Fusion proteins for treatment of retinal diseases: aflibercept, ziv-aflibercept, and conbercept

In the last few years, monoclonal antibodies have revolutionized the treatment of retinal neovascular diseases. More recently, a different class of drugs, fusion proteins, has provided an alternative treatment strategy with pharmacological differences. In addition to commercially available aflibercept, two other drugs, ziv-aflibercept and conbercept, have been studied in antiangiogenic treatment of ocular diseases. In this scenario, a critical review of the currently available data regarding fusion proteins in ophthalmic diseases may be a timely and important contribution. Aflibercept, previously known as VEGF Trap Eye, is a fusion protein of VEGF receptors 1 and 2 and a treatment for several retinal diseases related to angiogenesis. It has firmly joined ranibizumab and bevacizumab as an important therapeutic option in the management of neovascular AMD-, DME- and RVO-associated macular edema. Ziv-aflibercept, a systemic chemotherapeutic agent approved for the treatment of metastatic colorectal cancer, has recently drawn attention because of its potential for intravitreal administration, since it was not associated with ERG-related signs of toxicity in an experimental study and in human case reports. Conbercept is a soluble receptor decoy that blocks all isoforms of VEGF-A, VEGF-B, VEGF-C, and PlGF, which has a high binding affinity for VEGF and a long half-life in vitreous. It has been studied in a phase three clinical trial and has shown efficacy and safety. This review discusses three fusion proteins that have been studied in ophthalmology, aflibercept, ziv-aflibercept and conbercept, with emphasis on their clinical application for the treatment of retinal diseases.

Conbercept for patients with age-related macular degeneration: a systematic review

Background

Conbercept is a novel vascular endothelial growth factor (VEGF) inhibitor for the treatment of wet age-related macular degeneration (AMD). This systematic review aims to assess the efficacy and safety of conbercept in the treatment of wet AMD.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, VIP database, and Wanfang database were searched from their earliest records to June 2017. We included randomized controlled trials (RCTs) evaluating the efficacy and safety of conbercept in wet AMD patients. Outcomes included the mean changes from baseline in best-corrected visual acuity (BCVA) score (primary outcome), central retinal thickness (CRT), plasma level of vascular endothelial growth factor (VEGF) over time, and the incidence of adverse events (AEs).

Results

Eighteen RCTs (1285 participants) were included in this systematic review. Conbercept might improve BCVA compared to triamcinolone acetonide [MD = 0.11, 95% CI (0.08, 0.15)], and reduce CRT compared to the other four therapies (conservative treatment, ranibizumab, transpupillary thermotherapy, and triamcinolone acetonide). The incidence of AEs in patients receiving conbercept was significantly lower than those receiving triamcinolone acetonide [RR = 0.25, 95% CI (0.09–0.72)], but was similar to the other therapies. Conbercept seemed to be more effective than ranibizumab in lowering the plasma level of VEGF [MD = − 15.86, 95% CI (− 23.17, − 8.55)].

Conclusions

Current evidence shows that conbercept is a promising option for the treatment of wet AMD. Nevertheless, further studies are required to compare the efficacy, long-term safety and cost-effectiveness between conbercept and other anti-VEGF agents in different populations.

Electronic supplementary material

The online version of this article (10.1186/s12886-018-0807-1) contains supplementary material, which is available to authorized users.

Comparison of 12-month therapeutic effect of conbercept and ranibizumab for diabetic macular edema: a real-life clinical practice study

Background

To compare the efficacy of intravitreal conbercept and ranibizumab in the treatment of diabetic macular edema (DME) in a real-life clinical practice.

Methods

This was a retrospective study. Among 62 Chinese patients with DME, 32 patients (36 eyes) received intravitreal conbercept (IVC) injections and 30 patients (32 eyes) received intravitreal ranibizumab (IVR) injections, once a month for 3 months followed by as needed therapy. All participants had at least 12 months of follow-up. We compared the changes in best-corrected visual acuity (BCVA) letter score and central retinal thickness (CRT) between groups, as well as the number of intravitreal injections delivered. Safety was assessed with the incidence of adverse events (AEs).

Results

At month 12, the mean BCVA letter score improved by 9.3 ± 5.2 with conbercept, and by 8.9 ± 4.4 with ranibizumab, the mean CRT reduction was 138.4 ± 97.7 μm and 145.2 ± 72.5 μm, respectively. There was no statistically significant difference of improvement in BCVA (P = 0.756) and decrease in CRT (P = 0.748) between the two groups. The number of intravitreal injections delivered was significantly higher (P = 0.027) in the IVR group (7.2 ± 1.0 per eye) than in the IVC group (6.6 ± 0.9 per eye). There were no severe ocular adverse reactions or systemic adverse events.

Conclusions

Both conbercept and ranibizumab are effective in the treatment of DME, achieving the similar clinical efficacy. In comparison to ranibizumab, conbercept shows a longer treatment interval and fewer intravitreal conbercept injections are needed.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0554-8) contains supplementary material, which is available to authorized users.

One-Year Outcome of Conbercept Therapy for Diabetic Macular Edema

PURPOSE

To evaluate the therapeutic efficacy of conbercept for the treatment of diabetic macular edema (DME) with different baseline visual acuity.

METHODS

This is a retrospective, comparative study. A total of 107 eyes of 107 patients were included. According to the levels of baseline best corrected visual acuity (BCVA) and therapeutic regimen, the DME patients were divided into four groups: conbercept treatment subgroup with worse baseline VA (less than 69 letters, Snellen equivalent, 20/50 or worse; n = 37), untreated subgroup with worse baseline VA(n = 28); conbercept treatment subgroup with better baseline VA (78 to 69 letters, Snellen equivalent, 20/32 to 20/40; n = 25), untreated subgroup (n = 17). Patients received one initial intravitreal injection followed by re-treatments based on BCVA loss or increase of central macular thickness (CMT).

