Evaluation and optimization of the administration of a selectively replicating herpes simplex viral vector to the brain by convection-enhanced delivery

The direct intraparenchymal administration of oncolytic viral vectors by convection-enhanced delivery (CED) represents a promising new treatment strategy for malignant gliomas. However, there is no evidence to suggest that oncolytic viruses as large as herpes simplex virus-1 (HSV-1) can be administered by CED, as this has not been systematically examined in an animal model. In this study, the administration of a herpes simplex viral vector, HSV1, has been evaluated in detail in the gray and white matter of both rat and pig models, using high flow-rate infusions, co-infusing heparin or preinfusing the tissue with an isotonic albumin solution. Rat HSV-1 infusions at both slow (0.5 μl min(-1)) and high infusion rates (2.5 μl min(-1)) led to extensive tissue damage and negligible cell transduction. Co-infusion with heparin led to extensive hemorrhage. Preinfusion of tissue with an isotonic albumin solution facilitated widespread vector distribution and cell transduction in white matter only. Using this approach in pig brain led to widespread vector distribution with extensive transduction of astrocytes and activated microglia. In rat brain, enhanced green fluorescent protein expression peaked 48 h after vector administration and was associated with a vigorous immune response. These findings indicate that direct infusions of HSV-1-based viral vectors into the brain lead to minimal vector distribution, negligible cell transduction and extensive damage. Tissue preinfusion with an isotonic solution prior to vector administration represents an effective technique for achieving widespread HSV-1 distribution.

Left ventricular true and false aneurysms identified by cardiovascular magnetic resonance

Left ventricular aneurysms are uncommon complications of myocardial infarction. However, it is important to identify them because they are associated with increased morbidity and mortality. True aneurysms tend to be managed conservatively whereas false aneurysms, because of the risk of rupture, are usually treated with urgent surgery. Distinguishing these two subtypes is therefore critical and cardiovascular magnetic resonance (MR) is being used more frequently to characterise the type of aneurysm as well as to provide clear three-dimensional images of aneurysm morphology. We present a very rare case of a true and a false aneurysm of the left ventricle in the same patient. MR enabled accurate delineation of both aneurysms and the late gadolinium-enhancement images provided evidence confirming both true and false aneurysms to be present.

GCC expression in lymph nodes (LNs) as a significant determinant of recurrence in stage II colon cancer (CC) patients (pts)

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Background: A multi-center prospectively specified retrospective study Validating Indicators to Associate Recurrence (VITAR) is assessing the relationship between guanylyl cyclase C (GCC) gene expression in formalin fixed LNs and recurrence risk in stage II CC pts not treated with adjuvant chemotherapy. Here we report the preplanned initial analysis performed with 241 pts.

Methods: GCC mRNA was quantified by RT-qPCR using FFPE LNs tissues from untreated stage II CC pts diagnosed from 1999-2006 with at least 10 LN examined blinded to clinical outcomes. Cox regression models examined the relationship between GCC nodal status and the prespecified primary endpoint of recurrence risk.

Results: Twenty-ninepts (12%) had a disease recurrence or cancer death, median follow-up was 60 months and median LNs examined was 15. The ratio of the number of GCC+ LNs over the total number of informative LNs (LNR) significantly predicted higher recurrence risk for 84 pts classified as high risk (HR, 2.38; p=0.02). The estimated 5-yr recurrence rates were 10% and 27% for the low and high risk group, respectively. After adjusting for age, T stage, number of LNs assessed, and MMR status, the significant association remained (HR, 2.61; 95% CI, 1.17-5.83; p=0.02). In a subset of 181 pts with negative margin, T3 tumor only and ≥12 LN examined, the GCC LNR had a HR for recurrence of 5.06 (95% CI 1.61-15.91, p=0.003), translating into 5-yr recurrence rates of 4% among low risk pts and 27% for the high-risk group.

Conclusions: Our results suggest that GCC expression in LNs is a significant determinant of recurrence in appropriately staged CC pts not treated with adjuvant chemotherapy. The validation component of the study is ongoing.

[Table: see text]

[Table: see text]

Incidence and distribution of HER2-positive gastric and gastroesophageal junction (GEJ) adenocarinomas in British Columbia (BC)

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Background: HER2-positive rates have been reported as 20% of GC and 34% in GEJ adenocarcinoma in a recent global phase III trial with trastuzumab and chemotherapy. This study examines the incidence and distribution HER2-positive GC and GEJ adenocarcinomas in the province of BC.

Methods: Formalin fixed embedded tissue from patients (pts) with resected gastric or GEJ adenocarcinoma from 2004-2007 were identified retrospectively through the BC Cancer Agency registry and prospectively for pts with a new diagnosis of advanced disease. Biopsies and resection samples were analyzed via previously validated methods IHC (Ventana 4B5 antibody), FISH (Eurovision probes) and SISH (Ventana probes). IHC scores of 3 were considered positive, 2 were cequivocal and 0 or 1 were negative. A 10% cut-off was used to determine positive samples. Equivocal staining was considered positive via FISH or SISH. A ratio of > 2.0 was considered amplified for FISH and SISH. P values were calculated using a logistic regression model with HER2 positive as the endpoint.

