By Cameron Johnston
FORT LAUDERDALE -- May 14, 2007 -- A study that was halted prematurely has failed to show any difference in visual outcomes or safety concerns in patients with neovascularisation secondary to age-related macular degeneration who were treated with verteporfin photodynamic therapy (PDT) together with either intravitreal injections of either Macugen (pegaptanib sodium) or triamcinolone.
Peter Kaiser, vitreoretinal specialist, Cole Eye Institute, Cleveland, Ohio, United States, presented the study findings here Association for Research in Vision and Ophthalmology (ARVO).
"There is a scientific rationale for combining photodynamic therapy with either a steroid or an antiangiogenic agent. We would use verteporfin PDT to close down the neovascularisation from AMD, but then use an antiangiogenic therapy to prevent angiogenesis after that therapy," Dr. Kaiser said. "A steroid was used to inhibit inflammation and to break down the blood retinal barrier. The steroid is weakly antiangiogenic in itself."
Other studies have shown that it is possible to improve on the visual acuity achieved with PDT alone by using it in combination with a steroid, he added.
In this study, patients were randomised at baseline to receive: PDT plus Macugen 0.3 mg (n=38); PDT plus triamcinolone 1 mg (n=32); triamcinolone 4 mg (n=41).
Macugen was administered every 6 weeks and PDT could be repeated if retinal leakage was seen on fluorescein angiography at three months. Patients who received triamcinolone at baseline had a sham injection at six weeks, then the PDT/triamcinolone treatment was repeated at three months if there was leakage. This procedure was repeated over 12 months.
The study was halted before enrollment was completed, and only 111 patients out of a planned 339 took part. Six-month data from the study were presented here on May 8th.
After six months of follow-up, there were no significant differences between groups in terms of loss of 15 letters on the visual acuity test, which was the planned primary endpoint of the study. All percentages (PDT/Macugen 73.7%; PDT/triamcinolone 81.3%; triamcinolone alone 73.2%) were all much lower than what was expected, Dr. Kaiser said.
In terms of visual acuity, all three groups lost some visual acuity, but the between-group differences were not significant. Similarly, the mean change in visual acuity did not differ between groups. Between 50% to 60% of patients showed stable disease, and 6% to 8% showed some kind of improvement, which was much lower than what was expected, Dr. Kaiser said.
There was a significant difference in area of neovascularisation between the two steroid groups and the Macugen group. Dr. Kaiser said this represented "a disconnect" between what was seen in the visual acuity findings: one would have expected to see between-group differences in visual acuity since patients receiving the steroid had a greater reduction in lesion area compared with those who received Macugen. Mean lesion leakage area was also smaller in patients who received the steroid treatment, but the difference was not statistically significant.
All groups had a significant reduction in central retinal thickness.
Safety in this study was "reasonably good," Dr. Kaiser said. Although 14% of patients receiving triamcinolone had significant spikes in intraocular pressure, this was to be expected, and it did not result in any acute losses in visual acuity. There were no differences in cardiovascular adverse events.
In conclusion, there was no difference between groups in terms of the primary outcome, which was the number of patients who lost fewer than 15 letters, or the mean change in visual acuity There were no -- or minimal -- ocular adverse events, in particular, there were no acute changes in visual outcomes, Dr. Kaiser said.
Although the study was halted prematurely, Dr. Kaiser said patients will continue treatment until the 12 month endpoint and the results will be presented at a later date.
The study was funded by OSI/ Eyetech Inc.
[Presentation title: Verteporfin Therapy in Combination with Pegaptanib or Triamcinolone for West AMD: 6-Month Results of the VERITAS study. Oral 2870]
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