SRF tolerant ranibizumab regimen does not negatively impact visual outcomes
medwireNews: Tolerating some subretinal fluid (SRF) during a treat-and-extend (T&E) ranibizumab protocol does not detrimentally affect visual acuity in patients with neovascular age-related macular degeneration (AMD), study findings indicate.
Furthermore, when compared with treatment that aimed to completely resolve all SRF, the SRF tolerant regimen resulted in significantly fewer ranibizumab injections because significantly more patients were able to extend their treatment interval beyond 4 weeks, report Robyn Guymer (University of Melbourne, Victoria, Australia) and colleagues in Ophthalmology.
For the FLUID study, patients with treatment-naïve subfoveal choroidal neovascularisation secondary to AMD, and a best-corrected visual acuity (BCVA) of at least 23 letters, were randomly assigned to an intensive (n=173) or relaxed (n=174) treatment regimen.
The intensive (SRF intolerant) regimen involved monthly ranibizumab 0.5 mg injections until complete resolution of SRF and intraretinal fluid (IRF) before extending treatment intervals whereas the relaxed (SRF tolerant, but only up to 200 μm at the foveal centre) regimen required resolution of only IRF before treatment intervals were extended.
At 24 months, patients in the relaxed group had a mean change in BCVA from baseline of 2.6 letters, which was statistically noninferior to the 3.0-letter change observed among patients in the intensive group. Baseline values were 64.2 and 62.3 LogMAR letters, respectively.
Similar proportions of patients in the relaxed and intensive groups gained 15 letters or more (16.2 vs 16.3%) or lost fewer than 15 letters (87.9 vs 87.2%), and similar proportions achieved a VA of at least 20/40 (56.6 vs 53.5%) or a VA at or below 20/200 (8.1 vs 8.7%).
The mean change in central subfield thickness at 24 months was also not significantly different between the two groups, but tended to be smaller with the relaxed regimen than with the intensive regimen (127.3 vs 153.1 μm), the researchers note.
During the course of the study, significantly more individuals in the relaxed group were able to extend their treatment intervals to 12 weeks and maintain this frequency than in the intensive group (29.6 vs 15.0%), whereas significantly more patients in the intensive group than in the relaxed group never extended beyond 4-weekly intervals (13.5 vs 2.8%).
This resulted in individuals in the relaxed group receiving significantly fewer ranibizumab injections than those in the intensive group, at a mean of 15.8 versus 17.0.
Guymer and co-authors say that their study “will help ophthalmologists make evidence-based retreatment decisions”, but they caution that longer studies are needed to determine “what the longer term outcomes of tolerating this degree of SRF will be”.
By Laura Cowen
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