Results: Of the 87 samples, 64 (74%) were gastric and 23 (26%) GEJ. Overall, HER2 was positive 20% (IHC), 18% (FISH) and 18% (SISH). 13% of cases tested IHC 3+ while 24% tested IHC 2+. In equivocal IHC 2+ cases, 7% were considered positive by FISH. Positivity rates were higher for GEJ (26%, 22% and 17%) vs. gastric (8%, 11% and 9%) via IHC (p = 0.02), but did not significantly differ by FISH (p = 0.19), or SISH (p = 0.30) respectively. The majority of positive cases were intestinal type vs. other (diffuse type or mixed) 25% vs. 0% IHC p = 0.0002, 25% vs. 3% FISH p = 0.001, 20% vs. 3% SISH p = 0.006. The positivity rates were similar with biopsy vs resection specimens (12% vs. 16% IHC p = 0.64, 12% vs. 21% FISH p = 0.30, 12% vs. 10%, SISH p = 0.88).

Conclusions: The rates of HER2-positive disease in a Western population based study were similar to the ToGA study. HER 2 positivity was associated with cancers arising in the GEJ and of intestinal type. The frequency of positivity was similar for testing by biopsy versus resection specimens. This study is ongoing and updated results will be reported.

No significant financial relationships to disclose.

Adjuvant mFOLFOX6 with or without cetuxiumab (Cmab) in KRAS wild-type (WT) patients (pts) with resected stage III colon cancer (CC): Results from NCCTG Intergroup Phase III Trial N0147

CRA3507

Background: FOLFOX is standard adjuvant therapy for stage III CC. Adding Cmab to FOLFOX benefits pts with metastatic CC WT KRAS tumors. N0147 assessed the potential benefit of Cmab added to FOLFOX.

Methods: 21-56 days following resection and informed consent, KRAS status was centrally determined. Pts with wtKRAS CC were randomized to 12 biweekly cycles of oxaliplatin 85 mg/m2 d1, with leucovorin 400 mg/m2, 5FU 400 mg/m2 bolus IV, then 46-hr IV 5FU 2,400 mg/m2 on d1-2 (mFOLFOX6), without (arm A) or with Cmab (arm D) 250 mg/m2 d1&8, with Cmab at 400 mg/m2, cycle 1, d1. Primary endpoint was 3-yr disease free survival (DFS). Secondary endpoints included overall survival (OS) and toxicity. Planned accrual of 2,070 wtKRAS pts provided 90% power to detect hazard ratio (HR) of 1.33 with 2-sided α=0.05; with interim analyses after 25%, 50%, and 75% of planned events.

Results: 1,760 wtKRAS pts (Arm A-858, Arm D-902) were enrolled at the time of closure; median follow-up on 1,624 pts is 15.9 months. Trial closed to accrual when preplanned interim analysis after 50% of planned events demonstrated no benefit to addition of Cmab. 3-yr DFS favored FOLFOX alone (HR 1.18, 95% CI 0.92-1.52; p=0.33). No benefit of Cmab was observed in any subgroups assessed. Any grade ≥ 3 AE, diarrhea, and failure to complete 12 cycles was significantly increased in arm D. Increased toxicity and greater differences in all outcomes were observed in pts aged ≥ 70 ( Table ).

Conclusions: In this randomized phase III trial the addition of Cmab to mFOLFOX6 was of no benefit for pts with resected stage III wtKRAS CC. Supported by NIH Grant CA25224, Bristol-Myers Squibb, ImClone, Sanofi-Aventis, and Pfizer.

[Table: see text]

[Table: see text]

Subchronic Oral Toxicity Study of Furan in Fischer-344 Rats

Rodent studies have shown that furan is a hepatocarcinogen. Previous studies conducted with high doses showed tumors at nearly 100% incidence at all doses. In this paper, a ninety-day gavage experiment conducted with lower doses (0.0, 0.03, 0.12, 0.5, 2.0, and 8.0 mg/kg bw) to identify a no-observed adverse effect level for hepatotoxicity and to characterize non-neoplastic effects including gross changes and histopathology, clinical biochemistry, hematology, and immunotoxicology is reported. As indicated by changes in serum biomarkers, increased liver weights and gross and histological lesions, the liver is the major target organ affected by furan. There were no changes in body weights, food consumption, or histology in other organs. Some of the serum electrolyte markers, including phosphorus, were altered. There was a significant increase in serum thyroxine and triidothyronine in males. This increase was not accompanied by histological thyroid changes. Immunophenotypic analysis showed that thymic lymphocyte maturation was altered in male rats. Although altered clinical biochemistry and hematological parameters were observed at a dose of > 0.5 mg/kg bw, mild histological lesions in the liver were observed at > 0.12 mg/kg bw. Based on this finding, a furan dose of 0.03 mg/kg bw was proposed as the no-observed adverse effect level for hepatic toxicity.