Citations

BackgroundThe ability of von Willebrand factor (VWF) to bind platelet GP Ib and promote platelet plug formation is measured in vitro using the ristocetin cofactor (VWF:RCo) assay. Automated assay systems make testing more accessible for diagnosis, but do not necessarily improve sensitivity and accuracy.ObjectiveWe assessed the performance of a modified automated VWF:RCo assay protocol for the Behring Coagulation System (BCS®) compared to other available assay methods.MethodsResults from different VWF:RCo assays in a number of specialized commercial and research testing laboratories were compared using plasma samples with varying VWF:RCo activities (0–1.2 IU mL−1). Samples were prepared by mixing VWF concentrate or plasma standard into VWF‐depleted plasma. Commercially available lyophilized standard human plasma was also studied. Emphasis was put on the low measuring range. VWF:RCo accuracy was calculated based on the expected values, whereas precision was obtained from repeated measurements.ResultsIn the physiological concentration range, most of the automated tests resulted in acceptable accuracy, with varying reproducibility dependent on the method. However, several assays were inaccurate in the low measuring range. Only the modified BCS protocol showed acceptable accuracy over the entire measuring range with improved reproducibility.ConclusionsA modified BCS® VWF:RCo method can improve sensitivity and thus enhances the measuring range. Furthermore, the modified BCS® assay displayed good precision. This study indicates that the specific modifications − namely the combination of increased ristocetin concentration, reduced platelet content, VWF‐depleted plasma as on‐board diluent and a two‐curve calculation mode − reduces the issues seen with current VWF:RCo activity assays.

Background— Instruments to assess symptom burden and quality of life among patients with atrial fibrillation (AF) have not been well evaluated in community practice or associated with patient outcomes. Methods and Results— Using data from 10 087 AF patients in the Outcomes Registry for Better Informed Treatment of AF (ORBIT-AF), symptom severity was evaluated using the European Heart Rhythm Association (EHRA) classification system, and quality of life was assessed using the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire. The association between AF-related symptoms, quality of life, and outcomes was assessed using Cox regression. The majority of AF patients (61.8%) were symptomatic (EHRA >2) and 16.5% had severe or disabling symptoms (EHRA 3–4). EHRA symptom class was well correlated with the AFEQT score (Spearman correlation coefficient −0.39). Over 1.8 years of follow-up, AF symptoms were associated with a higher risk of hospitalization (adjusted hazard ratio for EHRA ≥2 versus EHRA 1 1.23, 95% confidence interval, 1.15–1.31) and a borderline higher risk of major bleeding. Lower quality of life was associated with a higher risk of hospitalization (adjusted hazard ratio for lowest quartile of AFEQT versus highest 1.49, 95% confidence interval, 1.2–1.84), but not other major adverse events, including death. Conclusions— In a community-based study, most patients with AF were symptomatic and had impaired quality of life. Quality of life measured by the AFEQT correlated closely with symptom severity measured by the EHRA class. AF symptoms and lower quality of life were associated with higher risk of hospitalization but not mortality during follow-up.

Summary Objective Patients with suspected mesial temporal lobe ( MTL ) epilepsy typically undergo inpatient video–electroencephalography ( EEG ) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography ( EC oG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory EC oG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions. Methods Ambulatory EC oG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal EC oG activity. EC oG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded. Results Eighty‐two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0–376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording. Significance About one third of the subjects implanted with bilateral MTL electrodes required >1 month of chronic ambulatory EC oG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory EC oG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video‐ EEG monitoring, and can contribute to treatment decisions.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer related death in the United States. Roughly 45,000 patients are diagnosed with the disease each year and of these patients 94% will not survive past 5 years. The most common genetic alteration associated with PDAC is an oncogenic mutation in the KRAS gene, which is believed to initiate the disease. Mutant Kras is generally thought to signal constitutively to its downstream effector proteins, such as Raf/MEK/Erk and PI3K/AKT. However, recently we and others have demonstrated that Epidermal Growth Factor Receptor (EGFR) signaling upstream of mutant Kras is necessary for unlocking its oncogenic potential in the pancreas, distinct from Kras driven tumorigenesis in the lung or colon. Unfortunately, while EGFR inhibition is effective in blocking pancreatic tumorigenesis in mice, it has limited benefit in treating human PDAC patients. Furthermore, it has been shown that wild-type Nras and Hras have indispensable signaling roles in cells expressing oncogenic Kras, and that both the mutant and WT Ras signals are required for cell growth. Here we show that pancreatic cancer cell lines containing oncogenic Kras still require upstream signaling to maintain high levels of both active Erk and AKT although these signals are not necessarily EGFR derived. We have identified a subset of pancreatic cancer cell lines that rely upon IR/IGFR signaling to maintain the high levels of Erk and AKT signaling required for continued cell growth. Additionally, this signaling appears to be independent of oncogenic Kras and instead correlates with the levels of active wild-type Nras and Hras. This data indicates that patients may benefit from the simultaneous inhibition of both the EGFR and IR/IGFR signaling pathways. Citation Format: Kenneth K. Takeuchi, Howard C. Crawford. EGFR and IR/IGFR activation sustains ERK1/2 and AKT signaling independently of mutant Kras in pancreatic cancer cells lines. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr B58. doi: 10.1158/1557-3125.RASONC14-B58

