OCT Alone Underestimates Disease Activity and Frequency of Retreatment of Neovascular AMD in the RADICAL Trial. Interim Results

Abstract

Purpose: : To present elective retreatment rates based on optical coherence tomography (OCT) and fluorescein angiography (FA) within the RADICAL study.

Methods: : Patients were randomly assigned to 1 of 4 treatment groups: (1) very low-fluence vPDT (15 J/cm²) + ranibizumab (0.5 mg) + dexamethasone (0.5 mg); (2) half-fluence vPDT (25 J/cm²) + ranibizumab + dexamethasone; (3) half-fluence vPDT + ranibizumab; (4) ranibizumab monotherapy. Inclusion criteria: ≥50 years; subfoveal CNV due to AMD; naïve to AMD treatment; BCVA letter score 73-24; lesion size <9 DA. All patients received their assigned treatment at baseline. Patients in the ranibizumab monotherapy group received mandatory treatment at months 1 and 2. Retreatment decisions for all treatment groups at subsequent monthly visits, were made by masked retina specialists. OCT was done initially and retreatment occurred if central foveal thickness was either ≥250 microns or ≥50 microns thicker than any previous visit. If retreatment was not required based on OCT, the patient then underwent FA to confirm the OCT finding. Retreatment based on FA was applied if there was evidence of CNV leakage or if the size of the lesion had increased.

Results: : 162 patients were enrolled. Results were analyzed for a 6-month safety review when all continuing patients had completed 6 months of follow-up (n=157). There had been 417 elective retreatments of which 214 (51%) were based on meeting the OCT retreatment criteria. Thus 203 treatments (49%) were given based on FA retreatment criteria after failing to meet OCT retreatment criteria. No new safety signal was noted. Updated information will be presented.

Conclusions: : Interim analyses of the ongoing RADICAL trial indicate that using OCT alone with the study-specific OCT retreatment criteria delays or withholds treatment in approximately half of retreatment decisions. FA subsequent to a negative OCT led to a doubling of the elective retreatments. The relevance of this finding to visual outcomes is unknown and warrants further evaluation.

Clinical Trial: : www.clinicaltrials.gov NCT00492284

Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)