Intravitreal triamcinolone could reduce need for PDT re-treatment in eyes with exudative AMD

By Cheryl Guttman

ORLANDO, FL - Adjunctive intravitreal triamcinolone acetonide may improve visual outcomes and minimise the need for photodynamic therapy (PDT) re-treatment in eyes with exudative age-related macular degeneration (AMD).

That is according to the results of an open, uncontrolled study evaluating the use of intravitreal triamcinolone acetonide 4.0 mg administered immediately after verteporfin (Visudyne) PDT.
Richard F. Spaide MD presented his findings at the annual meeting of the American Academy of Ophthalmology.

His study included two sub-groups: one comprising 13 eyes with no previous treatment and the second 13 eyes that underwent repeat PDT treatment and suffered vision loss before PDT.
Results from clinical and angiographic follow-up at three and six months indicated that the adjunctive use of triamcinolone might improve visual outcomes and minimise the need for PDT re-treatment relative to historical experience with PDT alone.

"Although our study has the limitations of being small and uncontrolled compared to the responses of eyes treated with verteporfin PDT in the TAP study, the results are very encouraging," Dr Spaide said.
He explained that interest in using intravitreal triamcinolone to treat exudative AMD is based on its anti-inflammatory, anti-angiogenic and anti-vascular permeability effects.
Verteporfin PDT may rapidly close the new vessels in eyes with CNV secondary to AMD.

But those effects are transient and it also stimulates inflammation and increases vascular permeability to cause oedema. After three months, there is typically a one-line loss of vision and most patients require re-treatment for persistent leakage, he said.
"Triamcinolone persists in the vitreous cavity for months after injection and based on its pharmacological profile, might be expected to address the limitations of verteporfin PDT and reduce the need for repeating this expensive modality," Dr Spaide said.

In his study, mean baseline ETDRS visual acuity was about 20/160 in both the newly and previously treated groups. After three months, patients in the newly treated group achieved a +1.9 line change, a statistically significant difference.
Of the 13 patients, four (31%) showed a visual acuity improvement of three lines or more. Based on an assessment of fluorescein angiograms at the three-month visit, only two (15%) eyes were treated again with PDT.

At the six-month visit, there was a further increase in mean acuity with the change from baseline averaging +2.3 lines. Based on the repeat angiograms, no eyes required further PDT.
In the previously treated eyes, the mean visual acuity change from baseline at three months was only +0.3 lines, which was not a statistically significant improvement.

Only one eye had gained three or more lines from baseline vision and by six months, mean visual acuity was no different from baseline. However, during the course of follow-up, none of the previously treated eyes required further PDT.
"These results are in contrast with those achieved in the TAP study where at the first three-month visit about 90% of patients required re-treatment and there was on average a one line loss in acuity.

"They also compare favourably with outcomes reported for other anti-angiogenic agents, including anecortave acetate, Eye001 and rhuFab V2. Compared to those agents, triamcinolone has the advantage of being a low-cost, generic medication that may potentially require fewer injections," Dr Spaide said.

Intraocular pressure (IOP) elevation was the most common complication observed in the series, occurring in five (19%). It was controlled with medical monotherapy in all. In addition, progression of nuclear sclerosis was observed in two eyes and a posterior subcapsular cataract was noted in a third.
Jost B. Jonas MD reported German data on intravitreal treatment with triamcinolone acetonide 25 mg in 71 eyes of 67 patients with exudative AMD.

Almost all eyes, 68 (95%) had totally or predominantly (greater than 50%) occult choroidal neovascularisation (CNV) membranes and 23 (32%) eyes were pseudophakic. Eyes undergoing simultaneous cataract surgery were excluded from the study.
The results showed early vision benefits, with significant improvements from baseline Snellen acuity after one and two months' follow-up.

Acuities remained numerically better than baseline thereafter. While the effects were not statistically significant, Dr Jonas suggested a treatment benefit might have been masked by triamcinolone-induced cataractous changes in the crystalline lens.

"Currently there are no effective modalities for reducing vision loss in eyes with predominantly occult CNV related to AMD.

"We have experience using the 25 mg dosage of triamcinolone acetonide in over 300 eyes with a range of proliferative, oedematous and neovascular ocular diseases and found it to be relatively well tolerated. We feel this modality merits further study as a treatment for exudative AMD," Dr Jonas said.
Visual acuity testing showed significant improvements from baseline after one and two months, increasing from a mean of 0.16 at baseline to 0.20.

At monthly follow-up visits thereafter, mean visual acuities were not significantly different compared to baseline. At three months, visual acuity in the majority of eyes was still slightly better than at baseline, while at six months most had lost vision and were below their baseline level.
Dr Jonas observed that the decline in vision benefit over time seemed to coincide with the disappearance of triamcinolone acetonide crystals from within the eye.

"That raises the issue of whether it might be useful to administer repeat injections at an appropriate interval to maintain a therapeutic intraocular concentration but the safety of serial treatment with a high dose of this steroid also remains a question," Dr Jonas said.

Repeat injections were administered to six eyes at three to seven months after the initial treatment. One eye was treated a total of four times. Those eyes exhibited a positive visual response to the first intravitreal injection but subsequently lost vision. Transient vision improvement was noted in three eyes after the repeat injection.

Like Dr Spaide's series, the most common side effects were cataractous changes in the crystalline lens and ocular hypertension. IOP was elevated to 22 mm Hg or higher in at least one follow-up measurement in 40% of eyes and raised to the 50 mm Hg to 60 mm Hg range in two eyes.

Those latter cases had pre-existing glaucoma and went on to require filtering surgery. IOP elevation was treated topically in the remaining eyes without development of any optic nerve glaucomatous changes during the available follow-up.

"No cases of post-injection endophthalmitis, rhegmatogenous retinal detachment or proliferative vitreoretinopathy occurred but the potential for those risks must also be considered cautiously with this treatment," he noted.

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