Stephan A. Bart, Sr., MD, CPI,

President, Chief Medical Officer

Dr Bart is the lead executive for Optimal Research and has oversight for the entire organization. He has been actively involved in research dating back to 1984 where he worked in a laboratory focusing on neuropharmacology. He obtained his Bachelor of Science in both Biology and Chemistry at Northeastern Illinois University and subsequently obtained his Doctorate in Medicine from Rush University in Chicago. Dr Bart then went on to do his postdoctoral training in Pediatric Transplantation, Family Medicine, and Obstetrics and Gynecology at the University of Pittsburgh and the University of South Florida. He is both Board certified and a Certified Physician Investigator with a broad therapeutic scope and is an industry KOL in several areas. He has completed more that 300 clinical trials as the Principal Investigator and functioned as coordinating Investigator across a spectrum of studies that encompass first in human Phase 1 through Phase 3 domestic and international programs.

Dr Bart has had a successful private practice as well as leadership positions in several organizations. Prior to Optimal Research, he was the Chief Medical Officer of Accelovance, a vaccine and immunology-focused CRO. He was the Chief Medical Officer and member of the Board of Directors for Idis, a global leader in named patient programs operating in more than 150 countries worldwide. He was the Chief Medical Officer and Executive Director of Business Development and Client Services for SNBL Clinical Pharmacology Center, and the Medical Director for Radiant research over the past 20 years.

Dr Bart has held faculty positions at Penn State University and the University of Maryland Medical Center and has published many articles in prestigious journals.

Dr. Stephen Daniels, DO

Principal Investigator

Dr. Daniels has served as an Executive Medical Director for clinical research since 1997 with a primary focus in the area of pain and analgesia. He has successfully conducted over 200 clinical trials in addition to providing consulting services to many major pharmaceutical companies. Dr. Daniels received his B.B.A. from Texas Wesleyan College, and his doctorate in osteopathic medicine from the University of North Texas Health Science Center in Fort Worth, TX. He completed his internship and Family Practice Residency through University of Texas Health Science Center, Houston, TX, San Jacinto Methodist Hospital, Baytown, TX He is a Diplomate of the American Academy of Family Physicians, a member of the Texas Medical Association and affiliated with numerous pharmaceutical industry associations/organizations.

Over the past 20 years, Dr. Daniels has been the first author and/or co-author of over 50 abstracts, presentations and publications in peer-reviewed medical journals.


Dr. Peta Gay Jackson Booth, MD

Principal Investigator

Dr. Jackson Booth has been primarily focused on vaccine studies since joining Optimal Research in 2016 where she currently serves as principal investigator and medical director. She has spent several years conducting basic research and clinical research. Her focus has been in the fields of Immunology and Oncology. Dr. Jackson Booth is board certified in Internal Medicine and has over 20 years of clinical practice experience. She has served in the U.S. Public Health Service as a Medical Officer at the National Cancer Institute (N.I.H).

Dr. Jackson Booth concurrently earned a BSc in Zoology with honors and a Doctorate in Medicine from Howard University, completing her studies in 1995. She did her internship in Internal Medicine at Washington Hospital Center in Washington, DC and residency at Johns Hopkins University/Sinai Hospital in Baltimore, MD. Outside of medicine, Dr. Jackson Booth enjoys HGTV, raising orchids and various adventures with her family and friends.


Randle Middleton, MD

Principal Investigator

Dr. Randle Middleton has been working in research for 16 years and has been with Optimal Research since its start. He received his Doctorate of Medicine from the University of Mississippi Medical School and did his Residency at Martin Army Community Hospital in Fort Benning, Georgia where he was Chief Resident. He has worked as a Family Practice Staff Physician at Bayne-Jones Army Community Hospital in Louisiana and has had his own Family Practice since 1997. He is affiliated with American Academy of Family Physicians, Alabama Academy of Family Physicians, and Madison County Medical Society. He has been the PI for Chronic Bronchitis, MI Reduction, Diabetic Prevention/Control, Depression, Asthma, Contraceptive and Women’s Studies, IBS, Cardiovascular, Osteoarthritis, High Blood Pressure, Acute Sinusitis, Metabolic Syndrome, Stroke, Acne, Hypercholesterolemia, and Smoking Cessation studies. He is most interested in vaccine studies in which he has conducted numerous studies of including influenza, H1N1, Anthrax, Plague, Pneumococcal, Tetanus, Meningitis, Ebola and more. He and his wife live in Huntsville, AL.

