SAN DIEGO, April 8, 2022 – Primmune Therapeutics, a biotech company harnessing the power of the innate immune system to treat solid tumors in the advanced cancer setting and for the clearance of human papillomavirus and related pre-cancerous cervical lesions, today announced the presentation of interim data from a first-in-human, Phase 1 study evaluating PRTX007, a novel, small molecule toll-like receptor 7 (TLR7)-specific agonist, at the American Association of Cancer Research (AACR) Annual Meeting in New Orleans. The study is a single-center, prospective, randomized, double-blind, placebo-controlled study with 9 single-ascending dose (SAD) cohorts and 4 multiple-ascending dose (MAD) cohorts where PRTX007 is administered orally to adult healthy volunteers. In addition to assessing the safety, tolerability and pharmacokinetics of PRTX007, the study is designed to evaluate pharmacodynamic responses relevant to dose selection for patients with cancer.

“These data from our ongoing first-in-human trial indicate that Primmune’s lead candidate, PRTX007, is well-tolerated in healthy volunteers and activates the desired components of innate and downstream adaptive immune responses while avoiding induction of proinflammatory cytokines,” said James Appleman, Ph.D., Co-Founder and Chief Scientific Officer at Primmune Therapeutics. “We look forward to the clinical advancement of PRTX007 for the treatment of solid tumors in combination with checkpoint inhibitors and as a monotherapy for the treatment of human papillomavirus-driven pre-cancerous cervical lesions and the underlying infection.”

Data show that PRTX007 was well-tolerated and expressed a favorable safety profile in the analyzed patient cohorts, with most adverse events (AEs) considered incidental and no instances of moderate, severe or serious AEs. In addition, every other day (QOD) dosing demonstrated stable systemic immune induction without evidence of counter-regulation. Both the clinical characteristics and unique pattern of immune induction by PRTX007 support its use in combination with immune checkpoint inhibitors.

Presentation details:

Title: PRTX007, an Optimized TLR7 Agonist for Systemic Immunotherapy of Cancers: Interim Analysis of Phase I Study in Healthy Volunteers
Presenting Author: Curtis Scribner, M.D., Chief Medical Officer, Primmune
Abstract Number: 8165
Poster Number: 8165
Poster Board Number: 8165
Poster Session: Phase I Clinical Trials 2
Session Date and Time: Tuesday, April 12, 9 a.m. CT to 12:30 p.m. CT
Location: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 33

Additional highlights from the poster presentation include:

  • Most AEs were incidental and not dose related. The most common drug-related AE was headache, seen across both treated and placebo groups independent of dose.
  • At the interim analysis, PRTX007 demonstrated a favorable safety profile when administered orally to all 9 SAD and 3 MAD cohorts tested.
  • PRTX007 demonstrated induction of interferon-stimulated genes (ISGs) without significant increases in circulating interferons (IFNs). There was no increase in expression or circulating levels of proinflammatory cytokines (e.g., TNFα, IL-6, IL-1β).

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 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. Furthermore, activated pDCs directly deliver interferons to target cells by paracrine transfer. This is functionally equivalent to administering a cocktail of all Type I/III IFN while avoiding the associated side effects and adverse events. PRTX007 is being rapidly advanced towards clinical trials for solid tumors in the advanced cancer setting and for clearing human papillomavirus-driven pre-cancerous cervical lesions.

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 the treatment of solid tumors in the advanced cancer setting and for clearing human papillomavirus-driven pre-cancerous cervical lesions. For more information, please visit

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