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NCT07850453Not yet recruitingPhase 2

Vortosiran for VTE Prevention

Randomized, Double-blind, Phase II Trial of Vortosiran to Evaluate Safety, Tolerability, and Pharmacodynamic Efficacy in Participants With Prior Venous Thromboembolism After Completion of Initial Anticoagulant Therapy (Cohort A) and in Cancer Patients at High Risk of Venous Thromboembolism (Cohort B)

Source: ClinicalTrials.gov · Last updated 30 Sept 2026

Brief summary (registry, in English)

Blood clots remain a serious cause of illness and death. Long-term treatment and prevention of these clots with blood thinners is often limited by bleeding risk, drug interactions, and daily dosing, leading many patients to stop treatment early. Both cancer and chemotherapy further increase the risk of clot formation. Vortosiran is an injectable therapy that lowers Factor XI (one of the body's natural clotting helpers) production in the liver, leading to a strong and long-lasting reduction in blood clotting activity with less risk of bleeding compared to current available treatments. Studies conducted so far have shown that vortosiran is safe and shows a dose-dependent Factor XI suppression (that is, a higher dose results in a higher level of suppression) that lasts for several months, supporting testing using a limited number of injections in patients who are at higher risk of blod clot formation. This study aims to study how safe and effective vortosiran is in patients who have had blood clots in the past and in cancer patients who are at high risk of developing blood clots.

Status (registry)
Not yet recruiting
Phase (registry)
Phase 2
Study type
Interventional
Enrollment
150 (estimated)
First submitted
17 Sept 2026
Start date
Oct 2026
Primary completion date
Jul 2027
Lead sponsor
Ribocure Pharmaceuticals AB
NCT number
NCT07850453
EudraCT number
2026-525479-15

What you commit to

  • Study type: Interventional · Phase 2
  • Planned participants: 150
  • From Oct 2026 to the primary completion date, Jul 2027
  • 29 sites in 4 countries
  • Visits and tests: ask the trial team, the registry does not list them

Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.

Who cannot take part

Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.

Prior treatment

  • Planned surgery that may change VTE/bleeding risk during the trial period and no recent surgery (≤2 weeks prior screening).
  • Planned surgery that may change VTE/bleeding risk during the trial period and no recent surgery (≤2 weeks prior screening).

Other illness

  • Any serious medical, psychiatric, or social condition that, in the investigator's opinion, would interfere with trial participation, compliance, or interpretation of trial results.
  • Clear indication for indefinite/extended anticoagulation for any reason, including but not limited to:
    • Atrial fibrillation or flutter requiring anticoagulation.
    • Mechanical heart valve or moderate/severe rheumatic mitral stenosis.
    • Recent or ongoing VTE requiring therapeutic anticoagulation (symptomatic or incidental).
    • Known antiphospholipid syndrome with a high-risk profile, defined as the presence of lupus anticoagulant.
    • Active cancer requiring anticoagulant prophylaxis or treatment.
    • Strong thrombophilia (eg, homozygous factor V Leiden, homozygous prothrombin mutation, combined thrombophilias, antithrombin deficiency) where guidelines favor extended anticoagulation.
    • Cohort B
  • Any serious medical, psychiatric, or social condition that, in the investigator's opinion, would interfere with trial participation, compliance, or interpretation of trial results.
  • Cancer types not eligible as the sole diagnosis:
    • Basal cell or squamous cell carcinoma of the skin only
    • Acute leukemia
    • Myeloproliferative neoplasm

