Step Pharma (“the Company”), the global leader in CTPS1 inhibition for targeted cancer treatment, today announces that it has advanced dencatistat, the Company’s first-in-class, highly selective, oral CTPS1 inhibitor, into a phase 2 clinical trial for essential thrombocythaemia (ET), a rare clonal blood disorder characterised by overproduction of platelets and risk of thrombosis.
The progress into phase 2 follows positive data from the Company’s phase 1b trial which was initiated in September 2025 and has enrolled participants across all ET mutation subtypes, including JAK2, CALR and MPL-mutated disease, as well as triple-negative ET. This diverse population has provided a clinically relevant dataset in ET with early benefits seen across all participants. Building on these initial encouraging results, the phase 2 trial will evaluate the safety, tolerability and efficacy of dencatistat in up to 50 individuals with high risk ET across sites in the US, EU and UK.
Andrew Parker, Chief Executive Officer, Step Pharma, commented:
“Treatment approaches for essential thrombocythaemia have remained largely unchanged for more than a decade so the advancement of dencatistat into a phase 2 trial is a key milestone. We believe dencatistat’s novel mechanism of action and encouraging safety profile positions it as a promising potential new treatment option for individuals who are resistant to or intolerant of existing therapies.”
The Company expects to progress towards phase 3 trial initiation in ET during 2028.
The ET programme originated from Step Pharma’s trial of dencatistat in lymphoma which revealed that continual treatment results in a reversible, dose-related reduction in platelet levels. This observation, which has been successfully managed through intermittent dosing schedules in both lymphoma and solid tumour, combined with dencatistat’s favourable safety profile, established a compelling basis to expand into ET.
Further details of the phase 2 clinical trial for ET, named the VECTRA trial, can be found on ClinicalTrials.gov under the identifier NCT06786234.
