Safety and effectiveness of MicroShunt implantation versus trabeculectomy: 2-year results from a randomized, multicentre study

Authors: Joseph F. Panarelli¹, N Douglas Baker², Michael C. Stiles³, Marlene R. Moster⁴, Henny J. M. Beckers⁵. ¹New York University, New York, NY, USA, ²Ophthalmic Surgeons and Consultants of Ohio, Columbus, OH, USA, ³Stiles Eyecare Excellence, Overland Park, KS, USA, ⁴Wills Eye Hospital, Philadelphia, PA, USA, ⁵University Eye Clinic, Maastricht University Medical Center, Maastricht, The Netherlands.

Author Disclosure Block:J.F. Panarelli: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Allergan, CorneaGen, Glaukos, New World Medical, Santen. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consulting/advisor fees, Consulting/advisor fees, Consulting/advisor fees, Consulting/advisor fees, Consulting/advisor fees, Consulting/advisor fees. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Santen. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Advisory boards and speaker bureaus. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Allergan. Funded grants or clinical trials; Description of relationship(s); Grant support. N.D. Baker: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Santen. Any direct financial payments including receipt of honoraria; Description of relationship(s); Honoraria. M.C. Stiles: Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Allergan, Sentiss. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Lecture fees/Honoraria, Lecture fees/Honoraria, Lecture fees/Honoraria. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Allergan, Glaukos, NicOx, Santen. Funded grants or clinical trials; Description of relationship(s); Grant support, Grant support, Grant support, Grant support, Grant support. M.R. Moster: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Qura, Santen. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consultant/advisor, Consultant/advisor, Consultant/advisor, Consultant/advisor, Consultant/advisor. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Bausch + Lomb, IRIDEX, MedEdicus, Novartis. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees, Lecture fees. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Aerie Pharmaceuticals, Alcon, Allergan, Bausch + Lomb, Glaukos, InnFocus, IRIDEX. Funded grants or clinical trials; Description of relationship(s); Grant support, Grant support, Grant support, Grant support, Grant support, Grant support, Grant support. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Name of for-profit or not-for-profit organization(s); Qura. All other investments or relationships that could be seen by a reasonable, well-informed participant as having the potential to influence the content of the educational activity; Description of relationship(s); Equity/owner. H.J.M. Beckers: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); Santen, Glaukos. Any direct financial payments including receipt of honoraria; Description of relationship(s); Consultant, speaker, Consultant, speaker. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); Santen. Membership on advisory boards or speakers’ bureaus; Description of relationship(s); Advisory Board (Asia). Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); InnFocus Inc, a Santen Company. Funded grants or clinical trials; Description of relationship(s); Funding research.

Abstract Body:

Purpose: The MicroShunt, a micro-incisional ab‑externo glaucoma filtration surgery device, is designed to drain aqueous humour from the anterior chamber to a bleb formed beneath Tenon’s capsule. In the first head-to-head study to compare MicroShunt surgery with trabeculectomy in patients with primary open‑angle glaucoma (POAG), both treatments showed intraocular pressure (IOP) and medication reductions at Year 1 (Y1).Year 2 (Y2) outcomes are reported herein.
Study Design: In this 2-year prospective, randomized study, patients aged 40 to 85 years with uncontrolled IOP (≥15 to ≤40 mmHg) on maximum tolerated glaucoma medication were randomized 3:1 to MicroShunt surgery (N=395) or trabeculectomy (N=132) across 24 sites in the USA and five sites in Europe (NCT01881425).
Methods: Patients underwent MicroShunt surgery or trabeculectomy with adjunctive use of Mitomycin C (0.2 mg/mL applied via sponges for 2 minutes). Outcome measures included IOP, supplemental glaucoma medication use and surgical complications.
Results: In the MicroShunt group, mean IOP reduced from 21.1 mmHg (baseline) to 13.9 mmHg (Y2) on an average of 0.9 medications (medication-free patients: 61.1%). In the trabeculectomy group, mean IOP reduced from 21.1 mmHg (baseline) to 10.7 mmHg (Y2) on an average of 0.4 medications (medication-free patients: 79.8%). The least squares mean difference in IOP was 3.4 mmHg between groups at Y2 (95% confidence interval 2.6 mmHg, 4.3 mmHg). Response rates (≥20% IOP reduction, no medication increase) at Y1 vs Y2 were 53.9% vs 50.6% (MicroShunt) and 72.7% vs 64.4% (trabeculectomy). The main reasons for failure were IOP reduction <20% (similar rate at both timepoints: MicroShunt, 29%; trabeculectomy, 9.1%) and IOP <6 mmHg at two consecutive visits (MicroShunt, 2.3% [Y1] vs 3.8% [Y2]; trabeculectomy, 8.3% [Y1] vs 15.2% [Y2]). Rates of cataract progression were 8.4% vs 13.9% (MicroShunt) and 12.2% vs 20.6% (trabeculectomy). Patients requiring glaucoma reoperations remained stable between Y1 and Y2 (MicroShunt, 6.8% vs 8.9%; trabeculectomy, 8.8% vs 8.9%), as did unplanned glaucoma related surgical interventions owing to an adverse event (MicroShunt, 5.3% vs 7.1%; trabeculectomy, 2.3% vs 2.3%). Needling rates were 19.0% vs 24.8% (MicroShunt) and 8.3% vs 9.1% (trabeculectomy).
Conclusions: In this randomized, multicentre study comparing the MicroShunt with trabeculectomy in patients with POAG, a greater IOP-lowering effectiveness was demonstrated following trabeculectomy. Between Y1 and Y2, more needlings were required in the MicroShunt group, there were more cases of cataract progression in the trabeculectomy group, and rates of glaucoma reoperations and unplanned reinterventions owing to an adverse event remained stable across both treatment groups.