SCORE studies: Intravitreal corticosteroid may improve odds of vision gain in CRVO

Triamcinolone may be more beneficial than the current standard of care for patients with central retinal vein occlusion. In addition, it appears to be equally efficacious as laser grid photocoagulation in treatment of branch retinal vein occlusion, but the drug does carry a slightly less optimistic adverse event profile.

Results from the Standard Care vs. Corticosteroid for Retina Vein Occlusion (SCORE) study on CRVO showed that about one-quarter of patients receiving intraocular corticosteroid therapy with triamcinolone achieved a 15-letter or better improvement in visual acuity at 12 months, which represented a five-times higher odds ratio of achieving the primary endpoint compared with observation.

The study employed observation as a comparator because earlier studies, notably the Central Vein Occlusion Study (CVOS), showed no difference in visual acuity gains in patients with CRVO treated with laser grid photocoagulation compared with observation.

The BRVO arm of the SCORE study, however, compared intraocular corticosteroids with laser grid photocoagulation, as earlier studies — the Branch Vein Occlusion Study (BVOS) in particular — showed a treatment benefit with laser compared with the natural history of the disease course.

In the SCORE-BRVO study, a similar number of patients in the laser and steroid groups achieved a 15-letter gain at 12 months, which was also the primary endpoint of that study. However, rates of adverse events were higher in the steroid groups compared with laser.

Michael S. Ip

“Steroids do work, but when compared to an equally efficacious and safer therapy, such as laser photocoagulation, we really don’t recommend the use of intraocular corticosteroids in the setting of a branch vein occlusion,” Michael S. Ip, MD, the lead author of the SCORE-CRVO study and an investigator in the SCORE-BRVO study, said in an interview with Ocular Surgery News.

CRVO

In a multicenter, randomized clinical trial of 271 patients, with 88 undergoing observation only, 92 receiving a 1-mg dose of intravitreal triamcinolone and 91 receiving a 4-mg dose, 6.8%, 26.5% and 25.6%, respectively, had gained 15 or more letters of visual acuity compared with their baseline score. Patients in the observation group were also more likely to lose 15 letters or more of vision: 43.8% compared with 25.3% (1 mg) and 25.6% (4 mg).

Patients were re-treated in the steroid arms of the study at 4-month intervals, with allowance for investigator discretion if the patient either encountered a contraindication to, or else required a deferral of, steroid injection, or if the patient required more frequent corticosteroid. Steroid therapy was stopped at 8 months if a patient had received at least two injections without “at least borderline improvement” in visual acuity.

Patients in the observation arm were permitted to cross over to the treatment arm if they lost 15 letters or more of visual acuity as a result of persistent macular edema. However, final visual acuity scores were analyzed based on original randomization assignment. At 12 months, 73 patients (83%) completed the study in the observation arm, 83 (90%) in the 1-mg group and 82 (90%) in the 4-mg group.

“The likelihood of a gain in visual acuity letter score of 15 or more at 12 months is five times greater with intravitreal triamcinolone than observation for eyes with a vision loss associated with macular edema secondary to perfused CRVO,” the study authors noted.

However, they added, “in contrast to the visual acuity results, there was no difference between the groups in retinal thickness at 12 months.”

“There is a disconnect between the central subfield thickness and visual acuity improvement,” Dr. Ip said. “There’s probably something to improvement in visual acuity and preservation of visual acuity in CRVO that the steroids are doing that is other than reduction in retinal thickness.”

The study authors speculated that the corticosteroid may confer an anti-inflammatory or neuroprotective effect on retinal tissue and/or photoreceptors.

BRVO

Whereas intraocular corticosteroids outpaced the standard of care in visual acuity gain in the SCORE-CRVO study, steroid was not demonstrably better than standard of care — laser grid photocoagulation — in the SCORE-BRVO study.

In the SCORE-BRVO study, 28.9% of 137 patients in the observation group, 25.6% of 136 patients in the 1-mg triamcinolone group and 27.2% of 138 patients in the 4-mg group gained 15 letters or more in visual acuity at 12 months.

All patients were re-treated at 4-month intervals and crossover was permitted at 8 months if the original treatment was deemed futile due to loss of 15 or more letters despite two or more treatments.

While the safety profile was essentially comparable between the corticosteroid arms and the standard-of-care arm in the SCORE-CRVO study, there was a statistically significant higher incidence of IOP rise and requirement for IOP lowering medication in the steroid-treated arms of the SCORE-BRVO study compared with laser, with the effect being dose-dependent.

In eyes that were phakic at baseline, 13% in the laser group, and 25% and 35% in the 1-mg group and 4-mg groups, respectively, developed new-onset lens opacity or progression of pre-existing cataract.

“If you look at the two doses of steroid vs. the laser, at none of the time points was there any advantage to using the intraocular corticosteroid as opposed to laser,” Dr. Ip said. – by Bryan Bechtel

• Michael S. Ip, MD, can be reached at University of Wisconsin, Fundus Photograph Reading Center, Park West One, 406 Science Drive, Suite 400, Madison, WI 53711-1068; 608-263-2853; fax: 608-262-1899; e-mail: msip@wisc.edu.