Phase 1 Study of the CTPS1 Inhibitor STP938 in Adult Subjects with Advanced Solid Tumours

• Research type

  Research Study

• Full title

  An Open-Label, Phase 1 Study to Evaluate Safety, Tolerability and Pharmacokinetics of the CTPS1 Inhibitor STP938 in Adult Subjects with Advanced Solid Tumors, with a Safety Expansion in Advanced CTPS2 Null Ovarian Cancer

• IRAS ID

  1009942

• Contact name

  Maureen Higgins

• Contact email

  mh@step-ph.com

• Sponsor organisation

  Step Pharma, SAS.

• Eudract number

  2024-512375-12

• Clinicaltrials.gov Identifier

  NCT06297525

• Research summary

  STP938 is a novel, potent orally available inhibitor of cytidine triphosphate synthase 1 (CTPS1). STP938-201 is an open-label, phase 1a/1b study which will explore STP938 in adult subjects with advanced solid tumors who have failed all available therapies known to be associated with clinical benefit, or are not eligible for, or refused standard of care (SOC).
  The study will be conducted in 2 parts.
  Part 1 (the phase 1a portion of the study) will consist of single agent STP938 dose escalation and exploration of different dosing schedules in order to establish the recommended Phase 2 dose (RP2D). The RP2D will be the lowest safe and biologically effective dose (and schedule) based on safety, efficacy, pharmacokinetic and pharmacodynamic data.

  Part 2 (the phase 1b portion of the study) will consist of a safety expansion cohort (10 subjects) at the RP2D for adult subjects with advanced ovarian cancer lacking CTPS2 expression; subjects will have failed, refused or be ineligible for SOC therapy. A second safety expansion cohort may be opened to recruit subjects in a second cancer type with a high prevalence of CTPS2 loss.

  The study will involve up to 70 patients at approximately 20 cancer centres in the United States, Europe and the United Kingdom.

  The anticipated median approximate duration of the study treatment is 3-6 months (13-14 visits). After the end of trial visit, subjects who have not progressed, relapsed or started subsequent anticancer treatment will be followed for up to 12 months, by telephone, every 3 months. Participants will receive STP938 capsules twice daily in 28 (or 21) day treatment cycles if they are tolerating the treatment, and it is deemed beneficial. The response to the treatment will be assessed by radiographic tumour assessment, using either a CT Scan or MRI . The following study procedures will be performed: (a) physical examinations(b) ECGs (c) blood tests, (d) urine tests (e) CT/MRI scans (f) tumour biopsies.

• REC name

  London - West London & GTAC Research Ethics Committee

• REC reference

  24/LO/0387

• Date of REC Opinion

  28 Jun 2024

• REC opinion

  Further Information Favourable Opinion