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The Comparison of Age-related Macular Degeneration Treatment Trial (CATT) follow-up study found that the initial gains in visual acuity achieved with two anti-vascular endothelial growth factor drugs were lower than those achieved at the end of the 2-year CATT study.
Reviewed by Maureen Maguire, PhD
Philadelphia-The Comparison of Age-related Macular Degeneration Treatments Trials (CATT) follow-up study found that the gains in visual acuity achieved at the end of the 2-year CATT study, a clinical trial of the anti-vascular endothelial growth factor (VEGF) drugs, ranibizumab (Lucentis) and bevacizumab (Avastin, both from Genentech), were not sustained 3 years later.
In the CATT clinical trial, patients were randomly assigned to either ranibizumab or bevacizumab and followed for 2 years after assignment to one of three dosing regimens.
In this study, 3 years after the end of the CATT clinical trial, the investigators, led by Maureen Maguire, PhD, from the Department of Ophthalmology, University of Pennsylvania, Philadelphia, and Daniel Martin, MD, from the Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, evaluated 647 patients who were recalled from the original CATT clinical trial cohort to determine how the visual acuity levels and anatomic outcomes survived over time in the CATT follow-up study.
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The CATT Research Group found that in these patients, who had an average follow-up of 5.5 years, half of the eyes had a visual acuity of 20/40 or better, 20% had a visual acuity of 20/200 or worse, and almost 10% had 20/20. The authors reported their findings in Ophthalmology (published online on May 1, 2016).
They reported that “the mean change in visual acuity was -3 letters from baseline and -11 letters from 2 years.”
These patients underwent examinations for age-related macular degeneration (AMD) a mean of 25.3 times after the end of the CATT study and received a mean of 15.4 treatments. Regarding the treatments, more than half of the patients (60%) were treated with a drug other than the one to which they had been assigned in the CATT study, according to Dr. Maguire.
Among 467 eyes that underwent fluorescein angiography, the images showed that the mean size of the lesions was 12.9 mm2, which was a mean of 4.8 mm2 larger than that at the 2-year visit. The investigators observed geographic atrophy in 41% of the eyes that could be graded and it was subfoveal in 17% of those eyes.
Spectral-domain optical coherence tomography images were available for 555 eyes. Among them, fluid was seen in 83%, specifically, intraretinal in 61%, subretinal in 38%, and subretinal pigment epithelial in 36%. The mean foveal thickness was 278 μm, which was lower by 182 μm from the baseline value and 20 μm below that from the 2-year evaluation, they reported. The retina was less than 120 μm thick in 36% of eyes.
Interestingly, the patients who had been randomly assigned to ranibizumab for 2 years had a greater decrease in visual acuity, i.e., -4 letters, compared with those who had been assigned to bevacizumab. This difference reached significance (p = 0.008). The investigators did not find significant differences in visual acuity or morphologic outcomes between the groups.
Dr. Maguire pointed out that in the CATT Follow-up Study there were multiple processes that caused the visual acuity decreases, but they seemed to be associated with an increase in the numbers of patients with abnormally thin retinas, that is, less than 120 μm; a greater prevalence of geographic atrophy, and an increase in the size of the lesions.
The investigators noted, “The CATT Follow-up Study results provided the most complete follow-up reported to date on the long-term outcomes for the treatment of neovascular AMD with anti-VEGF drugs. …Because very few patients continued to receive the originally assigned drug or dosing schedule between the end of year 2 and the follow-up of approximately 5 years, the CATT Follow-up Study results provide information primarily on overall treatment outcomes with anti-VEGF drugs and limited information on effects of different drugs and dosing regimens. The mean visual acuity at 5 years was 3 letters worse than baseline, highlighting an unmet need for further therapeutic advances.”
They also considered that with 50% of the patients having 20/40 or better visual acuity and 10% having 20/20, these results are a great step forward and would not have been possible before the anti-VEGF drugs were developed.
Maureen Maguire, PhD
Dr. Maguire has received financial support from Roche/Genentech for service on a Data Safety and Monitoring Committee for Genentech.
Daniel Martin, MD
Dr. Martin has no financial interest in this subject matter.
This article was adapted from a presentation by Dr. Maguire and Dr. Martin at the 2016 meeting of the Association for Research in Vision and Ophthalmology.