A Phase 1 Study of the CTPS1 Inhibitor STP938 in Adults with High Risk Essential Thrombocythaemia
Research type
Research Study
Full title
An Open-Label, Phase 1b Study to Evaluate Safety, Tolerability and Preliminary Activity of the CTPS1 Inhibitor STP938 in Adult Subjects with High Risk Essential Thrombocythaemia who are Resistant to or Intolerant of Hydroxycarbamide Therapy.
IRAS ID
1011011
Contact name
Maureen Higgins
Contact email
Sponsor organisation
Step Pharma, SAS
Research summary
The aim of the study is to assess a new drug called STP938 for the treatment of essential thrombocythaemia (ET). The study will assess how effective STP938 is in treating ET, and also assess any side effects of taking the drug. The study will enrol individuals with high risk ET who require treatment to lower their platelet count (in order to prevent blood clots). Individuals enrolling on the study will have already tried treatment with hydroxycarbamide (also known as hydroxyurea) but are in need of a different treatment as hydroxycarbamide either did not control the platelet count or produced side effects. Whilst there are other drugs available when hydroxycarbamide is not suitable, these drugs have side effects which can make them difficult to take.
STP938 is a new class of drug that inhibits the enzyme cytidine triphosphate synthase 1 (CTPS1). Inhibition of CTPS1 is a novel way of lowering the platelet count. This study is a phase 1b, open-label, multicentre trial. Participants will receive STP938 capsules every day, in cycles of 28 days, for approximately 12 months. Participants may continue to receive study drug for a longer period, so long as it is controlling the platelet count and not causing side effects. During the study, participants will visit the study site about 28 times (2 times per cycle) over an estimated 12 months. Once the treatment is complete, safety follow-up visit(s) will occur to make sure the participant is not experiencing any adverse effects. The following study procedures will be performed: (a) physical examinations (b) ECGs (c) blood tests, (d) urine tests (e) CT/MRI scans (f) bone marrow biopsies (g) drug administration (h) study drug blood level tests and (i) gene testing.
REC name
North West - Haydock Research Ethics Committee
REC reference
24/NW/0350
Date of REC Opinion
2 Jan 2025
REC opinion
Further Information Favourable Opinion