PROJECT SUMMARY Opioids account for close to 70% of overdose deaths in the United States, with fentanyl and heroin two of the most common causes. Treatment of opioid overdose currently relies on rapid administration of naloxone. New strategies to prevent opioid overdose are desperately needed as a part of a comprehensive approach to address the opioid epidemic in the United States. Opioid vaccines are an attractive approach to prevent opioid overdose and Opioid Use Disorder (OUD). These vaccines act by eliciting serum antibodies that bind and sequester the drug in the blood, preventing it from crossing the blood-brain barrier where it acts on the central nervous system. Current opioid vaccine strategies require multiple boosts and months to reach peak titers, and have yet to show protection against lethal overdose. Here, we propose to use a bacteriophage virus-like particle (VLP) vaccine platform to elicit high titer antibodies quickly to protect against lethal overdose with fentanyl and heroin. We have preliminary data showing the feasibility of this approach for oxycodone, with peak titers reached within 14 days after a single intramuscular immunization, and protection from lethal overdose with oxycodone. In this two phase UG3/UH3 proposal, we will engineer a combined vaccine to protect against fentanyl and heroin by displaying modified fentanyl, heroin, and two active metabolites of heroin (6-acetylmorphine and morphine) on our bacteriophage VLP platform. In Phase 1, we will explore the impact of attachment site on the specificity and affinity of the antibodies elicited and the efficacy of the combined vaccine to protect against lethal overdose, drug-induced respiratory depression, and drug-induced anti- nociception. At the end of Phase 1, we will have a lead candidate combined vaccine against fentanyl and heroin. In Phase 2, we will further explore the addition of adjuvants and administration site on vaccine efficacy. We will also examine the protection offered by our vaccine against lethal fentanyl and heroin overdose administered by oral, intravenous, inhalation routes. We will also develop a comprehensive Product Development Plan, a master cell bank (MCB), and engage industry partners to establish a process and non- GLP production runs of our VLP vaccines and a non-GLP safety pharmacology functional observation battery. Overall these studies will identify a lead fentanyl and heroin vaccine candidate that can protect against fatal overdose of these drugs, and provide the critical data necessary to move into IND-enabling studies by the end of the 5 years of funding.

PROJECT NARRATIVE Opioids account for close to 70% of overdose deaths in the United States, with fentanyl and heroin two of the most common causes. A vaccine that quickly elicits high-titer antibodies to fentanyl and heroin could prevent fatal overdose. Here, we will engineer and test heroin and fentanyl vaccines based on a highly immunogenic bacteriophage virus-like particle platform.