Experience, Longevity, Quality and Service.

CenExel Centers of Excellence offer world-class quality and experience. CIT champions that standard.

CenExel iResearch provides cutting-edge treatment while advancing medical research.

Founded in 2010, CenExel iResearch is dedicated to making a difference in our local and global communities, to improve our health today and in the future. We accomplish this through the successful execution of Phase I through Phase IV clinical research trials. We are a CenExel Center of Excellence, assuring unparalleled patient engagement, staff expertise, and valuable results.

Hundreds of clinical trials conducted since 2010.
View Current Studies
CenExel iResearch Savannah offers 6,000 square feet of facility space.
CenExel iResearch exceeds 100% of patient target in recruitment.
Full-service, Phase I CRO capabilities provided through strategic partnerships.
CenExel iResearch centralizes budgeting and contracting for faster study start-up.
group of people
CenExel iResearch serves a broad and diverse demographic.
Debra Hoffmeyer

CenExel iResearch Savannah is STARR site certified.

STARR site certification was created to promote empathy and communication between research site staff and patients, caregivers, and advocacy groups, as well as providing tools and support for best practices around areas identified by the stakeholders of The STARR Coalition.

Center Leadership

Debra Hoffmeyer

Heather Beitz

CEO and Clinical Operations Director

Prior to co-founding iResearch Atlanta in 2010, Ms. Beitz has experience in both the pharmaceutical and medical device industry and more extensively the investigator site side of clinical research. At a mid-size medical device company she served as the Senior Director of Research for the US and Asia Pacific and then at a large healthcare and consumer product company, as the Director of Global Clinical Affairs.

Prior to her industry experience, Ms. Beitz spent more than 10 years at a large Phase I-IV investigator site. There she held nearly every position, from clinical research coordinator, to rater, to site director and business development. Prior to her departure, she served as Vice President/COO. During her tenure, Ms. Beitz managed the 24/7, 40-bed, in-patient unit and out-patient clinic with over 75 employees.

Ms. Beitz earned her Bachelor of Arts degree from Armstrong University and her Masters of Education from the University of South Carolina. She is published in the field of micro-organisms, anti-bacterials and surgical scrubs..

David Poling

Sara Castle

Chief Operations Officer

Prior to co-founding iResearch Atlanta, Ms. Castle spent most of her career as a clinical research consultant, living in New England and working for Biotech and Pharmaceutical companies. There she focused on implementing new electronic data capture (EDC) tools and educating users and new research personnel on ICH, GCP compliance and CFR guidelines.

In 2004, Ms. Castle earned her Certificate of Clinical Trials Management through Boston University. She then co-founded a consulting company focused on providing regulatory and training services to investigator sites and pharmaceutical companies. The training services assisted investigator sites in streamlining staff activities and moving from paper-based to computer-based processes and templates. The regulatory services enabled pharmaceutical companies to eliminate bottle-neck activities at investigator sites and expedited study start.

David Poling

Kimball A. Johnson, M.D.

Medical Director

Kimball Johnson, MD, is a board-certified Diplomate of the American Board of Internal Medicine, and previously a Certified HIV Specialist by the American Academy of HIV Medicine.

She also earned board certification by the American Board of Integrative Holistic Medicine. A 1987 cum laude graduate of Emory University School of Medicine, Johnson holds a Bachelor of Science in physical education from Taylor University, where she studied exercise physiology and biomechanics. She began her medical career after college as a paramedic at Grady Memorial Hospital, where she gained priceless experience in patient care.

Johnson is a Diplomate of the American College of Physicians and the American Society of Internal Medicine. She has participated in numerous professional medical organizations, including the American Medical Association, the Southern Medical Association, the Medical Association of Georgia, the American Medical Women’s Association, the AIDS Research Consortium of Atlanta, the American College of Sports Medicine, and the American Academy of HIV medicine.

Johnson was involved in the HIV pandemic from the very beginning. She was a trailblazer in the HIV medical community at the onset of the US epidemic through its peak in Atlanta and was involved in the original AZT and DDI clinical trials, which was just the beginning of research trials for Dr. Johnson. Johnson went on to serve as a Sub-Investigator with Aids Research Consortium (ARCA) on multiple HIV trials.

She was in private practice in Internal Medicine, Integrative & Holistic Medicine & HIV medicine for over 30 years. A unique blend that offered “more tools in her toolbox” that could offer more options and solutions for her patients. This and her empathy, passion, and non-judgmental nature drew patients from all over the world to see her.

Since then Johnson has always been intrigued by infectious disease clinical trials, and when other physicians run away, she runs towards the disease. She has served on Rare Disease and Infections, and other clinical trials full time since 2009 as the Medical Director of iResearch Atlanta.

Together iResearch Atlanta and Dr. Kimball Johnson have worked on over 300 clinical trials together and have randomized over 10,000 patients into clinical trials for various disease states in Phase I-IV.

Johnson was certified as a CrossFit Level 1 (CF-L1) Trainer. She was a team physician for the American College of Sports Medicine and served as a physician for the 1995 Ironman Triathlon World Championship. She was physician coordinator for the Peachtree Road Race medical team from 1997-2007, and was a volunteer physician for the U.S. Olympic Training Center in 1999. Her other interests are dogs, dogs, and more dogs.

She is currently the Medical Director of iResearch Atlanta, iResearch Savannah & iAM Health & Wellness, a non-profit clinic that treats patients who currently have no healthcare until they can find a permanent clinic or doctor to manage their care.

She also serves as a Principal Investigator in multiple clinical trials including COVID19 studies.

2018 – 2020 Statistics

Therapeutic Areas

Clinical Trials

Patients Enrolled



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Reaching new heights in clinical research

Our Centers of Excellence provide unparalleled medical and scientific support in the design and execution of clinical trials. Our attention to detail assures quality, reliable results, and has helped CenExel to consistently achieve and exceed patient recruitment goals. We deliver the expertise, engagement, and results to ensure our clients achieve their clinical research goals.

To speed up study implementation, we provide centralized budgeting and contracting for sponsors engaging multiple Centers of Excellence. The geographic diversity of our network offers strong access to roughly 35 million subjects while our broad therapeutic expertise enables a variety of clinical trial strengths.

Top Therapeutic Areas of Expertise

Alzheimer’s Disease
Anxiety Disorder
Bipolar Disorder
Depressive Disorders
Parkinson’s Disease

Seasonal Influenza
Pandemic Influenza

Acute Post-op Pain:
Open Hernia Repair
Wisdom Tooth Extraction

Healthy Volunteer (all ages)
Sleep Apnea
Women’s Health

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