CTT Team
CTT Leadership
Leisel Koerber, BBA, CCRC
Executive Vice President
Leisel Koerber is Executive Vice President at Clinical Trials of Texas. Since 2006, she has held multiple positions in clinical research, including site director and clinical research coordinator. Leisel directs day-to-day operations and strategies, ensuring the success of over 100 studies per year. These trials include first-in-human through Phase IV, dermatology, internal medicine, women’s health, mental health, Alzheimer’s Disease, metabolic disorders, vaccines, healthy population, and device studies.
She has worked on more than 500 trials and was instrumental in the development of a proprietary clinical trial management system (CTMS) and electronic source document software. She has also worked to create and implement quality management systems. Leisel has a BBA from The University of Texas at San Antonio and is a CCRC.
Douglas Denham, DO, CPI
Chief Medical Director
Douglas Scott Denham, DO, CPI, is Chief Medical Director of Clinical Trials of Texas and is board-certified in family medicine, with more than 25 years of experience. He has served as Principal Investigator on more than 700 studies in the areas of diabetes, fatty liver, healthy volunteers, hyperlipidemia, seasonal allergies, vaccines, growth hormone, diabetic peripheral neuropathy, implantable devices, insulin pumps, clamp studies, renal studies, and more. His experience includes Phase I-IV protocols, including first-in-human studies.
At the University of North Texas Health Science Center, Texas College of Osteopathic Medicine, Dr. Denham earned his Doctoral degree in Osteopathic Medicine. He completed his residency at the University of Texas Health Science Center at San Antonio.
Edna Arce
Senior Recruitment Manager
Edna Arce is the Senior Recruitment Manager at Clinical Trials of Texas. She has worked in healthcare for more than 25 years and in research for more than 12 years, working on more than 700 trials. She oversees a team of 18, including prescreeners and quality/training personnel.
Meet the Investigators
Douglas Denham, DO, CPI
Chief Medical Director
Douglas Scott Denham, DO, CPI, is Chief Medical Director of Clinical Trials of Texas and is board-certified in family medicine, with more than 25 years of experience. He has served as Principal Investigator on more than 700 studies in the areas of diabetes, fatty liver, healthy volunteers, hyperlipidemia, seasonal allergies, vaccines, growth hormone, diabetic peripheral neuropathy, implantable devices, insulin pumps, clamp studies, renal studies, and more. His experience includes Phase I-IV protocols, including first-in-human studies.
At the University of North Texas Health Science Center, Texas College of Osteopathic Medicine, Dr. Denham earned his Doctoral degree in Osteopathic Medicine. He completed his residency at the University of Texas Health Science Center at San Antonio.
Parke Hedges, MD
Principal Investigator
Principal Investigator
Dr. Parke Hedges was born in Arkansas and spent his childhood years in Indiana. His family moved to Texas in 1969 and settled in the Houston area. After graduation from La Porte High School, Dr. Hedges attended Texas A&M University in College Station.
Dr. Hedges completed his internship at University of Texas Health Science Center at San Antonio. Dr. Hedges is affiliated with Methodist Hospital. He completed his residency in obstetrics and gynecology in 1986. He established his first private practice in Corpus Christi, but eventually returned to San Antonio. He is one of the founding members of Seven Oak’s Women’s Center. He has been honored by induction into the AOA Medical Honor Society. Dr. Hedges has also served as Chairman of the Department of Obstetrics and Gynecology or Methodist Hospital.
Dr. Hedges maintains an active private life spending time with his wife Donna and 3 Australian Shepherds. He is an avid orchid grower and active singer songwriter.
