ZZ Biotech's Stroke Drug Moves Closer to Pivotal Phase 3 Clinical Trial as the NIH Awards First Tranche of $30 Million Grant to the Keck School of Medicine of USC

In a significant development for the treatment of acute ischemic stroke, the National Institute of Neurological Disorders and Stroke (NINDS), part of the U.S. National Institutes of Health (NIH), awarded the first $4 million of a grant budgeted to total approximately $30 million to researchers at the Keck School of Medicine of the University of Southern California (USC) to conduct a pivotal Phase 3 clinical trial using ZZ Biotech's experimental treatment for acute ischemic stroke. The drug, 3K3A-APC, which is a genetically engineered variant of the naturally occurring activated protein C (APC), is proposed to protect the brain following a stroke by reducing bleeding and inflammation, and by blocking the cell death process in neurons, glia, and endothelial cells.

The grant award will fund a Phase 3 clinical trial, which will be led by principal investigator Patrick Lyden, M.D., professor of Physiology and Neuroscience and Neurology at the Keck School of Medicine of USC. The remainder of the grant will be funded in subsequent tranches, pending review of milestones over the 6-year grant period. The primary endpoint of the trial is to test 3K3A-APC as a cerebroprotectant, a drug that hastens or augments recovery after stroke. A secondary endpoint will gauge the efficacy of 3K3A-APC at minimizing brain bleeds when combined with two standard treatments for acute ischemic stroke.

"Following the success of the RHAPSODY Phase 2 clinical trial, feedback has been overwhelmingly positive, creating a sense of urgency on our part to resume the clinical progress of 3K3A-APC to bring relief to the approximately 700,000 people that suffer ischemic strokes annually," commented Patrick Lyden, M.D., professor of Physiology and Neuroscience and Neurology at the Keck School of Medicine of USC. "In addition to funding the upcoming Phase 3 trial, the grant is a recognition by the NINDS of the great need to find a suitable treatment that produces better patient outcomes while reducing the burdensome healthcare costs associated with ischemic stroke, the third leading cause of death and the most common cause of disability in industrialized nations."

This will be the second clinical trial of 3K3A-APC in stroke to be supported by grants from NINDS. The Phase 2 clinical trial, also led by Dr. Lyden, was conducted through the NINDS' Network for Excellence in Neuroscience Clinical Trials (NeuroNEXT). The Phase 3 clinical trial will be conducted through NIH StrokeNet.

"I am thrilled to be working with Dr. Lyden again in this important Phase 3 clinical study for 3K3A-APC. The continuing support from NINDS has given us access to some of the nation's best clinical trial sites," said Kent Pryor, PhD, ZZ Biotech's chief executive officer. "3K3A-APC is a potential game-changer for those suffering from acute ischemic strokes. I believe, based on the positive clinical results to date, our 3K3A-APC will potentially create the first new drug class to treat ischemic stroke since 2003."

The results from the RHAPSODY Phase 2 clinical trial study, which demonstrated the neuro- and vasculoprotective properties of 3K3A-APC, were published by Patrick Lyden, M.D. and his colleagues in the Annals of Neurology in 2019, and concluded:

• Total hemorrhage volume and hemorrhage incidence were both substantially reduced in 3K3A-APC treated patients.
• The incidence of any hemorrhage was reduced from 86.5% in placebo-treated patients to 67.4% in the combined treatment arms (p=0.046).
• Total hemorrhage volume was likewise reduced from an average of 2.1±5.8 mL on placebo to 0.8±2.1 mL in the combined treatment arms (p=0.066).
• All dose levels of 3K3A-APC tested were found to be safe and well-tolerated.

About 3K3A-APC

ZZ Biotech's experimental drug 3K3A-APC is a genetically engineered variant of human activated protein C (APC), a serine protease with two biochemical pathways in the body. 3K3A-APC was designed to enhance the beneficial cytoprotective and anti-inflammatory activities of APC while greatly reducing its anti-coagulant activity.

About Keck School of Medicine

Founded in 1885, the Keck School of Medicine of USC is one of the nation's leading medical institutions, known for innovative patient care, scientific discovery, education, and community service. Medical and graduate students work closely with world-renowned faculty and receive hands-on training in one of the nation's most diverse communities. They participate in cutting-edge research as they develop into tomorrow's health leaders. With more than 900 resident physicians across 50 specialty and subspecialty programs, the Keck School is the largest educator of physicians practicing in Southern California

About ZZ Biotech

Headquartered in Houston, Texas, ZZ Biotech, LLC, is a clinical stage company developing 3K3A-APC for ischemic stroke, other neurological diseases and wound healing applications. ZZ Biotech has completed a successful National Institute of Neurological Disorder and Stroke-funded Phase 2 clinical study, RHAPSODY, in acute ischemic stroke patients. In June 2020, the U.S. FDA designated 3K3A-APC for the treatment of acute ischemic stroke as a Fast Track development program. ZZ Biotech commenced a Phase 2 clinical biomarker study in ALS in December 2021.