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| General |
| Study Status |
Completed |
Application Number /
Requirement Number |
P080030 / PAS002 |
| Date Original Protocol Accepted |
06/25/2012
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| Date Current Protocol Accepted |
05/13/2016
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| Study Name |
New Enrollment Study
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| Device Name |
GLAUKOS ISTENT TRABECULAR BYPASS STENT MODEL GTS100R/L
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| Clinical Trial Number(s) |
NCT00323284
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| General Study Protocol Parameters |
| Study Design |
Randomized Clinical Trial
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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 |
Adult: >21
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| Detailed Study Protocol Parameters |
| Study Objectives |
Initial Phase:
Prospective, randomized, concurrently controlled, parallel group, multicenter investigation
Surgery consisting of implantation of one (1) GTS100 stent in conjunction with cataract surgery, or cataract surgery only
1:1 randomization plan (treatment group to control group)
Washout of ocular hypotensive medications at Month 23 (if on medications)
Follow-up through 3 years postoperative
Revised Phase:
Prospective, controlled, multicenter investigation
Surgery consisting of implantation of one (1) GTS100 stent in conjunction with cataract surgery (treatment group)
Surgery consisting of cataract surgery only in subjects randomized to control group in the GC-007 and GC-008 trials and the initial phase of GTS100-PAS2 (control group)
Washout of ocular hypotensive medications at Month 23 (if on medications)
Follow-up through 3 years postoperative
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| Study Population |
Males or Females, 22 years of age or older
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| Sample Size |
180 eyes of 180 subjects will comprise the treatment group. In addition, subjects randomized to cataract surgery only during the initial phase of this trial are included in the total study subject population. Subjects will be enrolled at a minimum of 20 sites and up to 45 sites; it is expected that about 400 subjects or more will undergo screening and baseline exams and operative procedures in order to obtain 180 eyes that received a GTS100 stent in conjunction with cataract surgery.
With estimated rates of 0.03 (3%) for PT and PC at 5 years, a Type I error rate of 5%, a Type II error rate of 20% (i.e., 80% power), a randomization ratio of 1:1, 1-sided testing, a two-group large-sample normal approximation test of proportions, and a ? of 0.05 (i.e., a non-inferiority margin of 0.05 or 5%), the required sample size is 288 subjects (or 144 per group). Due to the age of the study population, it is estimated that the study will have a drop-out rate of 20%.
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| Key Study Endpoints |
The primary endpoints will be the occurrence of STAEs. The STAEs include best corrected visual acuity (BCVA) loss greater than or equal to 3 lines, endophthalmitis, corneal decompensation, retinal detachment, severe choroidal hemorrhage, severe choroidal detachment, and aqueous misdirection.
Other important ocular adverse events includes increase in intraocular pressure (IOP) of greater than or equal to 10 mmHg at any time postoperative, and loss of best spectacle corrected visual acuity of greater than or equal to 2 lines (greater than or equal to 10 letters) postoperative as compared to baseline or best recorded visual acuity measured at any visit postoperative.
Additional safety events of interest include findings from IOP, best spectacle corrected visual acuity (BSCVA), visual field, pachymetry, and specular microscopy measurements, stent dislocation, stent migration, stent obstruction, secondary procedures, such as additional surgical procedures to lower IOP, and findings from slit-lamp, fundus and gonioscopic examinations.
The effectiveness outcomes, although not the primary endpoint of this safety study, are the outcomes of mean diurnal IOP reduction greater than or equal to 20% vs. baseline IOP without ocular hypotensive medication, and mean diurnal IOP less than or equal to 18 mmHg without ocular hypotensive medication, at 24 months. The rate of these effectiveness outcomes will be compared between the treatment and control groups.
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| Follow-up Visits and Length of Follow-up |
Three years
Visit 1 Screening (day -60 to day -5)
Visit 2 Baseline (after completion of appropriate medication washout period)
Visit 3 - Operative
Visit 4 6 Hours (+/- 4 hours)
Visit 5 Day 1 (+1 day)
Visit 6 Week 1 (7 +/- 2 days)
Visit 7 Month 1 (4 weeks +/- 7 days)
Visit 8 Month 3 (13 weeks +/- 14 days)
Visit 9 Month 6 (26 weeks +/- 30 days)
Visit 10 Month 12 (52 weeks +/- 30 days)
Visit 11 Month 18 (78 weeks +/- 45 days)
Visit 12 Month 23 (Minimum 4 weeks Prior to Month 24 Visit; 96 to 104 weeks)
Visit 13 Month 24 (104 weeks +/- 28 days)
Visit 14 Month 30 (130 weeks +/- 45 days)
Visit 15 Month 36 (156 weeks +/- 45 days)
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| Interim or Final Data Summary |
| Actual Number of Patients Enrolled |
357 subjects
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| Actual Number of Sites Enrolled |
A total of 47 sites received IRB approval; 40 of the 47 were initiated
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| Patient Follow-up Rate |
Accountability/follow-up rates were 86.5% (154/178) for the treatment group and 86.0% (148/172) for the control group at Month 36.
