Virpax(R) Pharmaceuticals Announces the Proposed Development of A Long Acting Naloxone and Naltrexone Liposomal Delivery To Reverse Opioid Related Respiratory Depression

Virpax Licenses Technology from Yissum Research Development Company of the Hebrew University of Jerusalem

MALVERN, PA / ACCESSWIRE / August 13, 2019 / Virpax® Pharmaceuticals, Inc. (“Virpax”), a company specializing in developing pharmaceutical products for pain management, announced today that it proposes the development of a naloxone/naltrexone IP-protected formulation (RES202) consisting of liposomes embedded in a hydrogel or a lyophilized formulation suitable for intramuscular delivery by first responders with minimal training via an auto-injector. The free naloxone, present in the hydrogel, is responsible for an initial rapid onset of action to counter the effects of opioid overdose. The liposomal-embedded naltrexone and naloxone then accounts for a 48 to 96-hour duration of action. Virpax has obtained proof of principle of safety, kinetics, and duration of action of the hydrogel/liposome combination when loaded with bupivacaine, with an effectiveness of up to 96 hours.

Naloxone is an opioid antagonist used for the emergency treatment of known or suspected opioid overdose, as manifested by respiratory and/or central nervous system depression. Naltrexone is a medication that blocks the effects of drugs known as opiates, or narcotics. Both naloxone and naltrexone compete with these drugs for opioid receptors in the brain. Opioid overdose can occur in various settings, including overdose with prescription pain medications, such as morphine, or by using illegal drugs, such as heroin, fentanyl, and other synthetic opioids. Current treatment options often require multiple doses to be effective; in more extreme scenarios repeat doses of current countermeasures may not be feasible. Consequently, the development of fast-onset, long-acting opioid antagonist effective against highly potent opioids is a high priority.

“Given the unpredictability of synthetic opiates, a longer-acting opioid antagonist delivery system combined with a fast-acting antagonist, offers family members, caregivers, and first responders the added coverage required for survival after overdose,” said Anthony P. Mack Chairman & CEO of Virpax.

About RES202

RES202 is a drug product based on a type of liposomal delivery system with large multi-vesicular vesicles (LMVVs) encapsulating high doses of the naltrexone in a unique way. These drug-loaded liposomes are composed of lecithin and cholesterol; both lipids are “GRAS” (Generally Recognized as Safe). The system delivers a naloxone medicine intended to provide quick onset, and naltrexone intended for duration that is slowly released from liposomes to provide peak performance properties. The formulation has the potential to block opioid side effects associated with respiratory depression for up to 96 hours. A critical component in the further development of RES202 is being performed by the highly esteemed Professor Chezy Barenholz and his team. Prof. Barenholz, PhD, serves as the Head of the Laboratory of Membrane and Liposome Research at the Department of Biochemistry of the Hebrew University-Hadassah Medical School, Jerusalem, Israel. Prof. Barenholz has 46 years of experience in research and development. Among his many accomplishments, Prof. Barenholz is the author of over 350 publications. He is a Co-Inventor of over 30 patent families, two of which underlie Doxil® for the treatment of breast and ovarian cancer. Prof. Barenholz was granted various awards for excellent contributions to the field of liposome science including the Donders Chair Professor from the Utrecht University, Netherlands, several innovation awards by the Hebrew University of Jerusalem, Israel, the Alec Bangham Award for life long contributions to the Science and Technology of Liposomes and the TEVA Founder Prize for major contributions to Medical Biotechnology granted by Teva Pharmaceuticals, a leading, worldwide pharmaceutical company. He is a renowned Specialist in Biochemistry, Biophysics, Nanotechnology and Cancer. He received B.Sc., M.Sc. (cum laude) and Ph.D. degrees, all in Biochemistry from the Hebrew University of Jerusalem, Israel. Prof. Barenholz has particular expertise with Naloxone and Naltrexone. “Virpax is honored to have Prof. Bareneholz conducting research that we anticipate will lead to further positive results for RES202,” said Jeffrey Gudin, MD, EVP, Chief Medical Officer.

About Virpax Pharmaceuticals

Virpax develops New Chemical Entities, New Molecular Entities and 505(b)(2)s for pain management using patented cutting-edge delivery technologies designed to satisfy unmet market requirements, enhance patient compliance and quality of life, all while creating value for its investors and partners. The company is focused on becoming a global leader in non-opioid pain management by developing and delivering innovative pharmaceutical products to its customers. For more information, please visit

Forward-Looking Statement

This news release contains “forward-looking statements” as defined by the Private Securities Litigation Reform Act of 1995. Virpax cautions readers that forward-looking statements are based on management’s expectations and assumptions as of the date of this news release and are subject to certain risks and uncertainties that could cause actual results to differ materially, including, but not limited to, those associated with the timing of the RES202 regulatory filings and clinical milestones and other risks and uncertainties identified in the Company’s filings with the Securities and Exchange Commission. Forward-looking statements reflect our analysis only on their stated date, and Virpax takes no obligation to update or revise these statements except as may be required by law.


Virpax Pharmaceuticals
Shana Panzarella, Chief of Staff

SOURCE: Virpax Pharmaceuticals

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