Dr Hedges has been honored by his selection to:
- Consumer Research Council of America – 2012
- America’s Top Obstetrician and Gynecologists 2002-2003, 2005-2006, 2007-2008, 2011-2012
- Best Doctors in America 1996-2011
- Texas Monthly – Texas Super Doctors 2008, 2009, and 2010
- Patient Choice Award 2009 and 2010
Pendleton Wickersham, MD
Principal Investigator
Pendleton B. Wickersham was born in Augusta, Georgia in 1975. After graduating magna cum laude from Rice University in 1996, he attended Baylor College of Medicine in Houston and earned his medical degree with honors in 2000. Dr. Wickersham then moved to Denver to complete his post-graduate studies. He completed his internship, residency, and fellowship at University of Colorado Health Sciences Center in Denver. He is board-certified in both internal medicine and rheumatology. Dr. Wickersham moved to San Antonio in early 2006 to pursue his dream of a thriving clinical practice. He is a partner in the San Antonio-based Arthritis Associates, PA. He is a frequent speaker and consultant and he has invented several medical devices. He enjoys exercising outdoors, reading, and fishing.
Terri Nutt, MD
Principal Investigator
Dr. Terri Nutt is a graduate of the prestigious and highly competitive B.S./M.D. program of Northeast Ohio College of Medicine, earning her Medical Degree in 1995. Upon graduation from medical school, she served 12 years with the US Air Force. She has served as a Flight Surgeon with Air Force Special Operations Command, Hurlburt Field, Florida and as Chief of Dermatology, Travis AFB, California. Her military honors include the Air Force Achievement Medal, Air Force Commendation Medal, Meritorious Service Medal, National Defense Service Medal, Air Force Outstanding Unit Award with Valor, and the Global War on Terrorism Service Medal. She completed her residency in Dermatology at San Antonio Uniformed Services Health Education Consortium in San Antonio, TX. After leaving the military in 2007, Dr Nutt has called San Antonio home and has been practicing at her current location since 2009. Dr. Terri Nutt is a Diplomate of the American Board of Dermatology and a Fellow of the American Academy of Dermatology. She is a member of the Texas Medical Association and the Bexar County Medical Society.
Barbara Corral, DNP, MSN, MA, FNP-BC
Director, Early Phase Services/Investigator
Barbara Corral started her career in research in 2007 working at The Center for Molecular and Behavioral Neuroscience at Rutgers University in academic research, where she had multiple publications. This experience sparked her interest in the medical profession and she decided to go to nursing school for her BSN. Barbara started her career at Jackson Memorial Hospital in Miami, FL, a level I trauma center, as a trauma nurse in 2011 and obtained her Family Nurse Practitioner license in 2015. As a Nurse and a Nurse Practitioner, she had the opportunity to work in multiple specialties. She is a well-rounded Family Nurse Practitioner with extensive experience in emergency, adult, pediatric and psychiatric medicine. She has been working in clinical trials since 2019 in both early and late-phase trials in leadership positions and as an investigator.
Corri Fancher, MSN, APRN, FNP-BC
Nurse Practitioner/Sub-Investigator
Corri Fancher graduated from Texas A&M University – Corpus Christi with her BSN. She worked at Methodist Hospital as a circulating nurse for two years prior to joining PRMA Plastic Surgery as an RN in their office. She also worked at Urology San Antonio during her graduate studies, receiving her MSN Family Nurse Practitioner from Texas A&M University – Corpus Christi. Since graduating and becoming an APRN, she has worked in clinical research as an investigator in studies across multiple phases and indications.
Kerry de Jesus, Psy.D
Principal Investigator/Rater
Dr. Kerry de Jesus is a psychologist licensed in both Texas and Hawaii. She has over 19 years experience providing psychological services to adults and children. She has worked in the specialty areas of neuropsychology and forensic psychology. Before joining Clinical Trials of Texas, Inc., Dr. de Jesus worked with a forensic psychiatric population at the Kerrville State Hospital. Dr. de Jesus received a Bachelor’s degree in Psychology from the University of Texas at San Antonio, a Master’s degree in Clinical Psychology from St. Mary’s University, and a doctorate in Counseling Psychology from Our Lady of the Lake University. She completed her doctoral internship at the San Antonio State Hospital and her post-doctoral training at the Kerrville State Hospital. Member of:
- American Psychological Association
- Texas Psychological Association
- Hawaii Psychological Association
Lisa Marten, MD
Principal Investigator
Lisa Martén, M.D. is Board Certified by the American Board of Ophthalmology with advanced fellowship training in Cornea and Refractive Surgery. Dr Martén performs the latest techniques involving bladeless iLasik and PRK procedures, Intacs for Keratoconus, Collagen Crosslinking, Implantable Collamer Lenses (ICL) and laser cataract surgery with multifocal lens implants. She trained at a referral center for Lasik, and treated many complications, helping her have a more careful approach when choosing candidates for surgery. She also has a background in nutrition and worked at a center for nutrition research in her home country of Costa Rica. She has extra insight into diseases that affect the eye such as Diabetes and Macular Degeneration.
