Meet The Team
Meet our Invesigators
Experienced Investigators. Passionate About Progress.
For more than three decades, Palmetto Clinical Research has been dedicated to one mission: helping improve patient care through high-quality, compassionate clinical research. Founded in 1987, our practice was built on a simple belief—clinical research is essential to discovering better treatments, supporting patient health, and shaping the future of medicine.
Today, Palmetto Clinical Research proudly serves the Lowcountry as one of the region’s most trusted independent research centers, providing patients access to innovative therapies while partnering with leading sponsors and pharmaceutical organizations to advance medical knowledge.
Dr. Colby Grossman
President & Co-Founder | MD, FACP, CPI
Dr. Colby Grossman is an Internal Medicine physician and the President and co-founder of Palmetto Clinical Research. A native of Greeleyville, South Carolina, Dr. Grossman earned his Bachelor of Science in Biology from the University of South Carolina before completing his Doctor of Medicine at the Medical University of South Carolina. He completed his Internal Medicine residency at Greenville Memorial Hospital in Greenville, South Carolina.
Dr. Grossman has been board certified in Internal Medicine since 1987 and is a Fellow of the American College of Physicians. He is also a Certified Principal Investigator (CPI) through the Association of Clinical Research Professionals (ACRP). In addition to his research work, he serves as co-chairman of the Quality Committee for Palmetto Primary Care Physicians.
With more than 30 years of experience conducting clinical trials, Dr. Grossman has been instrumental in shaping Palmetto Clinical Research into a trusted and respected research site.
“It’s great to be on the cutting edge. Research helps not only the patients that you’re working with, but patients that you’ll never know will also benefit from your work.”
— Colby Grossman, MD
Robert “Matt” Carlile
MD
Dr. Matt Carlile is board certified by the American Board of Psychiatry and Neurology. He earned his Bachelor of Science in Biochemistry from the University of Missouri–Columbia, with minors in Spanish, Mathematics, and Chemistry. He completed his Doctor of Medicine at Tulane University in New Orleans.
Dr. Carlile completed his Neurology residency at the University of Miami, where he served as Chief Resident, and went on to complete a Neuromuscular Fellowship at Washington University in St. Louis, Missouri.
He joined Charleston Neurology Associates in 2016 and has been practicing neurology in the region since that time. In 2018, Dr. Carlile joined Palmetto Clinical Research as a clinical research investigator. His clinical interests include all aspects of general neurology.
“Taking part in clinical research allows our patients access to the cutting edge of medicine and adds yet another dimension to what we can offer our patients.”
— Matt Carlile, MD
Brett Van Leer-Greenberg
Dr. Brett Van Leer-Greenberg, MD is a board-certified gastroenterologist with more than a decade of experience diagnosing and treating a wide range of gastrointestinal conditions. He earned his medical degree from Ross University School of Medicine in 2011 and completed his internship and residency training at St. Francis Hospital, where he developed a strong clinical foundation in internal medicine and digestive health. Today, he practices in Summerville, South Carolina, where he focuses on conditions affecting the gastrointestinal tract, pancreas, and esophagus, bringing both clinical expertise and a patient-centered approach to care.
In addition to his clinical work, Dr. Van Leer-Greenberg plays an active role in advancing medical knowledge through clinical research. He serves as an investigator with Palmetto Clinical Research, where he contributes to studies aimed at improving treatments and expanding access to innovative therapies for patients. The organization has completed hundreds of studies across therapeutic areas including gastroenterology, endocrine health, and neurology, providing patients with opportunities to participate in cutting-edge research while helping shape the future of medicine.
Known for his thoughtful approach and dedication to patient care, Dr. Van Leer-Greenberg combines evidence-based medicine with a commitment to compassionate communication and individualized treatment planning. Through both his clinical practice and research efforts, he remains focused on improving digestive health outcomes while supporting the development of new therapies that can benefit patients locally and nationwide.
Joseph Mathews
MD, FACP, FACE, ECNU, CCD
Dr. Joseph Mathews began his education at the College of Charleston, where he graduated cum laude with a Bachelor’s degree in Biology. He earned his Doctor of Medicine from the Medical University of South Carolina and completed both his Internal Medicine residency and Endocrinology fellowship at MUSC.
Dr. Mathews is board certified in Internal Medicine and in Endocrinology, Diabetes, and Metabolism by the American Board of Internal Medicine. He serves as the Director of Endocrinology at Palmetto Primary Care Physicians and has advanced training in diabetes management, thyroid biopsies, neck ultrasound, and clinical densitometry.
He is the only physician in the Lowcountry to hold ECNU certification and is a Fellow of both the American College of Endocrinology and the American College of Physicians. Dr. Mathews is nationally recognized for his work in Cushing’s Syndrome, serves on advisory committees related to the condition, and frequently lectures across the country.
He joined Palmetto Clinical Research as a clinical research investigator in 2018.
“As an Investigator with Palmetto Clinical Research, I am pleased to be involved with a team that is advancing medical knowledge and bringing cutting-edge medical care to our patients.”
— Joseph Mathews, MD