Abstract: 2242
Title: Preclinical development of GNTbm-TKI, a novel multi-receptor tyrosine kinase inhibitor, while combined with GNTbm-38 showing potent induced tumor microenvironment remodeling activity in cancer immunotherapy
Session Date/Time: 10/19/2025, 12:00-12:45 CEST
Poster Board Number: 1577P

Currently, although there are many options for cancer immunotherapy, they still cannot meet the needs of clinical treatment, especially for advanced solid tumors defined as 'cold tumors'. Genetic alterations of certain receptor tyrosine kinases (TKs), including TAM (TYRO3, AXL, and c-MER), are critical in creating environment conducive to tumor development in several cancers such as HNSCC, CRC, HCC, and RCC. GNTbm-TKI is a novel multi-targeted TKI, showing induction of immune activation in the tumor microenvironment (TME), that indicates the potential application in cancer immunotherapy for unmet medical needs.

The results of the study show that GNTbm-TKI strongly inhibited the activities of TYRO3, AXL, c-MER, BTK, ROS1, NTRK2, MET, and VEGFR2 at nanomolar level. GNTbm-TKI showed anti-proliferation activity in NCI-60 human cancer cell lines with low GI₅₀ values. GNTbm-TKI showed a superior in vivo efficacy in WT mice compared to immune-deficient mice in CT-26 model, indicating anti-cancer immune activation induced by the treatment. Furthermore, treatment with GNTbm TKI + GNTbm-38 (an immune activator of class ⅠHDACi) combined with ICI significantly improved tumor response rate and boosted survival rate through synergistic effect by normalizing tumor vessels, increasing activated CD8⁺ T cell infiltration into tumors, inducing memory T cell persistence, and strongly inhibiting mobilization of immunosuppressive cells into tumors. On the other hand, GNTbm-TKI + GNTbm-38 combined with anti-PD-1/VEGF bispecific antibodies in a humanized B-PD-1/PD-L1/VEGFA mouse model also greatly improved anti-cancer with a strong synergistic effect.

GNTbm-TKI is a potent immune-activating multi-tyrosine kinase inhibitor, and it is surprisingly found capable of significantly reshaping the tumor microenvironment when combined with GNTbm-38. When further combined with ICI or anti-PD-1/VEGF bispecific antibodies, it can greatly enhance anti-cancer efficacy, providing a scientific basis for future clinical trials.

About GNTbm-TKI
GNTbm-TKI is a new chemical entity independently developed by GNTbm. It is a drug candidate selected by an immuno-competent tumor-bearing animal testing platform, and has undergone many preclinical research studies to be demonstrated that it has very outstanding anti-cancer activity in tumor microenvironment. GNTbm-TKI is an oral drug with dual effects of strong immune activation and multi-tyrosine kinase, which is unique when compared to the mechanism of other TKI drugs. GNTbm-TKI can remodel the tumor microenvironment (TME) through a unique multiple regulatory mechanism based on its kinase targets which it selectively inhibits. GNTbm-TKI strongly inhibits tumor growth and development, suppresses tumor invasion and metastasis, inhibits tumor angiogenesis, and most importantly, possesses potent tumor immune regulatory activity. When GNTbm-TKI is combined with GNTbm-38, based on their respective unique mechanisms, they have a complementary and powerful tumor microenvironment remodeling function, capable of converting 'cold tumors' into 'hot tumors.' When further combined with ICI or anti-PD-1/VEGF bispecific antibodies, they exhibit exceptionally superior anti-tumor immuno-oncology activity, which can attract CTL to infiltrate into the TME, and activate CTLs and reduce CTL exhaustion. At the same time, it can also reduce the attraction of immunosuppressive cells (such as: TAM, Treg, and MDSCs) into the TME, so as to achieve the remodeling of the TME, which is more conducive to obtaining the therapeutic benefits of cancer immunotherapy. GNTbm-TKI monotherapy can be used in the treatment of advanced neuroendocrine tumor, and GNTbm-TKI can also be combined with GNTbm-38 or/and ICI/anti-PD-1/VEGF bispecific antibodies for treatment of a variety of solid tumors, mainly through a unique anti-cancer immune-regulating and multiple-tyrosine kinase inhibition mechanism to achieve anti-cancer treatment goals.

