Effects of the Inspire Implantable Nerve Stimulation System on Obstructive Sleep Apnea
Effects of the Inspire Implantable Nerve Stimulation System on Obstructive Sleep Apnea
The purpose of this clinical trial is to demonstrate long-term safety and efficacy of the Inspire system. The Inspire Upper Airway Stimulation (UAS) therapy is intended to treat moderate-to-severe obstructive sleep apnea by improving airway patency through stimulation of the hypoglossal nerve. Study objectives include demonstrating that the Inspire system improves key indices of sleep apnea in a pre-specified percentage of patients.
The STAR trial is a multicenter, prospective trial that includes a randomized controlled therapy withdrawal study. The primary and secondary endpoint data were collected during an in-laboratory sleep study 12 months after the device implant and were compared against the baseline sleep studies. Following the 12-month visit, 46 consecutive responding subjects were randomized 1:1 to either a therapy maintenance group (ON group) or a therapy withdrawal group (OFF group). A subsequent sleep study of the two randomized groups was conducted and results were compared between the two groups. In addition, quality of life questionnaires were administered at baseline and at the 12-month visit to further assess the effectiveness of Inspire therapy.
The STAR trial was conducted at 15 clinical sites in the United States and 7 in Europe. Of the 126 implanted subjects in the STAR trial, 87 or 69% were implanted in the United States. The remaining 39 subjects or 31% were implanted in Europe.
The STAR trial subjects were evaluated prior to implant to ensure the following: 1) that their pre-implant AHI (as scored during an in-laboratory sleep study prior to implant) was between 20 and 50 events per hour, 2) that any AHI contribution from central or mixed sleep apnea was less than 25%, 3) that subjects did not have primarily lateral OSA (defined as limited sleep apnea when lying on their side), and 4) that the subjects did not have a complete concentric collapse at the level of the soft palate while observed during a drug-induced sleep endoscopy (DISE).
After successful pre-implant screening, the subjects were implanted with the Inspire system. The subjects were allowed to recover for 1 month following surgery, at which time a second in-laboratory sleep study was conducted without activating the Inspire device. The results of this 1-month sleep study were averaged with the results of the pre-implant sleep study, and the average is defined as the subject's baseline.
The Inspire device is programmable in order to optimize a subject's response to therapy. The initial device settings are programmed in an office setting. Additional adjustments are made during an overnight sleep study whereby real time review of the polysomnogram (PSG) is available to aid in device setting adjustments during the 2 and 6-month visit.
At the 12-month in-laboratory sleep study, no device adjustments were allowed as this sleep study was the primary endpoint sleep study. Furthermore, no device adjustments were allowed at the 13-month sleep study which was the randomized controlled therapy withdrawal sleep studies.
Blinding was not possible during the study since the stimulation therapy evokes a physiological response in the subjects. However, the primary endpoints were based on the objective measures of AHI and oxygen desaturation index (ODI) which were collected during an overnight sleep study using PSG. The sleep studies were all scored by an independent core lab in order to minimize assessment bias. Furthermore, the sleep study results, as well as all other clinical results, were 100% source data verified by the Inspire clinical monitoring team.
Inclusion Criteria:
Exclusion Criteria: