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Primmune Therapeutics Provides Update on Phase 1 Healthy Volunteer Study of PRTX007, A First in Class Novel Oral TherAjuvant™

SAN DIEGO, November 2, 2021 – Primmune Therapeutics today announced interim results from its Phase 1 study in healthy volunteers with PRTX007, a novel orally-administered, small molecule toll-like receptor 7 (TLR7) specific agonist for acute viral diseases, including SARS-CoV-2, and cancer. This double blind, placebo-controlled Phase 1 study is evaluating the safety, pharmacokinetics (PK), pharmacodynamics (PD), and tolerability of PRTX007 in single- and multiple-ascending dose cohorts.

PRTX007 is Primmune’s lead TherAjuvant™, a reference to its combination of therapeutic and adjuvant mechanisms of action. PRTX007 is designed to provide immediate benefit to patients through controlled stimulation of the innate immune response while also potentiating long-term effective innate and adaptive immune responses. PRTX007 uniquely engages TLR7 and targeted immune cells without exacerbating inflammation, a critical feature in treating respiratory viral infections. More broadly, PRTX007 and other TherAjuvants™ differ from therapeutic vaccines in that the source of the antigens presented to the patient’s immune system come from the treated pathology. Additionally, TherAjuvants™ differ from most small molecule approaches in that they target the patient’s immune system and not tumor cells or virally encoded targets.

“PRTX007 is performing as expected and is echoing the pharmacology, safety and tolerability data that we generated in human peripheral blood mononuclear cells, in primate pharmacology studies and in 2-week rodent and primate GLP safety studies,” said James Appleman, Ph.D., Co-founder and Chief Scientific Officer at Primmune Therapeutics. “PRTX007 was derived from Primmune’s extensive TLR7 agonist discovery program and could potentially have utility both in treatment and prophylaxis, serving as a first-line defense against SARS-CoV-2, its mutants, and other future novel pathogens.”

The Phase 1 study of PRTX007 has completed the single-ascending dose cohorts with doses ranging from 50 mg – 600 mg. PRTX007 was safe and well tolerated with no dose modifications or treatment discontinuations. In general, systemic drug exposure increased proportionally with PRTX007 dose. The expected pattern of increased expression of interferon stimulated genes (ISGs) and increased levels of specific circulating chemokines and cytokines signaling an induction of innate immunity was observed.

In multiple-ascending dose (MAD) cohorts, initial PK data showed consistency for the 300 mg group and was comparable at day 1 and day 13 exposures. Additional data on subsequent MAD cohorts, induction of ISGs mRNA expression and chemokine/cytokines are expected by the end of 2021.

“PRTX007 has thus far demonstrated a benign safety and tolerability profile with increasing dose-dependent exposure; building our confidence as we rapidly advance towards clinical trials for acute viral diseases and cancer,” Curtis Scribner, M.D., Chief Medical Officer at Primmune Therapeutics.

About Primmune Therapeutics
Primmune Therapeutics is harnessing the power of the innate immune system to develop small molecule, orally administered toll-like receptor 7 (TLR7) agonists as immunotherapies called TherAjuvants™ for the treatment of viral diseases and cancers.

Media Contact:
Cammy Duong
ICR Westwicke