RESULTS

At month 12, the mean improvement of BCVA was significantly higher in both worse baseline VA group and better baseline VA group with conbercept treatment than that of corresponding untreated controls:18(15) letters vs. -4(6) letters, P < 0.001; 7(1) letters vs. -5(5) letters; P < 0.001; respectively. At month12 the mean CMT from baseline was significantly declined in both worse baseline VA group and better baseline VA group with conbercept treatment than that of respective untreated controls (-212.8 ± 11.9 vs.-44.3 ± 35.3µm,P < 0.001; -116.1 ± 88.9vs.-33.7 ± 49.8µm, P = 0.001; respectively).  At the end of twelve month follow-up, the BCVA improvement and CMT declination in worse baseline VA group were more prominent than that in better baseline group (P < 0.001). The mean numbers of injections were 6.7 ± 0.9, 6.5 ± 1.1 in worse baseline VA group and better baseline VA group, respectively (P = 0.35). The two groups have no significant difference in the number of injections.

CONCLUSION

Conbercept was effective in the treatment of DME at different levels of baseline BCVA. For worse baseline VA, BCVA improvement was more prominent than that of better VA subgroup.

Hyperreflective foci in OCT image as a biomarker of poor prognosis in diabetic macular edema patients treating with Conbercept in China

Purpose

To investigate the dynamic changes of hyperreflective foci (HF) in diabetic macular edema (DME) patients during the intravitreal Conbercept treatment in China.

Methods

DME Patients receiving intravitreal Conbercept (IVC) injections during the year 2016–2017 were retrospectively investigated. Thirteen patients (26 eyes) were recruited in this study. They received IVC once a month for 3 consecutive months. The number and location of HFs, the best-corrected visual acuity (BCVA) and central macular thickness (CMT) at each visit were analyzed and compared.

Results

After the first injection, BCVA (LogMAR) was increased from 0.75 ± 0.48 to 0.43 ± 0.24 (p < 0.05), CMT improved from 575.9 ± 191.9 to 388.2 ± 198.5 μm (p = 0.014). However, the BCVA and CMT had no statistical difference after the second and third injection as compared with those after the first injection respectively. The baseline number of HFs was 5.39 ± 4.24, 5.15 ± 5.17 and 0.88 ± 1.90 in the inner retinal, outer retinal and subretinal layer respectively. The number of HFs in these three retinal layers decreased significantly after the first injection (p = 0.0045, p < 0.0001 and p = 0.0045, respectively). However, after the second injection, only the number of HFs in the inner retinal layer experienced a further decrease. After the third injection, no statistically significant HFs changes was observed in each retinal layers. Correlation analysis showed that there was a positive significant correlation between the baseline number of HFs in the inner retina, outer retina, subretina and final BCVA (r = 0.571, p = 0.002; r = 0.464, p = 0.017; r = 0.405, p = 0.04 respectively). There was also a significant positive correlation between outer retinal HFs reduction, total retinal HFs reduction and increase of BCVA (r = 0.40, p = 0.043 and r = 0.393, p = 0.04 respectively).

There were no severe ocular adverse reactions or systemic adverse events.

Conclusions

Conbercept is effective and safe in the treatment of DME. HFs can act as a biomarker of poor final visual outcome.

Efficacy and safety of conbercept as a primary treatment for choroidal neovascularization secondary to punctate inner choroidopathy

Background

To evaluate the efficacy and safety of intravitreal conbercept (KH902) as the primary treatment of choroidal neovascularization secondary to punctate inner choroidopathy.

Methods

This study was a retrospective, consecutive, observational case series. We reviewed medical records of 16 eyes (16 patients) with naive subfoveal or juxtafoveal choroidal neovascularization secondary to punctuate inner choroidopathy that were treated with intravitreal conbercept injections. All patients completed at least six months of follow-up. Best-corrected visual acuity (BCVA) was measured, and anatomical features were assessed with fluorescein angiography, indocyanine green angiography, and optical coherence tomography.

Results

At the month-6 follow-up visit, best-corrected visual acuity improved from 0.70 ± 0.36 (with approximate Snellen equivalent of 20/100) to 0.44 ± 0.25 (20/50 in Snellen) logarithm of the minimum angle of resolution (logMAR) (P = 0.003). Mean improvement of vision was 2.6 lines, with 50% treated eyes (8 eyes of 16) showing an improvement of ≥3 lines and 62.5% (10 eyes of 16), obtaining an improvement of ≥2 lines; all 16 eyes had stable or improved vision. Mean central retinal thickness decreased from 294.94 ± 102.68 μm to 206.56 ± 61.71 μm (P = 0.005). Fifteen eyes (93.75%) showed absence of CNV leakage at the end of the study period. No conbercrept-related systemic or ocular adverse events were observed.

Conclusion

Intravitreal injection of conbercept significantly improved visual and anatomical outcomes in choroidal neovascularization secondary to punctate inner choroidopathy over a 6-month follow-up period.

Trial registration

ISRCTN85678307, retrospectively registered on May 11, 2017.

