SCORE Study Reports Detail Effectiveness of IVTA Injection
BY LEO SEMES, OD, FAAO
Two comparison trials of intravitreal triamcinolone (IVTA) injection for macular edema secondary to retinal vein occlusion have appeared recently. The first compared laser photocoagulation as the standard treatment for branch retinal vein occlusion (BRVO) and the second looked at treatment versus observation for central retinal vein occlusion (CRVO). These were know as SCORE (standard care versus corticosteroid for retinal vein occlusion) Study Reports.
The multicenter, randomized studies were designed to compare the efficacy and safety of 1mg and 4mg doses of preservative-free IVTA on eyes that had vision loss associated with macular edema secondary to BRVO and CRVO. Both studies were funded by the National Eye Institute with Allergan as a collaborator.
This month's column will review the progress made for managing patients who have BRVO and CRVO. It will not attempt to critique the details of SCORE Study Reports 5 and 6, but rather offer a succinct template for those who encounter retinal vein obstructions so that they can convey to patients expected management alternatives and outcomes.
In the SCORE Study Report 6, treatment for BRVO with 1mg or 4mg IVTA injection was compared to grid photocoagulation as the standard.
Less than one-third of eyes in the study achieved the primary outcome measure, which was a 15-letter improvement in visual acuity from baseline (15 ETDRS letters ≅ 3 lines, Snellen VA) at the 12-month time point.
At one year, the patients who were treated with the 1mg or 4mg IVTA injection, as well as the standard grid photocoagulation in eligible eyes that had vision loss secondary to macular edema from BRVO, showed similar improvements in visual acuity.
Elevated intraocular pressure (IOP) and cataract-formation rates were similar between the standard and 1mg IVTA groups, but higher in those receiving 4mg. Specifically 2 percent, 7 percent, and 26 percent of those in the standard, 1mg, and 4mg groups had elevated IOP that was managed with IOP-lowering topical medication (one year).
The study group calls for improved treatments and recommends grid laser photocoagulation for patients who have macular edema causing vision loss in BRVO. As noted above, less than one-third of study eyes had significant visual acuity improvement.
Currently, there is no proven treatment for patients who have vision loss secondary to macular edema in CRVO. SCORE Study Report 5 reported the results of a trial comparing observation as the standard modality against the same IVTA paradigm as in the SCORE Study Report 6, but for CRVO.
The results of this trial showed superiority of IVTA. At one year, only 7 percent of the observation group achieved the 15-letter improvement while 27 percent and 26 percent of the IVTA groups improved (1mg, 4mg, respectively). So, with the natural history being poor, IVTA is a promising alternative. The 1mg dose is the preferred treatment and is recommended by the study group.
FDA approval has now been granted to an intravitreal implant that offers sustained release of a steroid for the treatment of macular edema in these cases. This device is the Ozurdex (Allergan) implant. As the name implies, the active ingredient is dexamethasone. More information can be found at http://www.ozurdex.com/how-ozurdex-works.aspx. CLSFor references, please visit www.clspectrum.com/references.asp and click on document #172.
Dr. Semes is a professor of optometry at the UAB School of Optometry.