Statistical methods and tool for cut point analysis in immunogenicity assays

2013 ◽  
Vol 389 (1-2) ◽  
pp. 79-87 ◽  
Author(s):  
Lanju Zhang ◽  
Jianchun Jason Zhang ◽  
Robert J. Kubiak ◽  
Harry Yang
Keyword(s):  
Statistical Methods ◽  
Cut Point ◽  
Point Analysis ◽  
Immunogenicity Assays

scholarly journals Confirmatory cut point has limited ability to make accurate classifications in immunogenicity assays

Bioanalysis ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 245-256
Author(s):  
Robert J Kubiak ◽  
Rosalinda HGP Arends ◽  
Nancy Lee ◽  
Meina Liang ◽  
Jianchun Zhang ◽  
...  
Keyword(s):  
Competitive Inhibition ◽  
Cut Points ◽  
Limited Ability ◽  
Cut Point ◽  
Confirmatory Assay ◽  
Drug Naïve ◽  
Point Determination ◽  
Antidrug Antibodies ◽  
Immunogenicity Assays

Aim: Competitive inhibition with excess unlabeled drug is used to confirm the presence of antidrug antibodies (ADA) in study samples. We evaluated specific and nonspecific responses from both drug-naive and drug-treated subjects to identify conditions required by the confirmatory assay to make accurate ADA classifications. Results: Nonspecific signal measured in drug-naive samples used to determine assay cut points was uniformly low and close to the screening cut point. Confirmatory assays performed on incurred study samples with nonspecific responses significantly above the level observed during cut point determination resulted in incorrect ADA classifications. Conclusion: Intensity of confirmatory response should be proportional to the screening response and therefore, to ensure accurate ADA classifications, the confirmatory responses cannot be considered as independent but need to be evaluated in relation to the screening responses.

Association of time to adjuvant chemotherapy (TTAC) and overall survival among patients with rectal cancer treated with preoperative radiation.

2013 ◽  
Vol 31 (4_suppl) ◽  
pp. 461-461
Author(s):  
Gillian Gresham ◽  
Caroline Speers ◽  
Ryan Woods ◽  
Winson Y. Cheung ◽  
Kimberly Schaff ◽  
...  
Keyword(s):  
Adjuvant Chemotherapy ◽  
Cox Regression ◽  
Early Stage ◽  
Time Frame ◽  
Stage Ii ◽  
Stage Iii ◽  
Significant Prognostic Factor ◽  
Preoperative Radiation ◽  
Cut Point ◽  
Point Analysis

461 Background: Studies suggest that delayed adjuvant chemotherapy (AC) beyond 8 weeks is associated with inferior survival in early-stage colon cancer (CA). The optimal TTAC in rectal CA remains unclear. The objective of this study was to determine the prognostic effect of TTAC in stage II and III rectal CA treated with standard preoperative (op) chemoradiation. Methods: Patients with stage II/III rectal CA treated with pre-op chemoradiation, received post-op AC, and referred to the British Columbia Cancer Agency between 1999 and 2008 were included. Univariate and multivariate analyses were conducted using Kaplan Meier and Cox regression methods to evaluate the association between TTAC and outcomes. X-tiles cut-point analysis was performed to determine the optimal TTAC. Results: A total of 327 eligible patients were identified: median age 61 (range 22-85), 70% male, and 75% stage III. In terms post-op AC, 51% received 5-fluorouracil (5-FU), 32% received capecitabine, 12% received 5-FU and oxaliplatin, and 5% received other chemotherapy. Median TTAC was 7.0 weeks (wks) (range 1.6-33.3 wks). Cut-point analysis revealed the optimal TTAC to be 5.6 wks (HR: 0.42, 95%CI 0.22-0.82, p=0.0087). Initiation of AC within optimal TTAC (5.6 wks) and 6 wks from date of surgery (sx) was associated with a significant survival benefit while no significant effect was seen at 8 wks. TTAC of ≤ 6 wkswas found to be a significant prognostic factor in multivariate analysis (p=0.047) adjusted for ECOG, age, sex, stage, margin status, and grade. In stratified analysis by stage, patients with stage III disease benefited from AC (p=0.018) while those with stage II did not (p=0.71). Conclusions: In this study, the optimal TTAC was 6 weeks or less. Initiation of AC within this time frame was associated with improved OS. This is less than the optimal timeframe indicated in the literature for colon CA. [Table: see text]

Primary Central Nervous System Lymphoma: The Memorial Sloan-Kettering Cancer Center Prognostic Model

2006 ◽  
Vol 24 (36) ◽  
pp. 5711-5715 ◽  
Author(s):  
Lauren E. Abrey ◽  
Leah Ben-Porat ◽  
Katherine S. Panageas ◽  
Joachim Yahalom ◽  
Brian Berkey ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Prognostic Score ◽  
Radiation Therapy Oncology Group ◽  
Primary Cns Lymphoma ◽  
Cancer Center ◽  
Karnofsky Performance Score ◽  
Newly Diagnosed ◽  
Data Set ◽  
Cut Point ◽  
Point Analysis

Purpose The purpose of this study was to analyze prognostic factors for patients with newly diagnosed primary CNS lymphoma (PCNSL) in order to establish a predictive model that could be applied to the care of patients and the design of prospective clinical trials. Patients and Methods Three hundred thirty-eight consecutive patients with newly diagnosed PCNSL seen at Memorial Sloan-Kettering Cancer Center (MSKCC; New York, NY) between 1983 and 2003 were analyzed. Standard univariate and multivariate analyses were performed. In addition, a formal cut point analysis was used to determine the most statistically significant cut point for age. Recursive partitioning analysis (RPA) was used to create independent prognostic classes. An external validation set obtained from three prospective Radiation Therapy Oncology Group (RTOG) PCNSL clinical trials was used to test the RPA classification. Results Age and performance status were the only variables identified on standard multivariate analysis. Cut point analysis of age determined that patients age ≤ 50 years had significantly improved outcome compared with older patients. RPA of 282 patients identified three distinct prognostic classes: class 1 (patients < 50 years), class 2 (patients ≥50; Karnofsky performance score [KPS] ≥ 70) and class 3 (patients ≥ 50; KPS < 70). These three classes significantly distinguished outcome with regard to both overall and failure-free survival. Analysis of the RTOG data set confirmed the validity of this classification. Conclusion The MSKCC prognostic score is a simple, statistically powerful model with universal applicability to patients with newly diagnosed PCNSL. We recommend that it be adopted for the management of newly diagnosed patients and incorporated into the design of prospective clinical trials.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

point-Analysis Using the Extrapolation Method in the Analytical Electron microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 430-431
Author(s):  
Zenji Horita ◽  
Ryuzo Nishimachi ◽  
Takeshi Sano ◽  
Minoru Nemoto
Keyword(s):  
Electron Microscope ◽  
Extrapolation Method ◽  
X Ray ◽  
Absorption Correction ◽  
Point Analysis ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Data Points ◽  
Identical Composition ◽  
X Ray Absorption

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.

Review of Statistical Methods for Rates and Proportions.

1973 ◽  
Vol 18 (11) ◽  
pp. 562-562
Author(s):  
B. J. WINER
Keyword(s):  
Statistical Methods

Review of Statistical Methods in Education and Psychology.

1996 ◽  
Vol 41 (12) ◽  
pp. 1224-1224
Author(s):  
Terri Gullickson
Keyword(s):  
Statistical Methods
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