Lab values

  • Evidence of active hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) infection at Screening, defined as any of the following:
    • Positive hepatitis B surface antigen (HBsAg), or positive total hepatitis B core antibody (anti-HBc) with detectable HBV DNA;
    • Positive hepatitis C virus antibody (anti-HCV) with detectable HCV RNA; or
    • Reactive HIV-1/2 antigen/antibody test confirmed by a positive confirmatory test.
    • Participants who are total anti-HBc-positive must undergo HBV DNA testing, and participants who are anti-HCV-positive must undergo HCV RNA testing. Participants with undetectable HBV DNA or HCV RNA may be eligible provided there is no clinical or laboratory evidence of active liver disease.
  • eGFR \<30 mL/min (calculated per CKD-EPI 2021, expected to be reported in mL/min per 1.73 m2)
  • Evidence of active hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) infection at Screening, defined as any of the following:
    • Positive hepatitis B surface antigen (HBsAg), or positive total hepatitis B core antibody (anti-HBc) with detectable HBV DNA;
    • Positive hepatitis C virus antibody (anti-HCV) with detectable HCV RNA; or
    • Reactive HIV-1/2 antigen/antibody test confirmed by a positive confirmatory test.
    • Participants who are total anti-HBc-positive must undergo HBV DNA testing, and participants who are anti-HCV-positive must undergo HCV RNA testing. Participants with undetectable HBV DNA or HCV RNA may be eligible provided there is no clinical or laboratory evidence of active liver disease.
  • eGFR \<30 mL/min (calculated per CKD-EPI 2021, expected to be reported in mL/min per 1.73 m2)
  • High bleeding risk, defined as any of the following:
    • Any condition that, in the investigator's judgment, confers an increased risk of clinically significant bleeding.
    • Known intracranial malignancy at high hemorrhage risk, defined as known primary brain tumor, or known intracranial metastases with prior intracranial hemorrhage, known hemorrhagic metastases, or other intracranial lesion judged high risk by the investigator (no protocol-mandated screening imaging).
    • Active or untreated high risk gastrointestinal or GU lesions, including but not limited to active peptic ulcer disease, untreated/high risk esophageal or gastric varices, or GU lesions/tumors associated with active bleeding (eg, macroscopic hematuria from bladder/urinary tract tumor), unless adequately treated and clinically stabilized.
    • Clinically overt bleeding (eg, gastrointestinal bleeding, macroscopic hematuria, epistaxis requiring medical attention, or any bleeding requiring an acute care visit) within 4 weeks prior to screening.
    • Unexplained decrease in hemoglobin ≥2 g/dL within the 2 weeks prior to screening, unless evaluated and a bleeding source has been excluded or treated and clinically stabilized.
    • Red blood cell transfusion within the 2 weeks prior to screening, unless hemoglobin is clinically stable after correction and there is no evidence of ongoing bleeding (A patient is considered as clinically stabilized if there is no clinically overt bleeding for ≥7 days and no planned urgent endoscopic/urologic intervention for bleeding during the immediate treatment initiation period. A hemoglobin stability is defined as no further decrease \>1 g/dL over ≥72 hours \[without additional transfusion\] with the patient being clinically stable).
  • Hepatic disease with coagulopathy, including but not limited to:
    • Ascites, cirrhosis, encephalopathy, or jaundice
    • Hypoalbuminemia \<3.5 g/dL
    • Total bilirubin \>1.5 × ULN
    • Transaminases \>2 × the ULN
    • Biochemical evidence of biliary obstruction

Other

  • Cohort A
  • Women who are pregnant, currently breastfeeding, or planning pregnancy during the trial or within the defined post-treatment period are not eligible.
  • Women who are pregnant, currently breastfeeding, or planning pregnancy during the trial or within the defined post treatment period are not eligible.

Who the study is looking for

  • Cohort A
  • Adult male and female participants (≥18 years) meeting the specified below criteria for Cohort A.
  • Postmenopausal women are eligible without additional contraceptive measures.
    • Postmenopausal status is defined as:
    • Age ≥55 years with ≥12 months of spontaneous amenorrhoea, or
    • Age \<55 years with ≥12 months of spontaneous amenorrhoea and follicle-stimulating hormone in the postmenopausal range, or surgical menopause (bilateral oophorectomy, with or without hysterectomy) documented in the medical history.
  • Women of childbearing potential must agree to use highly effective contraception for the duration of trial treatment and for the specified post-treatment period.
  • Able and willing to provide written informed consent and to comply with trial procedures and follow-up.
  • Objectively confirmed symptomatic index of the lower limbs at the popliteal vein or more proximal, and/or symptomatic PE, documented by objective imaging modalities (eg. DVT: compression ultrasonography/duplex ultrasound; computed tomography/magnetic resonance venography; or contrast venography. PE: computed tomography pulmonary angiography; high probability ventilation/perfusion scan; or pulmonary angiography).
  • Completed 3 to 12 months of standard therapeutic anticoagulant therapy for the index VTE episode (vitamin K antagonists, DOACs, low molecular weight heparin, or fondaparinux at therapeutic dose) at least 2 weeks before randomization.
    • Cohort B
  • Adult male and female participants (≥18 years) meeting the specified below criteria for Cohort B.
  • Postmenopausal women are eligible without additional contraceptive measures.
    • Postmenopausal status is defined as:
    • Age ≥55 years with ≥12 months of spontaneous amenorrhoea, or
    • Age \<55 years with ≥12 months of spontaneous amenorrhoea and follicle-stimulating hormone in the postmenopausal range, or surgical menopause (bilateral oophorectomy, with or without hysterectomy) documented in the medical history.
  • Women of childbearing potential must agree to use highly effective contraception for the duration of trial treatment and for the specified post-treatment period.
  • Able and willing to provide written informed consent and to comply with trial procedures and follow-up.
  • Eastern Cooperative Oncology Group performance status 0-2 during screening
  • Newly diagnosed cancer site or progression of malignant disease, with:
    • No recent chemotherapy or radiotherapy (≤3 months), and
    • No recent surgery (≤2 weeks).
    • Histologically or cytologically confirmed active malignancy (solid tumor or lymphoma) requiring initiation of a new systemic cytotoxic chemotherapy course; newly diagnosed disease or documented progression/recurrence qualifies.

