Who We Are

Dr. Stephen Dilly, President, Chief Executive Officer, and Board Chair of SonomaBio, brings nearly forty years of executive management experience in the biopharmaceutical industry. Most recently, he served as President and CEO of Codexis (Nasdaq: CDXS) where he continues to serve as Chair of the Board of Directors. At Codexis, Stephen 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 recent 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. Additionally, Dr. Dilly has served in executive roles at Genentech, Chiron and SmithKline Beecham and 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, JD has played key roles in multiple biotech startups through critical growth phases, raising private venture financing, negotiating high-value pharma partnerships, scaling clinical trials, and supporting two 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 currently sits on the board of Fauna Bio.

Ms. Ash earned her Bachelor of Arts degree in Political Science from the University of Michigan, and her JD from Harvard Law School.

Joshua Beilke, PhD, MBA, is Chief Scientific Officer of SonomaBio, where he leads the company’s 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, MBA, is a global biotech financial executive with over 20 years of experience in corporate transactions, healthcare finance and strategy. She most recently served as Chief Financial Officer at Gyroscope Therapeutics, a global clinical-stage gene therapy company focused on disease of the eye, acquired by Novartis. Prior to Gyroscope, Stitt served as Vice President of Finance and Operations for MyoKardia, Inc., a biopharmaceutical company developing targeted therapies for the treatment of serious cardiovascular diseases, acquired by Bristol Myers Squibb. She served as Vice President of Finance and Investor Relations for Theravance Biopharma, Inc., after the company’s spin-off from Theravance, Inc., now Innoviva, Inc. She previously held roles in finance at Nektar Therapeutics, Alkermes and Blue Cross Blue Shield of Massachusetts.

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