TAMPA, Fla., June 15, 2026
TuHURA Biosciences, Inc. has announced the filing of an Investigational New Drug (IND) application with the U.S. Food and Drug Administration (FDA) for TBS-2025, its investigational VISTA-inhibiting monoclonal antibody, targeting molecularly defined subsets of Acute Myeloid Leukemia (AML) and other hematologic malignancies. The filing follows detailed FDA feedback on a previous IND submission and supports TuHURA’s strategy to advance a first-in-class immuno-oncology approach designed to overcome immune resistance mechanisms that drive disease progression in difficult-to-treat blood cancers. The company plans to initiate a combined Phase 1b/2 clinical study in the second half of 2026, focusing on patient populations with significant unmet medical needs and limited treatment options.
TBS-2025 Targets Key Immune Escape Mechanism in AML
TuHURA’s investigational therapy is designed to inhibit VISTA (V-domain Ig suppressor of T-cell activation), an immune checkpoint protein increasingly recognized as a critical driver of immune suppression in hematologic cancers. The company’s initial focus is on patients with NPM1-mutated AML, one of the most common genetic subtypes of the disease, accounting for a substantial proportion of AML cases. Future studies may also include patients with FLT3-ITD mutations, another high-risk genetic alteration associated with poor outcomes.
According to TuHURA, VISTA expression is elevated in these molecularly defined AML subsets and contributes to the ability of leukemia cells to evade immune detection. The planned development program will also evaluate patients with relapsed or refractory high-risk myelodysplastic syndromes (MDS), where elevated VISTA expression has similarly been linked to lower response rates and reduced survival. By targeting this immune escape pathway, TBS-2025 aims to restore anti-tumor immune responses and potentially improve outcomes in patient populations with few effective therapeutic alternatives.
Phase 1b/2 Study Designed to Accelerate Clinical Development
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The proposed clinical program incorporates FDA guidance and is structured to improve development efficiency. The Phase 1b portion will assess the safety, tolerability and preliminary efficacy of TBS-2025 as a monotherapy in patients with relapsed or refractory AML, particularly those who have failed or relapsed following treatment with menin inhibitors. If a safe and biologically active dose is established, the company plans to engage with the FDA regarding potential expansion into Phase 2 and the possibility of pursuing an accelerated regulatory pathway. The subsequent Phase 2 study is expected to evaluate TBS-2025 in combination with menin inhibitors, with the goal of improving complete response rates and extending the duration of response in patients with NPM1-mutated AML. Company executives noted that integrating Phase 1b and Phase 2 components into a streamlined study design could potentially reduce development timelines by several months while generating meaningful clinical data more rapidly.
Expanding the Role of Immunotherapy in Hematologic Malignancies
TBS-2025 represents a key component of TuHURA Biosciences’ broader strategy to overcome both primary and acquired resistance to cancer immunotherapy. Preclinical studies cited by the company suggest that VISTA inhibition may enhance immune recognition of leukemia cells and improve survival outcomes in AML models. Earlier Phase 1 studies in advanced solid tumors demonstrated a favorable safety profile for TBS-2025, providing a foundation for its advancement into hematologic cancer indications.
As immunotherapy continues to transform oncology treatment paradigms, the development of novel checkpoint inhibitors targeting pathways beyond PD-1 and PD-L1 has become an area of growing scientific interest. With its IND filing now submitted and FDA feedback anticipated in the coming months, TuHURA Biosciences is positioning TBS-2025 as a potential first-in-class therapy capable of addressing significant unmet needs in AML, MDS and other blood-related cancers, while advancing the next generation of precision immuno-oncology treatments.
Source: TuHURA Biosciences press release
