Efficacy and safety of intravitreal injection of conbercept for moderate to severe nonproliferative diabetic retinopathy

Abstract

Purpose: This study aimed to assess the effectiveness and safety of intravitreal injection of conbercept (IVC) in treating moderate to severe nonproliferative diabetic retinopathy (NPDR), with or without accompanying diabetic macular edema.

Methods: In this longitudinal retrospective study, 35 patients (50 eyes) with moderate to severe NPDR and Diabetic Retinopathy Severity Scale (DRSS) scores between 43 and 53 were treated at the Department of Ophthalmology, First Affiliated Hospital of Kunming Medical University, from October 2018 to January 2023. Treatment protocol included three monthly IVC injections followed by a pro re nata (PRN) regimen over a two-year follow-up period. Outcome measures were best-corrected visual acuity (BCVA), intraocular pressure, central macular thickness (CMT), extent of hard exudate (HE), and changes in DRSS scores. DRSS scores before and after treatment were analyzed using the Wilcoxon rank-sum test. Both systemic and ocular adverse events were meticulously documented to ascertain safety.

Results: From baseline to the final follow-up, the mean BCVA improved from 0.41 ± 0.39 to 0.23 ± 0.20 logMAR (p<0.05). The mean CMT decreased from 306.22 ± 77.40 to 297.97 ± 88.15 μm (p = 0.385). At 24 months, DRSS scores improved by ≥1 stage in 40 eyes (80%), ≥ 2 stages in 28 eyes (56%), ≥3 stages in 10 eyes (20%), and remained stable in 6 eyes (12%). The DRSS scores at each follow-up interval demonstrated statistically significant improvement from baseline (p<0.05). In 15 of 27 eyes (55.56%) with diabetic macular edema (DME), there was a significant reduction in the mean area of HE from baseline (p<0.05). No serious systemic adverse events were observed.

Conclusion: IVC is an effective and safe treatment for moderate to severe NPDR, demonstrating significant improvements in DRSS scores.

Keywords: Diabetic Retinopathy Severity Scale; VEGF – vascular endothelial growth factor; conbercept; diabetic macular edema; moderate to severe nonproliferative diabetic retinopathy.

Figure 1

Mean ± standard deviation logMAR BCVA from baseline to the 24-month follow-up. *p < 0.05 vs. baseline; **p < 0.001 vs. baseline. BCVA, best-corrected visual acuity; logMAR, logarithm of the minimum angle of resolution.

Figure 2

Mean ± standard deviation CMT from baseline to the 24-month follow-up. *p < 0.05 vs. baseline; **p < 0.001 vs. baseline. CMT, central macular thickness.

Figure 3

Distribution of patients with different Diabetic Retinopathy Severity Scale scores at baseline, month 12, and month 24.

Figure 4

Percentage of patients with an improvement of 1 step or more, 2 steps or more, and 3 steps in their Diabetic Retinopathy Severity Scale scores at month 6, month 12, month 18, and month 24.

Figure 5

Ultrawide-field fundus photography and optical coherence tomography 6 × 6 mm scan of NPDR eye accompanied with DME (A1,A2), and NPDR eye without DME (B1,B2). Compared with baseline (A1,B1), there were significant improvement in DRSS scores, decrease in hemorrhagic and hard exudates area in 24th month following (A2,B2).

Figure 6

Mean ± standard deviation HE area from 1-month to 24-month follow-up time points. *p < 0.05 vs. baseline; **p < 0.001 vs. baseline. HE, hard exudate.