Abstract
Purpose :
To provide the three year follow-up patient focused data analysis of Phase 1 and 2a clinical trials of high dose rAAV.sFLT-1 gene therapy (GT) for wet age-related macular degeneration (wAMD).
Methods :
Thirty-seven patients with advanced wAMD were randomized in a 2:1 ratio (GT:control). All patients received intravitreal ranibizumab at baseline and at Day 28. GT patients received rAAV.sFLT-1, 1x1011 vg subretinally at Day 7. All patients were assessed monthly for 12 months, at 18 and 36 months to pre-specified criteria and received retreatment anti-VEGF injections pro re nata.
Results :
All procedure-related adverse events were self-resolved by 12 months and there were no GT-related adverse events reported after. Control patients received a median of 7.0 anti-VEGF retreatments and lost a median of 7.0 early treatment diabetic retinopathy study (ETDRS) letters. A previously described, a subgroup of GT patients (HD-1) received a median of 2.5 retreatments over 36 months and lost a median of 4.0 ETDRS letters. The other subgroup of GT patients (HD-2), received 11.0 retreatments over 36 months, and lost a median of 7.0 ETDRS letters. Centre point thickness fluctuated over the 36 months and did not correlate with BCVA changes. At 36 months, 33% of control, and 51% of HD-1 patients showed maintenance/improvement of visual acuity. Only HD-1 patients maintained significant visual improvement at 36 months. Geographic atrophy development was significantly lower in the HD-1 than in control patients.
Conclusions :
Conclusions: These results demonstrated that GT was safe and that rAAV.sFLT-1 GT is bioequivalent to traditional anti-VEGF treatments. Those GT patients who responded at year one continued to do well and the presence of neutralising antibodies at base line did not seem to affect outcome. Over the long-term only GT patients maintained meaningful visual improvement, and had a lower tendency of developing geographic atrophy. We propose that increasing the dose of rAAV.sFLT-1 and the selection of treatment naïve patients might further increase the efficacy of GT.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.