About GNTbm
GNTbm (stock code: 7427, Taiwan) is a company that has developed new drugs against advanced cancers, and has marketed a new drug approved for advanced Her-2^-ER⁺ breast cancer in Taiwan. The GNTbm R&D team independently develops new drugs, and has multiple anti-cancer drug candidates with global development rights, with the goal of meeting the unmet clinical needs of patients with advanced cancers. GNTbm mainly focuses on the development of drugs with innovative mechanisms for the new generation of cancer immunotherapy, conducts clinical validation, and hopes to successfully provide novel immunotherapy with excellent efficacy and safety for varieties of cancer indications, to fulfil the unmet medical needs of patients around the world and improve the quality of life of patients.

Abstract: 2574

Title: Preclinical development of GNTbm-38, a novel class I histone deacetylase inhibitor, while combined with anti-VEGFR TKI or anti-PD-1 Ab: Assessment of immune activation and immune memory in cancer immunotherapy.

Session Date/Time: 6/2/2025, 1:30 PM-4:30 PM CT

Poster Board Number: 221

At present, there is no ICI-based drug combination for the treatment of advanced MSS colorectal cancer, which is a cold tumor. Studies have shown that epigenetic regulators such as class I HDAC inhibitors are an emerging and important drug component for combination therapy that can greatly increase the anti-cancer benefits of cancer immunotherapy. Therefore, rational drug combinations, containing class I HDACi, may provide opportunities in cancer immunotherapy.

GNTbm-38 is a new drug candidate independently developed by GNTbm. GNTbm-38 acts as a TME reprogramming regulator in immunotherapy. When combined with TKI, GNTbm-38 significantly improved tumor response rate and survival rate through synergistic effect by normalizing tumor vessels, increasing tumor antigen presentation, increasing activated CD8⁺ T cell infiltration into tumors, inducing memory T cell persistence, and inhibiting mobilization of immunosuppressive cells into tumors. On the other hand, treatment with GNTbm-38 plus anti-PD-1 antibody in the CT-26 model showed greatly improved tumor response rate and survival rate with a strong synergistic effect. Furthermore, in B-hPD-1/hPD-L1 mice (humanized model) subcutaneously injected with B-hPD-L1 CT-26 cells, treatment of pembrolizumab and GNTbm-38 resulted in a 46.5% inhibition on tumor growth. Therefore, our data provided a strong rationale to explore the combination of GNTbm-38 with anti-VEGF TKI with or without ICI. From these data GNTm-38 has been shown to display powerful induction of immune activation and immune memory in combination therapy with TKI/ICI against colon CT-26 cold tumor. Based on the in vitro, in vivo and preclinical studies, these data show that GNTbm-38 exhibits markedly superior pharmacokinetics, tolerability, and efficacy in animal models. It is expected to complete the US IND application by the end of 2025 and enter the clinical study.

About GNTbm-38

GNTbm-38 is a new chemical entity with potential as a pivotal drug component of a new generation of cancer immunotherapy independently developed by GNTbm. It is a drug candidate selected by an immuno-competent tumor-bearing animal testing platform, and has undergone many preclinical research studies to confirm that it has very outstanding anti-cancer activity in tumor microenvironment. GNTbm-38 is an oral drug with dual effects of epigenetic regulation of gene expression and immune activation, which is unique when compared to the mechanism of other epigenetic drugs. GNTbm-38 can remodel the tumor microenvironment (TME) through a unique epigenetic regulatory mechanism, including the cell composition and gene expression that affect the TME, so that "cold tumors" can be transformed into "hot tumors", which can attract CTL to infiltrate into the TME, and at the same time, it can also reduce the attraction of immunosuppressive cells (such as : TAM, Treg, and MDSCs) into the TME, so as to achieve the remodeling of the TME, which is more conducive to obtaining the therapeutic benefits of cancer immunotherapy. GNTbm-38 monotherapy can be used in the treatment of hematological tumors, and GNTbm-38 can also be combined with a unique multi-kinase inhibitor or immune checkpoint inhibitor for treatment of a variety of solid tumors, mainly through a unique anti-cancer immune-regulating mechanism to achieve anti-cancer treatment goals.

About GNTbm

GNTbm (stock code: 7427, Taiwan) is a company that has conducted clinical trials and developed a new drug against advanced breast cancer on the market in Taiwan. The GNTbm R&D team has the ability to independently develop new drugs, and has multiple anti-cancer drug candidates with global development rights, with the goal of meeting the unmet clinical needs of patients with advanced cancers. GNTbm mainly focuses on the development of drugs with innovative mechanisms for the new generation of cancer immunotherapy, conducts clinical validation, and hopes to successfully provide novel immunotherapy with excellent efficacy and safety for varieties of cancer indications, to fulfil the unmet medical needs of patients around the world and improve the quality of life of patients.