Open Label Extension of a Clinical Trial of Intravitreal Triamcinolone for Diabetic Macular Oedema-TDMX Study

A 25 fold increase in the risk of going blind on diagnosis of diabetes is one of the most daunting threats that patients face. People using insulin are particularly challenged because they are unable accurately to draw up their dose of drug. Most cases of vision impairment in diabetes are due to macular oedema that persists or recurs after laser treatment. There are now a number of uncontrolled, anecdotal reports that intravitreal triamcinolone (IVTA) is highly effective for the treatment of diabetic macular edema which is refractory to conventional laser treatment. We commenced the first placebo-controlled, double masked clinical trial of IVTA for refractory macular oedema in 2002. The 3 month results from this study provide the first scientific proof of principle that IVTA reduces macular thickness and improves vision. The two year results will be available in March 2005, but confidential interim analysis of efficacy data in September 2004 suggested that the beneficial effect of triamcinolone treatment persisted. Thus it appears that treatment with IVTA may be the most significant development for the prevention of blindness in people with diabetes since the introduction of laser treatment. It would also be a highly cost-effective intervention that could be administered by general ophthalmologists. The treatment cannot be recommended for routine use, however, until its long term efficacy and safety have been established. Since we already have a well studied group of patients who have received treatment for 2 years, we are in a unique position to extend the study in order to provide the long-term (5-year) safety and efficacy data that does not appear to be forthcoming from any other source. The completion of this study will have a direct and immediate effect on the risk of blindness in people with diabetes by allowing doctors to predict more accurately the long term effects of this promising new treatment.

Inclusion criteria

Participation in the study will be offered to all patients at the conclusion of the TDMO study. Currently we are still following 64 of the 69 (93%) eyes that were initially entered into the study that had reduced vision from diabetic macular oedema at baseline.

Exclusion criteria

• Uncontrolled glaucoma
• Loss of vision due to other causes (e.g. age related macular degeneration, myopic macular degeneration)
• known allergies to triamcinolone acetate, patient is already receiving systemic steroid treatment, intercurrent severe disease such as septicemia, any condition which would affect follow-up or photographic documentation (e.g. geographical, psycho-social, media opacities)