May 10, 2021 by John Fernandez
Baptist Health’s Miami Neuroscience Institute Leads U.S. Drug Trial to Treat ‘Large Vessel’ Ischemic Strokes
Baptist Health’s Miami Neuroscience Institute is set to take the lead in a national clinical trial that could improve treatment results for patients taken to the hospital suffering from acute ischemic strokes.
The most common strokes are ischemic, meaning they result from an obstruction within a blood vessel supplying blood to the brain. A quarter to about 40 percent of ischemic strokes are acute because they involve so-called large vessel occlusions, or LVOs, which is when one of the major arteries of the brain is blocked.
The clinical trial, expected to recruit about 16-20 acute stroke patients, is set to begin next month and targets ischemic stroke patients with LVOs. The novel drug being tested is an “oxygen carrier” labeled for the purpose of the trial as PP-007. This drug in pre-clinical studies has shown to be able to increase the amount of oxygen available to the brain when an artery is blocked, explains the trial’s lead investigator, Italo Linfante, M.D., medical director of Neuroendovascular Surgery at Miami Neuroscience Institute and Miami Cardiac & Vascular Institute, both part of Baptist Health South Florida.
The trial is an example of multidisciplinary collaboration between NeuroEndovascular Surgery (Dr Linfante and Guilherme Dabus, M.D.,), Stroke Neurology (Felipe De Los Rios, M.D., medical director of the Institute’s stroke program) and Neuroscience (Michael McDermott, M.D., neurosurgeon and the Institute’s chief medical executive).
The trial will be “randomized” — meaning there will be two primary groups of patients monitored: those who get standard care — excluding tPA; and those who get PP-007 with the mechanical thrombectomy.
The drug will be administered before or at the onset of a mechanical thrombectomy, a procedure during which doctors remove blood clots using a device threaded through brain arteries. If a stroke patient arrives at the hospital up to 24 hours after the onset of symptoms, they are no longer in the time window for tPA (tissue plasminogen activator) medication, a clot-busting solution used to treat ischemic strokes but they may undergo mechanical thrombectomy. The strict time window for tPA is about 4.5 hours for the onset of symptoms. Most stroke patients don’t make that strict time-frame before they get treated.
“The drug being tested in the trial acts by expanding the oxygen-carrying capacity of the blood and by increasing blood flow in the brain’s collaterals circulation.” said Dr. Linfante. “By supporting the oxygen delivery in the collateral vessels, this will help preserve more brain tissue until normal blood flow is restored with mechanical thrombectomy, which will hopefully translate into improved outcomes for large vessel occlusion (LVO) strokes.”
Some stroke patients fare better than others because they have well-developed collateral circulation systems “which can serve as a backup system when a large vessel is occluded,” says Dr. Linfante. “We hope to dramatically improve the outcomes in acute stroke patients who undergo mechanical thrombectomy,” says Dr. Linfante “because this unique medication has three mechanisms of action” he explains.
“No. 1, it is a vasodilator — i.e. increases blood flow in the collateral circulation; No. 2, it’s a plasma expander and therefore brings more blood into areas of the brain when an artery is blocked and; No. 3, it delivers oxygen in a much more efficient way, compared to red blood cells. In addition, once administered, this medication acts for 24 hours, ” says Dr. Linfante.
Although tPA clot-busting infusions have been the standard of care for stroke patients, they can only be administered to a few who can make it to a hospital that is able to properly care for stroke patients. Six years ago, the Institute’s stroke center at Baptist Hospital was certified to treat the most complex stroke cases, along with an elite group of facilities nationwide, by the Joint Commission which accredits U.S. healthcare organizations.
“There are many trials going on to try to avoid using tPA altogether,” says Dr. Linfante. “One day in the future, we may not be using tPA at all. It might end up in the history books. And that is fine because many stroke patients can’t make that very tight 4.5-hour treatment window for tPA.”