What We Do

We consistently enroll among the top 5% of all participating sites for clinical studies including NAFLD, NASH, MRSA, ABSSSI, pain, sepsis, community-acquired pneumonia, hospital-acquired pneumonia, diabetes, dermatology, vaccines, CV, influenza, and many others.

Through our corporate-wide commitment to research excellence, it is our goal to improve the process that will bring new medicines to our global community. We will settle for nothing less than changing the paradigm of clinical trials. We will do so by continuing to be on the progressive edge of efficient innovation to become the industry leader.

Meet Our Team

William O'Riordan, M.D. - Founder and Senior Medical Advisor

J. Scott Overcash, M.D. - La Mesa Medical Director, Principal Investigator

Michael Waters, M.D. - Chula Vista Medical Director, Principal Investigator

Kia Lee, MSN, ANP-BC - Chula Vista, Sub-Investigator

Hanh Chu, MSN, NP-C - Chula Vista, Sub-Investigator

Karla Zepeda, MSN, APRN, FNP-BC - Chula Vista, Sub-Investigator

Allison Davis, RN, BSN, CCRC - La Mesa, Director of Clinical Operations

Cecilia Barbabosa, RN - Chula Vista, Director of Clinical Operations

Clinical Team

All clinical staff are trained and certified in Good Clinical Practice, the Health Insurance Portability and Accountability Act, and on the NIH Protecting Human Research Participants course.

  
 

William O'Riordan, M.D.

Founder and Senior Medical Advisor 

Dr. William O’Riordan, Senior Medical Advisor, founded eStudySite in 1999 along with twelve healthcare providers with whom he had performed research for over ten years. Dr. O’Riordan has been involved in emergency medicine for more than thirty years at St. Francis Medical Center, Paradise Valley Hospital and Sharp Chula Vista Medical Center. His academic appointments include Harbor General Hospital–UCLA Medical Center and UCSD. His 20+ years of clinical investigation has been performed at Paradise Valley Hospital and Sharp Chula Vista Medical Center. As Principal Investigator, he has directed over 70 studies including cSSSI, Stroke, Acute Myocardial Infarction, Unstable Angina, Sepsis, Septic Shock, Hospital & Community Acquired Pneumonia, Hepatitis C, Atrial Fibrillation, Congestive Heart Failure, Hyponatremia, Complicated Appendicitis, UTI/Pyleonephritis, Occluded Central Venous Access Devices, genomic studies and more. He has served as Chief of Staff at Paradise Valley Hospital and President of the American College of Emergency Physicians in California. Dr. O’ Riordan has also served on numerous advisory adjudication committees including AstraZeneca, Basilea Pharmaceutica, Aventis Pharmaceuticals, Inc., Hoechst Marion Roussel among others. He is an examiner for the American Board of Emergency Medicine and a Fellow of the American College of Emergency Physicians. Dr. O’Riordan earned his medical degree from the University of Kansas Medical School and is licensed in Kansas and California.

 
J. Scott Overcash, M.D.
Medical Director-La Mesa, Principal Investigator
 
Dr. Overcash joined eStudySite in 2012 and is the Medical Director and serves as a Principal Investigator at our La Mesa site.  Dr. Overcash is a board certified Emergency Physician with over 10 years of clinical and research experience. He attended the University of North Carolina School of Medicine where he obtained his M.D. degree and completed their highly ranked Emergency Medicine residency program. Dr. Overcash is a Diplomate of the American Board of Emergency Medicine, a Fellow of the American Board of Emergency Medicine, board certified by the American Academy of Anti-Aging, and an active member of the Association of Clinical Research Professionals. His work has been published in national peer reviewed journals including the New England Journal of Medicine.
 
  
Michael Waters, M.D.
Medical Director-Chula Vista, Principal Investigator
 
Dr. Waters is the Medical Director and serves as a Principal Investigator at our Chula Vista site. Dr. Waters received his medical degree at UC Irvine School of Medicine, and is board certified in Emergency Medicine. His research experience includes, but is not limited to: pneumonia; skin infections; hepatitis; influenza; diabetes; and other infectious diseases.  He has clinical experience in general medicine including: pain management; cardiovascular diseases; and dermatology. 
 
