GenFleet Therapeutics, a clinical-stage biotechnology company focusing on cutting-edge therapies in oncology and immunology, unveiled the latest research findings of GFH375, an oral KRAS G12D (ON/OFF) inhibitor, at the poster presentation of the 2024 American Association for Cancer Research (AACR) Annual Meeting.
GFH375 (VS-7375) is a highly potent and selective KRAS G12D inhibitor targeting both "ON" (GTP-bound) and "OFF" (GDP-bound) states of the protein. With preliminary safety data, favorable oral bioavailability and potent efficacy across preclinical models, GFH375 also holds the potential for treating KRAS G12D mutant cancers with brain metastases.
"G12D mutation is the most prevalsent KRAS mutation detected in human carcinomas, and no G12D-targeted therapies have been approved yet. Preliminary research has shown potent efficacy and safety of orally administered GFH375 in animal models. Additionally, GenFleet's GFH925 (KRAS G12C inhibitor) has had its New Drug Application accepted with Priority Review Designation in China. GenFleet is well-positioned to rapidly deploy its proven expertise in developing RAS pathway inhibitors to deliver more cutting-edge innovative therapies. "stated Fusheng Zhou, Ph.D., Vice President of GenFleet's Drug Discovery Department.
Preclinical research also demonstrated the combination of avutometinib (RAF/MEK clamp) and GFH375 confers enhanced anti-tumor efficacy relative to either agent alone, indicating potential for future clinical combination. Avutometinib in combination with defactinib (FAK inhibitor) is being developed by Verastem Oncology with clinical development across multiple indications and was granted breakthrough therapy designation for the treatment of patients with recurrent low-grade serous ovarian cancer (LGSOC) regardless of KRAS status and after one more prior lines of therapy, including platinum-based chemotherapy. GenFleet entered into a discovery and development collaboration with Verastem Oncology (Nasdaq: VSTM) in 2023 to advance three oncology programs, the first program selected is GFH375.
Abstract Title: GFH375 (VS-7375): An oral, selective KRAS G12D (ON/OFF) inhibitor with potent anti-tumor efficacy
Abstract No. : 3318
Original mechanism targets both active and inactive KRAS G12D
GFH375 inhibits GTP-bound KRAS G12D and its binding with downstream proteins such as RAF; the drug candidate also targets the GDP-GTP exchange to inhibit the activation of KRAS G12D.
Potent single agent anti-tumor efficacy of GFH375 and its potential for treating KRAS G12D mutant cancers with brain metastases
GFH375 potently and selectively inhibits phospho-ERK signaling and proliferation in KRAS G12D mutant tumor cells. GFH375 also accumulates in tumor tissue and elicits sustained inhibition of the protein following a single oral administration.
GFH375 induces tumor regression in multiple KRAS G12D CDX tumor models via oral administration. It also demonstrates potent anti-tumor activity in an intracranial CDX tumor model, which suggests the potential of GFH375 as a treatment for KRAS G12D mutant cancers with brain metastases.
Combination of GFH375 and avutometinib enhances anti-tumor efficacy while retaining favorable toxicity profile in vivo
The combination of GFH375 and avutometinib enhances anti-tumor efficacy and leads to more significant tumor regression over either drug candidate alone. Meanwhile, the results exhibit favorable toxicity profile of this combination.
About RAS and KRAS mutations
RAS proteins, in active GTP-bound or inactive GDP-bound form, are binary molecular switches controlling cellular responses in signaling pathways including RAS-RAF-MEK-ERK and PI3K/AKT/mTOR. Three RAS genes encode for protein isoforms, namely Kirsten Ras (KRAS), Harvey Ras (HRAS) and Neuroblastoma Ras (NRAS), and KRAS is the most frequently mutated oncogene in humans.
About KRAS G12D and GFH375
Among KRAS mutations, G12D, G12V, and G12C represent the top three most frequently mutated alleles. KRAS G12D mutation is commonly found in pancreatic ductal adenocarcinoma, colorectal cancer, and lung adenocarcinoma. A large percentage of patients harboring KRAS G12D mutation are found without smoking history and with poor response to PD-1 inhibitors. Mutant-selective G12D inhibitor holds promise to benefit large segments of KRAS-driven PDAC patients since KRAS G12D alteration is the most frequently occurring somatic change in PDAC patients (about 40%) who are reported to have an overall 5-year survival rate lower than 10%.
GFH375 is an orally active, potent, highly selective small-molecule KRAS G12D (ON/OFF) inhibitor designed to target the GTP/GDP exchange, thereby disrupting the activation of downstream pathways and effectively inhibiting tumor cell proliferation. Preclinical studies demonstrated that the inhibition of GFH375 on tumor growth is enhanced along with the increase in dosage and duration of treatment; GFH375 also demonstrated low off-target risk in kinase selectivity and safety target assays.
GenFleet entered into a discovery and development collaboration with Verastem Oncology (Nasdaq: VSTM) to advance three novel oncology discovery programs related to RAS pathway-driven cancers. The risk-sharing structure of the collaboration provides Verastem Oncology a milestone-based option to license up to three compounds. The licenses would give Verastem Oncology development and commercialization rights outside of China while GenFleet would retain rights inside of mainland China, Hong Kong, Macau, and Taiwan.
