Intravitreal bevacizumab (Avastin) versus triamcinolone (Volon A) for treatment of diabetic macular edema: one-year results

Abstract

Purpose: The objective was to compare retinal morphology and function following intravitreal injections of bevacizumab (Avastin) or triamcinolone (Volon A) in patients with early diabetic macular edema (DME).

Patients and methods: The study was planned as a randomized, prospective, interventional clinical trial. A total of 30 diabetic patients with treatment-naïve, clinically significant macular edema were included in this study and randomized to two equal groups. One group initially received three injections of 2.5 mg bevacizumab in monthly intervals. The second group received a single injection of 8 mg triamcinolone, followed by two sham interventions. Functional and anatomic results were evaluated monthly using ETDRS vision charts and spectral-domain optical coherence tomography. According to the study protocol, retreatment after 3 months was dependent on functional and anatomic outcome in a PRN regimen.

Results: Baseline best corrected visual acuity (BCVA) was 0.30 logMAR and central retinal subfield thickness (CSRT) was 505 μm in the bevacizumab group and 0.32 logMAR and 490 μm CSRT in the triamcinolone group. After 3 months, BCVA improved to 0.23 logMAR (bevacizumab) and 358 μm CRST and 0.26 logMAR (triamcinolone) and 308 μm CSRT. After 12 months, BCVA further recovered in the bevacizumab group (0.18 logMAR) but slightly decreased in the triamcinolone group (0.36 logMAR).

Conclusion: Intravitreal bevacizumab and triamcinolone are both equally effective in reducing CSRT in early DME. After 6 months, rehabilitation of vision was comparable in both treatment arms, whereas at the final follow-up at month 12, BCVA was superior in the bevacizumab than in the triamcinolone sample. This may be related to cataract development following steroid treatment, as well as to substance-specific mechanisms within the angiogenic versus the inflammatory cascade.

Figure 1

Change in BCVA of both groups over 12 months in logMAR values. Blue symbols represent the bevacizumab, and red symbols represent the triamcinolone values. Asterisks indicate significant differences between groups. After 12 months, the functional results of the bevacizumab-treated cohort were significantly superior compared with the triamcinolone group.

Figure 2

SD-OCT measurements of retinal thickness (CRT) over 1 year. The X axis represents values (μm) as mean and 95% confidence intervals. Bevacizumab (blue line) as well as triamcinolone (red line) induced a significant reduction of retinal thickness because of resolution of macular edema. Asterisks indicate significant differences between groups.

Figure 3

(a) Retinal morphology under intravitreal treatment with triamcinolone over 1 year. In this patient, triamcinolone induced an obvious resolution of macular edema with sub- and intraretinal components. Accumulation of hard exudates is clearly visible in the outer nuclear layer. Recurrent edema typically developed in the parafoveal area and was successfully retreated with a further injection. (b) OCT images documenting the retinal response to anti-VEGF treatment with bevacizumab over 1 year. Consecutive injections induced a distinct regression of macular edema with decrease of intra- and subretinal fluid. Continuous treatment was necessary to maintain a stable effect. An exemplary case is shown at baseline with intra- and subretinal fluid. Typically subretinal fluid has subsided completely at month 12, but intraretinal cysts within the outer nuclear layer remain and are responsible for an increased CSRT at the last visit.

Figure 4

Results of intraocular pressure (IOP) measurements in mm Hg (mean and 95% CI) of both groups over 12 months. Blue symbols represent values of the bevacizumab, and red symbols represent values of the triamcinolone sample. Asterisks indicate significant differences between groups. Already at baseline, mean IOP values were slightly elevated in the triamcinolone sample. However, IOP remained constant in both groups over the entire study period.