal but only a positive cytology or demonstration of intrathecal synthesis of tumor markers is diagnostic. T1-weighted gadolinium-enhanced sequence of the entire neuraxis (brain and spine) plays an important role in supporting the diagnosis, demonstrating the involved sites and guiding treatment. Radionuclide CSF flow studies detect CSF compartmentalization and are useful for treatment planning. Standard therapy relies mainly on focal irradiation and intrathecal or systemic chemotherapy. Studies using other therapeutic approaches such as new biological or cytotoxic compounds are ongoing. The overall prognosis remains grim and quality of life should remain the priority when deciding which treatment option to apply. However, a sub-group of patients, tentatively defined here, may benefit from an aggressive treatment.

A phase I and pharmacokinetic study of docetaxel combined with Doxil (pegylated liposomal doxorubicin) without and with granulocyte colony stimulating factor.

The purpose of this study was (i) to determine the maximum tolerated dose (MTD) of docetaxel that can be administered in combination with Doxil, given without and with granulocyte colony stimulating factor (G-CSF), (ii) to define the pharmacokinetics (PK) of docetaxel when used in combination with Doxil, and (iii) to make preliminary observations on the anti-tumor activity of this combination in patients with metastatic solid tumors. Thirty-seven patients with metastatic cancer were enrolled. Courses were repeated every 3 weeks. Patients received a fixed dose of Doxil 30 mg/m(2) in combination with escalating doses of docetaxel ranging from 40 to 100 mg/m(2). After encountering dose-limiting febrile neutropenia, subsequent escalation was accomplished with G-CSF support. Selected patients at the recommended phase II dose underwent PK evaluation. The most common toxicity observed was neutropenia. Dose-limiting toxicity (30 mg/m(2) Doxil + 80 mg/m(2) docetaxel) was febrile neutropenia in three of six patients treated without G-CSF. Major non-hematological toxicities included alopecia, mucositis and hand-foot syndrome, and were observed after cumulative doses of chemotherapy. Objective responses (complete/partial) were documented in eight of 37 patients (four with breast cancer) and stable disease was seen in 17 patients. PK studies showed an increased tissue retention (decreased clearance) of docetaxel when given with Doxil. The recommended phase II dose of Doxil/docetaxel is 30/60 mg/m(2), q3 weeks, without G-CSF. Further dose escalation to 30/80 mg/m(2) is safe with G-CSF support. Anti-tumor activity, particularly against breast cancer, was observed at various dose levels. Our observations should provide evidence for phase II studies of this combination in patients with breast cancer and other anthracycline/taxane-sensitive cancers.