GDD Timing with Boston KPro for Glaucoma

(GDD-KPro Trial)

Overseen By Dominique Geoffrion, BSc

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)

Disqualifiers: Terminal glaucoma, terminal retinal diseases

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 6

40 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines the optimal timing for adding a tiny tube called a glaucoma drainage device (GDD) during or after surgery with the Boston keratoprosthesis (KPro), a special plastic that replaces a damaged cornea. The goal is to determine if inserting the GDD at the same time as the KPro surgery is more effective at preventing glaucoma, a condition that can damage the optic nerve and lead to vision loss, compared to waiting six months. Individuals who have experienced a failed corneal transplant and have poor vision in the surgical eye might be suitable candidates. Participants will be divided into two groups to receive the GDD either during the KPro surgery or six months later, with their vision and eye health closely monitored. The results will help establish the best timing to prevent glaucoma after KPro surgery. As an unphased trial, this study offers participants the chance to contribute to important research that could improve surgical outcomes for future patients.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that the Boston KPro and GDD are safe for glaucoma patients?

Research has shown that the Boston keratoprosthesis (KPro) can greatly improve vision for individuals unable to undergo traditional corneal transplants. However, some risks exist. A common issue is glaucoma, which involves optic nerve damage due to high eye pressure. Without proper management, this can lead to vision loss.

A glaucoma drainage device (GDD) can assist in managing this risk. This small tube lowers eye pressure by allowing fluid to drain from the eye. Studies have shown these devices to be generally safe and effective. Specifically, research on various GDDs, such as the Ahmed ClearPath, indicates they are safe when used alone or with other procedures for uncontrolled glaucoma.

Overall, both the Boston KPro and GDDs have demonstrated good safety records. The KPro can significantly enhance vision, while GDDs help control eye pressure, reducing the risk of glaucoma after surgery. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores different timing strategies for implanting a glaucoma drainage device (GDD) in patients receiving a Boston keratoprosthesis (KPro) type 1. Unlike traditional approaches, which often involve separate surgeries, this trial investigates the potential benefits of simultaneous implantation during the initial KPro surgery versus waiting six months after the KPro procedure. This could reveal whether timing affects outcomes such as intraocular pressure control and overall vision improvement. By optimizing the timing of GDD placement, this study aims to enhance the effectiveness and safety of treating glaucoma in patients requiring a KPro.

What evidence suggests that this trial's treatments could be effective for glaucoma?

This trial compares two approaches to using a glaucoma drainage device (GDD) with the Boston keratoprosthesis (KPro) to control eye pressure and prevent glaucoma. In one arm, participants receive simultaneous implantation of the GDD during the KPro surgery. Research has shown that this approach does not lead to more complications than having the KPro alone. In the other arm, participants receive the GDD six months after the KPro surgery. Studies have found that patients who received the GDD six months post-KPro experienced more retinal problems. This suggests that adding the GDD during the KPro surgery might better protect against vision issues. Overall, using the GDD early on seems to support better long-term eye health. ^{6 7 8 9 10}

Who Is on the Research Team?

Mona Harissi-Dagher, MD, FRCSC

Principal Investigator

Department of Ophthalmology, Centre Hospitalier de l'Université de Montréal

Are You a Good Fit for This Trial?

This trial is for adults over 18 who've had a failed corneal transplant and have poor vision (20/80 or worse) in the affected eye. They should be physically fit for surgery but not have end-stage glaucoma or terminal retinal diseases.

Inclusion Criteria

I am fit for surgery.

Pre-operative visual acuity of ≤20/80 or worse in the surgical eye

I need a corneal transplant because my cornea is not clear.

Exclusion Criteria

I have been diagnosed with terminal glaucoma.

I have a severe eye condition that affects my vision.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Preoperative Evaluation

Complete medical and ophthalmological history, thorough ophthalmological evaluation, A-scan and B-scan ultrasound

1-2 weeks

1 visit (in-person)

Surgery and Initial Postoperative Follow-up

Boston KPro surgery with simultaneous or delayed GDD implantation, followed by initial postoperative evaluations

1 month

Visits on postoperative day 1, week 1, and month 1

Ongoing Postoperative Monitoring

Standard ophthalmological exams, visual fields, and optic nerve evaluations

12 months

Visits at months 3, 6, and 12

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Boston keratoprosthesis type 1
• Glaucoma drainage device

Trial Overview The study tests if getting a Glaucoma Drainage Device (GDD) at the same time as Boston Keratoprosthesis (KPro) surgery is better than waiting 6 months. The goal is to see which timing best prevents glaucoma progression and maintains vision.

