Who We Are

Dr. Stephen Dilly, President, CEO, and Board Chair of Sonoma Biotherapeutics, brings forty years of executive management experience in the biopharmaceutical industry. Most recently, he served as President and CEO of Codexis (Nasdaq: CDXS) and continues to serve as Executive Chairman of its Board of Directors. At Codexis, Dr. Dilly led the transformation of the company from a life science tools provider into a full-service CDMO pioneering enzymatic oligonucleotide synthesis. Prior to Codexis, he served as President and CEO of Sierra Oncology (Nasdaq: SRRA) through its sale to GlaxoSmithKline for $1.9 billion. Dr. Dilly also served as CEO of Aimmune Therapeutics, acquired by Nestle Health Science for $2.6 billion. Previously, he served in executive roles at Genentech, Chiron and SmithKline Beecham.

Dr. Dilly has been associated with the development, approval and launch of more than twenty-five marketed drugs across multiple therapeutic areas. He holds both an MBBS (UK equivalent of MD) and a PhD in Cardiac Physiology from the University of London.

Lisa Taylor Ash, COO of Sonoma Biotherapeutics, leads the company’s legal, program management, regulatory, and quality functions. She brings experience guiding multiple biotech startups through critical growth phases, raising private venture financing, negotiating high-value pharma partnerships, scaling clinical trials, and supporting billion-dollar product launches.

Most recently at Shape Therapeutics, Ms. Ash was instrumental in building their legal department and eventually leading operations. Before that role, Ms. Ash served as Vice President, Head of Healthcare Law and Compliance at Juno Therapeutics, where she led a team of lawyers advising on issues related to the manufacturing and clinical development of CAR-T cell therapy. Ms. Ash has also served as the Senior Director of Compliance and Legal Affairs at Exelixis and Corporate Counsel, Healthcare Law at Pharmacyclics, and as a Healthcare Associate at Sidley Austin LLP. Ms. Ash is a board member and strategic advisor to Fauna Bio.

Ms. Ash earned her JD from Harvard Law School and her BA in Political Science from the University of Michigan.

Joshua Beilke, CSO of Sonoma Biotherapeutics, leads scientific strategy, translational development, and technical operations. Dr. Beilke is an immunologist with more than 20 years of experience advancing the understanding of immune tolerance and immune mediated disease.

Dr. Beilke joined SonomaBio in 2019 as Vice President of Translational Development and Seattle Site Head. Prior to SonomaBio, he served as Director of T Cell Biology and Engineering at Celgene, where he led efforts focused on CAR and engineered TCR signaling optimization, small molecule control of T cell activity, and ensuring robust biology throughout manufacturing. He also played a key role in early business development, contributing scientific diligence, and managing the scientific aspects of strategic partnerships.

Earlier in his career, Dr. Beilke worked at the Novo Nordisk Research Center, focusing on target discovery for biotherapeutic development in inflammatory diseases. He completed his postdoctoral training at the University of California, San Francisco, in the Lewis Lanier Lab, where his research focused on NK cells, NK‑like receptors in autoimmunity, and memory NK cell formation.

He earned his PhD from the Barbara Davis Center at the University of Colorado Health Sciences, where his research focused on active mechanisms of immune tolerance. He also holds an MBA from the University of Colorado.

Jessica Stitt, CFO & CBO of Sonoma Biotherapeutics, leads the company’s finance, business development, and corporate services functions. She is a global biotech financial executive with over 20 years of experience in corporate transactions and healthcare finance and strategy. She most recently served as CFO at Gyroscope Therapeutics, acquired by Novartis for $1.5 billion. Prior to Gyroscope, Ms. Stitt served as Vice President of Finance and Operations for MyoKardia, Inc., acquired by Bristol Myers Squibb for $13.1 billion. She previously served as Vice President of Finance and Investor Relations for Theravance Biopharma, where she was part of the team responsible for a range of strategic and financial transactions, including pharma partnerships, follow-on offerings, and royalty monetization. Earlier in her career, she held roles in finance at Nektar Therapeutics, Alkermes plc and Blue Cross Blue Shield of Massachusetts.

Ms. Stitt holds an MBA from Simmons School of Management and a BA from Saint Anselm College.