Underuse of exon mutational analysis for gastrointestinal stromal tumors.

BACKGROUND: Tyrosine kinase inhibitors (TKI) have become the guideline-recommended therapy for high-risk resected and advanced gastrointestinal stromal tumors (GISTs). Exon mutational analysis (EMA) is used to inform pretherapy response to TKI and may predict overall prognosis. Despite these benefits, EMA remains underused, and its impact on TKI therapy decision-making remains unexplored. MATERIALS AND METHODS: A retrospective cohort was established from 104 patients receiving treatment for GISTs from 2006 to 2017. Current National Comprehensive Cancer Network guidelines indicate that EMA should be considered for all patients undergoing TKI therapy to identify genotypes that are likely, or unlikely, to respond to treatment. We first tracked guideline-considered EMA use and subsequent impact on treatment decision-making. A questionnaire was then administered to gastrointestinal medical oncologists to assess EMA perception. RESULTS: Among 104 GIST patients, 54 (52%) received TKI therapy. Of these, only 22 (41%) received EMA. Informed by EMA, treatment decisions included 59% who continued with original TKI therapy, 32% who switched to an alternative TKI, and 9% who discontinued or received no TKI. Although 92% of physicians indicated EMA was a valuable tool, only 62% indicated they used it "frequently" or "always" to inform treatment decisions. CONCLUSIONS: Less than half of patients receiving TKI therapy for GISTs received EMA at a comprehensive cancer center. Despite this low uptake, when it was performed, EMA guided alternative treatment decision in 41% of patients. Physician survey responses indicated that interventions targeting physician education and an electronic medical record reminder may improve EMA uptake.

Regorafenib in advanced hepatocellular carcinoma (HCC): considerations for treatment.

PURPOSE: We report our institutional observations of ten patients with advanced hepatocellular carcinoma (HCC) (seven and three were Child-Pugh class A and B, respectively) who received compassionate regorafenib therapy between June 2016 and January 2017. These patients did not fit the rigid criteria of a clinical trial and represented the use of regorafenib in an everyday clinic situation. METHODS: Regorafenib (160 mg P.O. daily) was administered to patients on a 4-week cycle (3 weeks on, 1 week off) until disease progression (assessed using mRECIST criteria) or discontinuation secondary to toxicity (assessed using CTCAE criteria). Relevant clinical data were abstracted from patient medical records and reviewed retrospectively. RESULTS: The median duration of patient treatment was 6.6 weeks, and the median time to disease progression was 12.5 weeks. Most common treatment emergent adverse events were fatigue, diarrhea, and hand-foot skin reaction. Elevated AST and ALT were the most commonly observed laboratory-assessed adverse events, which reached grade 3 status in the Child-Pugh class B patients only. We observed intolerance to regorafenib treatment in one patient who had previously received a liver transplant. We also saw lithium toxicity in one patient receiving long-term lithium treatment, suggesting a potential and unexpected drug-drug interaction with regorafenib. CONCLUSIONS: Taken together, our observations indicate that regorafenib is beneficial in the treatment of patients with advanced HCC who progressed on or demonstrated intolerance to sorafenib therapy; however, careful selection and close monitoring of patients is necessary to maximize the benefit while minimizing the toxicities of regorafenib treatment.

Pancreatic cancer, treatment options, and GI-4000.

Although pancreatic cancer is but the eleventh most prevalent cancer in the US, it is predicted that of all the patients newly diagnosed with this disease in 2014, only 27% will still be alive at the end of the first year, which is reduced to 6% after 5 years. The choice of chemotherapy in the treatment of pancreatic cancer is dependent on disease stage and patient performance status but, in general, the most widely used approved regimens include 5-fluorouracil (5-FU) combinations and gemcitabine combinations. Recent therapeutic strategies have resulted in an improvement in survival of patients with pancreatic cancer but the magnitude of change is disappointing and vast improvements are still needed. The goal of immunotherapy is to enhance and guide the body's immune system to recognize tumor-specific antigens and mount an attack against the disease. Among newer immune therapies, GI-4000 consists of 4 different targeted molecular immunogens, each containing a different Ras protein (antigen) encoded by the most commonly found mutant RAS genes in solid tumors-RAS mutations exist in over 90% of pancreatic ductal adenocarcinomas. We will review pancreatic cancer epidemiology and its current treatment options, and consider the prospects of immunotherapy, focusing on GI-4000. We discuss the potential mechanism of action of GI-4000, and the performance of this vaccination series thus far in early phase clinical trials.

Angiotensin-induced abdominal aortic aneurysms in hypercholesterolemic mice: role of serum cholesterol and temporal effects of exposure.

OBJECTIVE: Understanding variations in size and pattern of development of angiotensin II (Ang II)-induced abdominal aortic aneurysms (AAA) may inform translational research strategies. Thus, we sought insight into the temporal evolution of AAA in apolipoprotein (apo)E(-/-) mice. APPROACH: A cohort of mice underwent a 4-week pump-mediated infusion of saline (n = 23) or 1500 ng/kg/min of Ang II (n = 85) and AAA development was tracked via in vivo ultrasound imaging. We adjusted for hemodynamic covariates in the regression models for AAA occurrence in relation to time. RESULTS: The overall effect of time was statistically significant (p<0.001). Compared to day 7 of AngII infusion, there was no decrease in the log odds of AAA occurrence by day 14 (-0.234, p = 0.65), but compared to day 21 and 28, the log odds decreased by 9.07 (p<0.001) and 2.35 (p = 0.04), respectively. Hemodynamic parameters were not predictive of change in aortic diameter (Δ) (SBP, p = 0.66; DBP, p = 0.66). Mean total cholesterol (TC) was higher among mice with large versus small AAA (601 vs. 422 mg/ml, p<0.0001), and the difference was due to LDL. AngII exposure was associated with 0.43 mm (95% CI, 0.27 to 0.61, p<0.0001) increase in aortic diameter; and a 100 mg/dl increase in mean final cholesterol level was associated with a 12% (95% CI, 5.68 to 18.23, p<0.0001) increase in aortic diameter. Baseline cholesterol was not associated with change in aortic diameter (p = 0.86). CONCLUSIONS: These are the first formal estimates of a consistent pattern of Ang II-induced AAA development. The odds of AAA occurrence diminish after the second week of Ang II infusion, and TC is independently associated with AAA size.

