The Technological Value of Selective CTPS1 Inhibition

Step Pharma's dencatistat (development code STP938), currently in development, is a first-in-class oral targeted therapy that selectively inhibits Cytidine Triphosphate Synthase 1 (CTPS1). Conventional cancer treatments do not differentiate between normal and cancer cells, leading to severe side effects. However, this compound selectively targets the CTPS1 pathway, which is essential for the survival of cancer cells and activated immune cells, while preserving the CTPS2 pathway, which is primarily used by normal cells. This approach is considered a prime example of precision oncology, offering the potential to significantly reduce toxicity and maximize therapeutic efficacy. It has garnered significant attention from the academic and investment communities due to its innovative approach of exploiting the 'metabolic dependence' of cancer cells on specific metabolic pathways.

Pipeline-in-a-Product Strategy Targeting Multiple Indications

Step Pharma is employing a 'pipeline-in-a-product' strategy, using dencatistat to simultaneously target multiple difficult-to-treat diseases. A Phase 1/2 clinical trial (NCT05463263) is underway in adult patients with relapsed/refractory B-cell and T-cell lymphomas, and a Phase 1 clinical trial (NCT06297525) is being conducted in patients with genuine solid tumors, including CTPS2-deficient ovarian cancer. Furthermore, in 2025, a Phase 2 clinical trial (VECTRA trial, NCT06786234) will be initiated to evaluate dencatistat for the treatment of essential thrombocythemia (ET) in patients who are resistant to or experience adverse effects from hydroxycarbamide, the current standard treatment. This single-molecule, multi-indication expansion strategy demonstrates a clever development approach by a biotech company, aiming to diversify clinical success and maximize commercial value.

Addressing the Unmet Needs in the Essential Thrombocythemia Market

The introduction of a new treatment option for patients with essential thrombocythemia (ET) is expected to bring significant changes to the medical field and the market. Currently, conventional cytotoxic agents such as hydroxycarbamide and anagrelide are used as first- and second-line standard treatments for ET patients. However, long-term use of these drugs can lead to serious limitations, including bone marrow suppression, cardiovascular side effects, and resistance. If dencatistat demonstrates positive data in the Phase 2 clinical trial, it will undoubtedly become an innovative and effective alternative for high-risk patients who do not respond to existing drugs. In particular, this will establish a solid foundation for Step Pharma to gain a significant technological advantage in the global ET market, which is estimated at approximately $965 million in 2025.

€38 Million Investment and Prospects for Collaboration with Major Pharmaceutical Companies

On October 15, 2025, Step Pharma successfully completed a €38 million (approximately $41 million) Series C funding round, led by V-Bio Ventures, with participation from Pontifax, Bpifrance, and other leading venture capital firms. Despite the challenging environment for biotech investments, the company was able to secure this significant funding due to the scientific validity of the CTPS1 inhibitor platform and the high commercial potential associated with the entry into multiple clinical trials. Step Pharma will use the funds to accelerate clinical trials for dencatistat in its three indications and to enhance patient-specific treatment strategies through partnerships with AI-based biotech companies such as Concr. If encouraging interim results are obtained in the Phase 2 clinical trial, there is a high probability that this will quickly lead to a major deal, such as a licensing agreement or co-development partnership with a global major pharmaceutical company.