One-year outcomes of novel VEGF decoy receptor therapy with intravitreal conbercept in diabetic retinopathy-induced macular edema

Purpose Conbercept is a novel recombinant fusion protein designed as a decoy receptor for vascular endothelial growth factor (VEGF) and placental growth factor. The primary purpose was to investigate the effect and safety of conbercept, based on a practical protocol, in the eyes of patients with diabetic macular edema (DME), and the secondary aim was to evaluate the efficacy of low-dose triamcinolone acetonide in patients with refractory DME who had little response to conbercept. Methods In this retrospective clinical study, 89 treatment eyes from 76 patients with clinically significant DME were initially treated with one to three consecutive monthly intravitreal conbercept (IVC) injections, followed by retreatment with conbercept or switch therapy to triamcinolone acetonide (TA) based on a 6-month observation of the curative effect of IVC. Results Sixty eyes were initiated on conbercept treatment for DME throughout the entire 1-year assessment period. After at least three consecutive monthly IVC treatments, 29 eyes further received intravitreal triamcinolone acetonide (IVTA) injections at month 6. From baseline to 1 year, the mean number of conbercept injections in the IVC group (n=60) was 4.5±1.0, and the mean number of conbercept injections in the IVC plus IVTA group (n=29) was 3.1±0.3. The mean best-corrected visual acuity (BCVA) and central macular thickness (CMT) were statistically significantly improved at 1 and 3 months after IVC treatments in the IVC group, and gradually improved at 9 months after IVTA treatments in the IVC plus IVTA group. There were no severe complications or conbercept-related adverse ocular and systemic side effects. Conclusions Conbercept could be effective for visual and anatomic improvements in DME eyes with relatively fewer intravitreal injections and longer treatment intervals in clinical practice. Low-dose TA may be useful for patients with refractory DME resistant to anti-VEGF therapy.