StereoTactic radiotherapy for wet Age-Related macular degeneration (STAR): study protocol for a randomised controlled clinical trial

Real-world experience of using stereotactic radiotherapy combined with anti-vascular endothelial growth factor to treat neovascular AMD

INTRODUCTION

Adjunctive treatment or longer-acting drugs are required to treat nAMD to help ease burdens for patients and hospital clinics alike. Stereotactic therapy is one such option, providing a reduction in the number of injections over time.

OBJECTIVE

To determine the clinical outcomes in a cohort of patients with nAMD receiving a combination therapy of stereotactic radiotherapy (SRT) with intravitreal anti-VEGF injections (IVI).

METHOD

A retrospective analysis of 74 patients with nAMD, who had received IVI and SRT (16 Gray maximum dose to the macula) at a large tertiary university eye hospital, between March 2018 and September 2019 was performed. The number of IVIs, visual acuity (VA), and central retinal thickness (CRT) were evaluated at 12, 24, and 36 months after patients received SRT and compared to the same time interval prior to SRT.

RESULTS

Follow-up data at 12, 24, and 36 months following and prior to SRT was available for 74, 48, and 22 patients respectively. Overall there was a significant reduction in the number of injections post-SRT. Twelve months following SRT, the median number of IVI was reduced by 1 (p < 0.05). The reduction in the median number of IVI was significantly reduced by 3 and 6 injections at 24- and 36-month follow-up respectively (p < 0.05). The CRT was significantly reduced post-SRT compared to the baseline values at all time periods. There was no statistically significant difference in VA at 12-month follow-up compared to baseline. The VA, however, significantly decreased at 24- and 36-month follow-up (p < 0.05).

CONCLUSION

A therapy combining SRT with IVI has shown an overall reduction in the number of injections required in nAMD patients at 12, 24, and 36 months following SRT compared to IVI treatment alone. These real-world outcomes are comparable to other studies while also confirming the maintenance of the reduced frequency of required IVI for patients with nAMD.

Stereotactic radiotherapy for neovascular age-related macular degeneration (STAR): a pivotal, randomised, double-masked, sham-controlled device trial

BACKGROUND

Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness. The first-line therapy is anti-vascular endothelial growth factor (anti-VEGF) agents delivered by intravitreal injection. Ionising radiation mitigates key pathogenic processes underlying nAMD, and therefore has therapeutic potential. STAR aimed to assess whether stereotactic radiotherapy (SRT) reduces the number of anti-VEGF injections required, without sacrificing visual acuity.

METHODS

This pivotal, randomised, double-masked, sham-controlled trial enrolled participants with pretreated chronic active nAMD from 30 UK hospitals. Participants were randomly allocated in a 2:1 ratio to 16-Gray (Gy) SRT delivered using a robotically controlled device or sham SRT, stratified by treatment centre. Eligible participants were aged 50 years or older and had chronic active nAMD, with at least three previous anti-VEGF injections, including at least one in the last 4 months. Participants and all trial and image reading centre staff were masked to treatment allocation, except one unmasked statistician. The primary outcome was the number of intravitreal ranibizumab injections required over 2 years, tested for superiority (fewer injections). The main secondary outcome was Early Treatment Diabetic Retinopathy Study visual acuity at two years, tested for non-inferiority (five-letter margin). The primary analysis used the intention-to-treat principle, and safety was analysed per-protocol on participants with available data. The study is registered with ClinicalTrials.gov (NCT02243878) and is closed for recruitment.

FINDINGS

411 participants enrolled between Jan 1, 2015, and Dec 27, 2019, and 274 were randomly allocated to the 16-Gy SRT group and 137 to the sham SRT group. 240 (58%) of all participants were female, and 171 (42%) of all participants were male. 241 participants in the 16-Gy SRT group and 118 participants in the sham group were included in the final analysis, and 409 patients were treated and formed the safety population, of whom two patients allocated to sham treatment erroneously received 16-Gy SRT. The SRT group received a mean of 10·7 injections (SD 6·3) over 2 years versus 13·3 injections (5·8) with sham, a reduction of 2·9 injections after adjusting for treatment centre (95% CI -4·2 to -1·6, p<0·0001). The SRT group best-corrected visual acuity change was non-inferior to sham (adjusted mean letter loss difference between groups, -1·7 letters [95% CI -4·2 to 0·8]). Adverse event rates were similar across groups, but reading centre-detected microvascular abnormalities occurred in 77 SRT-treated eyes (35%) and 13 (12%) sham-treated eyes. Overall, eyes with microvascular abnormalities tended to have better best-corrected visual acuity than those without. Fewer ranibizumab injections offset the cost of SRT, saving a mean of £565 per participant (95% CI -332 to 1483).

