The burden of anti-VEGF treatment for patients with neovascular age-related macular degeneration (nAMD) could be significantly reduced by delivering a one-off, minimally invasive dose of stereotactic radiotherapy (SRT).
According to a pivotal, randomised, doublemasked, sham-controlled trial published in The Lancet,1 the number of injections required to treat patients with nAMD using this approach could be reduced by around 25%, without sacrificing visual acuity.
Additionally, fewer ranibizumab injections offset the cost of SRT, leading to savings.
Age-related macular degeneration (AMD) affects 8% of adults globally and is a leading cause of blindness in many high-income and upper-middle income countries.
nAMD, the most aggressive form of AMD, is treated with long-term intravitreal injections of drugs that inhibit vascular endothelial growth factor (VEGF). While anti-VEGF injections are the most performed eye procedure in many countries, they impose a considerable economic and risk burden on patients.
In 2022, an estimated 62,000 Australians were receiving anti-VEGF treatment for nAMD through the Pharmaceutical Benefits Scheme (PBS), with 18,000 more receiving the drugs for diabetic macular oedema.2 The anti-VEGF drug aflibercept (Eylea) is among the costliest of PBS drugs to government. In 2022–23, the cost to government for aflibercept was AU$492,082,598 from 457,602 prescriptions.3
As well as the economic burden, each injection carries only a small risk of severe sight loss from infectious endophthalmitis, but risks accumulate with repeated treatment.
STUDY RESULTS
The SRT study, which took place in 30 National Health Service (NHS) hospitals in the United Kingdom, was led by Professor Timothy Jackson. It involved 411 participants aged 50 years and over (58% women, 42% men) enrolled between 2015 and 2019. All participants had chronic active nAMD, with at least three previous anti-VEGF injections, including at least one in the past four months. If two eyes were eligible, the participant chose one as the study eye.
Of all participants, 274 were randomly allocated to the 16-Gy SRT group and 137 to the sham SRT group. The final analysis included 241 participants in the 16-Gy SRT group and 118 participants in the sham group.
The authors reported a statistically significant 22% reduction (2.9 injections, p<0.0001) in ranibizumab retreatment for nAMD in the two years following 16-Gy SRT.
Best-corrected visual acuity (BCVA) change was non-inferior in the SRT vs sham and adverse event rates similar. Reading centre-detected microvascular abnormalities occurred in 77 SRTtreated eyes (35%) and 13 (12%) sham-treated eyes and they found that overall, “eyes with microvascular abnormalities tended to have better BCVA than those without”.
The delivery of fewer ranibizumab injections offset the cost of SRT, which saved a mean of £565 per participant (95% CI –332 to 1483).
The targeted radiation therapy was delivered via a new robotic system, with three beams of focussed radiation targeting small lesions in the affected eye.
The study was conducted in collaboration with the University of Bristol and Queen’s University in Belfast.
Macular Disease Foundation Australia CEO Dr Kathy Chapman said advances that might improve the burden on macular disease patients would be welcomed by the community.
“When anti-VEGF treatment entered the Australian market in 2007, it was a game changer for anyone diagnosed with nAMD. “With an estimated 90,000 people receiving sight-saving eye injections for nAMD and other macular conditions each year, any advances in treatment that reduce the number of eye injections required by a patient, without sacrificing visual acuity, will have a dramatic effect in reducing the burden of treatment, which often ends in people stopping treatment all together,” Dr Chapman said.
References
- Jackson, T.L., Desai, R., Peto, T., et al., Stereotactic radiotherapy for neovascular age-related macular degeneration (STAR): a pivotal, randomised, double-masked, sham-controlled device trial. The Lancet. 2024 June 11: S0140-6736(24)00687-1. DOI:10.1016/S0140-6736(24)00687-1.
- Butler, M., Cheaper medicines from today. Canberra: Minister for Health and Aged Care, media release, 1 Jan 2023, available at: health.gov.au/ministers/the-hon-mark-butler-mp/media/ cheaper-medicines-from-today [accessed June 2024].
- Top 10 drugs 2022–23 Aust Prescr 2023;46:93. DOI: 10.18773/austprescr.2023.030.
