AUG 25, 2012
By Chirag P. Shah, MD, MPH
Retina/Vitreous
This article reports results for the HORIZON study, which evaluated the long-term efficacy and safety of multiple intravitreal ranibizumab injections administered at the investigator's discretion in wet AMD patients who had completed the controlled, randomized treatment phase of the MARINA, ANCHOR or FOCUS trials. The injections were well-tolerated for more than four years. However, visual acuity gains declined with less frequent follow-up and treatment.
The study, published in June in Ophthalmology, included 853 patients with choroidal neovascularization secondary to wet AMD who had completed 24 months in one of the other studies. The majority were randomized to ranibizumab in their initial trial (n = 600), while smaller cohorts were randomized to control treatment and then crossed over to ranibizumab (n = 190) or were treatment naive (n = 83).
In the current extension study, they received ranibizumab 0.5 mg as needed per the investigator's discretion, with follow-up intervals initially at least every six months. This was later modified to every three months.
The authors found that the visual gains at two years after monthly ranibizumab in the initial studies were lost incrementally by four years on as-needed treatment. Likewise, patients initially in control groups (crossover or treatment naive) had lost 9.6 letters at two years, falling further to -16.1 letters after two subsequent years of as-needed treatment. However, systemic and ocular side effects were uncommon.
The authors conclude that treatment with ranibizumab for at least four years remained safe, and patients maintained vision at presentation. Based on our current appreciation of regular monitoring while on as-needed treatment, they speculate that patients were undertreated at the start of the HORIZON study. They say the results of this and other recent studies suggest that to maintain visual acuity gains in patients with wet AMD treated with ranibizumab, more frequent follow up is needed.