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CATT follow-up: Visual acuity in 50% of patients still 20/40 or better at 5 years
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Regardless of treatment drug, either bevacizumab or ranibizumab, visual acuity gains seen in the first 2 years of the CATT study were not maintained at 5 years, according to data reported at the American Society of Retina Specialists meeting in San Francisco.
However, visual acuity was 20/40 or better in half of patients at 5 years, Daniel F. Martin, MD, chairman of the Cleveland Clinic Cole Eye Institute and the study chair for CATT, said.
“While it was discouraging to see mean visual acuity decline over time, it is still extraordinary that half of our patients are 20/40 or better and 10% are 20/20 or better 5 years after their diagnosis of neovascular AMD,” he said. “This is a result that would have been unimaginable 10 years ago and a clear statement of just how revolutionary these drugs have been for this disease.”
CATT patients who were alive at the end of the initial 2-year National Eye Institute-funded clinical trial were invited to return for a follow-up assessment of visual acuity, review of records and imaging studies that included color fundus photography, fluorescein angiography and spectral-domain OCT.
Five-year data were available for 647 patients (71% of those eligible). Mean age was 83 years, and follow-up ranged from 4.3 years to 7.1 years.
Results were also presented at the Association for Research in Vision and Ophthalmology meeting in Seattle and published in Ophthalmology.
Visual acuity
At the 5-year visit, visual acuity was 20/40 or better in 50% of eyes and 20/200 or worse in 20%.
Mean change in visual acuity was a loss of three letters from baseline and 11 letters from 2 years.
“In clinical practice, we were all aware that some patients lose visual acuity over time despite initial gains. The reason for this later decline is multifactorial, but a major contributor is the gradual increase in atrophy, both of the retina and of the RPE and choriocapillaris (geographic atrophy),” Martin said. “But those initial gains, despite their eventual loss in some, are obviously extremely important. The natural history of this disease is 10 to 20 letters of loss in the first year, so any decrease in absolute loss or the speed with which that loss occurs is a major advance. And in many patients, the gains are maintained long term.”
After the 2-year CATT study ended, most patients received at least one drug that was different from their CATT-assigned treatment, and almost no patients received monthly treatment. As such, the CATT Follow-Up Study was not designed to compare outcomes by drugs or treatment algorithms. Instead, the primary goal was to understand the general effects of any anti-VEGF therapy on visual acuity and anatomical outcomes at 5 years. The drug comparison that the study design did allow was an assessment of whether or not 2 years of treatment with bevacizumab vs. ranibizumab produced any measurable difference in outcome at 5 years. The group initially assigned to ranibizumab for 2 years lost 13 letters of visual acuity as opposed to those assigned to bevacizumab who lost nine letters at 5 years; the difference was statistically significant (P = .008).
“We do not believe this is clinically relevant since the direction for both groups was the same. But it certainly appears that 2 years of initial treatment with bevacizumab did not disadvantage eyes in any way relative to ranibizumab. This becomes particularly important when one considers the large cost difference between drugs,” Martin said.
No other statistically significant differences in visual acuity or anatomic outcomes between the drugs or regimens were identified.
Anatomic outcomes
Fluid was identified in 83% of 555 eyes that had SD-OCT; 61% had intraretinal fluid, 38% had subretinal fluid, and 36% had subretinal pigment epithelium fluid.
“Most clinicians, including me, were surprised to learn that there is still fluid present in 83% of these eyes at 5 years. The amount of fluid that remains is very small in most patients. In some, it produces meaningful effects on visual acuity. In others, it may just be decompensated retina overlying an area or atrophy of scar. There is still much to learn about why this fluid persists,” Martin said.
Perhaps the most important anatomical changes were the increases in atrophy; 36% of patients had a retinal thickness of less than 120 µm at 5 years, a substantial increase from 22% at 2 years.
“In a previous paper, we showed that retinal thickness of less than 120 µm was associated with a lower level of vision on average,” Martin said.
There was a notable increase in geographic atrophy from 20% of eyes at year 2 to 41% at year 5.
“The atrophy that we observe is almost always in the bed of the original neovascular lesion. We typically do not think of geographic atrophy as occurring in neovascular AMD, and yet if I showed these images to a dozen retina specialists, virtually every physician, not knowing what was there before, would call it geographic atrophy,” Martin said. “We also observed in this study that the total CNV lesion continues to expand. The increase between year 2 and year 5 was 50% to a mean size of 13 mm2. Much of this expansion was due to expanding margins of atrophy. Understanding how this evolves and learning how to prevent atrophy and/or its expansion is one of the next major steps in our effort to further improve outcomes in these eyes.” – by Matt Hasson
- References:
- Jaffe GJ, et al. Ophthalmology. 2016;doi:10.1016/j.ophtha.2016.03.045.
- Martin DF. 5-year outcomes after initiating anti-VEGF therapy for neovascular AMD in the Comparison of AMD Treatments Trials (CATT). Presented at: American Society of Retina Specialists 34th annual meeting; Aug. 9-14, 2016; San Francisco.
- For more information:
- Daniel F. Martin, MD, can be reached at Cleveland Clinic Main Campus, Mail Code I30, 9500 Euclid Ave., Cleveland, OH 44195; email: martind5@ccf.org.
Disclosure: Martin reports no relevant financial disclosures.