Intravitreal conbercept improves outcome of proliferative diabetic retinopathy through inhibiting inflammation and oxidative stress

Conbercept is a newly-developed anti-vascular endothelial growth factor (VEGF) drug. This study aimed to evaluate the effects of conbercept on inflammation and oxidative response in proliferative diabetic retinopathy (PDR). Morphology changes in retinal microvasculature of PDR patients were determined by optical coherence tomographic angiography (OCTA). The mice were injected with streptozocin (STZ) for 20 weeks to induced PDR, then the changes in inflammatory factors, oxidative response and histological analysis were examined with Elisa assay, real time-PCR and commercial kits analysis. Conbercept treatment significantly alleviated the retinal pathological changes and significantly reduced intercellular cell adhesion molecule-1 (ICAM-1), macrophage inflammatory protein-1 (MIP-1), IL-1β, IL-6 and TNF-α protein levels but not prostaglandin E1 (PGE1), prostaglandin E2 (PGE2) and prostaglandin F2a (PGF2a) levels, all of which were remarkably elevated in aqueous fluid of PDR patients compared with non-PDR subjects. Meanwhile the inhibitory effects of conbercept on these inflammatory factors were proved by RT-PCR assays in mice experiments. And the inflammatory signal such as p-IKBα and p-p65 was correspondingly inhibited by conbercept in STZ-treated mice. Conbercept treatment significantly elevated the aqueous glutathione level of PDR patients and inhibited NOX-1, NOX-4 and ph22phox mRNA expressions and ROS production of PDR mice. Ki67 immunofluorescence staining showed that conbercept inhibited endothelial cell proliferation in retina of PDR mice. In conclusion, conbercept significantly inhibited the angiogenesis, inflammation and oxidative response in PDR mice, and these findings further reveals the molecular mechanisms of conbercept in treating PDR.

The efficacy of conbercept or ranibizumab intravitreal injection combined with laser therapy for Coats' disease

PURPOSE

The current treatment approaches for Coats' disease by intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents (ranibizumab or conbercept) combined with laser therapy were evaluated for the efficacy during the treatment.

METHODS

The medical records of 28 patients diagnosed with Coats' disease followed by the treatment with intravitreal injection of anti-VEGF agents and laser therapies at Tianjin Medical University Eye Hospital and Hebei Eye Hospital during July 2012 and October 2017 were reviewed retrospectively. Clinical outcomes were recorded with a minimum follow-up of 6 months. The patients were divided into ranibizumab- and conbercept-treated groups, as well as based on age: pediatric and adult groups.

RESULT

Twenty-eight patients were involved in this study. The average number of the injections was 2.82 ± 0.98. Laser photocoagulation was conducted in all patients, and the average number of lasers was 2.63 ± 0.74. The average follow-up period was 24.29 ± 9.85 months. Fourteen patients (50%) were stable, 12 (43%) patients were improved, and 2 patients (7%) showed recurred subretinal fluid and exudation. The final best corrected visual acuity (BCVA) increased markedly after intravitreal injection of ranibizumab or conbercept combined with laser therapy (p = 0.029, p = 0.009, respectively). The number of injections and lasers between conbercept and ranibizumab groups did not vary significantly (p = 0.160, p = 0.573, respectively). Nine patients (60%) in the ranibizumab-treated group and five (38%) in the conbercept-treated group reached a stable phase, and five (33%) and seven (54%) patients got the vision improved after treated with ranibizumab or conbercept, respectively. In pediatric and adult groups, the initial and final BCVA differed significantly (p = 0.03, p = 0.008, respectively). However, the injection number was remarkably different (p = 0.02), while the laser numbers did not have any markedly difference (p = 0.38).

CONCLUSION

Intravitreal injection of ranibizumab or conbercept combined with laser therapy is an effective therapeutic option in Coats' disease. Moreover, the intravitreal injection of ranibizumab or conbercept had no significant adverse effects and appeared to offer visual improvement in Coats' disease.

The anti-inflammatory and anti-oxidative effects of conbercept in treatment of macular edema secondary to retinal vein occlusion

To investigate the effects of conbercept on inflammatory and oxidative response in macular edema secondary to retinal vein occlusion (RVO-ME). Retinal microvasculature were detected by optical coherence tomographic angiography (OCTA). The inflammation related factors including prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), prostaglandin F2a (PGF2a), intercellular cell adhesion molecule-1 (ICAM-1) and macrophage inflammatory protein-1 (MIP-1) were determined in human and mice with RVO-ME. OCTA images showed that capillary non-perfusion, enlargement of the foveal avascular zone, telangiectatic vessels and some forms of intraretinal edema in RVO-ME and all these were alleviated by conbercept treatment. PGE1, PGE2, PGF2a, ICAM-1 and MIP-1 in aqueous fluid extracted from RVO-ME patients was significantly increased compared with non-RVO subjects, intravitreal injection of conbercept partly reduced ICAM-1 and MIP-1 levels but not PGE1, PGE2 and PGF2a. The glutathione level was reduced in aqueous fluid extracted from RVO-ME patients but was restored after conbercept treatment. The inflammation, angiogenesis and ROS generation was increased in RVO-ME mice, conbercept partly inhibited these effects. Mechanistically, conbercept inhibited vascular endothelial growth factor (VEGF), ICAM-1, MIP-1, NOX-1 and NOX-4 protein expressions, but not PGE1, PGE2 and PGF2a expressions. Conbercept alleviates RVO-ME through inhibiting inflammation, angiogenesis and oxidative responses. These findings further reveals the molecular mechanism of conbercept for treatment of RVO-ME.

Quantitative Analysis of Retinal Microvascular Changes after Conbercept Therapy in Branch Retinal Vein Occlusion Using Optical Coherence Tomography Angiography

PURPOSE

To quantitatively evaluate microvascular changes in eyes with macular oedema due to branch retinal vein occlusion (BRVO) using optical coherence tomography angiography (OCTA) before and after intravitreal conbercept injection and the correlation of such changes with best-corrected visual acuity (BCVA) and retinal thickness.