INTERPRETATION

SRT can reduce ranibizumab treatment burden without compromising vision.

FUNDING

Medical Research Council and National Institute for Health and Care Research Efficacy and Mechanism Evaluation Programme.

Vitrectomy, subretinal Tissue plasminogen activator and Intravitreal Gas for submacular haemorrhage secondary to Exudative Age-Related macular degeneration (TIGER): study protocol for a phase 3, pan-European, two-group, non-commercial, active-control, observer-masked, superiority, randomised controlled surgical trial

BACKGROUND

Neovascular (wet) age-related macular degeneration (AMD) can be associated with large submacular haemorrhage (SMH). The natural history of SMH is very poor, with typically marked and permanent loss of central vision in the affected eye. Practice surveys indicate varied management approaches including observation, intravitreal anti-vascular endothelial growth factor therapy, intravitreal gas to pneumatically displace SMH, intravitreal alteplase (tissue plasminogen activator, TPA) to dissolve the clot, subretinal TPA via vitrectomy, and varying combinations thereof. No large, published, randomised controlled trials have compared these management options.

METHODS

TIGER is a phase 3, pan-European, two-group, active-control, observer-masked, superiority, randomised controlled surgical trial. Eligible participants have large, fovea-involving SMH of no more than 15 days duration due to treatment-naïve or previously treated neovascular AMD, including idiopathic polypoidal choroidal vasculopathy and retinal angiomatous proliferation. A total of 210 participants are randomised in a 1:1 ratio to pars plana vitrectomy, off-label subretinal TPA up to 25 μg in 0.25 ml, intravitreal 20% sulfahexafluoride gas and intravitreal aflibercept, or intravitreal aflibercept monotherapy. Aflibercept 2 mg is administered to both groups monthly for 3 doses, then 2-monthly to month 12. The primary efficacy outcome is the proportion of participants with best-corrected visual acuity (BCVA) gain of ≥ 10 Early Treatment Diabetic Retinopathy (ETDRS) letters in the study eye at month 12. Secondary efficacy outcomes (at 6 and 12 months unless noted otherwise) are proportion of participants with a BCVA gain of ≥ 10 ETDRS letters at 6 months, mean ETDRS BCVA, Radner maximum reading speed, National Eye Institute 25-item Visual Function Questionnaire composite score, EQ-5D-5L with vision bolt-on score, Short Warwick and Edinburgh Mental Wellbeing score, scotoma size on Humphrey field analyser, and presence/absence of subfoveal fibrosis and/or atrophy and area of fibrosis/atrophy using independent reading centre multimodal image analysis (12 months only). Key safety outcomes are adverse events, serious adverse events, and important medical events, coded using the Medical Dictionary for Regulatory Activities Preferred Terms.

DISCUSSION

The best management of SMH is unknown. TIGER aims to establish if the benefits of SMH surgery outweigh the risks, relative to aflibercept monotherapy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04663750 ; EudraCT: 2020-004917-10.

In vitro evaluation of simulated stereotactic radiotherapy for wet age-related macular degeneration on three different cell lines

Low energy stereotactic radiotherapy has been proposed for the treatment of neovascular age related macular degeneration. We investigated the in vitro effect of the radiotherapy on pericytes, retinal pigment epithelium and endothelial cells. Primary human retinal pigment epithelium cells, human umbilical vein endothelial cells and human pericytes from Placenta were cultivated. In a pairwise protocol, one plate was irradiated at a dose of 16 Gy, while the second plate served as a non-irradiated control. Thereafter, cells were cultivated either in serum-free (non-permissive) or serum-stimulated (permissive) conditions. A life/dead assay, an XTT and a BrdU assay were performed up to 7 days after irradiation. No cell death occurred at any timepoint in any cell line after treatment nor in the control. Compared to the unirradiated controls, cell viability and metabolic activity were significantly reduced in irradiated cells in the XTT assay, except for non-permissive RPE cells. In the BrdU assay, proliferation was inhibited. While no cell death was detected in vitro, viability and proliferative capacity of all cell lines were significantly reduced. Therefore, it seems that low energy stereotactic radiotherapy inhibits angiogenesis without a direct induction of apoptosis but influencing microvascular function and stability.

Three-year clinical and optical coherence tomography follow-up after stereotactic radiotherapy for neovascular age-related macular degeneration

PURPOSE

The long-term clinical outcome of adjuvant stereotactic radiotherapy (SRT) in neovascular age-related macular degeneration (nAMD) patients was evaluated.

