Clinical researchers at the Jaeb Center for Health Research, Tampa, Florida and the Beetham Eye Institute, Harvard in Boston, (supported by the DRCR Retina Network) have reported results for long-term outcomes for eyes with visual impairment from CI-DME (center-involved diabetic macular edema). From an extension study after 5 years, mean visual acuity (VA) improved from baseline by 7.4 letters but decreased by 4.7 letters between 2 and 5 years. The DRCR Retina Network had conducted a randomized clinical trial (Protocol T) comparing aflibercept, bevacizumab and ranibizumab. Regardless, Dr. Thomas Ciulla, from the Indiana University School of Medical School in Indianapolis, commented that “the fact that these patients retained a reasonable improvement over 5 years is quite remarkable. The doctors involved in caring for these patients and the clinical investigators should be commended”.
The DRCR Retina Network had previously reported a protocol retreatment regimen for 2 years showing that results demonstrated improved mean VA using anti-VEGF treatment. When baseline VA impairment was mild (20/32-20/40), there were no apparent differences between agents for mean change in VA from baseline at 1 year (primary outcome) or 2 years. However, when baseline VA impairment was more severe (20/50-20/320), aflibercept was superior to both bevacizumab and ranibizumab at 1 year and bevacizumabat 2 years. Protocol T ended after 2 years of protocol-defined retreatment regimens. Participants were asked to return at 5 years from randomization to assess clinical outcomes and characterize follow-up treatments for DME and diabetic retinopathy (DR). During Protocol T, visits were scheduled every 4 weeks in year 1 and every 4 to 16 weeks in year 2, depending on treatment response. After Protocol T participation concluded at 2 years, follow-up and treatment were performed as standard care.
At the most recent follow-up outcomes, results have reported that sixty-eight percent (317/463) of eligible participants completed the 5-year visit. Between years 2 and 5, 68% (217/317) of study eyes received at least 1 anti-VEGF treatment (median, 4; interquartile range [IQR], 0-12). At 5 years, mean VA improved from baseline by 7.4 letters (95% confidence interval [CI], 5.9-9.0) but decreased by 4.7 letters (95% CI, 3.3-6.0) between 2 and 5 years. When baseline VA was 20/50 to 20/320, mean 5-year VA was 11.9 letters (95% CI, 9.3-14.5) better than baseline but 4.8 letters (95% CI, 2.5-7.0) worse than 2 years. When baseline VA was 20/32 to 20/40, mean 5-year VA was 3.2 letters (95% CI, 1.4-5.0) better than baseline but 4.6 letters (95% CI, 3.1-6.1) worse than 2 years. Mean CST decreased from baseline to 5 years by 154 μm (95% CI, 142-166) and was stable between 2 and 5 years (-1 μm; 95% CI, -12 to 9). In conclusion from the study, the researchers commented that, “of among the approximately two-thirds of eligible Protocol T participants who completed a 5-year visit, mean VA improved from baseline to 5 years with no protocol defined visit schedule or treatment protocol after study follow-up ended at 2 years. Although there were no substantial differences in mean retinal thickness at 2 and 5 years, mean VA decreased during this time”.