Current Bio3 Seminar Series

The Bio3 Seminar Series meets every second and fourth Friday of the month, during the academic year.  Refreshments are served 15 minutes prior to the seminar's starting time.

*Students are expected to attend the bi-weekly seminar series.*


Friday, September 13, 2019 at 10:00 AM

Xiaochun Li, Ph.D.
Associate Professor, Department of Biostatistics, School of Medicine, Fairbanks School of Public Health, University of Indiana

Title: A Machine Learning Approach to Causal Inference in the Presence of Missing Data

Abstract:Observational medical databases increasingly find uses for comparative effectiveness and safety research. However, the lack of analytic methods that simultaneously handle the issues of missing data and confounding bias along with the onus of model specification, limit the use of these valuable data sources. We derived a novel machine-learning approach based on trees to estimate the average treatment effect. In order to evaluate causal estimation by model-free machine-learning methods in data with incomplete observations, we conducted a simulation study with data generated from known models of exposure, outcome and missing mechanisms. Thus the true causal effect was known and used as the benchmark for evaluations. Two settings were studied. We compared the bias and standard error of causal estimates from our method to a multiply robust parametric method, the complete case analysis (CC) and a regression analysis after multiple imputations (MI). The proposed methods were applied to a real observational data set of implantable cardioverter defibrillator use.

Location: Proctor Harvey Amphitheater, Med-Dent Building C104
3900 Reservoir Rd. NW, Washington, DC 20057


Friday, September 27, 2019 at 1:00 PM

Ming T. Tan, Ph.D.
Chair and Professor, Department of Biostatistics, Bioinformatics & Biomathematics, Georgetown University Medical Center

Title: Statistics and Data Science in Biomedicine I: Discovery, Design and Analysis of Multi-drug Combinations: from Experiments to Clinical Trials

Abstract:This seminar presents applications of statistics and data science in the design and analysis of biomedical research studies including drug combinations, adaptive and/or targeted clinical trials designs, statistical learning and predictive modeling in head and neck cancer with a series of validation in three large randomized studies, and search for patient subgroups in precision medicine. Part I will focus on drug combinations which are the hallmark of therapies for complex diseases such as cancer. A statistical approach for evaluating the joint effect of the combination is necessary because even in vitro experiments often demonstrate significant variation in dose-effect. I will present a novel methodology for efficient design and analysis of preclinical drug combination studies with applications in the combination of Vorinostat and Ara-C and etoposide. Further discussion will be on the utilization of the preclinical data to guide early phase clinical trial design and a novel adaptive phase I design for drug combinations.

Location: Proctor Harvey Amphitheater, Med-Dent Building C104
3900 Reservoir Rd. NW, Washington, DC 20057


Friday, OCTOBER 11, 2019 at 10:00 am

Robert Makuch, Ph.D.
Professor, Department of Biostatistics, School of Public Health, Yale University

Title: Treatment Effects Assessment in Multi-Regional Clinical Trials (MRCTs) Using Bayesian Methods

Abstract: Multi-regional clinical trials (MRCTs) help to synchronize drug development globally, whereby the time lag in marketing authorization among different countries is minimized. However, there are statistical concerns associated with analysis and interpretation of MRCTs. The results of certain countries/regions could vary significantly from the overall results. In this case, controversy exists regarding the extent to which country-specific result should be minimized/ignored and medical scientists/regulators should defer to the overall global treatment effect. Rather than analyzing data separately in each region, our discussion today focuses on developing a Bayesian framework for assessing heterogeneity of regional treatment effects that leverages data collected in other regions. The goal is to make scientifically valid judgments about the play of chance versus real regional differences when comparing results to the overall trial outcome.

Location: New Research Building Auditorium
3970 Reservoir Rd. NW, Washington, DC 20057


FRIDAY, OCTOBER 25, 2019 AT 10:00 AM

Kellie J. Archer, Ph.D.
Professor and Chair, Division of Biostatistics, College of Public Health, Ohio State University

Title: Algorithmic and Statistical Methods for High-Dimensional Variable Selection

Abstract: Pathological evaluations are frequently reported on an ordinal scale. Moreover, diseases may progress from less to more advanced stages. For example, HCV infection progresses from normal liver tissue to cirrhosis, dysplastic nodules, and potentially to hepatocellular carcinoma. To elucidate molecular mechanisms associated with disease progression, genomic characteristics from samples procured from these different tissue types are often assayed using a high-throughput platform. Such assays result in a high-dimensional feature space where the number of predictors (P) greatly exceeds the available sample size (N). In this talk, various approaches to modeling an ordinal response when P>N will be described including algorithmic and statistical methods.

Location: New Research Building Auditorium
3970 Reservoir Rd. NW, Washington, DC 20057


(UPCOMING) Thursday, NOVEMBER 14, 2019 at 1:00 pm

Location: Pre-Clinical Building, LA4 
3900 Reservoir Rd. NW, Washington, DC 20057


(UPCOMING) Friday, NOVEMBER 22, 2019 AT 10:00 AM

Location: Proctor Harvey Amphitheater, Med-Dent Building C104
3900 Reservoir Rd. NW, Washington, DC 20057


The Bio3 Seminar Series are for educational purposes and intended for the faculty, students and staff of Georgetown University.  The seminars are not recorded and closed to the public.