How Is the Trial Designed?

Group I: Simultaneous implantation Active Control 2 Interventions

Simultaneous implantation of a glaucoma drainage device at the time of Boston keratoprosthesis type 1 surgery

Group II: Implantation at post-Kpro at 6 months Active Control 2 Interventions

Implantation of a glaucoma drainage device 6 months after Boston keratoprosthesis type 1 surgery

Boston keratoprosthesis type 1 is already approved in United States, European Union for the following indications:

Approved in United States as Boston KPro for:

• Corneal failure
• Herpetic keratitis
• Aniridia
• Autoimmune ocular disorders
• Pediatric corneal opacities

Approved in European Union as Boston KPro for:

• Corneal failure
• Herpetic keratitis
• Aniridia
• Autoimmune ocular disorders
• Pediatric corneal opacities

Who Is Running the Clinical Trial?

Centre hospitalier de l'Université de Montréal (CHUM)

Lead Sponsor

Trials

389

Recruited

143,000+

Published Research Related to This Trial

The Boston type I keratoprosthesis (KPro) showed significant improvement in visual acuity for patients with corneal graft failure, with a median best-corrected visual acuity improving from hand motions to 20/330 at 9 months post-surgery.

However, 50% of patients experienced increased intraocular pressure postoperatively, with 23% developing or progressing glaucoma, highlighting the need for careful management of eye pressure to ensure long-term success.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Glaucoma associated with Boston type I keratoprosthesis. Kamyar, R., Weizer, JS., de Paula, FH., et al.[2022]

In a study of 29 patients undergoing combined glaucoma drainage device (GDD) and Boston type I keratoprosthesis (KPro) surgery, 82.8% of KPro devices were retained over an average follow-up of 34.4 months, indicating a high retention rate for this combined procedure.

The surgery allowed for effective intraocular pressure (IOP) management without increasing the risk of complications or KPro failure, with 58.6% of patients experiencing improved visual acuity postoperatively.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Technique of combined glaucoma tube shunt and keratoprosthesis implantation. Law, SK., Huang, JS., Nassiri, N., et al.[2014]

In a study of 38 patients who underwent Boston type 1 keratoprosthesis (KPro) surgery, a significant increase in glaucoma diagnosis was observed, with 89% of patients diagnosed post-surgery after an average follow-up of 16.5 months.

Despite some patients experiencing improved visual acuity after surgery, 21% showed glaucoma progression, highlighting the need for careful monitoring and treatment of intraocular pressure in KPro patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Prevalence, progression, and impact of glaucoma on vision after Boston type 1 keratoprosthesis surgery. Talajic, JC., Agoumi, Y., Gagné, S., et al.[2022]

The Boston type 1 keratoprosthesis (KPro) shows promising short-term results, with 62% of patients achieving at least 6/60 vision at 2 years, but this drops to 51% at 5 years, indicating a decline in visual outcomes over time.

The device retention rate is high at 88% after 2 years but decreases to 74% by 5 years, and common complications such as retroprosthetic membrane and glaucoma highlight the need for careful patient selection and ongoing monitoring.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Systematic Review and Meta-Analysis of the Medium- and Long-Term Outcomes of the Boston Type 1 Keratoprosthesis. Priddy, J., Bardan, AS., Tawfik, HS., et al.[2020]

In a study of 137 keratoprosthesis (KPro) procedures involving 129 patients, concurrent implantation of a glaucoma drainage device (GDD) did not increase the risk of serious vision-threatening postoperative complications compared to KPro alone.

Over an average follow-up of 44 months, none of the GDDs placed with KPro became exposed, indicating that the combination procedure is safe and effective for managing both corneal and glaucoma issues.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of Concurrent Boston Type I Keratoprosthesis and Glaucoma Drainage Device Implantation. Lenis, TL., Chiu, SY., Law, SK., et al.[2022]

In a study of 96 eyes that underwent Boston keratoprosthesis (KPro) surgery, those with a glaucoma drainage device (GDD) had a significant risk of vision loss due to complications like glaucoma progression and tube occlusion, with 39% experiencing such issues.

