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General |
Study Status |
Completed |
Application Number / Requirement Number |
P110009 / PAS001 |
Date Original Protocol Accepted |
08/23/2013
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Date Current Protocol Accepted |
05/08/2014
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Study Name |
Long Term PAS
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Device Name |
MOBI-C CERVICAL DISC PROSTHESIS (TWO-LEVEL INDICATION)
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Clinical Trial Number(s) |
NCT00389597
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General Study Protocol Parameters |
Study Design |
Prospective Cohort Study
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Data Source |
New Data Collection
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Comparison Group |
Concurrent Control
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Analysis Type |
Analytical
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Study Population |
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
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Detailed Study Protocol Parameters |
Study Objectives |
The primary objective of the study is to evaluate the long-term overall success rate (see primary end-points for the definitions) of the investigational device as compared to the control in subjects enrolled in the pivotal IDE study of the Mobi-C (2- levels) device (IDE Number G050212). Design-Prospective Cohort, a long term follow-up of the IDE patients ( investigational and controls)
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Study Population |
All eligible Mobi-C patients (n=221 -randomized and n=8 - training cases) treated at two contiguous levels All eligible fusion patients (n=99- randomized at 24-months) treated at two contiguous levels under the LDR-001 Pivotal Study (IDE G050212)
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Sample Size |
Investigational¿n=221 -randomized and n=8 -training cases at treated at two contiguous levels. Control¿ all eligible fusion patients (n=99) treated at two contiguous levels
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Key Study Endpoints |
For Mobi-C: Pain/Disability Improvement of at least 25% in the Neck Disability Index (NDI) at 5 years and 7 years; no device failures at the index level requiring revision, re-operation, removal, or supplemental fixation; absence of major complications defined as 1) neurologic deterioration, 2) radiologic failure and 3) adverse events determined to be major complications and related to the study For Fusion ACDF: evidence of bridging trabecular bone and <2º total angular motion (from flexion to extension) and <50% radiolucency along the graft/endplate interface and for Mobi- C® subjects radiologic failure is defined as evidence of continuous bridging bone and <2º total angular motion.
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Follow-up Visits and Length of Follow-up |
7 years at 7th year
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Interim or Final Data Summary |
Actual Number of Patients Enrolled |
Out of a total of 339 subjects from the IDE study, 328 subjects were eligible for the PAS, as Mobi-C (221 randomized and 8 training) or ACDF (99) patients treated at two contiguous levels.
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Actual Number of Sites Enrolled |
The pivotal clinical study on two-level Mobi-c involved 24 sites.
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Patient Follow-up Rate |
At the 84-months, the total follow up rate was 82%; however, only 136 two-level Mobi-C subjects (66.3%) and 48 ACDF subjects (57.1%) had Actual ‘in-window’ efficacy data at the final timepoint.
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Final Safety Findings |
No unexpected Mobi-related adverse events were identified in this PAS. As a result, two-level Mobi-c TDR is rendered as a safe alternative to the standard of care procedure (ACDF).
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Final Effect Findings |
Based on the overall success as defined by the protocol-specified composite primary endpoint and alternative primary endpoints, the two-level Mobi-C TDR was shown to be as effective as control ACDF treatment. Non-inferiority for the two-level Mobi-C compared to ACDF with respect to individual subject success was demonstrated up to the time point of 84 months.
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Study Strengths & Weaknesses |
Although this Extended Follow-Up study demonstrated non-inferiority of the investigational two-level Mobi-c device, a further performance analysis of the two-level Mobi-c disc may help with elucidating possible long-term complications such as underdiagnosed Adjacent Level Disease and progressing Heterotopic Ossification, which can hamper long-term motion preservation as the general premise of TDR. In addition, further research on possible sex-based differences in the performance of two-level Mobi-c may augment the current device indications and may enable more informed pre-implantation risk-benefit assessment for the sex-stratified patient subgroups. Further research efforts may be also recommended for clarifying possible sex-related differences in Mobi-c performance at one level vs. two contigious levels: in contrast to a trend to higher overall success rates among males with one-level Mobi-c (P110002), males with the two-level Mobi-c experienced overall success less frequently, compared to their female counterparts (P110009).
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Recommendations for Labeling Changes |
The current labeling for two-level Mobi-c is recommended to be updated based on long-term device performance (7-years). The labeling changes should include the following in particular:
Language that reflects that owing to possible indeterminate results of radiographic imaging (i.e., shoulder obstruction), the actual incidence of Adjacent Level Disease may be higher than that reported in both – Mobi-c and ACDF - study groups. Language describing the progression of Heterotopic Ossification which is statistically significant over time (i.e., 84 months vs. 24-months), but for which the clinical significance (e.g., possible ROM limitation despite the anticipated motion preservation in Mobi-c patients) has not been determined. Language that mentions the possibility of sex-related trends in two-level Mobi-c performance, including the following: long-term (84-month) overall success outcomes were more frequent among females with two-level Mobi-c vs. females with two-level ACDF, whereas the same trend for males did not reach statistical significance; males with two-level Mobi-c were less likely to have long-term (84-month) overall success outcomes compared to females with two-level Mobi-c; long-term, clinically significant Heterotopic Ossification (Grade 3-4) was more likely to occur in males with two-level Mobi-c, compared to their female counterparts
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