This study will evaluate the safety and tolerability of stimulating the splenic neurovascular bundle (NVB) with the Galvani System, which consists of a lead, implantable pulse generator, external components and accessories. Participants eligible for implant will have active rheumatoid arthritis (RA) and have an inadequate response or intolerance to at least two biologic Disease Modifying Anti-Rheumatic Drugs (DMARDs) or JAK inhibitors (JAKis). Five participants will be implanted with the device and receive neurostimulation for 12 weeks.

The study will be an open-label single-arm study to evaluate the safety and tolerability of Galvani's neuromodulation system. Participants with active rheumatoid arthritis (RA) will be implanted with the Galvani system and receive active stimulation for 12 weeks. The total study duration in the study for each participant is approximately 5 months, with a 4-week screening period, 4 weeks recovery from surgery and a 12-week 'treatment' period. The participants will return to the clinic on pre-defined days for follow-up visits during the trial period. At Days 42 and/or Day 56, if study participants are not responding to stimulation, stimulation parameters might be adapted. At the end of the study (Day-84), participants will enroll in a long-term follow-up study up to 5-years after enrollment in this study.

Inclusion Criteria:

• Adult-onset RA of at least six months duration
• Male or female participants, 22-75 years of age
• Active RA
• Inadequate Response to at least 2 biologic DMARDs and/or JAK- inhibitors (JAKis)
• Have an appropriate washout from previously used biological DMARDs or JAKi
• A female participant should have no child-bearing potential

Exclusion Criteria:

• Inability to provide informed consent.
• Significant psychiatric disease or substance abuse.
• History of unilateral or bilateral vagotomy.
• Active or latent tuberculosis
• Known infection with human immunodeficiency virus (HIV); current acute or chronic hepatitis B or hepatitis C; previous hepatitis B.
• Currently implanted electrically active medical devices (e.g., cardiac pacemakers, automatic implantable cardioverter-defibrillators).
• Previous splenectomy
• Any investigational small molecule drug or biological within 2 weeks or 2 half-lives whichever is longer, before surgery.
• Uncontrolled other inflammatory diseases
• Current/recurrent infections that in the opinion of the PI risk>benefit.
• History of cancer within the past 5 years, except non-malignant skin cancer.
• Chronic use of morphine or oxicodone