Comparing XEN®-63 Gel Stent and PRESERFLO® MicroShunt (MINI-BATTLE)

Minimally Invasive Bleb-Forming Surgical Approaches for Treating Primary Open-Angle Glaucoma: A Randomized Controlled Trial Comparing XEN®-63 Gel Stent and PRESERFLO® MicroShunt

The goal of this randomized controlled clinical trial is to learn whether two minimally invasive bleb-forming glaucoma implants can effectively treat adult patients with open-angle glaucoma who require surgical lowering of intraocular pressure (IOP). Specifically, the study evaluates whether the PRESERFLO™ MicroShunt is at least as effective as the XEN®-63 Gel Stent in reducing IOP after surgery. 

The main questions it aims to answer are:

• Does the PRESERFLO™ MicroShunt provide IOP reduction at 12 months that is non-inferior to the XEN®-63 Gel Stent?
• How do the two devices compare over 24 months with respect to medication reduction, need for additional glaucoma procedures, complications, and preservation of visual function and ocular structures?

Participants will:

• Be randomly assigned (1:1) to receive either the XEN®-63 Gel Stent or the PRESERFLO™ MicroShunt during a single glaucoma surgery.
• Attend scheduled follow-up visits over 24 months for eye-pressure measurements, vision testing, visual-field testing, OCT imaging, endothelial-cell counts, and safety assessments.
• Receive standard postoperative care and report any complications or additional treatments during the study period.

Study Overview

• Status: Recruiting
• Conditions: GLAUCOMA 1, OPEN ANGLE, D (Disorder)
• Intervention / Treatment: Device: PRESERFLO™ MicroShunt; Device: XEN®-63 Gel Stent

• Study Type: Interventional
• Enrollment (Estimated): 166
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ingeborg Stalmans, MD, PhD; Phone Number: +3216340391; Email: oogziekten.glaucoomstudies@uzleuven.be
• Study Contact Backup: Name: Thomas Jacobs, MD; Phone Number: +16346108; Email: thomas.jacobs@uzleuven.be

Study Locations

• Belgium
  • Vlaams-brabant
    • Leuven, Vlaams-brabant, Belgium, 3000
      • Recruiting
      • University Hospitals UZ Leuven
      • Contact: Ingeborg Stalmans, Prof. Dr.; Phone Number: +3216340391; Email: oogziekten.glaucoomstudies@uzleuven.be
      • Contact: Thomas Jacobs, MD; Phone Number: +3216346108; Email: thomas.jacobs@uzleuven.be
• Germany
  • North Rhine-Westphalia
    • Bonn, North Rhine-Westphalia, Germany, D-53127
      • Recruiting
      • Universitätsklinikum Bonn
      • Contact: Karl Mercieca, Prof. Dr.; Phone Number: +44 7894 230224; Email: Karl.Mercieca@ukbonn.de
• Portugal
  • Lisbon District
    • Lisbon, Lisbon District, Portugal, 1649-028
      • Not yet recruiting
      • ULS Santa Maria
      • Contact: Luis Pinto, Prof. Dr.; Phone Number: +351 965 132 279; Email: abegaopinto@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• >40 years of age
• An established diagnosis of: Primary open angle glaucoma, Normal tension glaucoma, Pigment dispersion glaucoma (PDG) or Pseudoexfoliative glaucoma (PEX)
• Inadequately controlled on maximum tolerated medical therapy.
• Mean Deviation (MD) </= -3
• Intraocular pressure of 14-28 mmHg
• Endothelial Cell Count ≥1000 cells/mm2

Exclusion Criteria:

• An established diagnosis of: Closed-angle glaucoma or Secondary open-angle glaucoma (besides PDG and PEX)
• Lens status: Aphakic patients or Anterior chamber intraocular lens
• Previous procedures: Glaucoma shunt/valve/ surgery or cyclodestructive procedure, Selective laser trabeculoplasty within the past 3 months, Incisional ophthalmic surgery involving the conjunctiva within the past 3 months, Clear corneal cataract or trabecular meshwork surgery conducted within the past 6 months.
• Presence of intraocular silicone oil
• No light perception vision
• Current corticosteroid use (ocular or oral)
• Conjunctival pathologies (e.g., pterygium)
• Active inflammation (e.g., blepharitis, conjunctivitis, keratitis, uveitis)
• Vitreous present in the anterior chamber
• Active iris neovascularization or neovascularization of the iris within 6 months of the surgical date
• Unwillingness or inability to give consent, accept randomization or return for and participate in scheduled protocol visits

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PRESERFLO MicroShunt; The PFMS is a SIBS-polymer microshunt.	Device: PRESERFLO™ MicroShunt; The PRESERFLO™ MicroShunt is a SIBS-polymer microshunt. This devices bypasses the trabecular meshwork and lower eye pressure via a subconjunctival filtering bleb, aided by intra-operative mitomycin C to reduce scarring. It has already been approved for the European market and therefore bear the CE mark.
Active Comparator: XEN 63 Gelstent; The XEN 63 Gelstent is a hydrophilic gel implant made of cross-linked, purified collagen (gelatin).	Device: XEN®-63 Gel Stent; The XEN®-63 Gel Stent is a hydrophilic gel implant made of cross-linked, purified collagen (gelatin). This devices bypasses the trabecular meshwork and lower eye pressure via a subconjunctival filtering bleb, aided by intra-operative mitomycin C to reduce scarring. It has already been approved for the European market and therefore bear the CE mark.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Intraocular pressure	1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
adverse events		2 years
Number of medications	Number of topical glaucoma medications	2 year
secundary pressure-lowering surgery		2 years
Mean Deviation changes on the visual field		2 years
Retinal Nerve Fibre Layer Thickness changes on Optical Coherence Tomography		2 years
Endothelial Cell Count		2 years
Best Corrected Visual Acuity		2 years

Collaborators and Investigators

• Sponsor: Universitaire Ziekenhuizen KU Leuven
• Collaborators: University Hospital, Bonn; Hospital de Santa Maria, Lisbon

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2026
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: January 12, 2026
• First Submitted That Met QC Criteria: January 21, 2026
• First Posted (Actual): January 22, 2026

Study Record Updates

• Last Update Posted (Actual): April 29, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Surgery; Glaucoma; XEN; PRESERFLO; MicroShunt; MIBS; Minimally Invasive Bleb-Forming Surgery; Bleb-Forming Devices Without a Plate; Gelstent
• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma
• Other Study ID Numbers: S70640

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No