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– PRTX007 program to support DTRA’s efforts to establish biological defense solution against Lassa fever and other hemorrhagic viruses – SAN DIEGO--(BUSINESS WIRE)-- 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 United States 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. For more information, please visit .

– PRTX007 demonstrated a favorable safety pro all analyzed cohorts with no serious adverse events (SAEs) observed – – Well-controlled activation of innate and adaptive immune response observed without increases in proinflammatory factors – – Data support suitability of PRTX007 for investigation as a key component of combination therapy for curative treatment of chronic hepatitis B virus (HBV) infection – SAN DIEGO--(BUSINESS WIRE)-- Primmune Therapeutics, a biotech company harnessing the power of the innate immune system, today presented clinical data from its first-in-human, Phase 1 study of PRTX007, an orally administered prodrug of a novel, small molecule toll-like receptor 7 (TLR7)-specific agonist, at the 2023 American Association for the Study of Liver Diseases (AASLD) Annual Meeting (The Liver Meeting). The data presented highlight the suitability of PRTX007 for investigation as a combination therapy for curative treatment of chronic hepatitis B virus (HBV) infection. This was a first-in-human, phase 1, single-center, prospective, randomized, double-blind, placebo-controlled study of 9 single-ascending dose (SAD) cohorts and 4 multiple-ascending dose (MAD) cohorts of PRTX007 administered orally every other day (QOD) to adult healthy volunteers. In addition to the primary objective of assessing the clinical safety and tolerability of PRTX007, the study was designed to evaluate the pharmacokinetics and pharmacodynamics of PRTX007 and PRX034, and identify the specific active dosing range for use in future infectious viral disease studies via pharmacodynamic and immune markers. Data show that PRTX007 demonstrated a favorable safety pro all of the analyzed cohorts with no serious adverse events (SAEs) observed. QOD dosing was shown to activate the innate and adaptive immune responses, with significant increases in CD8+ T-cell and NK cell activation observed from pretreatment to end of dosing in all healthy volunteers. There were no clinically relevant increases in expression or circulating levels of proinflammatory cytokines observed for any dose range in the study. “We are encouraged by the results of this Phase 1 study which demonstrate the safety and tolerability of PRTX007 administration in healthy volunteers. These results should translate to treatment of patients with acute and chronic viral diseases, including chronic HBV infection, and support further exploration of PRTX007 in future infectious viral disease studies,” said James Appleman, Ph.D., Co-founder and Chief Scientific Officer at Primmune Therapeutics. “Well-controlled, coordinated activation of the innate and adaptive immune response was observed without increases in proinflammatory factors, signaling the potential of PRTX007 to be a key component of a combination therapy resulting in a functional cure of chronic HBV infection.” Presentation details: Title: Clinical validation of an orally-delivered, systemically activated TLR7 agonist to boost host immune response to chronic viral diseases, including hepatitis B virus Presenting Author: Curtis L. Scribner, M.D. Poster ID: 1463-C Presentation Date and Time: Friday, November 10 - 12:00 PM – 1:00 PM ET Location: Hynes Convention Center, Hall C (second floor) Additional highlights from the poster presentation include: PRTX007 demonstrated a favorable safety pro administered orally to all 9 SAD and 4 MAD cohorts tested. Most AEs were mild and not dose-related, with no instances of dose modification or discontinuation due to treatment-related AEs throughout the study. The most common drug-related AE was headache, seen across both treated and placebo groups independent of dose. Repeated oral QOD doses of PRTX007 increased the magnitude of antiviral mRNA response. The short half-life of PRTx007 enables a targeted, short pulse of exposure to the active agonist without accumulation of the drug between doses. PRTX007 demonstrated well-controlled expression of interferon-stimulated genes (ISGs) independent of dose, without significant increases in circulating IFNs. There was no increase in expression or circulating levels of proinflammatory cytokines (e.g., TNFα, IL-6, IL-1β). CD8+ T cells and NK cell activation (CD38+ markers) increased markedly from pretreatment to end of dosing in all HVs. About PRTX007 PRTX007, Primmune’s lead clinical development candidate, is designed to provide well-tolerated, controlled, long-term stimulation of the innate immune response while also potentiating long-term effective innate and adaptive immune responses. PRTX007 administration uniquely activates plasmacytoid dendritic cells (pDCs), leading to a systemic immune poly-IFN response without stimulating production of NF-κB-driven proinflammatory factors like IL-6, TNFα or IL-1β. 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, PRTX007 administration leads to systemic activation of anti-tumor effector CD8+ T cells and NK cells. About Primmune Therapeutics Primmune Therapeutics is a clinical-stage biotech harnessing the power of the innate immune system by developing small molecule, orally administered toll-like receptor 7 (TLR7) agonists. For more information, please visit .