Characteristics of the Intervention Free Interval in Patients Switching From a Fix- to a Flexible Treatment Regimen Based on Optical Coherence Tomography in Neovascular Age-Related Macular Degeneration

Abstract

Purpose: : Intravitreal ranibizumab significantly improves mean best-corrected visual acuity (BCVA) in patients with neovascular age-related macular degeneration (nAMD). However, frequent injections are often needed to maintain the success of anti-angiogenic treatment. This study evaluates effects of re-initiated therapy and the characteristics of the injection free interval after ranibizumab therapy following a fixed regimen was switched to a flexible regimen based on optical coherence tomography (OCT).

Methods: : 28 eyes of 28 patients with nAMD received ranibizumab treatment. 18 eyes were treated every three months while 10 patients were treated monthly. This fixed regimen was continued for at least 12 months. Treatment effects were examined monthly during this period and contained BCVA, Stratus and Cirrus (Carl-Zeiss Meditec) OCT imaging at all times. Following the fix treatment regimen, patients were monitored on a monthly basis and received further ranibizumab injections, if re-treatment criteria defined in the PrONTO study were fulfilled. Treatment effect was documented and compared to baseline treatment effects.

Results: : One patient left the study and was lost for follow up. 70% of all patients received further ranibizumab treatment after the fix regimen was abandoned. The mean injection free interval was 117 days. Those patients who received monthly ranibizumab injections showed a significantly extended injection free interval than those receiving injections every three months (mean time to following injection = 135 days versus 103 days). Eight patients did not receive further therapy within the first 9-month following the fix treatment regimen.

Conclusions: : This study showed that more than two thirds of our patients needed further anti-angiogenic treatment after a fix treatment regimen was left for an OCT guided regimen since the time of the injection free interval was clearly related to the dosing regimen in the first year of treatment. This indicates that potentially insufficient treatment in the initial therapeutic phase may result in a need for higher treatment frequency when switched to an OCT guided regimen.

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