Patrick Yassini, MD

Principal Investigator

Dr Yassini holds BS, MS, and MD degrees.  He is Board certified in family medicine as well as in Integrative holistic medicine and he is further fellowship trained in Metabolic Medicine.

Dr Yassini has been engaging in clinical research and practicing medicine in the community for over 15 years.  He has served as the president of the San Diego Academy of Family Physicians and currently serves as a delegate to the California Association of Family Physicians.  As associate clinical professor at University of California at San Diego he helps train our future physicians.  He also serves as an expert reviewer for the medical board of California. Dr Yassini’s unique practice style has been featured in San Diego Magazine’s Top Doctors edition, Fox 5 TV News, San Diego Reader, and Coronado Lifestyle Magazine.

Dr Yassini joined the Optimal Research team in 2013, has serves as principal investigator and is Medical Director of the San Diego Site.  What drives his interest clinical research is the passion to impact the lives of large populations of people for the better.

Murray A. Kimmel, DO

Principal Investigator

Dr. Kimmel graduated Temple University in 1982 with a Bachelor of Science degree in medical technology. He completed his doctor of osteopathic medicine from Philadelphia College of Osteopathic Medicine in 1992, after completing a residency for family medicine at St. Joseph’s Hospital in Philadelphia, then becoming board certified in Family Practice.

Along with providing primary care, Dr. Kimmel has been a principal investigator since 1998, conducting many studies in general medicine, nutraceuticals, biomedical devices and specializing in vaccine clinical trials. Dr. Kimmel is extremely dedicated to the practice of medicine and to his involvement and conduct of clinical research trials. Dr. Kimmel spends a lot of his time at the research site overseeing studies as well as tending to his patients at his private practice. When he is not working, Dr. Kimmel enjoys keeping fit by attending the gym and eating right and also tinkering with his Harley Davidson motorcycle.

Dr. Daniel Brune, MD

Principal Investigator

Dr. Brune is the principal Investigator for Optimal Research in Peoria IL. He has conducted clinical research for over 17 years and has participated in over 150 clinical trials. Dr. Brune earned his medical degree from the University of Illinois and completed his residency training at Methodist Medical Center. Dr. Brune holds a passion for being involved in the latest technologies and developments in medical research and finds vaccine trials to be his favorite, as the prevention of disease is essential to improved global health. He also enjoys lending his expertise as an investigator to all therapeutic areas in order to advance medicine. Dr. Brune has been with Optimal Research since 2005, and in his free time, enjoys hunting and fishing with family and friends.

Krystyna Kowalczyk

Chief Operations Officer

Krystyna Kowalczyk is the Chief Operating Officer for Optimal Research and oversees operational excellence across the team. She started in the research industry in 1981 and is now a tenured executive in the clinical research field with experience in biopharma, top tier CROs and SMOs. She has lead both regional and international teams in the successful execution of clinical research being part of the clinical operations team affiliated with 3 approved compounds.  She has overseen over 100 clinical trials across her career.  Her areas of focus have been Oncology, Respiratory, CNS, and Rare Diseases.  As a founding member of Novella Clinical, Ms. Kowalczyk successfully built the first CRO with a focus of using only web-based electronic data capture (EDC) in clinical trials. After acquisition of Novella by Quintiles, Ms. Kowalczyk continued to look for innovation opportunities in the clinical research space which led her to Optimal.  In her role as COO, she is responsible for supporting the team in both building onto the strong SMO infrastructure as well as innovating the way Optimal supports the acquisition of patients across clinical research.


