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

Trial Summary

What is the purpose of this trial?

Boston keratoprosthesis (KPro) is a piece of specialized plastic that replace sick cornea (transparent structure at the front of the eye) in patients who have failed or those who are expected to have poor results with traditional corneal transplantation. While the Kpro can offer dramatic improvement in vision, it is also associated with several complications. Glaucoma (optic nerve damage due to high pressure inside the eye) is one of the most common complications after KPro surgery and can potentially cause irreversible vision loss. The implantation of a glaucoma drainage device (GDD), a tiny tube that drains the liquid inside the eye by bypassing the natural drainage system, is an effective option to lower the eye pressure in patients with KPro. Given the frequency and potentially devastating effects of glaucoma among KPro patients, some surgeons recommend to put in a GDD as a preventative measure. However, there is no consensus on when is the best timing to perform such surgery in relation to the Boston Kpro surgery. Hypothesis: For patients undergoing the Boston KPro surgery, implanting a GDD simultaneously, at the time of surgery, is more efficacious than at 6 months later, in the prevention of the progression of glaucoma and in maintaining better visual functions. Methods: The investigators aim to recruit 40 patients over 4 years. Recruited patients will be randomly assigned to 2 groups: 1) simultaneous GDD implantation at the Boston KPro surgery, and 2) GDD implantation 6 months after the Boston KPro surgery. Once recruited, patients will be followed before the KPro surgery, postoperative day 1, week 1, month 1, 3, 6 and 12. Standard ophthalmological exam will be performed at each visit. Additional non-invasive glaucoma tests and evaluation (visual fields and optic nerve photo) will be performed on day 1, month 1, 3, 6 and 12. For patients assigned to group 2, a GDD will be implanted 6 months after the KPro surgery. They will have additional follow-ups on post-GDD surgery day 1, week 1 and month 1. Results of visual acuity, visual fields, optic nerve evaluation and complications will be compared between the two groups to determine the better timing of GDD implantation.

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 data supports the effectiveness of the treatment Boston KPro and GDD for glaucoma?

Research shows that combining a Boston type I keratoprosthesis (KPro) with a glaucoma drainage device (GDD) can be effective in managing severe eye conditions, as it addresses both corneal issues and glaucoma simultaneously. Studies have reported positive outcomes in terms of vision improvement and glaucoma management when these procedures are performed together. ^{1 2 3 4 5}

Is the combination of Boston KPro and glaucoma drainage device safe for humans?

Research shows that using the Boston KPro with a glaucoma drainage device is generally safe, but there can be complications. These complications may affect vision, so it's important to discuss potential risks with your doctor. ^{2 3 5 6 7}

How is the Boston KPro treatment different from other treatments for glaucoma?

The Boston KPro treatment is unique because it involves the implantation of an artificial cornea (keratoprosthesis) along with a glaucoma drainage device (GDD) in a single procedure, which can help manage both corneal and glaucoma issues simultaneously, unlike traditional treatments that address these conditions separately. ^{3 4 5 6 8}

Research Team

Mona Harissi-Dagher, MD, FRCSC

Principal Investigator

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

Eligibility Criteria

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 18 years old or older.

I am fit for surgery.

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

Exclusion Criteria

I have been diagnosed with terminal glaucoma.

I have a severe eye condition that affects my vision.

Timeline

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

Treatment Details

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.

Participant Groups

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+

Findings from Research

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]

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]

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]

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 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]

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 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]

References

1. England pubmed.ncbi.nlm.nih.gov

Long-term outcomes of Boston keratoprosthesis type I: the Chinese People's Liberation Army General Hospital experience. [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Prevalence, progression, and impact of glaucoma on vision after Boston type 1 keratoprosthesis surgery. [2022]

3. United States pubmed.ncbi.nlm.nih.gov

Technique of combined glaucoma tube shunt and keratoprosthesis implantation. [2014]

4. United States pubmed.ncbi.nlm.nih.gov

Glaucoma associated with Boston type I keratoprosthesis. [2022]

5. United States pubmed.ncbi.nlm.nih.gov

Safety of Concurrent Boston Type I Keratoprosthesis and Glaucoma Drainage Device Implantation. [2022]

6. England pubmed.ncbi.nlm.nih.gov

Complications associated with Boston keratoprosthesis type 1 and glaucoma drainage devices. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Systematic Review and Meta-Analysis of the Medium- and Long-Term Outcomes of the Boston Type 1 Keratoprosthesis. [2020]

8. United States pubmed.ncbi.nlm.nih.gov

Sequential versus concomitant surgery of glaucoma drainage implant and Boston keratoprosthesis type 1. [2022]