..one of the Top 12 Lasik Surgeons in the United States…
Dr. Martén received her undergraduate degree from Tulane University, as well as attending their School of Public Health Tropical Medicine for her Master’s Degree in Nutrition. She also earned her Medical Degree from their medical school in 2001. During her studies, she won the AMA Foundation Leadership Award for her work as the president of the Latin American Medical Student Association. She also participated in research and received a grant from the American Heart Association. After completing her internship, Dr. Martén came to San Antonio for her Ophthalmology residency at the UT Health Sciences Center where she is now an assistant clinical professor. She moved to Tennessee where she attended the Wang Vision Institute for her fellowship. Dr. Lisa Martén is currently the medical director and owner of the South Texas Eye Institute, the first clinic in San Antonio to perform Lasik. She has performed thousands of refractive procedures and was recently honored from among her peers as one of the Top 12 Lasik Surgeons in the United States. South Texas Eye Institute also partners with research organizations where Dr. Martén is an investigator for several clinical trials. Dr. Martén has been selected as America’s Top Ophthalmologist with special mention in Cornea and Refractive Surgery, and one of San Antonio’s Top Doctors. She is also proud to have been the official Eye Care Provider and Lasik Surgeon for the San Antonio Rampage AHL Hockey Team.
Born in New Orleans, LA and raised in San José, Costa Rica, Dr. Martén’s unique combination of cultures allows her to bring her patients quality care and the best service in their native language. Her patients value her dedication and the time she takes to explain eye conditions and their treatments. They also appreciate her donating her time for medical trips to Mexico and Costa Rica.
Alison Polston, DNP,APRN, FNP-BC
Sub-Investigator
Alison earned her Doctorate in Nursing Practice Degree from the University of Utah in Salt Lake City. She has extensive experience in community health, family medicine, pain management, metabolic diseases, and Rheumatology. She has been working with Clinical Trials of Texas since 2020 as a joint assessor and joint injector. Alison is fully bilingual in English and Spanish. In her spare time, she loves spending time with her family and dogs, traveling, dancing and reading,
Russell Stanley, DPM
Principal Investigator
Dr. Russell Stanley is a podiatrist serving the community of San Antonio, Tx. He earned his Bachelor of Science degree from the California State University, Northridge, in 1999. In 2004, he graduated with his DPM degree from the California College of Podiatric Medicine. He then did a four-year residency and trained at St. Barnabas Hospital & Trauma Center in Bronx, New York, where he served as Chief Resident of Podiatry during his final year. Instead of returning to California post-residency, he came to San Antonio where he has found home and happiness.
Dr. Stanley was raised in Los Angeles, California, enjoying the various cultures, ethnicities, and the western coastline. In 2008, Dr. Stanley moved with his wife and children to San Antonio. He joined San Antonio Podiatry Associates and helped to grow it into one of the larger podiatry groups in South Texas, now under the umbrella of Pacesetter Health. He is on the clinical and surgical staff at Methodist, Baptist, and Christus Santa Rosa Hospitals and also operates at ambulatory surgical centers while maintaining his private practice in the heart of the Medical Center. He has also participated as an investigator in numerous surgical and clinical research trials over 13 years and enjoys the hope and help many people have received under his care and the foresight of the various research sponsors.
