– Trial in Progress Poster Highlights Study Design, Dosing Regimen, and Protocol for the Ongoing Phase 1/2 Trial for TAC-001 in Patients with Advanced or Metastatic Solid Tumors

– First Presentation of Preclinical Activity for Tallac’s Nectin-4 Targeted TLR9 Agonist Antibody Conjugate, Which Shows Robust Immune Cell Activation and Anti-Tumor Response

BURLINGAME, CA, USA I November 11, 2022 I Tallac Therapeutics, Inc., a privately held biopharmaceutical company harnessing the power of innate and adaptive immunity to fight cancer, today announced that the Company presented data for two, first-in-class toll-like receptor 9 (TLR9) agonist antibody conjugates from its novel Toll-like Receptor Agonist Antibody Conjugate (TRAAC) platform at the Society for Immunotherapy of Cancer 37th Annual Meeting (SITC 2022).

A trial in progress poster for TAC-001, the company’s lead clinical candidate from its novel TRAAC platform and the first to enter the clinic, highlights the study design, dosing regimen, and study protocol for the Company’s ongoing Phase 1/2 clinical trial. The trial, known as INCLINE-101 (NCT05399654) is an open label, multicenter, dose escalation and expansion study of TAC-001 in patients with select advanced or metastatic solid tumors. It is designed to evaluate the safety, pharmacokinetics and preliminary anti-tumor activity of TAC-001 administered intravenously. The Company expects to report initial clinical data from the trial, which is currently enrolling patients in the USA and Australia, at medical conferences in 2023.

Additionally, the Company presented preclinical data demonstrating that its Nectin-4 targeted TLR9 agonist antibody conjugate triggers TLR9 signaling, induces myeloid and dendritic cell activation, phagocytosis, cytokine production and lymphocyte activation, resulting in potent anti-tumor efficacy.

This is Tallac’s third TRAAC molecule in the pipeline and is comprised of a CpG oligodeoxynucleotide conjugated to a novel Nectin-4-targeting antibody for systemic administration and tumor microenvironment (TME) delivery of a potent TLR9 agonist. Nectin-4 is a cancer associated antigen over-expressed in many solid tumor types with limited expression in normal tissues and its over-expression correlates with poor prognosis.

“TAC-001 and Nectin-4 TRAAC are differentiated molecules derived from our versatile immune activation platform which are designed to activate specific immune cell populations systemically or in the local tumor microenvironment,” said Hong I. Wan, Ph.D., president, CEO and co-founder of Tallac Therapeutics. “We are pleased to share the very first preclinical findings for Nectin-4 TRAAC, our third program, which demonstrate the drug’s ability to potently activate myeloid cells, leading to enhanced phagocytosis, increased expression of costimulatory molecules, secretion of pro-inflammatory cytokines and immune activation. Animal studies also showed that single-agent Nectin-4 TRAAC treatment led to durable tumor regression and eradication in checkpoint inhibitor refractory tumor models and rejection of tumor upon rechallenge, demonstrating potent anti-tumor immunological memory.”

TLR9 agonists are a class of immunotherapy that generate both innate and adaptive immune response, which may produce more robust and durable anti-cancer immunity to help overcome resistance to standard-of-care oncology treatments. TLR9 agonists have demonstrated clinical activity in melanoma patients when administered intratumorally. Tallac Therapeutic’s TRAAC platform is designed to deliver a potent and differentiated TLR9 agonist (T-CpG) for targeted immune activation via systemic administration.

About TAC-001

TAC-001 is a Toll-like Receptor Agonist Antibody Conjugate (TRAAC) comprised of a potent toll-like receptor 9 agonist (T-CpG) conjugated to an antibody against CD22, a receptor restricted to B cells, including tumor-infiltrating B cells. TAC-001 is designed to systemically deliver T-CpG to B cells by binding to CD22, leading to internalization of TAC-001, TLR9 signaling, B cell activation and a cascade of immune reactions. Preclinical studies demonstrate that the innate and adaptive immune responses triggered by TAC-001 leads to potent anti-tumor activity. TAC-001 is being developed for the potential treatment of solid tumors.

About Nectin-4 TRAAC

Nectin-4 is a Toll-like Receptor Agonist Antibody Conjugate (TRAAC) comprised of a CpG oligodeoxynucleotide conjugated to a novel Nectin-4-targeting antibody for systemic administration and TME delivery of a potent TLR9 agonist. Nectin-4 is a cancer associated antigen over-expressed in many solid tumor types with limited expression in normal tissues. Additionally, Nectin-4 over-expression correlates with poor prognosis. Preclinical data demonstrate that Nectin-4 TRAAC triggers TLR9 signaling, induces myeloid and dendritic cell activation, phagocytosis, cytokine production and lymphocyte activation, resulting in potent anti-tumor efficacy.

About Tallac Therapeutics, Inc.

Tallac Therapeutics is a privately held biopharmaceutical company harnessing the power of innate and adaptive immunity to fight cancer. Tallac’s pipeline of immunotherapy candidates are derived from the company’s novel Toll-like Receptor Agonist Antibody Conjugate (TRAAC) platform to deliver a potent Toll-like receptor (TLR9) agonist (T-CpG) for targeted immune activation via systemic administration. Several TRAAC molecules are in various stages of discovery and development. TAC-001, the company’s lead clinical candidate, is the first to enter the clinic and is currently in an ongoing Phase 1/2 clinical trial in patients with advanced or metastatic solid tumors. For more information, please visit www.tallactherapeutics.com.

SOURCE: Tallac Therapeutics