Meet the Team


Picture of Diane Catelier


Diane Catellier, DrPH – Principal Investigator, Senior Statistician

As senior member of the clinical trials resource team, Dr. Catellier will provide support for finalization of clinical trial design, advice on database management and data security requirements, input on interim monitoring and statistical analysis plans, and site and subject recruitment strategies, and provide oversight of other services provided by RTI staff and consultants. Dr. Catellier has served as Coordinating Center PI for five NIH-sponsored Phase III clinical trials, and has first-hand knowledge of the process steps that are needed to launch a large clinical trial protocol and the barriers that exist in conducting trials. Dr. Catellier has contributed to a compendium of best practices for Coordinating Centers that support large clinical trials that will serve as a resource to National Heart, Lung, and Blood Institute Program Staff for crafting application and review criteria for RFAs/RFPs and when evaluating Coordinating Centers as part of a large clinical trial program. She is particularly interested in design and analytic approaches to increase the efficiency and reduce the cost of clinical trials.


Picture of Donald Brambilla

Donald Brambilla, PhD – Co-Investigator, Senior Statistician

Dr. Brambilla has more than 27 years of experience collaborating with clinical investigators on the design and execution of multicenter clinical trials, including trials in various aspects of sickle cell anemia, reduction of inhibitors of Factor VIII in hemophilia, and treatments for thrombocytopenia (TTP, ITP). He knows the difficulties encountered in conducting trials in rare patient populations. In a recent trial in which he collaborated, fewer than 5,000 patients nationwide were eligible for the two trials of stroke prevention in children with sickle cell anemia. He helped develop strategies for screening, recruitment and retention, and proposed adjustments to sample sizes to compensate for losses and crossovers that resulted in successful completion of both trials. His collaborative work on multicenter trials and three clinical research networks taught him that many clinicians who have good ideas for improving the treatment of their patients lack the training, experience, or resources to design and complete trials to test their ideas. Dr. Brambilla has successfully collaborated with investigators to first outline the issues that needed to be addressed and work through them systematically and in a timely fashion such that trials in hemoglobinapathies were both well designed and successfully conducted and completed.

Picture of Rebecca McNeil


Rebecca McNeil, PhD – Co-Investigator, Statistician

Dr. McNeil has led the design, implementation, and analysis of clinical trials and prospective and retrospective epidemiologic studies across a wide spectrum of clinical domains in academic and federal settings. She has a particular interest in the health concerns of women and military veterans. Dr. McNeil brings experience in the analysis of longitudinal and multivariate data to assess multi-domain outcomes and recurrent events in complex chronic diseases.


Picture of Sreelatha Meleth


Sreelatha Meleth, PhD – Co-Investigator, Senior Statistician

Dr. Meleth has more than 17 years of experience collaborating on public health research studies. Prior to joining RTI in 2011, she spent 11 years as a biostatistician in the University of Alabama at Birmingham’s Comprehensive Cancer Center Biostatistics & Bioinformatics Unit, including terms as the interim director and co-director. During this time, Dr. Meleth led several Biostatistics Cores for the Specialized Program for Research Excellence. In these roles, she was actively involved in supporting clinicians in developing and implementing multicenter Phase 1, Phase 2, and Phase 3 clinical trial protocols. She has provided statistical support and guidance for proposals that span the gamut of health research from proteomics and biomarkers to treatment of various disease conditions and the design and conduct of randomized clinical trials and mixed-study designs. Dr. Meleth’s experience also includes identifying optimal cut points for biomarkers and comparing the effects of statistical preprocessing and missing data. She is well versed in linear mixed models, generalized linear mixed models, survival analysis, Cox regression, time series analysis, and generalized additive models and meta-analytic techniques.


Picture of Sonia Thomas


Sonia Thomas, DrPH – Co-Investigator, Senior Statistician

Dr. Thomas specializes in collaborative design, implementation, and analysis of clinical trials. She has been Data Coordinating Center Principal Investigator or Co-Investigator for numerous NIH-funded Phase III-IV multi-center trials across a variety of indications, particularly focusing on vulnerable populations. Her statistical expertise includes non-inferiority designs, interim analysis, methods to address missing data caused by early study discontinuation, and adjustment for multiple comparisons. Dr. Thomas has extensive experience developing study protocols, randomization schemes, and interim analysis plans to stop for early overwhelming efficacy or futility. She has co-authored over 80 peer-reviewed publications.


Picture of Deborah McFadden


Deborah Whitehurst McFadden, MBA – Senior Study Manager

Ms. McFadden has been participating in multisite clinical and epidemiologic studies as a data coordinator, analyst, or project manager since 1974. One of her early experiences was as the coordinator for a Natural History Study of the Development of Factor VIII Inhibitors in Hemophilia. She has extensive experience in developing study documents such as protocols, manuals of operations, consent forms, data collection forms, randomization procedures, training manuals, and other supporting documentation and in training clinical staff on the implementation of study procedures. She is a member of an RTI Institutional Review Board and is a reviewer for RTI’s Office of Research Protections.


Picture of Julie Croxford


Julie Croxford, RN, MPH – Clinical Research Nurse

Ms. Croxford has more than 20 years of national and international research experience. She has been involved extensively in the development of study documents such as protocols, manuals of operations, data collection forms, and other supporting materials and has conducted data quality assessments internationally. In her role as study coordinator on clinical trials, she conducts training and monitoring and oversees many aspects of study planning and implementation, including safety reporting and data collection and management.


Picture of Diane Earp


R. Diane Earp, BSMT, SBB – ASCP

Ms. Earp is the Corporate Quality Assurance Officer and Director of Regulatory Affairs, Quality Assurance, and Records Management at RTI International. She has extensive knowledge of FDA regulatory requirements for 510K, IDE, IND, NDA, PMA, BLA, and PLA submissions, manufacturing site registration and licensure, and annual reports, as well as validation plans, quality systems and procedural development in highly regulated industries. Additionally, she has experience designing, conducting, and reporting GMP, GLP, and GCP compliance audits; clinical trials; validation plans; and training protocols. Ms. Earp has effectively managed operations with budgetary oversight ranging from $4 million to $50 million and professional team in excess of 200 members (MDs, PhDs, engineers, health care specialties, and support staff) at multiple facilities and geographic locations.


Picture of Nigel Key


Nigel Key, MB ChB, FRCP (Consultant)

Dr. Key is an adult hematologist specializing in non-malignant hematologic disorders, particularly those affecting blood coagulation. He is the Harold R. Roberts Distinguished Professor, Chief of the Section of Hematology in the Division of Hematology/Oncology, and Director of the UNC Hemophilia and Thrombosis Center. He serves as a consultant for the Clinical Trials Development Resource for Hematologic Disorders. His clinical interests include the diagnosis and management of bleeding disorders including hemophilia and von Willebrand disease, as well as arterial and venous thromboembolic disorders. He has authored well over 150 peer-reviewed articles, approximately 25 book chapters, and is co-editor of a popular textbook on disorders of bleeding and clotting.



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