 
Kia Lee, MSN, ANP-BC
Sub-Investigator
 
Kia Lee is a Board Certified Adult Nurse Practitioner. Since joining eStudySite in 2007, Kia has Sub-Investigator experience in over 240 clinical trials within over 40 therapeutic indications, including:

Acute Diseases/Infections: Acute Bacterial Skin and Skin Structure Infections, Bacteremia, C-difficile, Complicated Intra-Abdominal Infections, Gonorrhea, Influenza, Pneumonia, RSV, Urinary Tract Infections, Acute Decompensated Heart Failure and Renal Insufficiency, Heart Failure, Venous Thromboembolism, Opioid Induced Constipation
 
Chronic Diseases/Infections: Anemia, Anemia with Chronic Kidney Disease Chron’s Disease, Chronic Lower Back Pain, Fatty Liver/NASH/NAFLD, Fibromyalgia, Hepatitis C, Herpes Zoster, HIV, Hypercholesterolemia, Hypertension, Iron Overload, Irritable Bowel Syndrome, Migraine, Morton’s Neuroma, Multiple Sclerosis, Osteoarthritis, Type 2 Diabetes, Ulcerative Colitis
 
Dermatology:  Acne, Actinic Keratosis, Atopic Dermatitis Psoriasis, Rosacea
 
Orphan Disease: Beta Thalassemia, Alport Syndrome, Hemochromatosis, Polyneuropathy
 
Vaccines: Influenza, Meningitis, Lyme Kia received the degrees of Master of Science Advanced Practice Nursing and RN from the University of San Diego, and a Bachelor of Arts in Psychology from University of North Carolina.
 
Kia received the degrees of Master of Science Advanced Practice Nursing and RN from the University of San Diego, and a Bachelor of Arts in Psychology from University of North Carolina.
 
 
Hanh Chu, MSN, NP-C
Sub-Investigator
 
Hanh Chu is a Board Certified Family Nurse Practitioner. Since joining eStudySite in 2011, Hanh has Sub-Investigator experience in over 190 clinical trials within over 40 therapeutic indication areas, including:
 
Acute Diseases/Infections: Acute Bacterial Skin and Skin Structure Infections, Bacteremia, C-difficile, Complicated Intra-Abdominal Infections, Gonorrhea, Influenza, Pneumonia, RSV, Urinary Tract Infections, Heart Failure, Venous Thromboembolism, Opioid Induced Constipation
 
Chronic Diseases/Infections: Anemia, Anemia with Chronic Kidney Disease Chron’s Disease, Chronic Lower Back Pain, Fatty Liver/NASH/NAFLD, Hepatitis C, Herpes Zoster, HIV, Hypertension, Iron Overload, Irritable Bowel Syndrome, Migraine, Morton’s Neuroma, Multiple Sclerosis, Osteoarthritis, Type 2 Diabetes, Ulcerative Colitis
 
Dermatology: Acne, Actinic Keratosis, Atopic Dermatitis Psoriasis, Rosacea
 
Orphan Disease: Beta Thalassemia, Alport Syndrome, Hemochromatosis, Polyneuropathy
 
Vaccines: Influenza, Meningitis, Lyme
 
Hanh received the degree of Master of Science, Nursing/Family Practice Nurse Practitioner, from the University of San Diego, and a Bachelors of Arts in Human Development from the University of California, San Diego.  
 
 
Karla Zepeda MSN, APRN, FNP-BC
Sub-Investigator
 
Karla Zepeda is a Board Certified Family Nurse Practitioner. Since joining eStudySite in 2018, Karla has Sub-Investigator experience in over 28 trials, including the following therapeutic indications:
 
Acute Diseases/Infections: Acute Bacterial Skin and Skin Structure Infections, Bacteremia, C-difficile, Complicated Intra-Abdominal Infections, RSV, Urinary Tract Infections
 
Chronic Diseases/Infections: Chron’s Disease, Fatty Liver/NASH/NAFLD, HIV, Migraine, Type 2 Diabetes, Ulcerative Colitis
 
Dermatology: Acne, Actinic Keratosis
 
Orphan Disease: Hemochromatosis
 
Karla received the degree Master of Science Nursing-Family Nurse Practitioner from Kaplan University and a Bachelor of Science in Nursing, from DeVry University.  
 
 
Allison Davis, RN, BSN, CCRC
Director of Clinical Operations, La Mesa Site
 
Allie Davis is the Director of Clinical Operations at our La Mesa site. With over 13 years research experience, she has experience as a Certified Clinical Research Coordinator and an ICU and Trauma RN. Since joining eStudySite in 2006, she has been instrumental in the evolution of operating practices within the Company, and has managed multiple research sites. She has a Bachelor of Science degree in Nursing.  
 
 
Cecilia Barbabosa, RN
Director of Clinical Operations, Chula Vista Site
 
Cecilia Barbabosa is the Director of Clinical Operations at our Chula Vista site, and has been with the Company since 2007. Cecilia joined the Company as a Research RN and Research Coordinator prior to becoming Site Director in 2013. Prior to joining eStudySite she was an Advanced Clinical and Medical-Surgical RN. Cecilia has Associate of Science Degree in Nursing Telemedicine.  
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