An exploratory study of the safety, tolerability and bioactivity of a single intravitreal injection of vascular endothelial growth factor Trap-Eye in patients with diabetic macular oedema

Aim: The aim of the study was to assess the safety and bioactivity of a single intravitreal injection of vascular endothelial growth factor (VEGF) Trap-Eye in subjects with diabetic macular oedema (DMO). Methods: Five subjects with DMO, foveal thickness ≥250 mm measured by optical coherence tomography (OCT), and best-corrected visual acuity (BCVA) between 20/40 and 20/320, were enrolled. Each participant received a single intravitreal injection of 4.0 mg of VEGF Trap-Eye followed by a 6-week observation period. Outcome measures included safety and biological activity, including changes in BCVA and excess retinal thickness assessed by OCT. Results: Injections of VEGF Trap-Eye were well tolerated with no ocular toxicity. One patient had an unrelated serious adverse event: hospitalisation for cellulitis of the left foot 27 days after injection of VEGF Trap-Eye. Median baseline BCVA was 36 ETDRS letters read at 4 m (not ETDRS visual acuity score; Snellen equivalent: 20/50) and median baseline excess central 1 mm foveal thickness (FTH) was 108 mm. At 4 weeks after injection, the median excess FTH was 59 mm and the median improvement in BCVA was nine letters. At 6 weeks after injection, four of the five patients showed improvement in excess FTH (median 74 μm; 31% reduction from baseline, p = 0.0625) and four of the five showed improvement in BCVA (median improvement of three letters). Conclusions: A single intravitreal injection of 4.0 mg of VEGF Trap-Eye was well tolerated and preliminary evidence of bioactivity was detected. These findings support additional studies investigating multiple injections of VEGF Trap-Eye in patients with DMO.