Tizona's TTX-080 Shows Dual Immune Activation in Advanced Solid Tumors, Advances to Phase 1b Colorectal Cancer Trial
核心洞察
Tizona Therapeutics (搜索) presented clinical translational data at SITC 2025 showing that TTX-080, a first-in-class HLA-G (搜索) antagonist, activates both innate and adaptive immune pathways in patients with advanced solid tumors (搜索).
The monoclonal antibody demonstrated biological activity even in low tumor mutational burden tumors, which are typically less responsive to traditional checkpoint inhibitors like PD-1 (搜索) and PD-L1 (搜索).
TTX-080 is currently being evaluated in a randomized Phase 1b trial combining the drug with cetuximab and FOLFIRI (搜索) in microsatellite stable metastatic colorectal cancer (搜索) patients.
Tizona Therapeutics (搜索) presented compelling clinical translational evidence at the 40th Annual Meeting of the Society for Immunotherapy of Cancer (SITC) demonstrating that its lead immunotherapy candidate TTX-080 can activate both innate and adaptive immune responses in patients with advanced solid tumors (搜索). The first-in-class, fully human monoclonal antibody targets HLA-G (搜索), offering a differentiated mechanism from traditional checkpoint inhibitors.
Novel Mechanism Shows Promise in Resistant Tumors
The data, presented in a poster titled "TTX-080, A First-in-Class HLA-G (搜索) Specific Antagonist, Increases Distinct Innate and Adaptive Immune Cells in the Tumor Microenvironment and Periphery" (Abstract #570), analyzed results from Tizona's single-arm Phase 1 trial evaluating TTX-080 as monotherapy and in combination with cetuximab or pembrolizumab.
"These translational data provide compelling evidence in humans that HLA-G (搜索) blockade can activate both innate and adaptive immunity, which is differentiated from the traditional PD-1 (搜索), PD-L1 (搜索), and CTLA-4 (搜索) checkpoints," said Courtney Beers, Ph.D., Chief Scientific Officer of Tizona Therapeutics (搜索).
Key Clinical Findings Demonstrate Broad Immune Activation
Analysis of patient tumor biopsies, blood samples, and pharmacokinetic data revealed that TTX-080 activates multiple immune pathways. The treatment increased antigen-experienced CD8+ T cells, activated CD4+ T cells, and Ki67+ NK cells, indicating robust engagement of both adaptive and innate immune systems.
The antibody also induced immune-regulating chemokines CXCL9 and CXCL10 and enhanced myeloid and effector T-cell gene signatures in the tumor microenvironment. Notably, TTX-080 demonstrated biological activity even in low tumor mutational burden (≤ 20 mut/Mb) tumors, which are historically less responsive to T-cell-focused checkpoint inhibitors.
Favorable Pharmacokinetic Profile Supports Clinical Development
TTX-080 exhibited well-behaved pharmacokinetics, supporting a biologically active dose of 20 mg/kg every three weeks (Q3W). The treatment showed low immunogenicity and minimal target-mediated drug disposition, characteristics that support its continued clinical development.
Advancing to Randomized Phase 1b Trial in Colorectal Cancer
Building on these promising results, Tizona is currently enrolling first or second line patients with microsatellite stable (MSS) RAS/RAF wild-type metastatic colorectal cancer (搜索) in an ongoing randomized Phase 1b study (NCT04485013). The trial evaluates TTX-080 in combination with cetuximab and FOLFIRI (搜索) versus cetuximab and FOLFIRI alone.
"Together, these data support the potential of this first-in-class antibody to extend benefit to patients whose tumors are unresponsive to existing treatment options," Beers noted.
Targeting HLA-G for Immune Tolerance Reversal
HLA-G (搜索) is a non-classical MHC class I molecule expressed on many solid tumors that drives immune suppression through the ILT2 (搜索) and ILT4 (搜索) receptors. By blocking these interactions, TTX-080 seeks to reverse immune tolerance and promote anti-tumor activity in ways distinct from currently available immunotherapies.
The clinical-stage biotechnology company is developing next-generation immunotherapies designed to overcome tumor immune evasion, with TTX-080 representing its lead program in this effort to modulate the immune system against resistant tumors.