Sonoma Biotherapeutics has announced positive interim results from its ongoing phase 1 Regulate-RA trial evaluating SBT-77-7101 in patients with refractory rheumatoid arthritis (RA).
The data were presented today at 8:00 a.m. CT during a late-breaking oral session at the 2025 American College of Rheumatology (ACR) Convergence in Chicago.
Jeff Bluestone, Chief Executive Officer and President, said: “We are very encouraged by these positive interim results from a first-in-human study of our proprietary program SBT-77-7101 in patients with refractory rheumatoid arthritis (RA), a severe form of RA that persists despite treatment with multiple conventional, biologic, and targeted synthetic therapies.”
He added: “The study is providing clinical and mechanistic evidence of therapeutic activity alongside emerging signs of durability and a favorable safety profile. We look forward to completion of the ongoing dose escalation of SBT-77-7101 and its advancement into the dose expansion phase.”
The trial is assessing three ascending doses of SBT-77-7101 in six participants across two cohorts. No dose-limiting toxicities, cytokine release syndrome or neurotoxicity were observed. By week 4, 67% of participants saw a 50% or greater reduction in swollen and tender joint counts. Additionally, 83% showed improvements in DAS28-CRP and CDAI scores.
Participants in the higher-dose cohort experienced deeper and more consistent responses, with one showing a durable effect through week 24. CAR+ Tregs were detected in both synovial tissue and blood, indicating systemic and local activity.
Joe Arron, Chief Scientific Officer, stated: “It is gratifying to see the preliminary safety, PK/PD, and efficacy data in the phase 1 REGULATE-RA clinical trial, as it validates the potential for antigen-directed Tregs to treat autoimmunity, even in highly refractory patients with high levels of baseline disease.”
