Sonoma Biotherapeutics

Sonoma Biotherapeutics is a clinical-stage biotechnology company developing engineered regulatory T cell (Treg) therapies intended to treat autoimmune and inflammatory diseases by restoring balance to the immune system. The company's stated strategy is to address the root cause of disease rather than broadly suppress immunity: Tregs are described as sentinel cells that detect and suppress unwanted immune responses, and the company engineers them to recognize the key antigens that drive specific autoimmune and inflammatory conditions, with the aim of durable disease control from a single treatment.

The company's approach combines engineered Treg cell therapy with effector T cell (Teff) conditioning. Its two most advanced programs described in 2021 coverage were a CAR-based Treg cell therapy for refractory rheumatoid arthritis and a Teff conditioning biologic designed to deplete active autoimmune cells and clear the inflammatory environment, potentially improving the effectiveness of Treg cell therapies; the latter was initially framed as a type 1 diabetes program usable alone or in combination. Additional disclosed pipeline areas include inflammatory bowel disease, type 1 diabetes and Crohn's disease. Manufacturing is performed through a proprietary process that isolates, expands and enhances Tregs from a patient's own immune system, and the company has described building out manufacturing capability to support initial clinical studies.

Sonoma operates from a South San Francisco headquarters with a second site in Seattle. Its leadership team includes President and CEO and Board Chair Stephen Dilly, COO Lisa Taylor Ash, CSO Joshua Beilke and Chief Financial and Business Officer Jessica Stitt. Its four scientific founders — Jeffrey Bluestone, Qizhi Tang, Fred Ramsdell and Alexander Rudensky — remain associated with the company as scientific advisors.

Founding story

Sonoma Biotherapeutics was founded in 2019 by Jeffrey Bluestone, an immunologist known for work on T-cell activation and immune tolerance, along with Alexander Rudensky (Memorial Sloan Kettering Cancer Center, co-discoverer of FOXP3), Fred Ramsdell (a biotechnology immunology veteran who led the team that discovered and characterized FoxP3 at Darwin Molecular, and former CSO of the Parker Institute for Cancer Immunotherapy) and Qizhi Tang (UCSF, among the first to grow regulatory T cells and apply them in experimental therapy). The four founders had worked together for years; Bluestone left the presidency of the Parker Institute for Cancer Immunotherapy and surrendered his tenure at UCSF to translate his laboratory research on immune tolerance into therapies, and the company launched with backing from life science investors.

Business model

Sonoma Biotherapeutics is a venture-backed, clinical-stage therapeutics developer. It funds internal R&D through private financing rounds and develops proprietary engineered Treg cell therapy products, including autologous products manufactured from a patient's own immune cells via an in-house manufacturing process. Sources describe use of financing proceeds to scale manufacturing operations to supply initial clinical studies; no product revenue or commercial arrangements are described in the sources.

No revenue model is described in the sources; the company is a clinical-stage therapeutics developer funded by private venture financing.

Traction

As of August 2021 the company was preclinical with roughly 50 employees and had raised $265 million in a Series B on top of $70 million across two Series A rounds; BioSpace reported over $335 million raised since launch. It planned to grow to 75 employees by the end of 2021. The company website subsequently describes it as clinical-stage with its lead Treg program in clinical trials.

Latest developments

The company's website describes it as clinical-stage, with its lead regulatory T cell program being evaluated in clinical trials and additional programs advancing through research toward the clinic. Leadership has changed since founding: Stephen Dilly, previously CEO of Codexis, Sierra Oncology and Aimmune Therapeutics, serves as President, CEO and Board Chair, while founder Jeffrey Bluestone is now an advisor and board member. In 2025, co-founder and former CSO Fred Ramsdell, who chairs the scientific advisory board, was named a winner of the Nobel Prize in Physiology or Medicine for the discovery of regulatory T cells and the FOXP3 gene.