Oxygen Biotherapeutics, Inc., (NASDAQ: OXBT) a developer of oxygen-carrying therapeutics, today announced that it has submitted to the U.S. Food and Drug Administration (FDA) results from two series of animal studies designed to address Agency concerns regarding the use of Oxycyte in treating traumatic brain injury (TBI) patients. These studies were conducted to probe both the interactions between Oxycyte and the immune system as well as assess the PFC-based emulsion’s potential to increase the risk of intracerebral hemorrhage (ICH). This research was funded as part of a $2.07 million grant that Oxygen Biotherapeutics has with the U.S. Army who is committed to developing treatments for TBI. Submission of these data represents an important step forward in responding to FDA questions and adding US clinical sites to those already participating in the development of Oxycyte.
In the immunocompetency work, mice were challenged with two of the most commonly encountered types of infections in TBI patients – pneumonia and influenza. Results from these studies clearly demonstrated that Oxycyte has little to no impact on the efficient clearance of these pathogens from the body and, presumably, those removed by similar mechanisms. The no adverse event level (NOAEL) for Oxycyte in the pneumonia and influenza experiments was determined to be 7.2 grams per kg. Exposure of mice to Listeria monocytogenes, a model for aggressive blood-borne bacteria that can lead to sepsis resulted in increased mortality following Oxycyte administration. While no NOAEL dose was determined in the Listeria study, the exposure level to Oxycyte in the mice at the NOAEL of the above studies (7.2 grams per kg) is almost ten times higher than that seen in man at the recommended maximum human dose. Additionally, across almost three dozen patients treated with Oxycyte to date, there have been no reports of such an infection, thereby putting the risk of this serious infection in perspective.
Because PFC emulsions are known to cause a transient decrease in platelet numbers in animals and humans the FDA has expressed concerned about TBI patients being at increased risk of de novo ICH or expansion of existing lesions. However, in a widely used rat ICH model, Oxycyte, at doses up to 12 mL/kg had little effect on hemostasis – despite producing the typical 30-40% drop in platelet count. Even more significant was the observation that hemorrhages produced by injecting collagenase into the brain never expanded in size following Oxycyte administration beyond those in the saline control group. In stark contrast, heparin, which was used as a positive control, caused the brain hemorrhage to expand to four times its original size.
“Submission to the FDA of these long-awaited studies represents another important step towards adding the United States to the growing list of countries participating in our current Phase IIb severe TBI trial,” stated Dr. Timothy Bradshaw, Oxygen Biotherapeutics’ Executive Vice President of Drug Development.