Age in the registry: 18 years to - · Sex: All · Does not accept healthy volunteers

Full criteria on ClinicalTrials.gov

Sites (29)

Sites in registry order. Pick your city on the disease page to sort them by distance.

SiteCityCountrySite status
Multiprofile Hospital For Active Treatment - Pazardzhik AD
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PazardzhikBulgariaUnknown status
Specialized Hospital for Active Treatment in Cardiology - Medica Cor EAD
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RousseBulgariaUnknown status
University Hospital for Active Treatment and Emergency Medicine N.I. Pirogov EAD
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SofiaBulgariaUnknown status
Acibadem City Clinic Tokuda University Hospital EAD
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SofiaBulgariaUnknown status
University Multiprofile Hospital for Active Treatment Alexandrovska
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SofiaBulgariaUnknown status
Multiprofile Hospital for Active Treatment "National Cardiology Hospital" EAD
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SofiaBulgariaUnknown status
Multiprofile District Hospital for Active Treatment "Dr. Stefan Cherkezov" AD
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Veliko TarnovoBulgariaUnknown status
Centre Oncologie Radiotherapie (CORT 37)
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Chambray-lès-ToursFranceUnknown status
Louis-Mourier (AP-HP)
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ColombesFranceUnknown status
CHU de Grenoble
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GrenobleFranceUnknown status
Hôpital Européen Georges Pompidou (HEGP)
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ParisFranceUnknown status
Cardiology Office Individual Specialist Medical Practice Elżbieta Dułak
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GdyniaPolandUnknown status
Oddział Kardiologii SPS Szpital Zachodni im św Jana Pawła iI
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Grodzisk MazowieckiPolandUnknown status
Uniwersytet Jagiellonski Collegium Medicum
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KrakowPolandUnknown status
"Department of Cardiology European Health Center Otwock"
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OtwockPolandUnknown status
University Clinical Research Support Center of Medical University in Poznan
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PoznanPolandUnknown status
Clinical Oncology Department, Mazowiecki Szpital Wojewódzki
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SiedlcePolandUnknown status
Aidport sp z o.o.
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SkorzewoPolandUnknown status
Zachodniopomorskie Centrum Onkologii
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SzczecinPolandUnknown status
Maria Skłodowska-Curie National Research Institute of Oncology
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WarsawPolandUnknown status
Centrum Medyczne LUX MED sp zoo ul 1 Sierpnia 8, 02-143 Warszawa
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WarsawPolandUnknown status
Klinika Sienna Sp. z o.o.
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WarsawPolandUnknown status
Gral Medical - Oncofort Pitesti
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PiteştiRomaniaUnknown status
Satu Mare County Emergency Hospital
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Satu MareRomaniaUnknown status
Spitalul European Polisano - Constitutiei Sibiu
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SibiuRomaniaUnknown status
Sigmedical Services S.R.L.
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SuceavaRomaniaUnknown status
Centrul Medical Cardiomed
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Târgu MureşRomaniaUnknown status
Spitalul Clinic Judeţean Mureş
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Târgu MureşRomaniaUnknown status
Institutului de Boli Cardiovasculare Timişoara
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TimișoaraRomaniaUnknown status

This page is information, not medical advice. Discuss any trial with your doctor.