Session Title: Free Paper Session 24: Vascular Diseases & Diabetic Retinopathy VII
Session Date/Time: Sunday 10/09/2017 | 10:00-11:30
Paper Time: 10:00
Venue: Room 117
First Author: : H.Mehta UK
Co Author(s): : S. Fraser Bell V. Nguyen L. Lim M. Gillies
The treatment burden of intravitreal vascular endothelial growth factor inhibitors for DME has been reported to reduce over time. Such a phenomenon of increasing treatment interval over time has not previously been reported with intravitreal triamcinolone, fluocinolone or dexamethasone, mainly because fixed interval dosing has been used in previous seminal clinical trials of intravitreal steroid in DME.
The BEVORDEX study (Clinicaltrial.gov# NCT01298076) was a multi-centre randomised clinical trial set in Australia.
The BEVORDEX study was the first head-to-head trial of bevacizumab (Avastin; Genentech, South San Francisco, CA) versus a slow-release dexamethasone implant (Ozurdex®; Allergan Inc., Irvine, CA) for the treatment of centre-involving DME. Study eyes were randomised to intravitreal bevacizumab (with re-treatment possible after 4 weeks) or intravitreal dexamethasone implants (with re-treatment possible after 16 weeks). Study eyes were assessed every 4 weeks for re-treatment according to pre-specified visual acuity and central macular thickness criteria. In this post-hoc analysis, changes in treatment interval over time were examined using mixed-effects regression models. We assessed whether mean treatment interval changed over time and whether changes in treatment interval depended on the treatment received. This analysis studied re-treatment intervals rather than counting the number of intravitreal procedures per year which could be biased by an initial loading phase.
There were 68 eyes from 47 patients that completed 2 years of follow-up in the BEVORDEX study. Of these, 67 study eyes received at least one re-treatment (one study eye in the dexamethasone implant group did not require re-treatment over 24 months). There were 32 eyes treated with bevacizumab and 35 eyes treated with dexamethasone implants. Study eyes received a mean of 14.6 (standard deviation, SD, 7.8) and 5.6 (SD 1.4) injections in the bevacizumab and dexamethasone implant treated groups respectively over 2 years. The mean re-treatment interval over the 2 year follow-up period was 70.8 (SD 43.8) days for the bevacizumab group and 145 (SD 45.4) days for the dexamethasone implant group. The mean treatment interval increased over time for both treatment groups (P=0.002); there was no statistically significant difference between the two treatments in how the re-treatment intervals changed over time (P=0.681).
The increase in treatment interval for both intravitreal bevacizumab and dexamethasone implants over time in the treatment of DME has implications when informing patients about potential treatment burden, planning services for delivery of intravitreal injections, and future clinical trial design. For drugs that have a disease-modifying effect, fixed interval treatment dosing may not be required beyond an initial loading phase.