METHODS

Twenty-eight eyes of 28 patients treated with a single intravitreal injection of conbercept for macular oedema due to BRVO were included in this study. The automatically measured values of the vessel density in the superficial (SCP) and deep retinal capillary plexus (DCP), the foveal avascular zone (FAZ) area, the FAZ perimeter, the vessel density within a 300 μm wide ring surrounding the FAZ (FD-300), the acircularity index (AI), the choriocapillaris flow area and the retinal thickness were obtained via OCTA before and at 1 month after initial injection and compared with those of age- and sex- matched healthy subjects.

RESULTS

In BRVO eyes, the vascular density in the SCP and DCP, the FD-300 and the flow area of choriocapillaris were significantly lower than those in healthy eyes, while the AI and the retinal thickness were significantly increased. After treatment, the retinal thickness in eyes with BRVO was significantly decreased in all quadrants, and the mean BCVA dramatically increased from 20/162 to 20/78 (p = 0.0017). The mean flow area of choriocapillaris significantly improved after treatment. Moreover, negative correlations between the logMAR BCVA and the whole vascular density in the SCP and DCP as well as the flow area of choriocapillaris were observed.

CONCLUSION

OCTA enables non-invasive, layer-specific and quantitative assessment of microvascular changes in eyes with BRVO before and after treatment, and it can be used as a valuable imaging tool for the evaluation of the follow-up in BRVO patients.

Correlation of retinal layer changes with vision gain in diabetic macular edema during conbercept treatment

Backgrounds

To assess the changes in individual retinal layer thickness and visual function associated with gains in visual acuity after an intravitreal conbercept injection in the diabetic macular edema (DME) on spectral domain optical coherence tomography (SD-OCT) and microperimetry during 1-year follow-up.

Methods

Retrospective observational study. Twenty patients with clinically significant DME in the study eye were imaged by SD-OCT every 3 months and MP1 microperimeter in the third month while receiving anti-vascular endothelial growth factor (VEGF) (conbercept) treatment. In each patient, seven retinal layers were segmented in 98 scans covering a 6 mm × 6 mm area of the macula at baseline and during 1 year of treatment. An automatic, full-threshold microperimetry of the central field (10° × 10°, 40 stimulated points) with the MP1 microperimeter. Thickness and microperimetry changes were quantitatively measured and evaluated for their correlation with increases in visual acuity.

Results

Although thicknesses of the inner nuclear layer (INL) and the outer nuclear layer (ONL) were reduced the most after treatment (p < 0.05), decreases of the ganglion cell layer (GCL) (r = 0.591, p = 0.006) and inner plexiform layer (IPL) (r = 0.663, p = 0.001) in central subfield area was associated with best-corrected visual acuity (BCVA) gain, and had the best estimation of BCVA gain (adjust R² = 0.544). Mean macular sensitivity in the central subfield was also well correlated with BCVA gain (r = 0.531, p = 0.016).

Conclusions

Neural recovery occurred after the resolution of edema during conbercept treatment, due to the decreases in GCL and IPL associating with gains in vision and improved microperimetry.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1131-0) contains supplementary material, which is available to authorized users.

Comparison of aqueous humor levels of PlGF and VEGF in proliferative diabetic retinopathy before and after intravitreal conbercept injection

AIMS

The aim of this paper is to observe the change of aqueous humor levels of placenta growth factor (PlGF) and vascular endothelial growth factor (VEGF) in proliferative diabetic retinopathy (PDR) patients before and one week after intravitreal conbercept injection.

METHODS

A prospective case series study was conducted in 24 active PDR patients (24 eyes). All the patients had received 0.5 mg of intravitreal conbercept followed by vitrectomy one week later. The aqueous humor was collected before conbercept injection and at the beginning of vitrectomy.

RESULTS

Before conbercept injection, the aqueous humor median levels of VEGF-A, VEGF-B and PlGF were457.0pg/mL(IQRfrom392.9to860.6pg/mL), 43.6pg/mL(IQRfrom33.6to81.6pg/mL), 37.5pg/mL(IQRfrom25.0to53.6pg/mL), respectively. One week after conbercept injection, the aqueous humor levels of VEGF-A, VEGF-B and PiGF decreased significantly. The aqueous humor VEGF-A levels in PDR patients with fibrovascular membranes were lower than those without them. There was positive correlation between aqueous humor VEGF-B and PiGF levels (P = 0.007). No significant correlation was found between VEGF-A and PiGF levels. No ocular and systemic adverse events were observed.

CONCLUSIONS

The aqueous humor levels of PlGF was correlated with VEGF-B, and levels of VEGF-A, VEGF-B, and PlGF decreased after intravitreal conbercept injection in active PDR patients.

Short-term effect of intravitreal conbercept injection on major and macular branch retinal vein occlusion

OBJECTIVE

To evaluate the effectiveness of intravitreal conbercept injection on major and macular branch retinal vein occlusion (BRVO).

METHODS

This retrospective analysis involved 43 patients with BRVO (major BRVO n = 24; macular BRVO, n = 19) who were diagnosed by fluorescein fundus angiography (FFA) and injected with intravitreal conbercept. The following outcomes were measured at baseline and follow-up (1-6 months): best-corrected visual acuity (BCVA), central foveal thickness (CFT), total retinal volume in a 6-mm diameter section of the macula, choroidal thickness under the central fovea of the macula, relative area of retinal hemorrhage, complications, and times when repeated injection was performed.

RESULTS

There were significant differences between the two groups in terms of BCVA, CFT, and total retinal volume in a 6-mm diameter section of the macula at 6 months after treatment. Choroidal thickness under the central fovea of the macula and relative area of retinal hemorrhage showed no significant differences between the two groups at 6 months after treatment; however, they significantly differed from baseline measurements.

