Conbercept Injection in Treatment of Severe Proliferative Diabetic Retinopathy

Study Overview
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Brief Summary
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To evaluate efficacy of different intravitreal Conbercept injection therapy in the treatment of severe proliferative diabetic retinopathy.

Detailed Description
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To assess the clinical effects of preoperative, intraoperative or preoperative combined with intraoperative intravitreal conbercept (IVC) injection in pars plana vitrectomy (PPV) with silicone oil tamponade for severe proliferative diabetic retinopathy (PDR). Methods. These patients were randomly assigned to three groups: Group 1 received an IVC injection 3 to 5 days before surgery; Group 2 received an IVC injection at the end of surgery; and Group 3 received an IVC injection 3 to 5 days before PPV as well as an IVC injection at the end of PPV. Follow-up examinations were performed for at least six months after surgery.

Official Title
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Different Conbercept Injection Methods in Treatment of Severe Proliferative Diabetic Retinopathy

Conditions
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Proliferative Diabetic Retinopathy, Tractional Retinal Detachment

Intervention / Treatment
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* Drug: Conbercept


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects of either sex aged ≥ 18 years. Diagnosis of diabetes mellitus (type 1 or type 2); Active proliferative diabetic retinopathy was clinically evident; Study eyes required a vitrectomy and silicone oil tamponade due to vitreous hemorrhage with significant fibrous proliferation, tractional retinal detachment in the posterior pole or complicated retinal detachment, which can be detected by B-scan ultrasonography. Ability to give informed consent. Exclusion Criteria: Coexistent ocular disease that may interfere with visual outcome; Prior vitreoretinal surgery or anti-vascular endothelial growth factor (VEGF) pharmacotherapy in either eye; A macula-involving retinal detachment for >6 months in the study eye; Iris or angle neovascularization and neovascular glaucoma; known allergy to any components of conbercept formulation severe external ocular infection; pregnancy or current oral contraceptive intake; usage of anticoagulant or antiplatelet therapy; preoperative or postoperative poor diabetes control [serum hemoglobin A1c (HbA1c) >11.0%]; uncontrolled systemic diseases, such as hypertension, cardiac diseases or presenting abnormal coagulation-associated blood diseases; <6 months of follow-up post initial surgery.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: IVC Preoperative group<br>Conbercept injection before vitrectomy | Drug: Conbercept<br>* Conbercept is a humanized soluble fusion protein which has a high binding affinity to the Fc region of human immunoglobulin G1 simultaneously. Prior clinical studies have demonstrated that intravitreal conbercept (IVC) inhibits the process of angiogenesis in vivo and in vitro, and has been recognized as a novel effective treatment strategy for neovascularization, providing an alternative treatment option for ophthalmologists.<br>|
| Experimental: IVC Postoperative group<br>Conbercept injection at the end of vitrectomy | Drug: Conbercept<br>* Conbercept is a humanized soluble fusion protein which has a high binding affinity to the Fc region of human immunoglobulin G1 simultaneously. Prior clinical studies have demonstrated that intravitreal conbercept (IVC) inhibits the process of angiogenesis in vivo and in vitro, and has been recognized as a novel effective treatment strategy for neovascularization, providing an alternative treatment option for ophthalmologists.<br>|
| Experimental: IVC Pre- and Post-operative group<br>First conbercept injection before vitrectomy and second at the end of operation. | Drug: Conbercept<br>* Conbercept is a humanized soluble fusion protein which has a high binding affinity to the Fc region of human immunoglobulin G1 simultaneously. Prior clinical studies have demonstrated that intravitreal conbercept (IVC) inhibits the process of angiogenesis in vivo and in vitro, and has been recognized as a novel effective treatment strategy for neovascularization, providing an alternative treatment option for ophthalmologists.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Best-corrected Visual Acuity |  | 6 months | 
| Duration of Surgery | To evaluate the influence of these three methods to the final duration of surgery. We carefully estimated the time of the vitrectomy from insertion to extraction of the 23-gauge three-port trocars. | during the operation time | 
| Intraoperative Bleeding | The grading criteria for intraoperative bleeding: Grade 1, spontaneous cessation of minor bleeding or bleeding that stopped by transient elevation of perfusion pressure; Grade 2, moderate bleeding requiring endodiathermy or broad blood clots formed far away from the bleeding site; Grade 3, thick blood clots exceeding half of the posterior pole or affecting the operation field. | Time between the insertion and extraction of three 23-gauge vitrectomy ports | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative Preretinal Blood | The grading criteria for postoperative preretinal blood: Grade 1, isolated blood clots within 10 disk area but without covering the posterior pole; Grade 2, broad blood clots exceeding 10 disk area regardless of involvement of the posterior pole; Grade 3, broad blood clots exceeding 10 disk area as well as involving the posterior pole. Maximal extent of preretinal blood within 1 week postoperatively was used for grading the extent of hemorrhage. | postoperatively, up to 1 week | 
| Reabsorption Time of Blood | To monitor the reabsorption time of preretinal blood. | follow up period, up to an average of 6 months after the operation | 
| Recurrent Vitreous Hemorrhage | Recurrent vitreous hemorrhage(VH) was referred to any new episode of VH occurring after one week postoperatively, dividing into early stage (≤ 4 weeks) and late stage (> 4 weeks). | follow up period, up to an average of 6 months after the operation | 
| Frequency of Intraoperative Electrocoagulation | The number of times electrocoagulation, which was used to stop bleeding, was carefully counted. | during the operation time | 
| Number of Participants With Neovascular Glaucoma (NVG) |  | follow up period, up to an average of 6 months after the operation | 
| Recurrent Retinal Detachment |  | follow up period, up to an average of 6 months after the operation | 
| Need for Reoperation | due to recurrent retinal detachment or unclear vitreous hemorrhage | follow up period, up to an average of 6 months after the operation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Conbercept, Proliferative diabetic retinopathy, Silicone oil tamponade