– PRTX007 program to support DTRA’s efforts to establish biological defense solution against Lassa fever and other hemorrhagic viruses –

SAN DIEGO, March 20, 2024 – Primmune Therapeutics, a biotech company harnessing the power of the innate immune system, today announced that it was awarded a $22,480,552 contract by the Defense Threat Reduction Agency (DTRA) to develop PRTX007 as an oral broad spectrum antiviral TLR7 agonist for the treatment of Lassa fever. PRTX007 is a clinical-stage novel oral small molecule that specifically activates toll-like receptor 7 (TLR7), which drives the innate immune system’s primary response to viral infections, enabling broad spectrum antiviral activity.

The objective of the program is to evaluate the efficacy of PRTX007 in a series of animal models for Lassa fever and establish an effective treatment method of Lassa virus in humans. In addition, the program will support the development of US-based manufacturing capabilities.

“The scientific community has long recognized the therapeutic potential of systemically acting toll-like receptor agonists in the treatment of acute and chronic viral diseases, precancerous lesions and solid tumors,” said James Appleman, Ph.D., Co-founder and Chief Scientific Officer at Primmune Therapeutics. “PRTX007 is unique in that administration engages a coordinated innate and adaptive immune response which is required for therapeutic benefit, while avoiding excessive systemic inflammation – historically, a challenge associated with TLR7 agonists.”

Primmune’s PRTX007 program will support DTRA’s efforts to counter current threats and challenges from Lassa fever and other hemorrhagic viruses through the development of a timely and effective biological defense solution. Primmune and DTRA expect the program to be completed by June 30, 2026.

“Primmune has demonstrated broad spectrum antiviral activity with PRTX007 and with related compounds from our discovery and development program,” said Charlie McDermott, President, Chief Executive Officer and Director of Primmune Therapeutics. “PRTX007 has been shown to be amenable to scale-up, long-term storage and tableting, with the potential to be deployed as a single agent or in combination with direct antiviral compounds or other therapeutic modalities – underscoring its potential utility as a first line of defense against future novel pathogens in real-world settings.”

Research and development funds in the amount of $845,610.00 were initially provided to Primmune on January 30, 2024. The contract agreement includes committed funding of $10.6 million, which will be provided to Primmune across a 14-month base period, with the potential to receive option period funding in the amount of $11.9 million, pending the achievement of performance milestones throughout the base period.

“Treating African hemorrhagic fever viruses such as Lassa fever, Marburg virus disease and Ebola virus disease poses many challenges due to the underlying pathophysiology of the diseases and their highly infectious nature,” said Curtis Scribner, M.D., Chief Medical Officer at Primmune Therapeutics. “PRTX007’s novel immunologic approach has the potential for combination use with direct acting anti-viral agents – enabling widely applicable utility in the treatment of Lassa fever and other hemorrhagic viruses.”

About PRTX007

PRTX007 is Primmune’s lead clinical development candidate. In a 130 person healthy volunteer SAD/MAD clinical study, PRTX007 was well-tolerated while also driving controlled, long-term systemic stimulation of the innate immune response. PRTX007 administration uniquely activates selected plasmacytoid dendritic cells (pDCs) functions, leading to a systemic immune poly-IFN response without stimulating production of NF-κB-driven proinflammatory factors like IL-6, TNFα or IL-1β. These activated pDCs directly deliver interferons to target cells by paracrine transfer. Conceptually, this is equivalent to administering a therapeutically effective cocktail of all Type I/III IFNs while avoiding the associated side effects and adverse events. Furthermore, repeated PRTX007 administration leads to pDC-mediated systemic activation of CD8+ T cells and NK cells, both of which are important for treatment of viral diseases and cancer

About Primmune Therapeutics

Primmune Therapeutics is a clinical-stage biotech harnessing the power of the innate immune system for therapeutic benefit through development of novel small molecule, orally administered toll-like receptor 7 (TLR7) agonists.

Media Contact: MacDougall Advisors, Karen Sharma, ksharma@macdougall.bio, 781-235-3060