Comparison Of Different Dosing Regimens Of Intravitreal Conbercept Injection In Patients With Macular Edema Secondary To Branch Retinal Vein Occlusion

Objective:To compare the difference of short-term efficacy between three initial monthly intravitreal conbercept(IVC)injections followed by pro re nata(PRN)dosing and one initial IVC injection followed by PRN dosing in managing patients with macular edema(ME)secondary to branch retinal vein occlusion(BRVO).To compare the mean injection numbers and the pharmacoeconomic evaluation between two groups and to investigate baseline predictors of final visual acuity(VA)in IVC treatment of BRVO-ME.Methods:In this prospective,randomized,and comparative study,60 patients who were diagnosed as ME secondary to BRVO were divided randomly into 3+PRN group(n=30)and 1+PRN group(n=30).1+PRN group switch to PRN dosing after one injection and 3+PRN group switch to PRN dosing after three loading injections.Best-corrected visual acuity(BCVA),central macular thickness(CMT)and mean injection numbers were compared between the two groups in six months follow-up period.Pharmacoeconomic evaluation was assessed by average cost-effectiveness ratio(ACER)and incremental cost-effectiveness ratio(ICER)between two groups.Possible baseline predictors of final VA were also investigated in both groups.Results:The mean BCVA(LogMAR)were improved from 0.82±0.17 to 0.35±0.12 in 3+PRN group and from 0.80±0.24 to 0.38±0.13 in 1+PRN group respectively.The CMT were decreased from 541.5±92.3μm to 256.6±44.1μm in 3+PRN group and from 505.3±84.0μm to 261.4±24.7μm in 1+PRN group respectively.There was no statistically significant difference either BCVA or CMT between two groups at any time point(P>0.05).The BCVA and CMT gains at the last visit were-0.47±0.24 logMAR and 284.9±46.2μm in 3+PRN group and-0.42±0.29 logMAR and 243.9±50.7μm in 1+PRN group,respectively(P>0.05).The percentage of patients who achieved BCVA>0.5 at the last visit was 53.3%and 46.7%in 3+PRN group and 1+PRN group,respectively(P>0.05).During the study period,the mean number of injections were 3.64±0.73 in 3+PRN group and 2.30±0.91 in 1+PRN group respectively(P<0.0001).In both groups,four factors were associated with better visual outcome at the 6th month after the first injection,including younger age,shorter duration,better baseline BCVA and integrity of photoreceptor inner and outer segment(IS/OS).Pharmacoeconomic evaluation showed that 1+PRN regimen cost less for per gain of BCVA or CMT than 3+PRN regimen.Based on the findings of Pharmacoeconomic evaluation,1+PRN dosing regimen was more cost-effective in managing BRVO-ME.Conclusion:1.IVC treatment for BRVO-ME is effective and safe,1+PRN and 3+PRN dosing regimens can achieve similar functional outcomes in short follow-up period.2.1+PRN dosing regimen need fewer injections and was more cost-effective than 3+PRN dosing regimen in IVC treatment for BRVO-ME.3.Younger age,shorter duration,better baseline BCVA and integrity of IS/OS were associated with better visual outcome at the 6th month after the first injection in IVC treatment for BRVO-ME.