CONCLUSION

In general, intravitreal injection of conbercept may have a better short-term effect in patients with macular BRVO than in patients with major BRVO.

Diabetic macular edema in proliferative stage treated with anti-vascular endothelial growth factor agent and triamcinolone acetonide by laser-based strategies

AIM

To appraise the effect of treatment for diabetic macular edema (DME) in proliferative stage with sufficient panrentinal photocoagulation (PRP) therapy and intravitreal injections (IV) Conbercept and posterior subtenon's triamcinolone acetonide (STTA) sequential therapy.

METHODS

This prospective clinical randomized controlled trial of cross-over design was conducted in three phases. The participants included cases of DME in proliferative stage. They were divided into two groups and treated with PRP before enrollment. Group A were treated with IV-Conbercept 0.5 mg for one month in the 1^st phase. Group B were treated with STTA 40 mg (twice per two weeks). The interventions were exchanged in the second phase (2mo) between the two groups. In the third phase (3-6mo) no other treatment was given. Best corrected visual acuity (BCVA), central macular thickness (CMT) measured by OCT and complications were compared.

RESULTS

After phase I: in Group A, BCVA improved from 0.201±0.17 to 0.37±0.24 (F=5.88, P=0.004). CMT changed from 449±155.10 to 304.1±84.70 µm (F=14.9, P<0.01). In Group B, BCVA changed from 0.195±0.19 to 0.26±0.20 (F=0.76, P=0.41) while CMT changed from 463.82±152.92 to 366.00±115.40 µm (F=3.70, P<0.03). The improvement of BCVA was better in Group A (P<0.05). After phase II: in Group A, BCVA raised to 0.47±0.27 (F=0.26, P<0.01), CMT reduced to 260.67±62.97 µm (F=-188.3, P<0.01); in Group B, BCVA raised to 0.51±0.26 (F=0.31, P<0.01), CMT reduced to 261.93±50.15 µm (F=-201.9, P<0.01). But there were no difference between two groups (P>0.05). After phase III: in Group A, BCVA maintained 0.42±0.25 (F=0.22, P=0.001), CMT maintained 267.8±58.34 µm, (F=-0.27, P<0.01); in Group B, BCVA was 0.47±0.25 (F=-0.27, P<0.01), CMT was 272.71±49.16 µm (F=-191.1, P<0.01). No serious complications happened in all phases.

CONCLUSION

PRP+Conbercept is better than PRP+STTA in DME with proliferative stage but PRP+Conbercept+STTA sequential therapy may be a wiser choice for persistent effectiveness on anatomical as well as functional status.

Concentrations of VEGF and PlGF Decrease in Eyes After Intravitreal Conbercept Injection

INTRODUCTION

Conbercept is a new anti-vascular endothelial growth factor drug approved for the treatment of age-related macular degeneration by the China Food and Drug Administration (CFDA) in 2013. In this study, we for the first time evaluated the concentrations of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) after patients with proliferative diabetic retinopathy were treated with intravitreal conbercept (IVC) injection.

METHODS

Sixteen patients with proliferative diabetic retinopathy were randomly divided into two equal groups (A and B). Nine patients with rhegmatogenous retinal detachment were used as the control group. The patients in group A received 0.5 mg IVC and their aqueous humor was collected. After 7 days, all patients underwent vitrectomy, and their aqueous and vitreous humor were collected.

RESULTS

In the aqueous humor, the concentrations of VEGF and PlGF were higher pre- than post-IVC injection in group A. Similarly, the concentrations of VEGF and PlGF in group A (pre-IVC) and group B were higher than those in the control group. In vitreous humor, the concentrations of VEGF and PlGF were higher in group B than those in the control group, and the concentrations of VEGF were lower in group A (post-IVC) than those in group B.

CONCLUSIONS

Our study proved that the concentration of VEGF and PlGF reduced after IVC injection in aqueous humor. However, the concentration of PlGF did not reduce after IVC injection in vitreous humor.

Clinical effect of conbercept on improving diabetic macular ischemia by OCT angiography

BACKGROUND

Varying degrees of macular ischemia generally occur in diabetic retinopathy (DR). This study aims to evaluate the effect of conbercept with 3+ pro re nata (PRN) on macular perfusion status in patients with diabetic macular edema (DME) and quantitatively assess changes in foveal avascular zone (FAZ) areas and capillary density in macular regions by applying optical coherence tomography angiography (OCTA).

METHODS

Fifty patients were divided into ischemic (n = 31) and non-ischemic (n = 19) groups according to the presence of ischemia on OCTA at baseline. All patients received intravitreal injections of 0.5 mg of conbercept with 3+ PRN principle. The FAZ areas and macular vessel density measured using OCTA were evaluated at baseline, 3 months, and 6 months after treatment in both groups.

RESULTS

At months 3 and 6, the FAZ area in the ischemic group changed from 0.510 ± 0.171 mm2 to 0.441 ± 0.158 mm2 then to 0.427 ± 0.153 mm2 (p = 0.003, p = 0.296); in the non-ischemic group, it remained stable (p = 0.269, p = 0.926). The superficial vessel density changed from 41.1 ± 4.1 to 42.5% ± 4.7% then to 42.6% ± 4.6% (p = 0.043, p = 0.812), and the deep vessel density changed from 40.7 ± 4.4 to 42.3% ± 3.6% then to 42.3% ± 4.7% (p = 0.072, p = 0.961) in the ischemic group. In the non-ischemic group, the superficial vessel density changed from 44.8 ± 3.2 to 46.0% ± 3.5% then to 45.7% ± 3.3% (p = 0.108, p = 0.666), whereas the deep vessel density changed from 43.6 ± 3.6 to 43.8% ± 3.2% then to 43.5% ± 4.5% (p = 0.882, p = 0.736). Reperfusion in macular nonperfusion areas was observed.