Dr. Xiangfei "Scott" Cheng

Director of Immunology

Dr. Xiangfei “Scott” Cheng is the Director of Immunology and Laboratory Services for Optimal Research and oversees teams across six states in the US.  He holds his M.D and Ph.D. degrees and brings more than 20 years of combined experiences in leadership, clinical trial, drug development, preclinical and clinical studies to this company.  Scott completed his postdoctoral work at Northwestern University, Chicago, IL, USA in 1996 and had more than 90 publications in peer-reviewed journals with oral and poster presentations.  Before joining Optimal Research, he held a faculty position at University of Maryland School of Medicine.  Research areas of interest include Isolation of PBMC, Vaccine Immunization, Clinical Trials, Translational Medicine, Transplantation Immunology, Immunomodulation, Co-stimulation Pathway Blockade,  T Cell Co-Stimulation, Cell Signaling, T Cell Receptor (TCR), Drug Development, Drug trials, Immunoassay, Cell-based assays, Biomarkers Analysis, Clinical Development, Hematology, Thrombosis, Fibrinolysis, Immuno-oncology, Gene Therapy of Cancer, Stem Cell Expansion, Differentiation and Engraftment, Cell and Molecular Biology, Regulation of Surface Proteinase and Signal Transduction of Serpin-Proteinase Complex by LRP, Constitute of cDNA library with phage lambda gt11 and expression of protein, Biochemistry, Protein Chemistry,  Immunochemistry, Immunohistochemistry, Design, development and execution of animal models for in vivo preclinical study. 

Vanessa Watson, CCRC 

Director of Operations

Mrs. Watson is responsible for the operational oversight of the Optimal Research sites. She started her career in clinical research in 1998 working in a multi-therapeutic site environment with Radiant Research and progressed from Clinical Research Coordinator to Site Manager over 7 years. She started a Phase I unit for healthy and renal impaired subjects before moving on to become a Project Manager at SCIREX, LLC. In 2005, Mrs. Watson assumed to the position of Director of Operations for SCIREX which then became Premier Research where she oversaw the site network operations, recruitment, budgeting and training. She then went on the assume responsibility for the departmental strategy, business development, and model development as the Sr. Director of Operations. Most recently, Mrs. Watson has taken on the role of Director of Operations at Optimal Research where her knowledge of acute pain and general medicine will aid in the organic and non-organic growth of the site network. Mrs. Watson holds a Bachelor’s of Science degree from McGill University in Environmental Biology, has received a certificate in Management and Leadership Skills from the University of Texas.  She has been a member of ACRP and a Certified Clinical Research Coordinator since 2001 and is an active member of SCRS.

Jolee Holt, MSN, RN, CCRC

Director of Oncology Network

Jolee Holt brings 18 years of phase II-IV clinical research experience to Optimal Research, including the conduct of 500+ adult oncology studies.  Her experience includes the management of studies originating through the NCI, Pharmaceutical companies, single IND's and expanded access programs.   In addition to her oncology experience, Jolee has extensive experience in operational management and quality measures of clinical research at the site level with a successful audit history with the FDA.    Prior to joining Optimal Research, Jolee held roles at Cancer Care Associates, and Oklahoma Cancer Specialists and Research Institute for two decades while also providing industry knowledge as a private oncology operations consultant.  

Jolee holds a Master’s Degree in Nursing and is a Certified Clinical Research Coordinator through ACRP.

Holly Hoefer, MS, CPC-H

Director Patient Recruitment & Marketing

Holly Hoefer is the Director of Patient Recruitment and Marketing for Optimal Research and oversees study enrollment for the six core sites as well as supports enrollment for the consortium.  She has consulted with or recruited  over 50 clinical trials across her career with Optimal Research.  Her areas of focus have been oncology, pediatrics, infectious disease, men and womens' health and bariatrics.  Holly utilizes the latest in patient recruitment and patient identification technology to successfully enroll trials. 

Holly Hoefer holds a Bachelors of Science degree from Georgia Southern University, and subsequently earned a Masters degree in Health Communications from Boston University.  Holly also holds a CPC-H certification, for hospital billing and coding,  and has been in patient recruitment since 2004.