Abstract Background: Previous data on the relationship between PD-L1 expression and activity of anti-PD-1 and anti-PD-L1 antibodies have been conflicting. MK-3475, a humanized monoclonal IgG4 antibody against PD-1, has demonstrated durable antitumor activity in MEL and NSCLC. We evaluated tumor PD-L1 expression and its relationship with outcomes in a phase I clinical trial of MK-3475. We also evaluated T cell activation as a pharmacodynamic marker of MK-3475 activity. Methods: 135 MEL pts received MK-3475 10 mg/kg Q2W, 10 mg/kg Q3W, or 2 mg/kg Q3W. Tumor response was assessed by RECIST 1.1 per independent central review, including requirement for a confirmatory CT scan. Pretreatment biopsy was required. Serial blood samples were collected before infusion at the start of cycles 1-5 (Q2W dosing) or 1-4 (Q3W dosing). Tumor PD-L1 expression was assessed by IHC. A preliminary cutoff of 1% of stained cells was used to define PD-L1 positivity. Absolute CD4+ and CD8+ T cell counts and the percentage of activated (HLA-DR as marker) CD4+ and CD8+ T cells in peripheral blood were assessed by multiplex flow cytometry (n = 101). Results: Median PFS was 36 weeks, 6-month overall survival (OS) rate was 89%, and 12-month OS rate was 81%. Median duration of response and OS were not reached. In the 116 pts with measurable disease, ORR was 41%. PFS and response rate were significantly associated with tumor PD-L1 expression (Table). At week 6, a statistically significant percent increase from baseline in the percentage of activated (HLA-DR+) CD4+ and CD8+ T cells was observed at all doses (pooled mean percent change [SE], +24.0% [4.7%] for HLA-DR+/CD8+, +17.5% [2.7%] for HLA-DR+/CD4+). Conclusions: Tumor PD-L1 expression levels were associated with tumor response and PFS in MEL pts treated with MK-3475; activity was also observed in pts with low PD-L1 expression. As assessed by HLA-DR expression, post-treatment T cell activation in the circulating pool was increased at all doses tested. Patients WithMeasurable Disease and Interpretable PD-L1 IHC ResultsPatients With InterpretablePD-L1 IHC Results and PFS and OS Data PD-L1 TumorExpressionNORR, n (%)NPFS at 6 months, % (95% CI)Median PFSOS at 6 months, % (95% CI)Median OSPositive (membrane staining in ≥1% of cells)5529 (53)6058 (47-72)10.6 mo93(87-100)Not reachedNegative (membrane staining in <1% of cells)161* (6)2232 (16-64)2.9 mo75(58-97)Not reachedHR (95% CI) for PD-L1-positive vs negative____0.54(0.28-1.05)_0.67(0.25-1.83)One-sidedP value(PD-L1 association test)_<0.004 (logistic regression)__0.034(Cox regression)_0.220(Cox regression)*IPI-pretreated patient who received MK-3475 10 mg/kg Q2W. Citation Format: Adil I. Daud, Omid Hamid, Antoni Ribas, F. Stephen Hodi, Wen-Jen Hwu, Richard Kefford, Jedd Wolchok, Peter Hersey, Jeffrey S. Weber, Richard Joseph, Tara C. Gangadhar, Roxana S. Dronca, Amita Patnaik, Hassane Zarour, Anthony M. Joshua, Kevin Gergich, Dianna Wu, Jared K. Lunceford, Kenneth Emancipator, Marisa Dolled-Filhart, Nicole Li, Scot Ebbinghaus, S. Peter Kang, Caroline Robert. Antitumor activity of the anti-PD-1 monoclonal antibody MK-3475 in melanoma(MEL): Correlation of tumor PD-L1 expression with outcome. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT104. doi:10.1158/1538-7445.AM2014-CT104