The study suggests that while GDD can be beneficial, it should only be used in carefully selected patients due to the high risk of complications, particularly vitreous incarceration, which necessitates a complete pars plana vitrectomy before implantation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Complications associated with Boston keratoprosthesis type 1 and glaucoma drainage devices. Robert, MC., Pomerleau, V., Harissi-Dagher, M.[2022]

In a study of 35 eyes, glaucoma drainage implant (GDI) placement during Boston keratoprosthesis (KPro) surgery resulted in similar long-term failure rates compared to GDI placement before KPro, with 5-year failure rates of 23.5% and 27.8%, respectively.

Patients who had GDI placed concomitantly with KPro experienced significantly better best-corrected visual acuity at multiple follow-up points, indicating that this approach may offer better visual outcomes without increasing complication rates, which were similar in both groups.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sequential versus concomitant surgery of glaucoma drainage implant and Boston keratoprosthesis type 1. Patel, V., Moster, MR., Kishfy, L., et al.[2022]

In a study of 103 eyes from 100 patients who received Boston keratoprosthesis type I (B-KPro type I) over 8 years, 82.7% achieved a visual acuity of 10/200 or better at 6 months, demonstrating its effectiveness in improving vision for severe ocular surface disorders.

The procedure showed a high retention rate, particularly beneficial for patients with chemical burns, although some complications were noted, including retroprosthetic membrane formation in 19.4% of eyes and corneal melting in 18.4%.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Long-term outcomes of Boston keratoprosthesis type I: the Chinese People's Liberation Army General Hospital experience. Wang, LQ., Wu, TY., Chen, XN., et al.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11892478/

Management of glaucoma with Boston type 1 keratoprosthesis Retinal complications appeared more often when glaucoma drainage device implantation was performed no more than 6 months before aphakic type keratoprosthesis ...

2. annualmeeting.ascrs.org annualmeeting.ascrs.org/-/media/files/2021-papers/sps-316/76507-presentation-agv-versus-baerveldt-for-kpro-type-1.pdf

P-429 Longterm outcomes of Ahmed glaucoma valve (AGV ... Comparing long-term outcomes of glaucoma drainage devices (GDD) in. Boston keratoprosthesis type 1 (KPro) patients : Ahmed glaucoma valve (AGV) versus.

3. aaojournal.org aaojournal.org/article/s0161-6420(16)30767-9/pdf

Safety of Concurrent Boston Type I Keratoprosthesis and ... Purpose: To evaluate the safety of concurrent Boston type I keratoprosthesis (KPro) and glaucoma drainage device (GDD) implantation.

4. ascrs.confex.com ascrs.confex.com/ascrs/21am/meetingapp.cgi/Paper/76507

Ahmed Glaucoma Valve Versus Baerveldt Glaucoma Implant The primary outcome was GDD failure, defined by tube removal or additional glaucoma surgery. Secondary outcomes included best-corrected visual acuity (BCVA), ...

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3539166/

Glaucoma Associated with Boston Type 1 Keratoprosthesis As modifications in the implant design and postoperative management have evolved, the retention rates of the Boston Type I KPro have dramatically improved, ...

6. sciencedirect.com sciencedirect.com/science/article/pii/S0002939421003159

Long-term Outcomes of Boston Type I Keratoprosthesis ... The anatomical success rate of the KPro implantations was 88.9%, with an average time to removal of 28 months (range, 22-35 months; Figure 2a). KPro removal was ...

7. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/33493469/

Glaucoma Risk Factors and Outcomes Following Boston ... High preoperative IOP signals a higher risk for glaucoma development and progression after KPro surgery.

8. aes.amegroups.org aes.amegroups.org/article/view/7706/html

Boston type I keratoprosthesis - Hu - Annals of Eye Science Here we explore indications, surgical technique and postoperative outcomes as well as several core tenants in the management of BKPro patients: ...

9. aaojournal.org aaojournal.org/article/s0161-6420(15)00306-1/fulltext

Boston Keratoprosthesis: Outcomes and Complications The reviewed articles on BI-KPro use suggest that the device improves vision in cases of severe corneal opacification that were not amenable to corneal ...

10. sciencedirect.com sciencedirect.com/science/article/abs/pii/S000293942100026X

Glaucoma Risk Factors and Outcomes Following Boston ... High preoperative IOP signals a higher risk for glaucoma development and progression after KPro surgery.