Single-dose test of CITY-FXI in adults with and without Factor V Leiden or Prothrombin G20210A mutation

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a first-in-human, randomized, double-blind, placebo-controlled single ascending dose trial conducted at one center. It includes two parts: ascending single doses in healthy volunteers and ascending single doses in adults with confirmed Factor V Leiden or prothrombin G20210A mutation. The main goals are to characterize safety, tolerability, pharmacokinetics, and pharmacodynamics after a single administration of CITY-FXI compared with placebo. Participants are monitored for adverse events, blood markers of coagulation, and drug levels over a defined follow-up period.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Males and women of non-childbearing potential (WONCBP) aged 18 to 45 years (inclusive, for Part A only)
* Male and female participants aged 18 to 60 (inclusive, for Part B only), and aged 18 to 65 years (inclusive, for Part C only)
* Body Mass Index (BMI) between 18 and 25 kg/m2 (inclusive, for Parts A and B only) and 18 and 35 kg/m2 (inclusive, for Part C only) and a minimum weight of 50 kg (Parts A, B, and C)
* Ability and willingness to comply fully with all study procedures and lifestyle considerations
* Confirmed diagnosis of FVL or prothrombin G20210A mutation via genetic testing (Part B only)
* Women of childbearing potential (WOCBP) must agree to use acceptable highly effective contraceptive methods (Parts B and C only)
* History of provoked venous thromboembolism (VTE) within the last 10 years and/or confirmed diagnosis of heterozygosity for FVL or prothrombin G20210A mutation via genetic testing (Part C only)

Exclusion Criteria:

* Any clinically significant systemic disease or disorder, including but not limited to cardiovascular, hepatic, or oncological conditions
* History or evidence of any bleeding disorders
* History of clinically significant spontaneous bleeding
* Prior treatment with an investigational agent
* Confirmed diagnosis of homozygous mutations, or combined thrombophilic defects (e.g., FVL with prothrombin G20210A mutation) (Parts B and C only)

Where it's running

• Richmond Pharmacology
  London, United Kingdom Recruiting

Study contacts

• Study coordinator: City Therapeutics
• Email: clinicaltrials@citytx.com
• Phone: 857-219-5440

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• Engagement study for people with Factor V Leiden and Prothrombin G20210A mutations

  This study tests how to connect with adults who have or may have Factor V Leiden or Prothrombin G20210A mutations and introduces them to clinical trials.

  Recruiting Richmond Pharmacology Limited · London · NCT07584265

• Aspirin vs. rivaroxaban for blood clot prevention in newly diagnosed multiple myeloma

  In newly diagnosed multiple myeloma patients on IMiD-based therapy, this study tests whether aspirin or rivaroxaban is better at preventing blood clots.

  Recruiting Phase 4 The First Affiliated Hospital with Nanjing Medical University · Nanjing, Jiangsu · NCT07907211

• TRiP-cast score test in adults with acute lower-limb injuries requiring immobilization

  This study tests whether the TRiP(cast) score can predict risk of blood clots in adults with acute lower-limb injuries treated as outpatients.

  Recruiting University of Monastir · Monastir · NCT07863115

• Pulmonary Embolism Registry from Emergency Care to Long-Term Follow-Up

  This registry follows adults with acute pulmonary embolism to see how care is given in the real world and what happens over time.

  Recruiting at 16 sites Azienda Ospedaliero-Universitaria Careggi · Bagno a Ripoli, Tuscany and 15 other locations · NCT07855679

• YKYY033 Injection safety and tolerability in adults

  This study tests whether a single dose of YKYY033 injection is safe and tolerable in healthy adults aged 18–55.

  Recruiting Phase 1 Youcare Pharmaceutical Group Co., Ltd. · Beijing, Beijing Municipality · NCT07786779

• Blood-clot prevention with REGN7508 and REGN9933 in people with PICC lines

  This study tests whether REGN7508 and REGN9933 can help prevent blood clots in people who have a PICC line.

  Recruiting Phase 3 Regeneron Pharmaceuticals · Tbilisi · NCT07697599

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.