Phoenix, Arizona

Principal Investigator
Charles Steven Plimpton, MD completed his undergraduate degree at Arizona State before heading to University of Arizona, where he completed his medical degree in 1988. In 1992, he completed his OBGYN residency in Phoenix, where he has run his private practice for over 30 years. In addition to his private practice, Dr. Plimpton has served as an assistant clinical professor at the Creighton University School of Medicine, Phoenix since 2015 and conducted clinical trials as a principal investigator since 2017 with a focus on women’s health and pediatric vaccines. Dr. Plimpton is a highly respected physician in the community having earned Phoenix Magazine’s “Top Docs” award four times.

Sub Investigator
Carlos Lopez, MD graduated from medical school in Montemorelos, Mexico in August 1992. He has been a pediatrician since 1999 after he graduated from Pediatric Training Program at Texas Tech University. Dr. Lopez opened his private practice in Phoenix in 2001. Dr. Lopez began working in research in 2017 with a focus on women’s health and pediatric vaccine trials. His hobbies include reading, outdoor activities, and music. He also fluently speaks Spanish and Brazilian Portuguese. He loves to spend time with his family and kids.

Sub Investigator
Iva Tirres, NP has worked in the medical field for 10 years after earning her Bachelor of Science and her Master of Science in Nursing degrees from Grand Canyon University. Pivoting her focus from wound care to infectious diseases, Iva joined the clinical research industry in 2022 as a sub-investigator. In her role as a sub-investigator, Iva has been highly involved in all aspects of the trials at the Phoenix site.

Site Director
After many years as a bedside nurse, Wendy Barrett, MSN, RN entered the clinical research industry in 2014 at St. Joseph’s Hospital and Medical Center as a research supervisor before moving on to become the research program manager. She transitioned to a new role at MedPharmics in 2022 as the Director of Clinical Operations, before MedPharmics was acquired by Velocity Clinical Research. Prior to her interest in research, Wendy earned undergraduate nursing degrees from the University of South Dakota and Grand Canyon University. Additionally, Wendy earned her Master of Science in Nursing Administration from Western Governors University.