CONCLUSION

Anti-vascular endothelial growth factor treatment may have a positive effect on macular perfusion status. Furthermore, OCTA had advantages in quantifying and calculating blood flow index in the study of macular perfusion status.

What is the impact of intravitreal injection of conbercept on neovascular glaucoma patients: a prospective, interventional case series study

Background

The aim of the present study was to evaluate the efficacy and safety of intravitreal conbercept combined with trabeculectomy and panretinal photocoagulation for neovascular glaucoma (NVG).

Methods

Fifty patients (54 eyes) with NVG were included in this prospective study. Fifty-two eyes initially underwent intravitreal conbercept (0.5 mg/0.05 ml) treatment followed by trabeculectomy and panretinal photocoagulation. Preoperative and postoperative best-corrected visual acuity (BCVA), intraocular pressure (IOP), the number of antiglaucoma medications, and surgical complications were recorded. The levels of VEGF-A, TGF-β₁ and PLGF in aqueous humour samples collected during surgery were measured by enzyme-linked immunosorbent assay (ELISA). Light microscopy and transmission electron microscopy were used to observe the surgically excised trabecular tissue; enucleation was performed in 2 eyes, and light microscopy was used as the histopathological control.

Results

The follow-up period after trabeculectomy was 1 year. Of the 52 eyes, 39 completed 1 year of follow-up, and 13 were lost to follow-up. Recurrence of iris neovascularization was observed in 5 eyes, 9 had hyphema, 16 had filter-bled scarring, and no eye had complications attributable to the drug. The mean IOP was reduced from 48.1 ± 14.2 to 23.2 ± 8.7 mmHg, and the mean number of antiglaucoma medications used decreased from 3.0 (3.0, 4.0) to 1.0 (0.0, 1.0) after 1 year (both P < 0.05). The complete success rate was 76.9, 76.9, 71.0, 51.6, and 32.3% at 1 week, 1 month, 3 months, 6 months and 12 months, respectively, when the cut-off IOP was 18 mmHg. After patients underwent intravitreal injection, the concentrations of VEGF-A and TGF-β₁ in the aqueous humour in NVG patients decreased from 168.8 ± 13.4 and 159.6 ± 15.4 pg/ml to 160.2 ± 7.6 and 151.9 ± 2.3 pg/ml, respectively (both P < 0.05). Light microscopy revealed neovascularization regression in the iris in specimens treated with intravitreal conbercept. Electron microscopy revealed trabecular endothelial cell degeneration in the conbercept-treated specimens.

Conclusions

Our initial findings suggest that intravitreal conbercept is an effective treatment for managing NVG that has fewer short-term postoperative complications.

Trial registration

Current Controlled Trials ChiCTR1800019918, 8 December 2018, retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12886-019-1138-6) contains supplementary material, which is available to authorized users.

Macular hole retinal detachment after intravitreal Conbercept injection for the treatment of choroidal neovascularization secondary to degenerative myopia: a case report

BACKGROUND

We report a case of macular hole (MH) formation and retinal detachment after intravitreal conbercept injection for the treatment of choroidal neovascularization (CNV) secondary to degenerative myopia.

CASE PRESENTATION

A 60-year-old woman presented with blurred vision in her left eye was diagnosed as CNV secondary to degenerative myopia. Intravitreal injection of conbercept, an anti -vascular endothelial growth factor (VEGF) agent, was uneventfully performed in the left eye. Unfortunately, a full thickness MH and retinal detachment was found three weeks postoperatively by ophthalmoscopy and spectral-domain optical coherence tomography. Vitrectomy, internal limiting membrane peeling and silicone oil tamponade were then performed, and macular retina was reattached soon after surgery. However, MH still kept open during three months' follow-up.

CONCLUSION

MH is a quite rare complication of intravitreal anti- VEGF agent injection, tangential contraction secondary to CNV shrinkage and regression caused by anti-VEGF agent is proposed to be the major pathogenesis of MH formation.

Comparison of conbercept and ranibizumab combined mitomycin C-augmented trabeculectomy for neovascular glaucoma

PURPOSE

To compare the efficacy and security of conbercept and ranibizumab combined with trabeculectomy and panretinal photocoagulation for neovascular glaucoma (NVG).

METHODS

One hundred and sixty patients with NVG were randomly divided into a conbercept group comprised of 80 patients and a ranibizumab group comprised of 80 patients. The postoperative and preoperative visual acuities, intraocular pressures frequency of anti-glaucoma medications, and surgical complications were recorded. The expressions of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor (FLT-1), and placenta-like growth factor (PLGF) in the aqueous humor were determined using an enzyme-linked immunosorbent assay. Examining the fundus and obtaining photographs used indirect ophthalmoscopy. Kaplan-Meier and log-rank analyses estimated the success rates.

RESULTS

All patient follow-up periods were at 1 year. The differences observed in IOP and the frequencies of anti-glaucoma medications at various follow-up time points were not statistically significant (all P > 0.05). The differences observed in both the group visual acuities at various follow-up time points were not statistically significant (P > 0.05). Rates of surgery complications were 18.75% and 25.00% in the conbercept group and ranibizumab group, respectively. The expressions of VEGF, FLT-1, and PLGF significantly decreased (all P < 0.05). The recurrence percentages were 30.00% and 36.25% after conbercept and ranibizumab treatment, respectively.