METHODS

This case-control study included patients with unilateral nAMD, who underwent SRT complementary to standard anti-VEGF treatment. Only patients with monthly follow-up over at least three years were considered. Number of intravitreal injections, visual acuity (VA), central retinal thickness (CRT), and subfoveal choroidal thickness (SFCT) were evaluated and compared to baseline as well as to an age- and gender-matched control group, who received anti-VEGF monotherapy.

RESULTS

Twenty patients were irradiated and had complete follow-up. Cumulatively, SRT patients needed significantly less injections than non-irradiated ones over three years (14 vs. 18, p ​= ​0.014), while median VA did not show statistically significant changes (0.4 logMAR at baseline to 0.65 logMAR at final follow-up, p ​= ​0.061). CRT remained steady, but SFCT showed a continuous thinning of almost 50 ​μm (p ​= ​0.031) in irradiated patients over three years. Multiple linear regression analysis revealed that SFCT and VA at time of irradiation are significant prognostic factors of VA change in SRT patients over the following three years (F(2,17) ​= ​23.946, p<0.001, R² of 0.738).

CONCLUSIONS

SRT significantly reduced the cumulative anti-VEGF treatment burden over three years, however, this was mainly driven by the results of the first year after irradiation. A thinner SFCT at time of irradiation was associated with poorer visual outcome. While further research and investigation are warranted to elucidate the underlying pathogenesis, SFCT could be a potential biomarker when evaluating a patient's suitability for SRT.

Evaluation of Month-24 Efficacy and Safety of Epimacular Brachytherapy for Previously Treated Neovascular Age-Related Macular Degeneration: The MERLOT Randomized Clinical Trial

Importance

Although anti-vascular endothelial growth factor (VEGF) treatment offers better outcomes than the natural history of neovascular age-related macular degeneration (ARMD), a less burdensome, less expensive, and more durable treatment is needed.

Objective

To assess the efficacy and safety of epimacular brachytherapy (EMB) for chronic, active, neovascular ARMD.

Design, Setting, and Participants

The Macular Epiretinal Brachytherapy vs Ranibizumab (Lucentis) Only Treatment (MERLOT) pivotal device trial was conducted at 24 National Health Service hospitals across the UK. Patients who had neovascular ARMD and received intravitreal ranibizumab were enrolled between November 10, 2009, and January 30, 2012. Eligible patients were randomized 2:1 and were stratified by lens status and angiographic lesion type to receive either EMB plus as-needed ranibizumab or as-needed ranibizumab monotherapy. Participants were followed up monthly for 24 months and then assessed at a final visit at month 36. Masking of participants and clinicians was not possible, but best-corrected visual acuity (BCVA) and imaging were analyzed by masked assessors. Analysis followed the intent-to-treat approach.

Interventions

Pars plana vitrectomy with 24 Gy EMB plus as-needed ranibizumab vs as-needed ranibizumab monotherapy.

Main Outcomes and Measures

Coprimary outcomes were the number of as-needed ranibizumab injections and the mean change in Early Treatment Diabetic Retinopathy Study (ETDRS) BCVA with a noninferiority margin of -5 ETDRS letters. Secondary outcomes were the percentage of participants losing fewer than 15 ETDRS letters and gaining 0 or more or 15 or more ETDRS letters and the mean change in angiographic total lesion size, choroidal neovascularization size, and foveal thickness on optical coherence tomography.

Results

Of 363 participants, 329 (90.6%) completed 24 months of follow-up (222 participants in the EMB group and 107 in the ranibizumab group). The mean (SD) age of the combined groups was 76.5 (7.4) years. The mean (SD) number of ranibizumab injections was 9.3 (6.7) in the EMB group and 8.3 (4.5) in the ranibizumab group, with a difference of 1.0 injection (95% CI, -0.3 to 2.3; P = .13). The mean (SD) BCVA change was -11.2 (15.7) ETDRS letters in the EMB group and -1.4 (10.9) ETDRS letters in the ranibizumab group, with a difference of 9.8 ETDRS letters (95% CI, -6.7 to -12.9). In the EMB group, 65.6% of participants (160 of 244) lost fewer than 15 ETDRS letters vs 86.6% (103 of 119) in the ranibizumab group, with a difference of 21% (95% CI, 12.4%-29.5%; P < .001). Microvascular abnormalities occurred in 20 of 207 eyes (9.7%) in the EMB group and 1 of 97 eyes (1.0%) in the ranibizumab group. These abnormalities occurred outside the foveal center, and there were no unexpected safety concerns.

