An interventional study of Active treatment and Sham (No Treatment) in Rheumatoid Arthritis, sponsored by Surf Therapeutics. Recruiting at 3 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-07.
Sponsored by Surf Therapeutics · Not applicable, Interventional, and Treatment
This two-stage, multicenter clinical trial is designed to evaluate the feasibility, safety, and preliminary efficacy of splenic ultrasound stimulation to activate immune-neuromodulation (SUSTAIN) in patients with rheumatoid arthritis (RA) and at least moderate disease activity. The findings from this trial will directly inform the design and power calculations for a future pivotal trial by identifying an appropriate effect size and confirming protocol feasibility and safety.
Stage 1 is an open-label pilot study of 6-10 participants. To maintain a seropositive-enriched cohort, enrollment of seronegative participants (those with RF ≤14 IU/mL and Anti-CCP \<20 U/mL) is capped at 3 participants in Stage 1. All participants will receive daily active SUSTAIN therapy for 8 weeks. The initial active ultrasound parameter set (Experimental Treatment 1) will be based on the best available evidence at the start of the trial. If interim review of early efficacy data from the first 3-5 participants, specifically, the magnitude and direction of change in DAS28-CRP from Baseline to Week 4, suggests that a second parameter set may be warranted, the Sponsor may elect to enroll an additional 3-5 participants to receive a second active ultrasound parameter set (Experimental Treatment 2). This decision will be made by the Sponsor prior to enrollment of the first participant assigned to Experimental Treatment 2 and will be documented in a protocol decision memo. If the Sponsor determines that Experimental Treatment 1 demonstrates sufficient early signal, Stage 1 will be completed using a single parameter set.
The primary objective of Stage 1 is to assess feasibility, defined as ≥70% adherence to scheduled treatment sessions, and safety, defined by the absence of device-related serious adverse events (SAEs) or Grade ≥2 adverse events (AEs) requiring medical intervention per CTCAE criteria. Data from Stage 1 will be used to refine trial procedures and confirm readiness for Stage 2.
Stage 2 consists of a double-blind, randomized, sham-controlled study enrolling 30-40 participants, randomized 1:1 to receive daily active or sham SUSTAIN therapy for 8 weeks. Selection of the Stage 2 active treatment ultrasound parameter set will be based on the safety profile and magnitude/direction of the DAS28-CRP change from Baseline to Week 4 of the two experimental treatments. Enrollment of seronegative participants is capped at 10 in Stage 2, such that at least 75% of enrolled participants are seropositive. Randomization is stratified by serostatus to maintain balance across arms. This stage is designed to further characterize safety and adherence in a larger cohort, and to estimate treatment effect size using clinical and biomarker-based secondary endpoints.
All participants will be followed through Week 12 to assess post-treatment safety and durability of clinical and immunologic effects.
2,888 studies on the registry are indexed under Arthritis, Rheumatoid; 390 are open to participants now.
This study's planned enrollment of 40 is below the median of 94 across 1,984 interventional studies indexed under Arthritis, Rheumatoid.
Browse Arthritis, Rheumatoid studies →Surf Therapeutics is the lead sponsor of 2 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Conventional synthetic DMARDs:
Biologic DMARDs:
JAK inhibitors:
Corticosteroids:
NSAIDs:
Daily active stimulation for 8 weeks
Device: Active treatment
Daily sham stimulation, for 8 weeks, which will look and feel the same as active stimulation, but with no ultrasound energy entering the body
Device: Sham (No Treatment)
Daily active ultrasound stimulation
Daily sham ultrasound stimulation
Incidence of Adverse Events
All adverse events (AEs) regardless of treatment group that occur over the 12 week enrollment period will be coded and summarized by frequency, severity, and relatedness using the latest MedDRA version (v28.1).
Time frame: 12 weeks
Adherence to Therapy
Proportion of patients adherent to treatment, defined by completing ≥70% of the 56 scheduled ultrasound treatments
Time frame: 8 weeks
American College of Rheumatology (ACR) 20, 50 and 70 response rates
Difference between treatment and control groups in the proportion of subjects who achieve at least 20%, 50%, and 70% improvement from baseline to Week 8 in tender and swollen joint counts of 28 joints (scale 0=best to 28=worst) and 3 out of the following 5 measures: Health Assessment Questionnaire Disability Index (HAQ-DI) score (scale 0=no difficulty to 3=unable to do), subject global assessment (0=best to 10=worst), subject pain (0=no pain to 10=worst), evaluator's global assessment (0=best to 10=worst), or high sensitivity C-reactive protein (hsCRP) concentration (mg/mL).
Time frame: Week 8
Change in Disease Activity Score-28 for Rheumatoid Arthritis with CRP (DAS28-CRP).
Defined by EULAR based on a composite score of 4 items: tender and swollen joint counts of 28 joints (scale 0=best to 28=worst), subject global assessment (0=best to 10=worst) and high-sensitivity C-reactive protein (hsCRP) concentration (mg/L). DAS28-CRP response based on the minimal clinically important difference (MCID) of -1.2 from baseline to week 8.
Time frame: Week 8
Change in Heath Assessment Questionnaire Disability Index (HAQ-DI)
Haq-DI assesses physical function through eight daily activity domains (scale 0=no difficulty to 3=unable to do). Change from baseline to week 8 based on the MCID of -0.22.
Time frame: Week 8
Change in Clinical Disease Activity Index (CDAI) score for Rheumatoid Arthritis
The CDAI assesses disease activity by summing tender joint count (TJC), swollen joint count (SJC), patient global assessment (PGA), and physician global assessment (EGA). CDAI will be assessed from Baseline to Week 8.
Time frame: Week 8
Change in Simplified Disease Activity Index (SDAI) for Rheumatoid Arthritis (RA)
The SDAI is a measure of disease activity that includes all the 4 components of the CDAI, plus CRP. SDAI will be assessed from baseline to Week 8.
Time frame: Week 8
Change in high sensitivity CRP (hsCRP)
The primary endpoint is the change in hsCRP from baseline to weeks 2, 4, 6 and 8.
Time frame: Weeks 2, 4, 6, and 8
Plan to share: No
No publications or documents are linked to this record.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Surf Therapeutics