Here at the SchragLAB, we believe Retinal Health = Brain Health. Consequently, we have been leading a charge to develop the world’s first effective treatment for strokes of the retina due to central retinal artery occlusion (CRAO). CRAO is a somewhat rare disorder which we estimate afflicts 50,000-65,000 Americans and is an important cause of blindness in older adults.
Last month, we published the results of our cohort study from Vanderbilt University Medical Center evaluating the efficacy of early treatment with a “clot buster” called tPA or alteplase. We found that treating patients within 4.5 hours of onset resulted in three-times higher probability of recovery compared to patients who were untreated. To make sure this result was reproducible, we updated out 2015 patient level meta-analysis with patient level data from four new cohorts. This showed that treatment was highly effective at early timepoints across studies from all over the world. Importantly, early treatment also appears to be quite safe. Because alteplase is a potent blood thinner, it has the potential to cause bleeding. There have been a few incidences of significant bleeding in patients treated for CRAO, but most have been due to treatment at late timepoints or combining alteplase with other blood thinners. When administered according to established protocols, symptomatic bleeding is rare. We appreciate the recent blog from Dr. Richard Jackson reviewing this work.
The next step in this effort is to establish a national registry to increase the statistical power of the study and to identify centers who treat large numbers of patients. The major obstacle to a successful clinical trial, in my opinion, is enrolling an adequate number of patients. This requires hospitals to have effective protocols in place for rapid triage, evaluation and treatment and robust collaboration among neurologists, ophthalmologists and emergency physicians. We are optimistic that we can identify a large-enough group of high-volume centers to conduct a trial in the near future. We discuss this issue in greater details here. If you would like to participate in such an effort, I’d be happy to hear from you at matthew.schrag@vanderbilt.edu.
In the meantime, we are excited about two randomized clinical trials underway in Europe, the REVISION trial led by Sven Poli at the University of Tubingen in Germany and the THEIA trial led by Benoit Guillon at Nantes University in France, both of which will evaluate the efficacy of alteplase within 4.5 hours. We are also looking forward to the start of a trial of tenecteplase for CRAO led by colleagues in Norway (more on that later).
As always, we are grateful to our national and global partners, including Brian Mac Grory at Duke University who is spearheading our registry efforts, Valerie Biousse at Emory University who has helped us foster interdisciplinary collaboration and Andrew Lee and Celia Chen who are leading the charge against CRAO in Australia, to recognize just a few of our key collaborators.