Conclusions and Relevance

The MERLOT trial found that despite the acceptable safety of EMB, it did not reduce the number of ranibizumab injections and was associated with worse visual acuity than anti-VEGF treatment alone; these results do not support EMB use as an adjunct treatment for chronic, active neovascular ARMD.

Trial Registration

ClinicalTrials.gov Identifier: NCT01006538.

Low-Energy Stereotactic Radiotherapy for Treatment of Exudative Age-Related Macular Degeneration in a Treat-and-Extend Regimen

BACKGROUND AND OBJECTIVE

To evaluate the effectiveness and safety of low-energy stereotactic radiotherapy (SRT) combined with anti-vascular endothelial growth factor (VEGF) treatment following a treat-and-extend regimen (TER) in wet age-related macular degeneration (AMD).

PATIENTS AND METHODS

Before/after SRT, the authors compared retrospective consecutive case series of 50 patients requiring frequent anti-VEGF treatment (every 4 or 6 weeks) in wet AMD, treated with a single session of SRT and TER (same manner pre/post-SRT). Outcomes were visual acuity (VA), recurrence-free interval, and central retinal thickness (CRT).

RESULTS

After SRT, CRT was reduced from baseline (407.3 μm ± 153.2 μm) to 12 months (320.2 μm ± 112.1 μm; P < .001), with statistical significance from month 2 onward. VA was stable for 12 months (64.0 letters ± 15.1 letters vs. 63.6 letters ± 16.2 letters). The mean recurrence-free interval increased from 4.24 weeks ± 0.66 weeks to 7.52 weeks ± 3.05 weeks at 12 months (P < .001). No severe side effects were observed.

CONCLUSION

Low-energy SRT, combined with anti-VEGF TER, was associated with reduced injection frequency and preserved VA during 12 months of follow-up. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:86-93.].

Subfoveal Choroidal Thickness as a Potential Predictor of Clinical Response to Stereotactic Radiotherapy for Neovascular Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVE

Stereotactic radiotherapy (SRT) is a new adjuvant treatment modality that has been shown to reduce the need for repetitive intravitreal injections (IVIs) in patients with neovascular age-related macular degeneration (nAMD). The authors aimed to determine baseline predictors of clinical response to SRT.

PATIENTS AND METHODS

This was a retrospective, observational case series of patients with nAMD who underwent SRT and subsequently had at least 12 months of complete follow-up. After SRT and one mandatory IVI, patients were examined every 4 weeks and received further treatment on a pro re nata basis. Examination included enhanced depth imaging spectral-domain optical coherence tomography (SD-OCT) to measure subfoveal choroidal thickness (SFCT) and central macular thickness (CMT). Patients' data were retrieved from medical records and included demographics, disease duration, lesion size, best-corrected visual acuity (BCVA), previous number of IVIs, and type of drug applied.

RESULTS

A total of 35 eyes of 35 patients (76.23 years ± 7.05 years) were included, and 21 eyes (60%) responded well to SRT. The annual injection rate decreased from 6.86 before SRT to 3.46 afterward, whereas BCVA improved from 0.49 logMAR at baseline to 0.37 logMAR at final follow-up. From a morphologic point of view, CMT and SFCT decreased by 71 μm and 37 μm, respectively, at 12-month follow-up compared to baseline. Of all investigated parameters, only SFCT proved to be significant, as a higher baseline SFCT was found to be a strong negative predictor for the number of IVIs needed after SRT (regression coefficient: -0.678; P < .001).

CONCLUSIONS

Baseline SFCT may help predict which patients with nAMD will respond more favorably to SRT. The authors found eyes with a thicker baseline SFCT needed fewer IVIs after SRT. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:320-328.].

Potential selection bias in candidates for stereotactic radiotherapy for neovascular AMD

PURPOSE

Stereotactic radiotherapy (SRT, IRay) was able to reduce the need for intravitreal injections of anti-VEGF (IVI) in patients with neovascular AMD (nAMD) in a phase II randomized clinical trial. Certain morphologic characteristics, such as lesion size < 4 mm² or lack of fibrosis, were associated with a better response. The purpose of this cross-sectional study was to investigate eligibility for SRT in a clinical routine setting and to compare clinical features of eligible and non-eligible patients.

