Comparison Of Two-Year Outcomes Of A Supraciliary Drainage Device For Open Angle Glaucoma According To Pre-Operative Intraocular Pressure And Medication Use: A Pooled Analysis From The Star-I, Star-Ii And Star-Iii Studies

To describe the influence of baseline intraocular pressure (_bIOP) and baseline number of classes of medication used (_bMed) in patients with medically uncontrolled, open-angle glaucoma (OAG) on the clinical outcomes 2 years after implantation with a novel, supraciliary, minimally-invasive glaucoma surgery (MIGS) drainage device, MINIject® (iSTAR Medical, Belgium). This was implanted in a standalone ab-interno procedure in phakic and pseudophakic eyes.

The STAR-I (NCT03193736), STAR-II (NCT03624361) and STAR-III (NCT03996200) trials are 3 prospective, multi-centre, interventional, single-arm, studies which evaluate the safety and efficacy of a supraciliary MIGS in OAG patients. Across the trials, patients were treated at 11 sites in Germany, France, Spain, Colombia, India and Panama. The MINIject® implant is 5mm long and is comprised of a network of hollow spheres made of soft, flexible medical grade silicone.

Data from 66 patients who completed 2-year follow-up from the three trials were pooled in a meta-analysis. Patients did not undergo a washout of medications at baseline or any time-point in the follow-up period.

In this post-hoc analysis, clinical outcomes of patients with a high _bIOP (defined as >24mmHg prior to surgery) were compared to those with a moderate _bIOP (defined as 21-24mmHg). In addition, outcomes were also compared between patients with higher _bMed (3 or 4 medication classes pre-operatively) and those with lower _bMed (1 or 2 medication classes). Success was defined as IOP >5 and ≤21mmHg with ≥20% reduction in IOP from baseline, without (complete) or regardless of (qualified) glaucoma hypotensive medication use at follow-up.

At 2-years, the high _bIOP group achieved a 41.8% IOP reduction (from mean _bIOP 28.1mmHg, n=21) with 0.7 fewer medications compared to a 38.1% reduction (from mean 22.1mmHg, n=45)(p=0.448) and 1.0 fewer medications in the moderate _bIOP group. There was greater mean absolute IOP reduction in the high _bIOP group (-12.13mmHg Vs -8.44mmHg; p=0.008).

The high _bMed group (mean _bMed 3.3, n=28) had a 34.6% IOP reduction compared to 42.7% (p=0.076) in the low _bMed group (mean _bMed 1.5, n=38). Medication was similarly reduced by 1.3 and 0.7 (p=0.143) in the high and low _bMed groups respectively. The likelihood of complete success was greater in the low _bMed group (p=0.003), but both groups had a similar qualified success rate (67.9%, 84.2%; p=0.144).

This post-hoc analysis indicates that this supraciliary MIGS device, implanted as a standalone procedure, may achieve comparable levels of relative IOP reductions at 2 years in patients regardless of a high (mean 28.1mmHg) or moderate (mean 22.1mmHg) baseline IOP. Mean absolute IOP reduction was in fact greater in the high baseline IOP group.

Likewise, a comparable reduction in IOP was achieved despite the number of medications used pre-operatively, although there was a trend towards greater IOP reduction for patients on lower baseline medications. There was no statistical difference regarding amount of medication reduction at 2 years between patients using 3-4 medications at baseline and those using 1-2 medications.