Virpax Announces Results of Maximum Tolerated Dose Study for Probudur

Virpax Pharmaceuticals, Inc. (“Virpax” or the “Company”) (NASDAQ: VRPX), a company specializing in developing non-addictive products for pain management, post-traumatic stress disorder, central nervous system (CNS) disorders and anti-viral barrier indications, today announced results for a Maximum Tolerated Dose (MTD) study in Sprague-Dawley Rats for Probudur.

Probudur is Virpax’s injectable long-acting liposomal bupivacaine formulation that is injected at the wound site. Probudur is being developed to significantly reduce or eliminate the need for opioids after surgery in approved indications. Probudur is a local anesthetic that binds to the sodium channel, preventing pain signals from reaching the brain. In pre-clinical trials, Probudur has shown long duration pain control for at least 96 hours, with a rat incisional model demonstrating analgesia for up to five days and in vitro studies demonstrating a slow release of bupivacaine that lasted for up to six days.

The study was designed to determine the MTD of free bupivacaine, Probudur, and Probudur plus free bupivacaine when administered as a single subcutaneous injection to the wound. Probudur, with its liposomal formulation, is intended to provide both immediate and extended pain relief at the wound site. The dosing ranges were selected based on a prior preliminary study. All doses of Probudur were well-tolerated. There were no noteworthy effects on body weight, clinical chemistry, hematology, or coagulation. It was also observed that bupivacaine appears to be less toxic in the presence of liposomes than when administrated as a free drug.

Histopathology was conducted on the injection site and all treatment groups showed some changes which were minimal to moderate in severity. Effects were slightly more pronounced at the high dose of Probudur. In vivo MTD studies in rats indicated that Probudur provided a better therapeutic window as compared to free bupivacaine.

“These results confirm our belief that Probudur is well-tolerated in animals and a single injection of this proprietary liposomal formulation of bupivacaine has the potential to provide both immediate relief as well as sustained relief at the wound site,” stated Gerald Bruce, CEO of Virpax Pharmaceuticals. “Probudur’s proprietary formulation allows for both rapid onset and prolonged duration of action, obviating the need for simultaneous administration of free bupivacaine. We are now another step closer to completing our required preclinical studies and plan to file an Investigational New Drug Application (IND) for Probudur by the end of the year.”