Chang and colleagues are developing an outcome for geographic atrophy trials that measures vision loss rather than structural changes.
Geographic atrophy is a condition without a dedicated therapy—yet. One of the challenges is the need for a validated endpoint that measures vision loss, rather than structural loss measurement that is currently used.
A team of investigators used data from the phase 3 Chroma and Spectri trials of intravitreous lampalizumab for geographic atrophy (GA) to develop these new endpoints.
Dolly Chang, MD, PhD, a clinical instructor at Stanford University Byer Eye Institute and assistant medical director at Genentech spoke with MD Magazine® about this research, which she presented at the 2019 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) in Vancouver, BC.
“One of the challenges for designing a clinical trial for GA therapy is that we need to have a better outcome and currently the GA area is the more validated outcome, but it's a structural endpoint and what patients really care about is more of how much vision they lose over time,” said Chang.
So, the context is that geographic atrophy is an advanced form of age-related macular degeneration and it affects about 5 million people worldwide. So, the rate is actually very similar to neovascular AMD, however there's no therapy for it so far, so there is a huge medical need.One of the challenges for designing a clinical trial for GA therapy is that we need to have a better outcome and currently the GA area is the more validated outcome, but it's a structural endpoint and what patients really care about is more of how much vision they lose over time. But this part is challenging because it's highly subjective. So, in our research we were mainly looking at microperimetry. It is device that allows us to quantify the retinal sensitivity at different locations of the retina. So, in this way we are hoping that they provide more correlation with the structural loss over time. So, that's mainly what our research is focusing on.Sure, so, we used the data from the lampalizumab trials, and the reason why is because this is still by far the largest trial for geographic atrophy therapy. And what we did is we used the microperimetry sub-study which is conducted on 277 participants and we followed the patient at each visit until week 96.