Pancreatic cancer, treatment options, and GI-4000.

Although pancreatic cancer is but the eleventh most prevalent cancer in the US, it is predicted that of all the patients newly diagnosed with this disease in 2014, only 27% will still be alive at the end of the first year and only 6% will make it past 5 years. The choice of chemotherapy in the treatment of pancreatic cancer is dependent on disease stage and patient performance status but, in general, the most widely used approved regimens include 5-fluorouracil (5-FU) combinations and gemcitabine combinations. Recent therapeutic strategies have resulted in an improvement in survival of patients with pancreatic cancer but the magnitude of change is disappointing and vast improvements are still needed. The goal of immunotherapy is to enhance and guide the body's immune system to recognize tumor-specific antigens and mount an attack against the disease. Among newer immune therapies, GI-4000 consists of 4 different targeted molecular immunogens, each containing a different Ras protein (antigen) encoded by the most commonly found mutant RAS genes in solid tumors--RAS mutations exist in over 90% of pancreatic ductal adenocarcinomas. We will review pancreatic cancer epidemiology and its current treatment options, and consider the prospects of immunotherapy, focusing on GI-4000. We discuss the potential mechanism of action of GI-4000, and the performance of this vaccination series thus far in early phase clinical trials.

Benzo[a]pyrene potentiates the pathogenesis of abdominal aortic aneurysms in apolipoprotein E knockout mice.

The objective of this study was to determine the effect of benzo[a]pyrene (BaP), an abundant environmental polycyclic aromatic hydrocarbon compound, on the pathogenesis of abdominal aortic aneurysms (AAA). Earlier studies have shown that BaP promotes vasculopathy, including atherosclerosis, a predisposing factor for AAA development. In two experimental arms, 203 apolipoprotein E knockout (ApoE-/-) mice were evaluated in 4 groups: BaP, angiotensin II (AngII), BaP+AngII and control. Mice in the first arm were exposed to 5mg/kg/week of BaP for 42 days, and in the second arm to 0.71mg/kg daily for 60 days. In arm one, AAA incidence was higher in the BaP+AngII (14/28) versus AngII (8/27) group (p < 0.05), rupture (n=3) was observed only in BaP+AngII treated mice (p < 0.05). In the second arm, AAA incidence did not differ between AngII (17/30) and BaP+AngII (16/29) groups. However, intact AAA diameter was larger in the BaP+AngII (2.3 ± 0.1mm) versus AngII (1.9 ± 0.1mm) group (p < 0.05), but AAA rupture did not differ (p=NS). In both experimental arms, BaP+AngII mice showed increased expression of tumor necrosis factor alpha (TNF-α), cyclophilin A (Cyp A), and matrix metalloproteinase-9 (MMP9) (p < 0.05). No AAA occurred in control or BaP groups. These findings suggest the role of BaP exposure in potentiating AAA pathogenesis, which may have potential public health significance.

Quantitative estimates of the variability of in vivo sonographic measurements of the mouse aorta for studies of abdominal aortic aneurysms and related arterial diseases.

OBJECTIVES: Burgeoning interest in reducing the morbidity and mortality associated with abdominal aortic aneurysms (AAAs) has led to experimental strategies to elucidate the disease process and attain pharmacologic regression using the apolipoprotein E(-/-) (ApoE(-/-)) mouse model of angiotensin-induced AAAs and in vivo sonography. However, the variability of in vivo sonographic measurements of the mouse aorta has not been established. Thus, our purpose was to determine quantitative estimates of the variability of in vivo sonographic measurements of the mouse aorta as a guide for the design and assessment of studies focused on regression of AAAs and related arterial diseases. METHODS: We used Bland-Altman, locally weighted scatterplot-smoothing regression, and resampling (bootstrapping) methods for variability analyses of multiple in vivo short- and long-axis sonographic measurements of ApoE(-/-) mouse aortas. We measured distinct aortic sites in vivo at the baseline and after angiotensin-induced AAAs and ex vivo using digital calipers. RESULTS: We analyzed 236 data points from 10 male mice (14 weeks old; mean weight ± SD, 29.7 ± 1.6 g). Overall intramouse differences between short- and long-axis and in vivo and ex vivo measurements were 0.038 (95% confidence interval [CI], 0.031-0.046) and 0.085 (95% CI, 0.062-0.109) mm, respectively. Intermouse differences in short-axis measurements were 0.047 (95% CI, 0.042-0.053), 0.049 (95% CI, 0.044-0.055), and 0.039 (95% CI, 0.036-0.042) mm for infrarenal, suprarenal, and thoracic measurements, respectively; differences in long-axis measurements were 0.054 (95% CI, 0.044-0.064), 0.029 (95% CI, 0.024-0.034), and 0.046 (95% CI, 0.037-0.054) mm. Bland-Altman and locally weighted scatterplot-smoothing analyses showed excellent agreement between measures with no variation in discrepancies vis-à-vis the target measurement. CONCLUSIONS: These data establish previously undefined estimates of measurement variability relevant for in vivo sonographic studies of AAA regression in a commonly studied mouse model.