Clarifying the Optimal Application of SLT Therapy Trial (COAST)

West Virginia University

Status: Enrolling

Conditions: Glaucoma and Ocular Hypertension

Treatments: Procedure: Low Energy SLT; Procedure: Standard Energy SLT

Study type: Interventional

Funder types: Other

Identifiers

NCT04967989

UG1EY031654

Details and patient eligibility

About

The goal of this study is to understand if SLT performed at low energy is as effective as SLT performed at standard energy, and also to see if repeating SLT at low energy once a year will prevent or delay the need for daily eye drop medications better than waiting for SLT to wear off before repeating it.

Enrollment: 790 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Age 18 or older and in good health

2. Each eye with one of the following qualifying diagnoses (diagnoses may differ between eyes):

   1. High-risk ocular hypertension (OHT): IOP > 21 mmHg without glaucomatous optic neuropathy (excavation, diffuse or focal thinning or notching of the neuroretinal rim, visible nerve fiber layer defects, or asymmetry of the vertical cup-to-disc ratio of >0.2 between eyes)
   2. Mild primary open-angle glaucoma: glaucomatous optic neuropathy, visual field mean deviation better than -6.0 dB with no points in the central 5° <15 dB (see figure on next page)
   3. Moderate primary open-angle glaucoma: glaucomatous optic neuropathy, visual field mean deviation equal to or worse than -6.0 dB but no worse than -12.0 dB and no central 5° points <15 dB or mean deviation -12.0 dB or better with 1 central 5° points <15 dB (see figure on next page).

3. Each eye with BCVA 20/200 (UK 6/60) or better

Exclusion criteria

1. Use of topical IOP-lowering medications for more than 6 cumulative months at any time in the past 5 years (this is a modification implemented during active enrollment)
2. Any history of IOP-lowering laser (prophylactic iridotomy not included) or surgical procedure
3. Advanced POAG in either eye (worse than moderate POAG as defined above)
4. Glaucoma other than POAG (including pigmentary and pseudoexfoliation glaucoma) in either eye
5. Mean IOP > 35 mmHg at either the screening or baseline visit in either eye
6. Narrow or closed angle (Shaffer Grade 0, 1, or 2) in either eye
7. Contraindications to SLT or any other study intervention
8. Any corneal pathology that would preclude accurate assessment of IOP by Goldmann tonometry in either eye
9. Any intraocular surgical procedure within the past 6 months in either eye
10. Inability to attend all scheduled study visits
11. Pregnant or planning to become pregnant in the next 4 years

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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790 participants in 4 patient groups

Trial 1: Initial standard energy SLT

Active Comparator group

Description:

Standard energy SLT is performed as follows: beginning at 0.8 mJ, energy will be titrated up or down within the first 5-10 spots until champagne bubbles are visualized with every 2nd or 3rd spot. Energy can be titrated throughout the procedure, in response to variations in pigmentation, to ensure the appearance of champagne bubbles with every 2nd or 3rd spot throughout the full 360° treatment. Energy should be increased if no bubbles are seen with 5 consecutive spots and decreased if bubbles are seen with 5 consecutive spots.

Treatment:

Procedure: Standard Energy SLT

Trial 2: Month 12 Randomization: Annual Low Energy Repeat SLT

Experimental group

Description:

At month 12, eligible subjects will be randomized to undergo repeat SLT either annually at low energy or as needed at standard energy. Low energy SLT will consist of 100 treatment spots delivered at 0.4 mJ per spot throughout the full 360° treatment, with the exception that energy can be reduced to 0.3 mJ if bubbles are seen with 5 consecutive spots and can be increased back to a maximum of 0.4mJ is no bubbles are seen with 5 consecutive spots.

Treatment:

Procedure: Low Energy SLT

Trial 2: Month 12 Randomization: As-Needed Repeat SLT at Standard Energy

Active Comparator group

Description:

At month 12, eligible subjects will be randomized to undergo repeat SLT either annually at low energy or as needed at standard energy. Standard SLT will be performed as follows: beginning at 0.8 mJ, energy will be titrated up or down within the first 5-10 spots until champagne bubbles are visualized with every 2nd or 3rd spot. Energy can be titrated throughout the procedure, in response to variations in pigmentation, to ensure the appearance of champagne bubbles with every 2nd or 3rd spot throughout the full 360° treatment. Energy should be increased if no bubbles are seen with 5 consecutive spots and decreased if bubbles are seen with 5 consecutive spots.

Treatment:

Procedure: Standard Energy SLT

Trial 1: Initial Low Energy SLT

Experimental group

Description:

Note: This arm was discontinued following a planned interim analysis. Low energy SLT will consist of 100 treatment spots delivered at 0.4 mJ per spot throughout the full 360° treatment, with the exception that energy can be reduced to 0.3 mJ if bubbles are seen with 5 consecutive spots and can be increased back to a maximum of 0.4mJ if no bubbles are seen with 5 consecutive spots.

Treatment:

Procedure: Low Energy SLT