StereoTactic Radiotherapy for Wet Age-Related Macular Degeneration (STAR): A Randomised, Double-masked, Sham-controlled, Clinical Trial Comparing Low-voltage X-ray Irradiation With as Needed Ranibizumab, to as Needed Ranibizumab Monotherapy.

Age-related macular degeneration (AMD) leads more people to go blind than all other eye diseases combined. 'Wet' AMD occurs when abnormal new blood vessels grow into the macula. The macula is an area inside the back of the eye, which is tightly packed with the light-sensitive cells that give fine central vision for driving, reading, facial recognition etc. Most patients are treated with repeated injections of ranibizumab (Lucentis), bevacizumab (Avastin) , or aflibercept (Eylea) into the eye (these drugs suppresses the new vessel growth). Unsurprisingly, the need for hospital visits every 1-2 months, and regular injections into the eye, is not favoured by patients.

The proposed study investigates the use of radiation to treat wet AMD. Radiation preferentially damages proliferating cells, such as those forming the abnormal new blood vessels. It has the potential to kill off the abnormal cells, unlike the injections which just suppress the disease.

The radiation is delivered using a robotically controlled device that aims three beams of radiation in through the white of eye, to overlap at the macula. Initial studies of stereotactic radiotherapy (SRT) were promising, and established the best dose of radiation. They showed that radiation has the potential to significantly reduce the need for injections. Each injection costs the National Health Service (NHS) approximately £600, hence the potential cost savings are substantial. For those who respond well, disease activity is reduced, and injections can be eliminated or greatly reduced.

Eye charities have run focus groups of people with wet AMD to help set priorities, and participants identified the burden of treating wet AMD as one of their most pressing concerns, as it greatly restricts their freedom and quality of life. Repeated injections also carry risks of rare but blinding complications, and long term they may possibly lead to other eye diseases such as glaucoma and atrophy of the macula.

The preliminary SRT studies were not designed to determine if the visual outcome was the same, better, or worse than standard injection therapy, and follow up was too short to determine long term risks. A larger study is therefore required to confirm that SRT reduces the number of injections and to determine if the visual outcomes are acceptable. There is also a need for longer term safety monitoring, as radiation damage typically has a delayed onset.