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Targeting STAT5 oligomerization in leukemia

Dr Anna Orlova , Veterinärmedizinische Universität Wien; Prof. Richard Moriggl , University of Veterinary Medicine, Vienna

University of Veterinary Medicine, Vienna


Currently, only 25% of patients that receive a diagnosis AML will survive next 5 years. In patients over 65 years old the prognosis is even worse as they are normally not eligible for bone marrow transplant and chemotherapy due to the toxicities associated with treatment. The standard of care has not changed dramatically over past 40 years. It is most often cytarabine-based chemotherapy and for some genetically mutated cases targeted inhibitors (e.g., midostaurin for FLT3-mutated cases). Our goal is to develop a new class of targeted anti-cancer drugs specifically targeting oncogene specific transcription in cancer cells. The transcription factor STAT5 is a key driver of acute myeloid leukemia (AML). We have shown that oligomerization of STAT5 occurs in leukemic cells but not in healthy cells and is mediated via its N-terminal domain. We have also shown that genetic deletion of the N-terminal domain in mouse models prevents the onset of leukemia. This provides compelling genetic validation of our approach to selectively target cancer cells by blocking the tumorigenic effects of STAT5 oligomerization. Our goal is to develop novel STAT5 oligomerization inhibitors for the treatment of hematopoietic cancers, with AML as a primary indication.



We developed a proprietary cell-based phenotypic screening system to identify small molecule inhibitors of STAT5 oligomerization. In this assay system, cell survival is strictly dependent on STAT5 N-domain oligomerization. We have recently screened and identified three active chemotypes that show direct interaction with the STAT5 N-domain and show promising potency in AML cell lines. We have demonstrated direct target engagement with STAT5 using cellular thermal shift assay (CETSA). Selected compounds show promising potency both in vitro and in vivo AML models. Importantly we observe strong synergy with current standards of care in AML. Our most advanced chemotypes are currently in early hit-to-lead optimization and we aim to nominate a preclinical development candidate in 24 months.

Our goals are:

A. raise a seed round of 1.5 million to develop our current series through to optimized lead and nominate our preclinical development candidate; B. use this data package to develop this molecule through to clinical proof of concept either alone or in partnership with partner pharmaceutical company.

The ultimate beneficiary of our product is the patient suffering from hard to treat leukemias or other cancers where STAT5 oligomerization is a driver. Since STAT5 oligomerization is specific to cancer cells, we expect this approach to yield a safe and efficacious targeted therapy. The business model foresees the development of innovative therapeutics in close collaboration with the pharmaceutical industry.

Commercial Opportunity

Our goal is to develop the first-in-class therapeutic through to clinical proof-of-concept in AML as a first indication. To do this we are looking for potential investors and partners that can help us achieve this.

Development Status

Hit-to-lead optimization.

Patent Situation

US provisional application, priority date 5.06.2020

Further Reading


Targeting STAT5 oligomerization in leukemia