CONCLUSION

The conbercept effects were similar with that of ranibizumab. Intravitreal injection of conbercept was effective for NVG treatment, which provides a new therapeutic drug for NVG treatment.

The fellow eye effect of unilateral intravitreal conbercept injections in eyes with diabetic macular edema

AIMS

To investigate whether intravitreal conbercept injection affects contralateral untreated eyes in bilateral diabetic macular edema (DME) patients.

METHODS

In this retrospective study, 15 patients (30 eyes) with type 2 diabetes were followed after bilateral DME diagnosis in the Department of Ophthalmology, Peking Union Medical College Hospital from 2015 to 2018. Patients underwent examinations including best corrected visual acuity (BCVA), slit-lamp microscopy, indirect ophthalmoscope, color fundus photography, fundus fluorescein angiography, optical coherence tomography, and glycated hemoglobin (HbA1c). Each patient received conbercept (0.5 mg) intravitreally in the severe eye. Nonparametric Wilcoxon signed-rank tests and Pearson's correlation coefficient were used to assess changes in BCVA and central retinal thickness (CRT) and relations between BCVA changes in treated and untreated eyes, respectively.

RESULTS

The mean follow-up time was 10.60 ± 2.29 months, and the mean injection number of 15 treated eyes was 9.13 ± 0.68. HbA1c remained below 10% during treatment with no significant changes between the initial and final visits (7.81 ± 1.17 vs 7.62 ± 1.19%) (P = 0.576). In untreated eyes, CRT significantly decreased from the initial to final visits (368.93 ± 125.45 vs 306.27 ± 89.70 μm) (P = 0.028). In untreated eyes, BCVA showed no significant difference between the initial and final visits (0.38 ± 0.30 vs 0.40 ± 0.30 logMAR) (P = 0.937), but BCVA changes in treated and untreated eyes were positively correlated (r = 0.527, P = 0.044).

CONCLUSIONS

Intravitreal conbercept injection results in decreased CRT and increased BCVA in untreated eyes, which is consistent with the changes in treated eyes for patients with bilateral DME.

Intravitreal conbercept for choroidal neovascularisation secondary to pathological myopia in a real-world setting in China : Intravitreal conbercept was safe and effective in treating myopic choroidal neovascularization

Background

To evaluate the 12-month efficacy and safety of intravitreal conbercept for myopic choroidal neovascularization (CNV).

Methods

A retrospective, observational study. Thirty-four eyes of 34 pathologic myopic patients with CNV were treated with intravitreal conbercept (IVC) 0.5 mg with a follow up of 12 months. After the first injection, administration of conbercept followed a pro re nata (PRN) regimen. Outcomes included best corrected visual acuity (BCVA), central retinal thickness (CRT), CNV size, the total number of treatments, and adverse events.

Results

The mean patient age was 55.88 ± 16.17 years, and the mean eye spherical equivalent was − 8.72 ± 3.75 D. The mean number of IVC over 12 months was 2.12 ± 0.69. Overall, best-corrected visual acuity(BCVA)improved from 0.86 ± 0.33 logMAR at baseline to 0.44 ± 0.32 logMAR at month 12 (p < 0.001), mean improvement of vision was 4.12 ± 2.69 lines. Mean central retinal thickness reduced from 285.9 ± 104.6 µm at baseline to 192.1 ± 97.5 µm at month 12 (p < 0.001). Mean CNV size decreased from 0.52 ± 0.38 mm² at baseline to 0.31 ± 0.19 mm² at 12 months (p < 0.05). All the 34 eyes had reduced or stable size of CNV. Thirty-two eyes (94.12 %) showed the absence of CNV leakage at the end of the study period. No severe systemic or ocular adverse events were observed.

Conclusions

Intravitreal conbercept 0.5 mg was safe and effective for treatment of myopic CNV over 12 months in a real-world setting.

Real-world outcomes of two-year Conbercept therapy for diabetic macular edema

AIM

To evaluate the two-year outcomes of patients treated for diabetic macular edema (DME) with intravitreal Conbercept (IVC).

METHODS

The clinical data of 30 DME patients (36 eyes) were retrospectively reviewed. The patients were treated with IVC for 3mo. Additional IVC was given at subsequent monthly visits, if needed (3+PRN). The patients were followed up for 24mo.

RESULTS

The best-corrected visual acuity (BCVA) at 24mo significantly increased (66.7±15.3 letters) in comparison with the baseline (54.4±15.4 letters, P<0.0001). The mean improvement in BCVA was 11.0±2.9 letters. At 24mo, 44.1% of the eyes surveyed gained ≥15 letters, 52.9% of the eyes gained ≥10 letters, and 70.6% of the eyes gained ≥5 letters. No vision loss was noted in 96.8% of the eyes, and 5.9% of the eyes lost ≥5 letters, but ≤10 letters. The central retinal thickness (CRT) at 24mo was significantly reduced (277.1±122.9 µm) in comparison with the baseline (510.9±186.1 µm, P<0.0001). At 24mo, 43.3% of the patients had a CRT ≤250 µm. The mean number of injections over 24mo was 10.6±2.0. No severe eye or systemic adverse events related to either the drug or injection were noted.

CONCLUSION

IVC is safe and effective for the treatment of DME.

One-year results of intravitreal conbercept in treatment-naïve subjects with polypoidal choroidal vasculopathy

PURPOSE

To evaluate the functional and structural outcomes of intravitreal conbercept monotherapy using a "3 + pro re nata (PRN)" regimen in treatment-naïve subjects with polypoidal choroidal vasculopathy (PCV) up to 12 months.

