Committed to improving your quality of life through clinical research.

For over a decade, iResearch has been dedicated to assisting pharmaceutical companies find new cures to help patients better manage their healthcare.

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.

Core Clinical Team

Nancy Backus, M.D.

Principal Investigator

Dr. Nancy Backus is an Internal Medicine Specialist in Savannah, Georgia with over a decade of experience in the field. She graduated from Mercer University School of Medicine.
Eric Chang

Yael Elfassy, M.D.

Principal Investigator

Dr. Yael R. Elfassy is a pediatrician in Savannah, Georgia and is affiliated with multiple hospitals in the area, including Memorial Health University Medical Center and Candler Hospital. She received her medical degree from Xavier University School of Medicine.

Michael Mobley, M.D.

Principal Investigator

Dr. Michael C. Mobley is a psychiatrist in Savannah, Georgia. He received his medical degree from Medical College of Georgia and has been in practice for nearly 50 years.

Safety and quality are paramount

Our physicians have extensive backgrounds in their respective medical specialties and always prioritize patient safety.




50+ years of collective clinical trial experience


Assisted by expertly-trained medical staff


Trust our state-of-the-art facilities

We insist on the best equipment and surroundings to ensure safety and comfort.

6,000 sq ft in dedicated research facilities


Extensive experience with pharmaceutical and medical device research

Virtual Tour


iResearch Savannah

6349 Abercorn St.
Savannah, GA 31405

Monday-Friday: 8:30AM – 5:30PM

We’re a CenExel
Center of Excellence

Centers of Excellence provide unparalleled attention to detail to assure consistent and first-class quality in patient care. We have supported tens of thousands of studies, the variety and complexity of which have resulted in a great depth of experience for the principal investigators and research staff at each Center.

We deliver engagement, expertise, and results.


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