Correlation of oncogenic mutations in circulating cell-free DNA (cfDNA) and tumor tissue through a multiplex sequencing platform in patients under consideration for phase I trials

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Background: Previous studies suggest that tumoral cfDNA is a potential biomarker in cancer. Methods: Prospective collection of samples from patients (pts) referred to a phase I trials unit, in 2 cohorts: “A”(manual isolation of cfDNA, Sep09-Dec10) and “B”(robotic isolation, Jan11-Sep11) and from 41 healthy volunteers (HV). CfDNA and tumor DNA from matched formalin-fixed paraffin-embedded (FFPE) tissue were isolated, quantified and analyzed for 238 oncogenic mutations (OM) in 19 oncogenes using Sequenom OncoCarta Panel 1.0. Mutation data were used for trial allocation when available. Statistical analyses used Pearson’s Chi-squared test and Mann-Whitney test. Results: 280 pts were included: breast (60; 21%), ovarian (44; 16%), and colorectal (42; 15%). 265 (95%) plasma and 194 (69%) FFPE samples were suitable for analysis. In 181 pts (65%) both samples were available for comparison. Median turnover time for cfDNA 7 days (range 5-14). Median [cfDNA] (concentration; ng/ml) in pts was higher than in HV (“A” 21 v 6.4;p<0.01, “B” 34 v 24;p<0.01). Detection of OM in cfDNA was more frequent when [cfDNA] was above the HV range (67% v 33% p=0.002). Among 181 pts with both samples analyzed, 53 OM were detected in cfDNA, with high concordance with tumor analysis (Table), especially for RAS in colorectal tumors (10/11 91%) and PIK3CAin breast (4/4 100%). In contrast, 29 pts (16%) had OM detected in tumor but not in plasma. The rate of concordance between OM detected in plasma v FFPE was independent of [cfDNA]. 154 pts were enrolled in phase I trials and 26 were given a matched drug according to the mutational analysis. Conclusions: cfDNA may be a useful tool to detect OM in a time frame suitable for clinical decision-making. Concordance of OM found in cfDNA with FFPE samples is high; discordance in this study may be explained by limitations of multiplexed-sequencing techniques, tumor heterogeneity or biologic evolution of the disease. [Table: see text]

Phase I trial of combretastatin A4 phosphate (CA4P) in combination with bevacizumab in patients with advanced cancer

PURPOSE

The vascular disrupting agent (VDA) combretastatin A4 phosphate (CA4P) induces significant tumor necrosis as a single agent. Preclinical models have shown that the addition of an anti-VEGF antibody to a VDA attenuates the revascularization of the surviving tumor rim and thus significantly increases antitumor activity.

EXPERIMENTAL DESIGN

Patients with advanced solid malignancies received CA4P at 45, 54, or 63 mg/m(2) on day 1, day 8, and then every 14 days. Bevacizumab 10 mg/kg was given on day 8 and at subsequent cycles four hours after CA4P. Functional imaging with dynamic contrast enhanced-MRI (DCE-MRI) was conducted at baseline, after CA4P alone, and after cycle 1 CA4P + bevacizumab.

RESULTS

A total of 63 mg/m(2) CA4P + 10 mg/kg bevacizumab q14 is the recommended phase II dose. A total of 15 patients were enrolled. Dose-limiting toxicities were grade III asymptomatic atrial fibrillation and grade IV liver hemorrhage in a patient with a history of hemorrhage. Most common toxicities were hypertension, headache, lymphopenia, pruritus, and pyrexia. Asymptomatic electrocardiographic changes were seen in five patients. Nine of 14 patients experienced disease stabilization. A patient with ovarian cancer had a CA125 response lasting for more than a year. DCE-MRI showed statistically significant reductions in tumor perfusion/vascular permeability, which reversed after CA4P alone but which were sustained following bevacizumab. Circulating CD34(+) and CD133(+) bone marrow progenitors increased following CA4P as did VEGF and granulocyte colony-stimulating factor levels.

CONCLUSIONS

CA4P in combination with bevacizumab appears safe and well tolerated in this dosing schedule. CA4P induced profound vascular changes, which were maintained by the presence of bevacizumab.

Radiological Findings of a 62-Year-Old Male with Loss of Weight and Appetite

Plain X-rays are still important basic first-line investigations for the family physician practising in the private and public sectors. They are useful in the detection of pathology in the skeletal system as well as some disease processes in the soft tissues. Notable examples include chest X-rays which can be used to identify diseases such as pneumonia, carcinoma of the lung or pulmonary oedema. The chest X-ray presented here is of a 62-year-old man presenting with a 3-month history of loss of weight and appetite as well as a chronic cough.

Colonic Diverticulosis as a Risk Factor for Peritonitis in Chinese Peritoneal Dialysis Patients

Objectives

The risk of development of enteric peritonitis in Chinese peritoneal dialysis (PD) patients with colonic diverticulosis is not known. There have been no reports on whether colonic diverticulosis may affect peritonitis outcomes. The objectives of this study were to examine whether colonic diverticulosis is a risk factor for the development of enteric peritonitis and to study its influence on the outcome of enteric peritonitis.

Patients and Methods

All continuous ambulatory PD patients that had barium enema and colonoscopic examinations performed between January 1994 and January 2006 were included. They were divided into 2 groups: patients with diverticulosis and patients without diverticulosis. Their demographic and clinical characteristics, colonic examination findings, and peritonitis data were compared and analyzed.

Results

104 Chinese patients received 110 colonoscopies and 51 barium enema examinations. 25 patients (24.0%) had colonic diverticulosis. Patients with diverticulosis were older (65.4 ± 14.7 vs 58.4 ± 14.0 years, p = 0.033). The most common site of involvement of diverticulosis was the ascending colon (56%). 128 episodes of enteric peritonitis were recorded in 49 patients. Compared with patients without enteric peritonitis, more patients in the enteric peritonitis group had diverticulosis (38.8% vs 10.9%, p = 0.001) and diverticulosis most often involved the ascending colon (20.4% vs 7.3%, p = 0.082). Multivariate logistic regression analysis showed that the presence of diverticulosis (hazard ratio 5.17, 95% confidence interval 1.86 – 14.40; p = 0.002) and diverticulosis involving the ascending colon (hazard ratio 6.89, 95% confidence interval 1.43 – 33.32, p = 0.016) were independent risk factors for the development of enteric peritonitis. Enteric peritonitis in patients with diverticulosis had a higher but nonsignificant treatment failure rate (26.9% vs 18.4%, p = 0.282).

Conclusion

In this selected cohort of PD patients with indications of colonic examinations, diverticulosis, especially involving the ascending colon, may be a risk factor for the development of enteric peritonitis. Colonic diverticulosis does not appear to affect the outcome of enteric peritonitis. Further studies are warranted to determine ways to prevent enteric peritonitis in PD patients with diverticulosis.