Clinical and technical evidence

A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.

Published evidence

One post-market clinical follow‑up study involving 51 people with overactive bladder, and a single-centre case series involving 5 people with faecal incontinence, are summarised in this briefing.

Two publications reviewing the procedural and technical considerations of the rechargeable sacral neuromodulation (SNM) device were also identified but are not included in this briefing. One of these was based on 1 clinician's experience of 11 Axonics SNM system implant cases, done at a single Canadian centre. The other was an expert review done by urologists from a centre in the US.

Table 2 summarises the clinical evidence as well as its strengths and limitations.

Overall assessment of the evidence

Two of the publications included in this briefing (Blok et al. 2018a; Blok et al. 2018b) report outcomes from the RELAX‑OAB prospective, multicentre post-marketing study of 51 patients. This was designed to confirm safety, efficacy and technical performance of the Axonics SNM system in people with symptoms of overactive bladder. Results from RELAX‑OAB suggest that the device is a safe and effective therapy to treat refractory idiopathic overactive bladder, and that patients are able to charge the device and are satisfied overall with rechargeable SNM therapy.

The evidence base for the use of Axonics SNM system in the treatment of faecal incontinence is very limited, consisting of 1 single-centre, case series involving a total of 5 people. Data from this study, which were published in a conference abstract, suggest that Axonics SNM provides satisfactory efficacy, but the findings cannot be fully assessed for statistical or clinical significance.

For both indications, prospective controlled studies comparing clinical outcomes with current standard care in a larger patient population would be useful to confirm equivalence between the 2 SNM devices. Available evidence is based on short-term data with a maximum follow‑up of 1 year. An extended follow‑up would be desirable, given the intended duration of implant with the rechargeable SNM device.

Table 2 Summary of selected studies

Blok et al. (2018)a

Study size, design and location

Prospective, multicentre, single-arm, open-label study involving 51 people with symptoms of OAB in 7 European centres (2 in Netherlands, 2 in Belgium, 2 in France and 1 in the UK).

Intervention and comparator(s)

Intervention: Axonics rechargeable SNM System (in a single-implant procedure).

No comparator.

Key outcomes

91% (31/34) of people who responded to therapy during the initial trial period continued to respond to therapy with Axonics at 3 months. People whose OAB responded to treatment showed a statistically significant and clinically meaningful improvement in all aspects of quality of life (ICIQ-OABqol; p<0.0001 for all comparisons). Across all 51 people who had the implant, no serious device-related adverse events or unanticipated adverse events were seen within the 3‑month post-transplant period. 19.6% of people experienced device-related adverse events. The most frequent adverse event was discomfort because of stimulation (accounting for 5 events in 4 people [7.8%]), which was resolved with device reprogramming. No surgical intervention was needed because of device- or therapy-related adverse events. One patient's device was explanted because of an infection at the implant site.

6-month and 1-year follow‑up data have been published as conference abstracts. 94% of people whose OAB responded to treatment continue to respond to therapy 6 months and 1 year post-transplant, with statistically and clinically significant improvements in quality-of-life measures. Improvement from baseline in ICIQ-OABqol scores were 26.2 and 21.1 points at 6 months and 1 year, respectively (above the minimally important difference of 10 points).

Strengths and limitations

Strengths: multicentre study with a high follow-up rate at 3 months (91%) and prospectively reported outcomes. The study continued to follow all patients for the duration of the study, regardless of trial period response and it used a validated high-quality QoL questionnaire (ICIQ-OABqol).

Limitations: non-comparative study and only 1 of the centres was in the UK. The longest published follow-up was 1 year. An extended follow-up may be desirable because of the intended implant duration for this device. Funding for the RELAX-OAB study was provided by the company, Axonics Modulation Technologies, Inc.

Blok et al. (2018)b

Study size, design and location

Cohort and study design is the same as that reported by Blok et al. (2018)a.

Intervention and comparator(s)

Intervention: Axonics rechargeable SNM System (implanted in a single procedure).

No comparator.

Key outcomes

At 3 months, 98% (47/48) of patients charged their neurostimulator without any problems before their follow-up visit. 96% of patients successfully charged as early as within 2 weeks of implant. Average stimulation amplitude across all subjects was 1.8 mA (±1.1 mA). 69% of subjects had ≥14‑day recharge intervals (time between charging) and 98% of patients had ≥7‑day recharge interval. Across all 51 implanted patients, no charging-related adverse events happened. 83% of all implanted subjects and 94% of people whose OAB responded to treatment were satisfied with their therapy.

Strengths and limitations

The strengths and limitations listed for Blok et al. (2018)a also apply. Estimates of battery life and neurostimulator battery recharge intervals were not based on patient-reported or diary-based tracking but were provided by the manufacturer, Axonics Modulation Technologies, Inc.

Dudding et al. (2017)

Study size, design and location

N=5

Case series involving patients with faecal incontinence considered for SNM.

Intervention and comparator(s)

Intervention: Axonics rechargeable SNM System.

No comparator.

Key outcomes

All patients reported a good response to therapy at 1 month post-implantation, defined as a >75% reduction in episodes of faecal incontinence. The St Mark's continence score was reduced from a mean of 18 at baseline to 5 at 1 month. At 3 months, 4 out of 5 patients continued to benefit from therapy. Recharging was done at a median of 7 days (range: 7 to 10 days) with no patient needing greater than 60 minutes per charging session. No patient reported any problems with recharging the device.

Strengths and limitations

This is a UK NHS study. It is a single-site case series involving a small sample of people with no comparator group. The statistical and clinical significance of efficacy outcomes were not reported and no baseline demographics were available.

Abbreviations: OAB, overactive bladder; ICIQ-OABqol, International Consultation on Incontinence Questionnaire–Overactive Bladder Symptoms Quality of Life; RELAX-OAB, Treatment of refractory overactive bladder with the Axonics SNM system; QoL, quality of life; SNM, sacral neuromodulation.

Recent and ongoing studies

One ongoing study (active, not recruiting) was identified: