Phase I/II Randomized Study of Proton Beam with Anti-Vascular Endothelial Growth Factor for Exudative Age-Related Macular Degeneration: One-Year Results

Intravitreal Anti-Vascular Endothelial Growth Factor Therapies for Retinal Disorders

Vascular endothelial growth factors (VEGFs) are key mediator of retinal and choroidal neovascularization as well as retinal vascular leakage leading to macular edema. As such, VEGF plays an important role in mediating visually significant complications associated with common retinal disorders such as diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Various drugs that inhibit vascular endothelial growth factors (anti-VEGF therapies) have been developed to minimize vision loss associated with these disorders. These drugs are injected into the vitreous cavity in a clinic setting at regular intervals. This article provides an overview of the various anti-VEGF drugs used in ophthalmology and the common retinal conditions that benefit from this therapy.

One-Year Efficacy and Safety of Proton-Beam Irradiation Combined with Intravitreal Conbercept for Refractory or Recurrent Polypoidal Choroidal Vasculopathy: A Pilot Study

Introduction

To investigate the efficacy and safety of proton-beam irradiation (PBI) combined with intravitreal conbercept (IVC) injection for refractory or recurrent polypoidal choroidal vasculopathy (PCV).

Methods

A prospective interventional clinical trial included 12 patients with refractory PCV (defined as persistent exudation or fluid after six consecutive injections at monthly intervals and/or photodynamic therapy) or recurrent PCV (defined as new exudative signs after six monthly injections and/or photodynamic therapy) treated between January 2019 and September 2020. Every patient underwent single PBI (14 GyE) with concomitant IVC (0.5 mg) within 1 week and further doses of IVC were administered pro re nata.

Results

By the 12-month follow-up, the subretinal fluid was completely absorbed in 9 eyes (81.8%). The angiographic regression and closure rates of the polyps were 60% (12/20) and 90% (18/20), respectively. The mean number of IVC injections was 3.1 ± 1.37. The mean BCVA improved by 20 letters (P = 0.006). The mean central macular thickness (CMT) decreased from 476.50 ± 123.63 μm to 317.70 ± 89.34 μm (P = 0.004). The areas of branching vascular networks and polyps decreased by 37.2% and 72.3%, respectively. Radiation retinopathy was observed in five eyes, but no systemic adverse events were observed.

Conclusion

PBI combined with IVC appears to promote polyp regression and closure, reduce CMT, and improve BCVA, with a favorable safety profile, after 12 months. Therefore, PBI may be a useful adjuvant therapy for patients with refractory or recurrent PCV.

Trial Registration

Proton-Beam Irradiation Combined with Intravitreal Conbercept for Refractory or Recurrent Polypoidal Choroidal Vasculopathy: Prospective Phase II Clinical Study (ChiCTR2000038987).

Radiotherapy for neovascular age-related macular degeneration

BACKGROUND

Radiotherapy has been proposed as a treatment for new vessel growth in people with neovascular age-related macular degeneration (AMD).

OBJECTIVES

To examine the effects of radiotherapy on neovascular AMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS and three trials registers and checked references of included studies. We last searched the databases on 4 May 2020.  SELECTION CRITERIA: We included all randomised controlled trials in which radiotherapy was compared to another treatment, sham treatment, low dosage irradiation or no treatment in people with choroidal neovascularisation (CNV) secondary to AMD.