METHODS

Cross-sectional study of 468 patients treated for nAMD in one study center within a period of 4 months. Clinical features, such as visual acuity or number of IVI since diagnosis and within 6/12 months, as well as the presence for exclusion criteria for SRT were analyzed. Exclusion criteria were sub-divided into lesion-associated (relevant fibrosis, lesion size > 4 mm², PE tear), ocular comorbidity (e.g., macular comorbidity, vascular disease) and systemic comorbidity (e.g., dementia or tremor).

RESULTS

Exclusion criteria were met by 255 patients (54.5%). Exclusion was most dominantly associated with lesion-associated criteria (80.0%) and less often with ocular (20.8%) or systemic (9.4%) comorbidity. A total of 213 patients (45.5%) fulfilled eligibility criteria. Eligible patients had a better VA at time of analysis (0.36 vs. 0.56 logMAR, p < 0.0001) and at baseline (0.38 vs. 0.56 logMAR, p < 0.0001) compared to non-eligible patients. The numbers of previous intravitreal injections since diagnosis in strictly PRN-treated patients served as a surrogate marker for lesion activity and was comparable within the last 6/12 months. Non-eligible patients had a higher number of different anti-VEGF drugs (1.8 vs. 1.6, p = 0.038).

CONCLUSIONS

SRT in addition to anti-VEGF can be an option in every second patient with nAMD. Due to morphological exclusion criteria, patients eligible for SRT had a better VA and a better clinical response compared to non-eligible patients.

A longitudinal study to assess the frequency and cost of antivascular endothelial therapy, and inequalities in access, in England between 2005 and 2015

OBJECTIVES

High-cost antivascular endothelial growth factor (anti-VEGF) medicines for eye disorders challenge ophthalmologists and policymakers to provide fair access for patients while minimising costs. We describe the growth in the use and costs of these medicines and measure inequalities in access.

DESIGN

Longitudinal study using Hospital Episode Statistics (2005/2006 to 2014/2015) and hospital prescribing cost reports (2008/2009 to 2015/2016). We used Poisson regression to estimate standardised rates and explore temporal and geographical variations.

SETTING

National Health Service (NHS) care in England.

POPULATION

Patients receiving anti-VEGF injections for age-related macular degeneration, diabetic macular oedema and other eye disorders.

INTERVENTIONS

Higher-cost drugs (ranibizumab or aflibercept) recommended by the National Institute for Health and Care Excellence or lower-cost drug (bevacizumab) not licensed for eye disorders.

MAIN OUTCOME MEASURES

National procedure rates and variation between and within clinical commissioning groups (CCGs). Cost of ranibizumab and aflibercept prescribing.

RESULTS

Injection procedures increased by 215% between 2010/2011 and 2014/2015. In 2014/2015 there were 388 031 procedures (714 per 100 000). There is no evidence that the dramatic growth in rates is slowing down. Since 2010/2011 the estimated cost of ranibizumab and aflibercept increased by 247% to £447 million in 2015/2016, equivalent to the entire annual budget of a CCG. There are large inequalities in access; in 2014/2015 procedure rates in a 'high use' CCG were 9.08 times higher than in a 'low use' CCG. In the South-West of England there was twofold variation in injections per patient per year (range 2.9 to 5.9).

CONCLUSIONS

The high and rising cost of anti-VEGF therapy affects the ability of the NHS to provide care for other patients. Current regulations encourage the increasing use of ranibizumab and aflibercept rather than bevacizumab, which evidence suggests is more cost-effective. NHS patients in England do not have equal access to the most cost-effective care.

Recent developments in age-related macular degeneration: a review

Background

Visual impairment in elderly people is a considerable health problem that significantly affects quality of life of millions worldwide. The magnitude of this issue is becoming more evident with an aging population and an increasing number of older individuals.

Objective

The objective of this article was to review the clinical and pathological aspects of age-related macular degeneration (AMD), diagnostic tools, and therapeutic modalities presently available or underway for both atrophic and wet forms of the disease.

Methods

An online review of the PubMed database was performed, searching for the key words. The search was limited to articles published since 1980 to date.

Results

Several risk factors have been linked to AMD, such as age (>60 years), lifestyle (smoking and diet), and family history. Although the pathogenesis of AMD remains unclear, genetic factors have been implicated in the condition. Treatment for atrophic AMD is mainly close observation, coupled with nutritional supplements such as zinc and antioxidants, whereas treatment of wet AMD is based on targeting choroidal neovascular membranes.

Conclusion

Identification of modifiable risk factors would improve the possibilities of preventing the progression of AMD. The role of anti-vascular endothelial growth factor (anti-VEGF) agents has transformed the therapeutic approach of the potentially blinding disease “wet AMD” into a more favorable outcome.