Sonoma Biotherapeutics Announces Leadership Transition as Stephen Dilly, MBBS, PhD, Becomes President and CEO; Co-founder Jeff Bluestone, PhD, Assumes Advisory Role
Sonoma Biotherapeutics, Inc., a clinical-stage biotechnology company advancing engineered regulatory T-cell (Treg) therapies for autoimmune and inflammatory diseases, announced a significant leadership transition as part of its next phase of corporate and clinical growth. The company has appointed industry veteran Stephen Dilly, MBBS, PhD, as its new President, Chief Executive Officer, and member of the Board of Directors, effective immediately. Dr. Dilly, the former CEO of Codexis, Inc., and current Chair of the Codexis Board, steps into the role at a pivotal moment for Sonoma Biotherapeutics as it accelerates development of its engineered Treg platform.
The company also announced that its co-founder, Jeff Bluestone, PhD—who has served as a driving scientific and strategic force behind SonomaBio since its inception in 2019—will transition into a new role as Advisor while remaining on the Board of Directors. Dr. Bluestone’s leadership has guided the company from its earliest conceptual foundations through the establishment of its clinical pipeline, including its lead candidate, SBT-77-7101.
This leadership evolution comes just weeks after SonomaBio reported encouraging interim clinical data from its first-in-human trial evaluating SBT-77-7101 in patients with refractory rheumatoid arthritis. The positive safety and early efficacy signals marked a major milestone for the company and the broader Treg therapy field, underscoring the therapeutic potential of SonomaBio’s engineered regulatory T-cell platform.
Reflecting on his transition, Dr. Bluestone emphasized both pride in the company’s accomplishments and confidence in its future direction. “At Sonoma Biotherapeutics, we’ve taken engineered regulatory T cells from an early scientific concept to a clinical reality supported by data showing the potential for life-changing treatments,” he said. “I am immensely proud of all that we have achieved and excited for the Company to build on our momentum with SBT-77-7101, especially for patients with refractory rheumatoid arthritis who have limited treatment options. With this progress, I believe now is the right time to make way for new leadership that will propel the company toward its ultimate goal—delivering innovative, curative therapies to patients with autoimmune and inflammatory diseases.”
Dr. Bluestone added that he is “thrilled to welcome Stephen,” noting that Dr. Dilly’s extensive experience in company building, clinical development, and commercialization makes him uniquely suited to lead SonomaBio through its next phase. “I look forward to partnering with Stephen and the Board as Advisor and continuing to support our mission to transform the treatment landscape for patients who need better solutions,” he said.
Dr. Dilly expressed enthusiasm about joining Sonoma Biotherapeutics at such a critical inflection point. “SonomaBio’s platform has the potential to represent a true scientific breakthrough for chronic immunological conditions,” he said. “The opportunity to develop therapies that might not only treat—but potentially cure—autoimmune and inflammatory diseases is extraordinary. I have deep admiration for Jeff and the entire SonomaBio team for building a world-class scientific foundation and advancing the company to this stage.”
He added, “I am honored to lead Sonoma Biotherapeutics as we continue to mature our clinical programs and translate our science into meaningful therapeutic solutions. I am also exceptionally grateful to Jeff for his longstanding leadership and for remaining engaged as Advisor and Board member. His scientific vision and commitment to patients have shaped every part of this company’s identity.”
Rick Klausner, MD, Chair of Sonoma Biotherapeutics’s Board of Directors, praised Dr. Bluestone’s legacy and welcomed Dr. Dilly’s appointment. “On behalf of the Board, I would like to thank Jeff for his years of scientific dedication, boundless energy, and impassioned leadership that built SonomaBio into the company it is today,” he said. “Under Jeff’s guidance, the company transformed groundbreaking immunological insights into a robust therapeutic platform now entering a new era of clinical validation.”
Dr. Klausner continued, “We are pleased to welcome Stephen as the next President and CEO of SonomaBio. Stephen is a proven leader with deep experience in building, growing, and guiding innovative biotech companies. His track record in drug development, operational leadership, and value creation will be invaluable as SonomaBio continues to advance its programs and expand its impact.”
Dr. Dilly brings nearly four decades of experience across biotechnology and pharmaceutical development, with a distinguished record of leading companies through critical stages of growth, regulatory milestones, and strategic transactions. Most recently, he served as Chairman, CEO, and President of Codexis, Inc., where he guided the company’s strategic evolution and continues to serve as Chairman of the Board.
Prior to Codexis, he served as President and CEO of Sierra Oncology, where he oversaw development of the company’s clinical programs through its eventual acquisition by GlaxoSmithKline. Before that, he was President and CEO of Aimmune Therapeutics, which was later acquired by Nestlé Health Science following the approval of its food allergy immunotherapy product.
Dr. Dilly’s earlier career includes senior roles at Genentech, Chiron, and SmithKline Beecham, contributing to the development, approval, and launch of more than 25 marketed therapies across diverse disease areas. He holds an MBBS and a PhD in cardiac physiology from the University of London.
With this leadership transition, SonomaBio positions itself for continued advancement of its pioneering Treg platform, with a focus on broadening clinical development and building the infrastructure necessary to support future late-stage trials and potential commercialization. As the company moves forward, the combined experience of Dr. Dilly, ongoing guidance from Dr. Bluestone, and continued scientific innovation aim to accelerate SonomaBio’s mission of delivering transformative therapies for patients living with autoimmune and inflammatory diseases.
About Sonoma Biotherapeutics
Sonoma Biotherapeutics is a clinical-stage biotechnology company developing engineered regulatory T cell (Treg) therapies to treat serious autoimmune and inflammatory diseases by restoring immune system balance. Founded by pioneers in Treg biology and cell therapy, including Dr. Fred Ramsdell, whose foundational research in Treg biology was recognized with a 2025 Nobel Prize, Sonoma Biotherapeutics combines deep scientific expertise with proprietary platform technologies to advance a new generation of targeted and durable Treg cell therapies. In addition to its lead, proprietary Treg program, SBT-77-7101, Sonoma Biotherapeutics is collaborating with Regeneron to advance a pipeline of Treg cell therapies for autoimmune diseases.
Source Link: https://www.businesswire.com/
