Trial Outcomes & Findings for ReActiv8 Implantable Neurostimulation System for Chronic Low Back Pain (NCT NCT02577354)

ReActiv8 Implantable Neurostimulation System for Chronic Low Back Pain

Comparison of responder rates for low back pain VAS between Treatment and Control groups. The Primary Efficacy Endpoint is a comparison of responder rates between Treatment and Control groups, where a "responder" is a participant with ≥30% reduction from baseline in average low back pain VAS, without any increase from baseline in pain medications and/or muscle relaxants for any reason including non low back pain reasons. The instrument used for evaluating pain is the continuous Visual Analog Scale (VAS) comprised of a horizontal line 10 cm in length, anchored by 2 verbal descriptors, where zero indicates no pain and 10 indicates worst imaginable pain. The value reported is a 7-day average low back pain. Any increase in dosage of a pain medication or any new pain medication taken for any reason counts as an increase in medications.

Comparison of change in LBP VAS (120 days from baseline) between the Treatment and Control groups. The instrument used for evaluating pain is the continuous Visual Analog Scale (VAS) comprised of a horizontal line 10 cm in length, anchored by 2 verbal descriptors, where zero indicates no pain and 10 indicates worst imaginable pain. The value reported is a 7-day average low back pain. A change to a lower score (negative value) indicates improvement.

The CPRA, which was prespecified in the clinical protocol and statistical analysis plan prior to the start of the trial, was performed using the same data as used for the primary endpoint analysis and was included as part of the primary endpoint analysis

The primary safety assessment is of serious device and/or procedure related adverse events in all participants at 120 days. The 8 events reported below are 6 implant site pocket infections, 1 intra-operative upper airway obstruction, and 1 non-radicular, focal numbness on the surface of the thigh.

Comparison of change in ODI (120 days from baseline) between Treatment and Control groups. ODI is reported as a score from 0 to 100%, where 0%-20% indicates minimal disability, 21%-40% indicates moderate disability, 41%-60% indicates severe disability, 61%-80% indicates crippled, and 81%-100% indicates bedbound or an exaggeration of symptoms. A change to a lower score (negative value) indicates improvement.

Comparison of change in EQ-5D (120 days from baseline) between Treatment and Control groups. The EQ-5D Index is scored on a scale of -0.594 to 1.00, with a score of 1.00 indicating full health. A change to a higher score (positive value) indicates improvement.

PPR is a patient-reported percent of pain relief at 120 days compared to the pain at baseline, where 0% indicates no pain relief compared to baseline, and 100% indicates complete pain relief compared to baseline.

A questionnaire completed with the following item: Since I enrolled in the study, my overall status is 1) Very much improved, 2) Much improved, 3) Minimally improved, 4) No change, 5) Minimally worse, 6) Much worse, 7) Very much worse

Resolution of back pain (remitter rate) was defined as a participant with 7-day average low back pain VAS ≤2.5 cm on the 10 cm VAS.

A "responder" is a participant with ≥30% reduction from baseline in average low back pain VAS, without any increase from baseline in pain medications and/or muscle relaxants for any reason including non low back pain reasons. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

Change in LBP VAS at 1 year compared to baseline. The instrument used for evaluating pain is the continuous Visual Analog Scale (VAS) comprised of a horizontal line 10 cm in length, anchored by 2 verbal descriptors, one for each symptom extreme for Low Back Pain. Zero indicates no pain and 10 indicates worst imaginable pain. The value reported is a 7-day average low back pain. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy. A change to a lower score (negative value) indicates improvement.

Change in ODI at 1 year compared to baseline. ODI is reported as a score from 0 to 100%, where 0%-20% indicates minimal disability, 21%-40% indicates moderate disability, 41%-60% indicates severe disability, 61%-80% indicates crippled, and 81%-100% indicates bedbound or an exaggeration of symptoms. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy. A change to a lower score (negative value) indicates improvement.

Change in EQ-5D at 1 year compared to baseline. The EQ-5D Index is scored on a scale of -0.594 to 1.00, with a score of 1.00 indicating full health. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy. A change to a higher score (positive value) indicates improvement.

PPR is a patient-reported percent of pain relief compared to the pain at baseline, where 0% indicates no pain relief compared to baseline, and 100% indicates complete pain relief compared to baseline. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

A questionnaire with the following item: Since I enrolled in the study, my overall status is 1) Very much improved, 2) Much improved, 3) Minimally improved, 4) No change, 5) Minimally worse, 6) Much worse, 7) Very much worse After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

Resolution of back pain (remitter rate) was defined as a participant with 7-day average low back pain VAS ≤2.5 cm on the 10 cm VAS. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

This pre-specified analysis of the primary endpoint examines the impact of rescue medications taken for acute pain conditions for reasons other than low back pain, by excluding those participants from the analysis who took rescue medications for reasons other than low back pain. Nine participants in both groups increased pain medications. In the control group, all nine participants increased pain medications due to low back pain. In the treatment group, three of the nine participants increased pain medications due to low back pain, while six of the nine participants increased pain medications for reasons other than low back pain. Since any increase in pain medications automatically considers a participant a non-responder, these six participants are removed from this analysis to eliminate the confounding factor of increases in pain medications for reasons other than low back pain.

The Treatment Satisfaction Questionnaire asking the participant if they are satisfied with the treatment.

The Treatment Satisfaction Questionnaire asking the participant if they are satisfied with the outcome of the treatment. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

Clinical Global Impression consists of the following question completed by the Investigator prior to unblinding: In your opinion as a clinician, compared to the patient's situation at baseline, would you say the patient is: 1) Much better, 2) Slightly better, 3) About the same, 4) Slightly worse, 5) Much worse.

Clinical Global Impression consists of the following question completed by the Investigator prior to unblinding: In your opinion as a clinician, compared to the patient's situation at baseline, would you say the patient is: 1) Much better, 2) Slightly better, 3) About the same, 4) Slightly worse, 5) Much worse. After the 120 day visit, participants crossed over to have their device programmed to deliver stimulation at a patient-appropriate level. At the one-year time point, participants in the Control/Crossover group have received 8 months of patient-appropriate therapy.

Any increase or decrease of dosage or frequency of an opioid taken for the treatment of low back pain was considered a change.