David Pyrce

Chief Executive Officer

David brings over 30 years of biotechnology and pharmaceutical industry leadership, together with deep Wall Street experience. He leads all aspects of RESTEM’s business operations, with a focus on the fast-track translation of research studies to IND-enabling studies, human clinical studies, and commercial revenue generation. David brings proven executive management skills, extensive product development and commercial expertise, as well as deep experience in securing strategic capital, establishing strategic partnerships, and the scale-up of commercialization activities, further accelerating growth opportunities and enhancing our leadership position in the industry. Prior to joining RESTEM, David was SVP, Strategy/Innovation & Chief Commercial Officer of a public natural killer cell therapy company, which he helped build and grow from eight employees to a $300 million IPO and over 300 employees and a $15 billion exit in 2021. Prior, David was the Founder, Chairman, and CEO of a next-generation sequencing based molecular diagnostics and neoantigen-based therapeutics company utilizing artificial intelligence and machine learning tools to enable the development of patient-specific therapies. He was also the Founder, CEO, and Managing General Partner of a biotech-focused investment management firm on Wall Street. David received his MBA from the Stuart School at the Illinois Institute of Technology in Chicago and has dual Bachelors’ degrees in Chemistry and Biology from Northern Illinois University.

Rafael Gonzalez, PhD

Founder | Chief Development & Science Officer

Dr. Rafael Gonzalez has always been passionate about helping those suffering from degenerative disorders. He graduated from University of California, Irvine with his Ph.D in Anatomy and Neurobiology and has since been responsible for the development of clinical stem cell applications for several diseases and trauma states. He leads multiple investigational new drug applications with patented stem cell technology, works on the clinical development of immune-based therapies with natural killer cells, and has several publications to back his expertise. He also teaches worldwide for the American Academy of Antiaging on age related disorders and the role of the immune system and cell therapeutics to aid in maintaining health. Dr. Gonzalez is well respected in the regenerative medicine sector for his ability to understand all aspects of cell-based therapeutics and their clinical applicability.

Toai Nguyen, PhD

Laboratory Manager | Lead Scientist

Dr. Nguyen has more than 30 years in the field of biological sciences. He has spent over 20 years in academia with a focus on molecular biology, virology, biochemistry, and genetics, where he lectured undergraduate and graduate students as Principal Scientist at University of California, Irvine. For the past 11 years, Dr. Nguyen has been implementing a development program by leading all GLP and cGMP testing to include validation of our cell-based and their derivatives platform. He also leads our reference lab with many years of experience with in vitro cell testing. He has several publications in cell and molecular biology and biochemistry.

Nickolas Chelyapov, PhD

Senior Scientist of Immune Based Therapeutics 

With over 45 years of experience in the biotechnology sector, Dr. Chelyapov has studied, researched, and developed various vaccines, molecular disease targets, nano delivery systems and cell-based technologies designed to target age related disorders. He has several publications and patents in all aspects of biology and is a pioneer in developing cell-based therapeutics for senescence. He is dedicated to helping age-related disorders through targeted removal of old cells, which may force a natural regenerative healing response. In his tenure with RESTEM, he has developed highly active NK cells along with an understanding of various extraordinary properties that these cells are capable of.

Tatiana Estrada-Hernandez

Research Associate III

With her extensive experience in cell therapy and her master’s degree in Pharmacology, Tatiana is responsible for incredible breakthroughs at RESTEM. She has worked in the field for over 10 years conducting in-vivo and pre-clinical studies, as well as biological manufacturing. She has developed and validated new mouse tumor models to evaluate the efficacy of novel immunotherapy products, with many publications behind her. At RESTEM, Tatiana establishes innovative in-vitro methods to study engineered cell therapies, as well as conducts pharmacological evaluation of test agents in various in-vitro oncology models. In particular, she conducts revolutionary studies on natural killer cells for cell therapy.

Marisol Castro-Paiz

Clinical, Regulatory and Quality Systems Director

Marisol Castro-Paiz has an impressive 25 years of experience in the biotechnology, pharmaceutical, and medical device industries behind her, as well as certifications in clinical trials administration from UCSD, project management from PMI, and quality assurance auditing from AQS. She graduated from Stanford University with a B.S. degree in Biological Sciences with Honors. As Director of Clinical, Regulatory, and Quality Systems for RESTEM, she directs and oversees Quality Control and Quality Assurance (QC/QA), contract lab manufacturing and testing in compliance with cGMP and with GTP for HCT/P, in-house cleanroom programs for aseptic processing, non-clinical safety testing, domestic and international regulatory affairs, clinical Phase 1 INDs and projects in collaboration with investigators and CROs for clinical data management and operations.

Heather Vest

Business/Operations Manager

Heather joined the team at The BioBox in 2022 after 6 years in the veterinary industry. Stemming from her years in management, she has experience in marketing, budgeting, event planning, team leadership, and client services. As the Business/Operations Manager at The BioBox, Heather is responsible for ensuring company efficiency, both in day-to-day operations and in long-term planning, as well as marketing, contract development, project oversight, sales, and overall company growth. She obtained her BS in Biology from University of California, Santa Barbara, and her MBA in Marketing from University of Redlands.