Abstract
Purpose :
Intravitreal ranibizumab is the first-line treatment for diabetic macular oedema (DME) in the UK, but 25-40% of patients have a partial or no response. Intravitreal corticosteroids are second-line, but guidance on when to switch therapy is incomplete. We performed a retrospective, observational clinical study to identify whether 12-month outcomes can be predicted from the response to the first three injections of ranibizumab.
Methods :
We analysed data of 100 patients who had been treated with intravitreal injections of ranibizumab for DME and who had at least one year of follow-up. Treatment was given as a loading dose of 3 injections followed by an as needed (PRN) retreatment regime; rescue laser treatment was not used. We recorded visual acuity (VA) and graded a change of 5+ letters as significant. We also recorded changes in central retinal thickness (CRT) and DME morphology, partial improvement being >10% reduction in excess CRT and significant improvement being >90% reduction. These were recorded at baseline, 3 months and at 12 months.
Results :
After 3 injections of ranibizumab, 51% of patients showed a significant improvement in VA and 84% of this cohort maintained this improvement at 12-months. Of the 33% who showed no improvement or a worsening of VA after 3 injections, 82% had no improvement after 12-months (p-value <0.05). The remaining 16% demonstrated a non-significant improvement in VA, of these eyes 50% showed a significant improvement at 12-months and the remainder showed a worsening or stable VA. Similarly, 80% of patients who had a significant reduction in CRT at 3-months maintained this at 12-months whereas 82% of patients who did not have a significant reduction in CRT at 3 months did not improve by 12-months.
Conclusions :
The response to three ranibizumab injections is a good predictor of the 12-month outcome of continued treatment in DME, when measured by change in visual acuity. Similar predictions can be made following a 3-month measurement of CRT excess compared to baseline, in the absence of rescue laser therapy. This may help guide whether an early switch to alternative therapy such as corticosteroids is likely to be beneficial.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.