Title: Stereotactic radiotherapy for wet age-related macular degeneration: year 4 results of a randomised, double-masked, sham-controlled trial
Abstract:
Aim: To investigate the long term, real-world safety and efficacy of Stereotactic Radiotherapy (SRT) for exudative Age-Related Macular Degeneration (AMD).
Methods: This randomised, double-masked, sham-controlled clinical trial recruited 411 participants with active, chronic, previously-treated exudative AMD, randomised 2:1 to a single treatment with 16 Gray SRT or sham SRT. The primary outcome was the number of ‘as required’ ranibizumab injections over 2 years, tested for superiority (fewer injections). The main secondary outcome was Best-Corrected Visual Acuity (BCVA), tested for non-inferiority at a 5-letter margin. After year 2, participants reverted to standard care, with masking maintained, returning at years 3 and 4 for repeat study visits. The year 2 analyses were repeated at year 4.
Results: At year 2 the primary outcome was met, with significantly fewer injections, and with non-inferior BCVA (as reported already). At year 4, the SRT group (n 222) received a mean ± standard deviation of 19.1 ± 10.9 injections versus 21.6 ± 11.3 with sham (n 106), an adjusted reduction of 3.2 injections (95% confidence interval of difference: -5.7 to -0.7). However, BCVA change was 8.3 letters worse than sham (95% confidence interval of difference: –12.7 to –4.0). Adverse event rates were similar between groups, but reading centre-detected microvascular abnormalities occurred in 126 SRT-treated eyes (58%, 126/218) and 16 (16%, 16/102) sham-treated eyes.
Conclusions: Long-term, standard care, masked follow-up after the primary outcome reversed this trial’s initial conclusion, and no longer supports the use of SRT for exudative AMD. Other trials might consider extended, real-world, masked follow-up.
