The BlueWind Medical Device, Revi, is a novel implantable tibial neuromodulation (iTNM) system that uses an external, wearable, battery-operated unit.  The compact implant is positioned sub-facially over the posterior tibial nerve above the ankle. A Clinician Programmer is used to individually tailor the stimulation parameters (i.e., frequency, pulse width and amplitude) for optimization of efficacy.

This pivotal trial was conducted in the U.S. and Europe to evaluate the safety and efficacy of the device for treating Urgency Urinary Incontinence (UUI) in women.  This is the first abstract report of two-year follow-up results from the OASIS Study.

The OASIS Study is a prospective, multi-center, single arm, open-label pivotal clinical study evaluating the safety and efficacy of the Revi device in adult females with UUI; i.e., wet OAB.  Inclusion criteria required at least 9 UUI episodes during a 7-day diary.
Subfascial implantation of the Revi device occurred under local anesthesia; test stimulation of the posterior tibial nerve was completed during the procedure. A total of 151 UUI subjects underwent Revi System implantation. After initial healing, the device was activated 4-6 weeks after implantation. Subjects performed daily stimulation treatments at home for 30-minutes twice daily. Subjects continuing to long-term follow-up (i.e., after 12 months) were asked to treat themselves per physician discretion but not less than two 30-minute treatment sessions per week. Stimulation parameters were individually tailored according to a predefined algorithm per patient sensation and response. Multiple treatment programs were provided for patients when needed. 

Subjects were followed for one-year post-activation, after which they either consented to extended follow-up or exited the study. Voiding diaries were collected at 1, 3, 6, 9, 12, 18, and 24-month follow-up visits, and quality of life and patient satisfaction questionnaires were collected at 6, 12, and 24-month follow-up visits.  

The primary effectiveness endpoint defined therapy responders as subjects who experienced at least a ≥ 50% reduction in UUI episodes at 6 months. Adverse events were prospectively collected throughout the study, and relatedness through 12 months was adjudicated by an independent Clinical Events Committee (CEC). An independent Data Safety Monitoring Board (DSMB) is currently engaged to conduct reviews of the data and the adverse events observed through 36 months.

Ninety-seven subjects (64%) completed the 24-month assessment, and of these 79% of these subjects were therapy responders (≥50% reduction in UUI episodes), with 56% achieving a ≥75% reduction in UUI. Importantly, therapeutic response over the 24 months was durable, with comparable efficacy at 6-, 12-, and 24-months (response rates 78%, 82%, and 79%, respectively) (Fig 1). In addition, high satisfaction and patient impression of improvement were reported at 24-months based on the BSW (Benefit Satisfaction and Willingness to Continue) and PGI-I (Patient Global Impression of Improvement) questionnaires, with 97% (88/91) of the subjects satisfied with the therapy and 80% (78/97) reported feeling much better or very much better at 24 months.
One delayed surgical site-related adverse event was reported between 12 and 24 months due to an exuded non-absorbable, braided suture, resulting in a superficial skin infection that was successfully managed without necessitating device explantation.  There were no Serious Adverse Events (SAEs) related to the device or the procedure through 24 months.

While not all subjects elected to continue in the long-term follow-up portion of the study, the 97 subjects that completed the 24-month assessment demonstrated great similarity with the population completing the initial 6-month assessment (n=144) in demographics (age: 59.6 vs. 59.0), baseline OAB parameters (UUI/day: 4.5 vs. 4.8;  voids/day: 10.1 vs. 10.1), and response rates at 6 months (82% vs. 78%). 

Overall, of the 151 subjects implanted with the Revi System, 149 completed at least one follow-up visit after activation of the device. Nearly all (91%) of the subjects (136/149) reported a ≥ 50% reduction in UUI episodes at one or more follow-up visits. Significantly, of the 13 subjects that did not respond with a ≥ 50% in UUI at any of the follow-up visits through 24-months, 6 subjects reported experiencing treatment benefit and 8 subjects reported an ongoing desire to complete treatments (based on the BSW at the 6-month follow-up visit).

Subjects receiving Revi therapy for two years demonstrated sustained efficacy with very rare adverse events. Subjects that completed both the 6-month assessment (n=144) and the 24-month assessment (n=97) had similar demographics and results at the 6-month visit, indicating that results at 24-months are representative of the overall OASIS Study population. The majority of subjects treated with the Revi System experienced UUI treatment success with high subject satisfaction through 2 years.

Implantable Tibial Neuromodulation (iTNM) has emerged as a promising intervention for UUI, with the BlueWind Revi System recently receiving FDA marketing authorization for patients with UUI in the United States.  Revi is the only implantable neuromodulation device for UUI on the market whose labeling does not require prior treatment attempts with current second-line therapy.  Long-term follow-up results from this pivotal study demonstrate treatment durability, a very favorable safety profile, and ongoing patient satisfaction at 24-months.

Continence 12S (2024) 101509
DOI: 10.1016/j.cont.2024.101509