Implantable tibial nerve stimulation outperforms sham in INTIBIA Pivotal Trial

Implantable tibial nerve stimulation produced significantly greater improvements in quality of life compared with a sham control in patients with urgency urinary incontinence (UUI), according to results from the INTIBIA Pivotal Study. The trial marks the first randomized, double-blind, sham-controlled trial of an investigational implantable tibial nerve stimulation device to assess quality-of-life outcomes.¹

The study, presented at the 2026 American Urological Association Annual Meeting, enrolled 208 patients with UUI across 23 sites in the United States and the Netherlands. Patients were randomly assigned 2:1 to implantable tibial nerve stimulation active treatment (ITNS-ON; n=139) or a sham control (ITNS-SHAM; n=69). Patients and investigators were blinded for the first 3 months, after which patients in the sham arm were unblinded and their devices activated. Follow-up assessments occurred at 3, 6, and 12 months.

"This is the first pivotal trial of an ITNS device where there's been a sham control," said Catherine A. Matthews, MD, FACOG, FACS, FPMRS, a study investigator. "This is really novel and foundational in terms of giving level 1 medical evidence to a question that all of us really need an answer to." She emphasized that the high placebo response rates historically observed across overactive bladder therapies make a sham-controlled design not merely preferable but scientifically obligatory.

"If you're going to investigate a novel therapy for overactive bladder, it is really beholden to us as scientists to have a sham-controlled arm."

At 3 months, significantly more patients in the ITNS-ON arm reported feeling "much better" or "very much better" on the Patient Global Impression of Improvement compared with patients in the sham arm (29.2% vs. 13.4%; P = .0133). On the Overactive Bladder Questionnaire (OABq) Short Form, significantly more patients in the ITNS-ON arm exceeded the minimally clinically important difference (MCID) for both Symptom Bother Score (62.8% vs. 41.8%; P = .0046) and Health-Related Quality of Life Total Score (57.4% vs. 42.4%; P = .0463). By 12 months, 71.5% and 74.2% of patients in the ITNS-ON arm exceeded the minimum clinically important difference (MCID) thresholds for those respective scales, and 83% reported any level of improvement on the Patient Global Impression of Improvement (PGI-I) scale.

Matthews stressed the importance of grounding results in clinically meaningful thresholds rather than statistical significance alone.

"I've seen so many presentations in the medical literature with something described as ‘statistically significant’—for example, -2.5 vs 2.1 voids per day—it's still 2 voids per day less or more, and those numbers have no clinical bearing for a patient," she said. The MCID framework was applied specifically to ensure that observed differences reflected genuine patient-level impact.

One apparent discrepancy in the data—the absence of a significant between-group difference on the ICIQ-UI SF at 3 months despite meaningful separation on the OABq and PGI-I—reflects the limitations of that particular instrument rather than a signal of treatment failure.

"The ICIQ short form has only 1 question out of 6 that actually relates to quality of life," Matthews explained. "It's really about urgency and frequency of symptoms, not about quality of life." The OABq Short Form, by contrast, includes approximately 20 questions probing the functional and experiential dimensions of the condition. Additionally, stimulation thresholds could not be adjusted between randomization and the 3-month assessment—a constraint that does not reflect real-world clinical practice. Once adjustments were permitted after unblinding, the ICIQ-UI SF MCID was exceeded in 71.5% of ITNS-ON subjects by 12 months.

The Intibia device is investigational and not currently approved for use in any market.

REFERENCE

1. Mangel J, Miller K, Erickson T, Dieter A, Roovers JP, Matthews CA. Randomized, controlled, double-blind trial in patients with urgency urinary incontinence: quality of life outcomes with the INTIBIA system. Presented at: 2026 American Urological Association Annual Meeting; May 15-18, 2026; Washington, DC. https://www.auajournals.org/doi/10.1097/01.JU.0001192572.07890.f8.07