DATA COLLECTION AND ANALYSIS

We used standard procedures expected by Cochrane. We graded the certainty of the evidence using GRADE. We considered the following outcomes at 12 months: best-corrected visual acuity (BCVA) (loss of 3 or more lines, change in visual acuity), contrast sensitivity, new vessel growth, quality of life and adverse effects at any time point.  MAIN RESULTS: We included 18 studies (n = 2430 people, 2432 eyes) of radiation therapy with dosages ranging from 7.5 to 24 Gy. These studies mainly took place in Europe and North America but two studies were from Japan and one multicentre study included sites in South America. Three of these studies investigated brachytherapy (plaque and epimacular), the rest were studies of external beam radiotherapy (EBM) including one trial of stereotactic radiotherapy. Four studies compared radiotherapy combined with anti-vascular endothelial growth factor (anti-VEGF) with anti-VEGF alone. Eleven studies gave no radiotherapy treatment to the control group; five studies used sham irradiation; and one study used very low-dose irradiation (1 Gy). One study used a mixture of sham irradiation and no treatment. Fifteen studies were judged to be at high risk of bias in one or more domains. Radiotherapy versus no radiotherapy There may be little or no difference in loss of 3 lines of vision at 12 months in eyes treated with radiotherapy compared with no radiotherapy (risk ratio (RR) 0.82, 95% confidence interval (CI) 0.64 to 1.04, 811 eyes, 8 studies, I² = 66%, low-certainty evidence). Low-certainty evidence suggests a small benefit in change in visual acuity (mean difference (MD) -0.10 logMAR, 95% CI -0.17 to -0.03; eyes = 883; studies = 10) and average contrast sensitivity at 12 months (MD 0.15 log units, 95% CI 0.05 to 0.25; eyes = 267; studies = 2). Growth of new vessels (largely change in CNV size) was variably reported and It was not possible to produce a summary estimate of this outcome. The studies were small with imprecise estimates and there was no consistent pattern to the study results (very low-certainty evidence). Quality of life was only reported in one study of 199 people; there was no clear difference between treatment and control groups (low-certainty evidence). Low-certainty evidence was available on adverse effects from eight of 14 studies. Seven studies reported on radiation retinopathy and/or neuropathy. Five of these studies reported no radiation-associated adverse effects. One study of 88 eyes reported one case of possible radiation retinopathy. One study of 74 eyes graded retinal abnormalities in some detail and found that 72% of participants who had radiation compared with 71% of participants in the control group had retinal abnormalities resembling radiation retinopathy or choroidopathy. Four studies reported cataract surgery or progression: events were generally few with no consistent evidence of any increased occurrence in the radiation group. One study noted transient disturbance of the precorneal tear film but there was no evidence from the other two studies that reported dry eye of any increased risk with radiation therapy. None of the participants received anti-VEGF injections. Radiotherapy combined with anti-VEGF versus anti-VEGF alone People receiving radiotherapy/anti-VEGF were probably more likely to lose 3 or more lines of BCVA at 12 months compared with anti-VEGF alone (RR 2.11, 95% CI 1.40 to 3.17, 1050 eyes, 3 studies, moderate-certainty). Most of the data for this outcome come from two studies of epimacular brachytherapy (114 events) compared with 20 events from the one trial of EBM. Data on change in BCVA were heterogenous (I² = 82%). Individual study results ranged from a small difference of -0.03 logMAR in favour of radiotherapy/anti-VEGF to a difference of 0.13 logMAR in favour of anti-VEGF alone (low-certainty evidence). The effect differed depending on how the radiotherapy was delivered (test for interaction P = 0.0007). Epimacular brachytherapy was associated with worse visual outcomes (MD 0.10 logMAR, 95% CI 0.05 to 0.15, 820 eyes, 2 studies) compared with EBM (MD -0.03 logMAR, 95% CI -0.09 to 0.03, 252 eyes, 2 studies). None of the included studies reported contrast sensitivity or quality of life. Growth of new vessels (largely change in CNV size) was variably reported in three studies (803 eyes). It was not possible to produce a summary estimate and there was no consistent pattern to the study results (very low-certainty evidence). For adverse outcomes, variable results were reported in the four studies. In three studies reports of adverse events were low and no radiation-associated adverse events were reported. In one study of epimacular brachytherapy there was a higher proportion of ocular adverse events (54%) compared to the anti-VEGF alone (18%). The majority of these adverse events were cataract. Overall 5% of the treatment group had radiation device-related adverse events (17 cases); 10 of these cases were radiation retinopathy. There were differences in average number of injections given between the four studies (1072 eyes). In three of the four studies, the anti-VEGF alone group on average received more injections (moderate-certainty evidence).

AUTHORS' CONCLUSIONS

The evidence is uncertain regarding the use of radiotherapy for neovascular AMD. Most studies took place before the routine use of anti-VEGF, and before the development of modern radiotherapy techniques such as stereotactic radiotherapy. Visual outcomes with epimacular brachytherapy are likely to be worse, with an increased risk of adverse events,  probably related to vitrectomy. The role of stereotactic radiotherapy combined with anti-VEGF is currently uncertain. Further research on radiotherapy for neovascular AMD may not be justified until current ongoing studies have reported their results.

Phase I/II randomized study of proton beam with anti-VEGF for exudative age-related macular degeneration: long-term results

BACKGROUND/OBJECTIVE

To determine if treatment of exudative age-related macular degeneration (eAMD) using proton beam therapy (PBT) combined with intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy is safe and effective long term.

SUBJECT/METHODS

Thirty eyes with newly diagnosed eAMD were enrolled in a phase I/II prospective, sham-controlled double-masked university study. Eyes were randomized 1:1:1-24 GyE, 16 GyE or sham radiation, and treated with three initial monthly intravitreal ranibizumab or bevacizumab. Subsequent anti-VEGF reinjection was based on monthly optical coherence tomography and examination for 2 years and standard of care thereafter.

RESULTS

A total of 23 eyes completed 2-year study follow-up, of which 16 maintained monthly follow-up. Mean best-correct visual acuity (BCVA) at 2 years was similar among treatment groups (p > 0.05). The 24 GyE group required fewer anti-VEGF injections when compared with the sham group at 2 years (4.67 ± 1.9 vs 9.67 ± 3.5; p = 0.017). Extended follow-up (mean 4 years) available in 22 eyes showed persistent reduced need for anti-VEGF therapy among eyes treated with 24 GyE compared with sham radiation (2.0 ± 1.6 vs 4.84 ± 2.4 per year, p = 0.008). New and increasing geographic atrophy (GA), noted in some eyes in all treatment groups, resulted in decreased mean BCVA from baseline for the 24 GyE group on extended follow-up (p = 0.009). Possible mild radiation retinopathy noted in 15% of eyes was not visually significant.

CONCLUSIONS

Initial treatment combining PBT (24 GyE) with intravitreal anti-VEGF therapy appears to decrease the need for anti-VEGF reinjection in eyes with newly diagnosed eAMD. Radiation retinopathy risk was low and does not appear visually significant. Long-term vision was limited by GA development especially in the 24 GyE group.