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| Final Safety Findings |
The primary safety endpoint is the occurrence of sight-threatening adverse events (STAEs). A total of 51 STAEs were reported for 39 treatment subjects (21.3%) and 95 STAEs were reported for 59 control subjects (21.4%). 5 events of loss of BSCVA of 3 lines or more compared to baseline or best recorded visual acuity at any time postoperatively persisting at time of study exit were reported: 1 event involved 1 treated subject (0.5%), and 4 events were reported for 4 control subjects (1.4%). 6 events of IOP increase = 10 mmHg vs. baseline occurring = Month 1 were reported- 2 events for 2 treated subjects (1.1%) and 4 events for 3 control subjects (1.1%); all events resolved within ~4 months except one event in a control subject that was ongoing at study exit. Ten events of IOP increase requiring secondary surgical interventions (SSI) were reported. 3 events involved 3 treated subjects (1.6%) (3/183) and 7 events were reported for 6 control subjects (2.2%)(6/276). Statistical comparison of the STAE rate over 3 years is not statistically different between the groups.
The slit lamp examination found no severe corneal edema during the study in any subject. There were no clinically meaningful changes in pachymetry between the groups. The proportion of eyes with a Visual Field mean deviation (MD) decrease of >2 dB was similar among groups: 19.1% (29/152) of stent eyes vs. 22.6% (33/146) of control eyes at Month 36. The proportion of eyes with Visual field pattern standard deviation (PSD) decrease of >2 dB was 5.9% (stent group) (9/152) and 10.3% (control group) (15/146) at Month 36. Specular microscopy showed that three subjects (2.9%) (3/102) in the stent group and 10 control subjects (7.2%) (10/138) had an average endothelial cell loss (ECL) >30% at Month 36. Otherwise, the percent change in average ECL from screening was similar in both groups and stable through the study conclusion aside from an initial reduction in both groups of approximately 10% at Month 3.
Postoperative goniosynechiae were reported in 2 treatment eyes and 9 control eyes. A single transient angle abnormality was observed postoperatively in one treatment eye on Day 1 (hemorrhage covering the snorkel). 2 subjects who had stents that were visualized on Day 1 after implantation but after Week 1 were unable to be visualized again by gonioscopy. 1 of these stents was later visualized through Month 36 and the other until ~3 months prior to Month 36 with ultrasound biomicroscopy (UBM). Post-operative AEs also showed stent obstruction was reported for 6 subjects (3.3%)(6/183); 3 of these subjects had an IOP at Month 36 of 17.5mmHg or below without adjunct ocular hypotensive medications. 2 subjects required a single additional ocular hypotensive medication for IOP control, and the final subject had an IOP of 24.5 mmHg at Month 36 with ongoing stent obstruction on two ocular hypotensive medications.
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| Final Effect Findings |
The effectiveness outcomes in this study included mean diurnal IOP reduction >= 20% versus baseline IOP without ocular hypotensive medication and mean diurnal IOP =< 18 mmHg without ocular hypotensive medication at 24 months in the treatment (cataract surgery with iStent) group compared to the control (cataract surgery only) group.
The final findings revealed that 77.8% (123/158) of the cataract surgery with iStent group achieved mean diurnal IOP reduction >= to 20% without hypotensive medications compared to 42.7% (106/248) of the cataract surgery only group. In addition, 68.4% (108/158) of the cataract surgery with iStent treatment group achieved mean diurnal IOP <= 18 mmHg without ocular hypotensive medications compared to 33.5% (83/248) of the cataract surgery only group. Therefore, based on the observed rates, the treatment group (cataract surgery and iStent) had a higher rate of achieving both effectiveness outcomes and thus reduction in IOP after 24 months.
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| Study Strengths & Weaknesses |
Strength: This was a new enrollment post approval study that provides further follow up and long-term safety data for the iStent with high rate of subject accountability for both the treatment (86.5%, 154/178) and control (86.0%; 148/172) groups.
Weakness: The control group is comprised of three separate randomized groups, with one newly randomized group, and two groups from the prior study, such that there are differences among the control groups. In addition, there was a relatively large number of protocol deviations.
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| Recommendations for Labeling Changes |
Given the significant clinical findings from the post approval study, it is recommended that the device label be updated with long-term device performance results regarding safety.
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