METHODS

Thirty subjects (30 eyes) with PCV participated in this interventional, retrospective study. All subjects received intravitreal injections of 0.5 mg (0.05 ml) conbercept using a "3 + PRN" regimen for 12 months. The changes in best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) parameters, polyp lesion area, and regression rate were evaluated at baseline, month 3, and month 12.

RESULTS

At the study end-point, BCVA improved significantly from 52.80 ± 17.17 ETDRS letters at baseline to 62.20 ± 18.96 letters (P < 0.001), with a mean gain of 9.40 ± 14.97 letters. The central retinal thickness (CRT) significantly reduced from 454.93 ± 147.31 μm at baseline to 308.73 ± 106.80 μm (P < 0.001) at end-point, and the total macular volume (TMV) decreased from 9.51 ± 1.04 mm³ at baseline to 8.32 ± 0.84 mm3 at end-point (P < 0.001). The mean volume of pigment epithelial detachment (PED) decreased from 0.73 ± 0.97 mm³ at baseline to 0.48 ± 0.71 mm³ (P < 0.05) at month 3. At month 12, the mean volume of PED was 0.57 ± 0.80 mm³ (P > 0.05 compared to baseline). After the 3-monthly loading injections, 6 eyes (20.0%) showed complete polyp regression, whereas a total of 19 eyes (63.5%) showed complete regression at month 12. The average injections given per subject were 7.70 ± 1.81.

CONCLUSION

Intravitreal conbercept using the "3 + PRN" regimen was effective in the treatment of PCV.

The effect of adjunctive intravitreal conbercept at the end of diabetic vitrectomy for the prevention of post-vitrectomy hemorrhage in patients with severe proliferative diabetic retinopathy: a prospective, randomized pilot study

BACKGROUND

To investigate the effect of intravitreal conbercept (IVC) injections on the incidence of postoperative vitreous hemorrhage (VH) in eyes undergoing surgery for severe proliferative diabetic retinopathy.

METHODS

This was a pilot prospective, comparative, and randomized study. Thirty patients, who underwent vitrectomy for severe proliferative diabetic retinopathy, were assigned randomly to either group 1 (intravitreal conbercept [IVC] injection at the end of pars plana vitrectomy) or group 2 (no IVC injection). Postoperative follow-up was performed on the first day, first week, first month, third month, sixth month and first year after surgery. The primary outcome was the incidence of postoperative VH. Secondary outcomes were the initial time of vitreous clearing (ITVC), best-corrected visual acuity (BCVA) and central retinal thickness (CRT) after surgery.

RESULTS

A total of 30 eyes, from 30 patients, were included. Fifteen eyes were enrolled in the IVC group and fifteen in the control group. The incidence of early and late postoperative VH was not significantly different between the control and IVC groups. ITVC was shorter in the IVC group than that in the control group, but this was not significant (7.38 ± 10.66 vs 13.23 ± 17.35, P = 0.31). Final BCVA, 1 year after surgery, showed significant improvement compared to baseline in both groups. However, analysis of the BCVA at any postoperative visit after surgery showed no significant differences between the two groups. There were two cases of recurrent VH identified at 3 and 6 months after surgery in each group, requiring a second round of surgery. Foveal thickness was significantly different between the two groups at the 3-month, 6-month and 1-year follow-up visits.

CONCLUSIONS

In this pilot study, the effect of IVC injection in reducing the incidence of postoperative VH after diabetic vitrectomy at the end of vitrectomy was not shown.

TRIAL REGISTRATION

The study was registered with the Chinese Clinical Trial Registry. (Reference Number: ChiCTR1800015751).

Three-year follow-up of Coats disease treated with conbercept and 532-nm laser photocoagulation

BACKGROUND

Coats disease is an idiopathic exudative outer retinopathy caused by abnormal retinal vascular development.

AIM

To evaluate the long-term outcomes of intravitreal conbercept injection with laser photocoagulation as a treatment for Coats disease in adults.

METHODS

This retrospective case series study included patients diagnosed with Coats disease and treated with intravitreal conbercept injection and 532-nm laser photocoagulation at the Ophthalmology Department of Shenzhen People’s Hospital between January 2016 and January 2017. Best-corrected visual acuity (BCVA) measurements, noncontact tonometry, ophthalmoscopy, fundus photography, fundus fluorescein angiography and optical coherence tomography were performed before treatment and at 1 wk, 1 mo, 3 mo, 6 mo, 9 mo, 12 mo, 24 mo and 36 mo after therapy. Best-corrected visual acuity was measured using the early treatment of diabetic retinopathy study chart.

RESULTS

The study included eight eyes of 8 patients (7 men) aged 36.10 ± 6.65 years. The average BCVA of the affected eye before treatment was 51.17 ± 15.15 letters (range, 28–70 letters), and the average central macular thickness was 303.30 ± 107.87 µm (range, 221–673 µm). Four eyes were injected once, three were injected twice, and one was injected three times. Average follow-up duration was 37.33 ± 2.26 mo. Average BCVA of the affected eye was 51.17 ± 15.15 letters before treatment and was increased by 13.50 ± 3.20, 16.25 ± 7.73, 18.25 ± 8.96, 18.03 ± 5.27, 18.63 ± 3.35, 19.75 ± 6.96, 18.05 ± 5.36 and 17.88 ± 3.45 letters at 1 wk, 1 mo, 3 mo, 6 mo, 9 mo, 12 mo, 24 mo and 36 mo after treatment, respectively (P < 0.01). The patients showed varying degrees of subretinal fluid resorption after treatment. None of the patients had serious complications such as increased intraocular pressure, development/progression of cataracts, endophthalmitis or retinal detachment.

CONCLUSION

Intravitreal injection of conbercept combined with 532-nm laser photocoagulation may be a feasible treatment for Coats disease in adult patients.