Clinical trial NCT00000167: Complications of Age-Related Macular Degeneration Prevention Trial
Official title: Complications of Age-Related Macular Degeneration Prevention Trial (CAPT)
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Macular Degeneration
Keywords: Age-Related Macular Degeneration
Lead sponsor: National Eye Institute (NEI)
Sponsor class: NIH
First posted: 1999-09-24
Enrollment: 1052
Sex: ALL
Minimum age (years): 50
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: PREVENTION

Brief summary: To determine whether application of low-intensity laser treatment of eyes with drusen in the macula can prevent later complications of age-related macular degeneration and thereby preserve visual function.

Detailed description: Complications of age-related macular degeneration (AMD) are the leading cause of severe vision loss among people aged 65 and over in the United States and many Western countries. Most, (approximately 90 percent), of this vision loss is due to the neovascular (or wet) form of AMD. The word neovascular describes the development of new, abnormal blood vessels in the back of the eye. Unfortunately, the majority of these new vessels are not amenable to currently available treatments.

The first sign that an eye may develop AMD is the presence of drusen, yellowish deposits under the retina. Current data suggests that eyes with large drusen are at increased risk for developing the vision threatening complications of AMD. Since the 1970s investigators have reported consistently that laser photocoagulation causes a reduction in large drusen. However, results of the effects of laser treatment on preventing later complications of AMD have been less consistent and based on relatively small numbers of patients.

Further study into the ability of a treatment to prevent vision loss from the advanced forms of AMD would have profound public health implications. A treatment that could reduce the risk of developing neovascularization by 30 percent might reduce the risk of blindness from AMD by one half. The Complications of Age-related Macular Degeneration Prevention Trial (CAPT) will assess whether treating drusen by laser photocoagulation reduces the risk of loss of visual acuity.

The CAPT is a multi-center, prospective, randomized clinical trial designed to assess the safety and effectiveness of low-intensity laser treatment in preventing vision loss among patients with large drusen in both eyes. A total of 1052 participants were enrolled in the study. Participants had one eye randomly assigned to laser treatment performed by a CAPT-certified ophthalmologist. The other eye was not treated. Both eyes were observed carefully for any changes for a period of five years. The effectiveness of the treatment was assessed using the following criteria:

Change in visual acuity (primary outcome measure of the study)

Incidence of complications of AMD such as neovascularization, serous detachment of the pigment epithelium, and geographic atrophy

Changes in contrast threshold and critical print size for reading

Quality of life assessments for patients, using the Visual Function Questionnaire 25 (VFQ-25), were conducted at the time of enrollment and at 5 years.

STUDY RESULTS:

Follow-up of patients was excellent; less than 3% of visual acuity examinations were missed. At 5 years, 188 (20.5%) treated eyes and 188 (20.5%) observed eyes had visual acuity scores ≥3 lines worse than at the initial visit (p= 1.00). The cumulative 5-year incidence rates for treated and observed eyes for CNV were 13.3% and 13.3% (p=0.95), respectively; and for GA were 7.4% and 7.8% (p=0.64), respectively. The contrast threshold doubled in 23.9% of treated eyes and in 20.5% of observed eyes (p=0.40). The critical print size doubled in 29.6% of treated eyes and in 28.4% of observed eyes (p=0.70). Seven (0.7%) treated eyes and 14 (1.3%) observed eyes had an adverse event of a ≥6 -line loss in visual acuity in the absence of late age-related macular degeneration or cataract.

As applied in CAPT, low intensity laser treatment did not demonstrate a clinically significant benefit on vision in eyes of people with bilateral large drusen.

Eligibility criteria: Patients eligible for CAPT can be either male or female and meet the following criteria:

Age at least 50 years old

Vision in each eye must measure 20/40 or better.

At least 10 large drusen in each eye

Available for follow-up examinations for 5 years after enrollment

Final eligibility is determined through a detailed eye examination by a CAPT-certified ophthalmologist.

Primary outcomes:
measure: Change in visual acuity (3-line loss)
timeFrame: 5 years
Secondary outcomes:
measure: Incidence of complications of AMD such as neovascularization, serous detachment of the pigment epithelium, and geographic atrophy
timeFrame: 5 years
measure: Changes in contrast threshold and critical print size for reading
timeFrame: 5 years
Other outcomes:
Locations:
city: Mesa
country: United States
facility: Retinal Consultants of Arizona, Ltd.
state: Arizona
city: Peoria
country: United States
facility: Retinal Consultants of Arizona, Ltd.
state: Arizona
city: San Francisco
country: United States
facility: West Coast Retina Medical Group, Inc.
state: California
city: Tampa
country: United States
facility: University of South Florida Eye Institute
state: Florida
city: Atlanta
country: United States
facility: Emory Eye Center
state: Georgia
city: Chicago
country: United States
facility: Northwestern University
state: Illinois
city: Harvey
country: United States
facility: Illinois Retina Associates, S.C.
state: Illinois
city: Iowa City
country: United States
facility: University of Iowa
state: Iowa
city: Louisville
country: United States
facility: Ophthalmology & Visual Sciences at the University of Louisville, School of Medicine
state: Kentucky
city: Baltimore
country: United States
facility: The Johns Hopkins University
state: Maryland
city: Boston
country: United States
facility: Ophthalmic Consultants of Boston
state: Massachusetts
city: Royal Oak
country: United States
facility: Associate Retinal Consultants, P.C.
state: Michigan
city: Rochester
country: United States
facility: Mayo Clinic
state: Minnesota
city: St. Louis
country: United States
facility: Barnes Retina Institute
state: Missouri
city: Edison
country: United States
facility: Retina-Vitreous Center, P.A.
state: New Jersey
city: Lakewood
country: United States
facility: Retina-Vitreous Center, P.A.
state: New Jersey
city: Charlotte
country: United States
facility: Southeast Clinical Research Associates
state: North Carolina
city: Cleveland
country: United States
facility: Retina Associates of Cleveland
state: Ohio
city: Columbus
country: United States
facility: The Ohio State University, Department of Ophthalmology
state: Ohio
city: Portland
country: United States
facility: Casey Eye Institute
state: Oregon
city: Portland
country: United States
facility: Retina Northwest, P.C.
state: Oregon
city: Philadelphia
country: United States
facility: Scheie Eye Institute
state: Pennsylvania
city: Dallas
country: United States
facility: Texas Retina Associates
state: Texas
city: Madison
country: United States
facility: University of Wisconsin - Madison, Department of Ophthalmology and Visual Sciences
state: Wisconsin
Study officials:
affiliation: Scheie Eye Institute, The University of Pennsylvania School of Medicine
name: Stuart L Fine, MD
role: STUDY_CHAIR
References:
citation: Brader HS, Ying GS, Martin ER, Maguire MG; Complications of Age-Related Macular Degeneration Prevention Trial-CAPT Research Group. New grading criteria allow for earlier detection of geographic atrophy in clinical trials. Invest Ophthalmol Vis Sci. 2011 Nov 29;52(12):9218-25. doi: 10.1167/iovs.11-7493.