A Phase 2 interventional study of Vortosiran and Placebo in Venous Thromboembolism (VTE), Cancer and Pulmonary Embolism (Diagnosis), sponsored by Ribocure Pharmaceuticals AB. Not yet recruiting at 30 sites in 4 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-30.
Sponsored by Ribocure Pharmaceuticals AB (part of Suzhou Ribo Life Science Co., Ltd.) · Phase 2, Interventional, and Treatment
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Among 37 studies in Venous Thromboembolism with a site in Poland — 5 open to participants now, 5 under way, 2 of them phase 3. Venous Thromboembolism · Poland.
Among the 37 studies in Venous Thromboembolism with a site in Poland, this one is the 31st largest by planned enrollment of the 34 interventional ones that give a count, is one of 3 that started in 2026, is one of 11 in phase 2, and was the 36th registered.
713 studies on the registry are indexed under Venous Thromboembolism; 147 are open to participants now.
Browse Venous Thromboembolism studies →5 of the 37 studies in Venous Thromboembolism with a site in Poland are open now. Recruiting first, the newest first:
Azienda Ospedaliero-Universitaria Careggi · Sites in Poland, Italy, Spain
Ages 18+
University of Calgary · Sites in Poland, Belgium, Canada and 4 more countries
Ages 18+ · Women only
Regeneron Pharmaceuticals · Sites in Poland, United States, Bulgaria and 5 more countries
Ages 18+
Medical University of Gdansk · Sites in Poland
Ages 18+
A study can be open while its sites in Poland have not opened yet or have stopped. Only those recruiting at a site in Poland →
Of the 113 Venous Thromboembolism studies recruiting now, 90 (80%) set no upper age limit and 13 (12%) stop at 75 or younger; 9 take children under 18; 10 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
37 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 2 14 · Phase 3 21 · Phase 4 1
First in 2002; this study’s year is marked. 3 started in 2026.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 150 is below the median of 241 across 402 interventional studies indexed under Venous Thromboembolism.
Median enrollment 1,184 across the 34 interventional studies, 5,000 across the 3 observational. Of the 32 that completed or were terminated, 15 (47%) have results posted.
This tab as a report to print or save as PDF → With an account.
31 of 37 have an industry lead sponsor. The 10 most frequent:
This study is registered under Ribocure Pharmaceuticals AB, one of the names counted as Suzhou Ribo Life Science Co., Ltd.. Under that name alone:
Ribocure Pharmaceuticals AB is the lead sponsor of 6 studies on the registry; 4 are open to participants now.
Suzhou Ribo Life Science Co., Ltd. has 1 study filed under Venous Thromboembolism — fewer than ten, so there is no comparison to draw.
2 of the studies in Venous Thromboembolism with a site in Poland that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07015905Phase 3Regeneron PharmaceuticalsREGN7508 Versus Apixaban and Enoxaparin for Thromboprophylaxis After Total Knee Arthroplasty in Adults | 2027-02-20 |
| NCT07850453Ribocure Pharmaceuticals ABVortosiran for VTE Prevention | 2027-07 |
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Among the 37 studies in Venous Thromboembolism with a site in Poland, from their registry updates:
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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.
Venous thromboembolism, encompassing DVT and PE, is a common condition with a durable risk of recurrence after completion of initial therapy with systemic anticoagulation. In a systematic review and meta-analysis of patients with a first unprovoked VTE who completed at least 3 months of anticoagulant therapy and then discontinued treatment, the cumulative incidence of recurrent VTE was approximately 10% in the first year, 25% at 5 years, and 36% at 10 years, with recurrent events carrying measurable case fatality (Khan et al, 2019). Decisions about extended therapy are frequently individualized because continued anticoagulation reduces VTE recurrence but also exposes patients to ongoing bleeding risk, treatment burden, and complexity of care.
Venous thromboembolism, including in patients with cancer and chemotherapy, remains a major cause of morbidity and mortality. Despite effective anticoagulants, long-term management is constrained by clinically meaningful bleeding risk, drug-drug interactions with anticoagulation therapy, and the need for continuous dosing and adherence. Furthermore, many patients discontinue therapy when they perceive recurrence risk to be moderate or when bleeding risk, treatment burden, or patient preference argues against indefinite anticoagulation. These combined factors constitute an unmet need for a convenient strategy that can reduce recurrent VTE risk with a lower risk of bleeding.
Vortosiran is a subcutaneously administered siRNA designed to selectively inhibit hepatic synthesis of FXI, resulting in robust and durable suppression of FXI activity. FXI inhibition is novel and innovative anti-thrombotic strategy inhibiting blood clot formation by the intrinsic pathway without interfering with hemostatic control through the extrinsic and commen clotting pathways. Thereby reducing blood clot formation and VTE without increasing the risk of bleeding compared to current available anti-coagulant treatments.
This Phase II trial is designed to establish dose-related FXI suppression, characterize safety with repeated dosing, and generate an initial signal on clinical outcomes in two VTE prevention settings.
This multicenter, randomized, double-blind, placebo-controlled, parallel-group Phase II trial will be conducted in two cohorts. Cohort A and Cohort B are independently enrolled and randomized. Participants are randomized (2:2:1) to low-dose vortosiran, high-dose vortosiran, or matched placebo, with dosing on Day X and Day Y and follow-up through Week 56. This trial aims to evaluate vortosiran in two complementary populations where FXI suppression could provide clinically relevant benefit and where the risk-benefit of conventional anticoagulation is often challenging.
Key Inclusion Criteria:
Cohort A
women are eligible without additional measures.
Postmenopausal status is defined as:
Cohort B
Postmenopausal women are eligible without additional contraceptive measures.
Postmenopausal status is defined as:
Newly diagnosed cancer site or progression of malignant disease, with:
Key Exclusion Criteria:
Cohort A
Evidence of active virus (HBV), virus (HCV), or (HIV) infection at Screening, defined as any of the following:
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.
Clear indication for indefinite/extended anticoagulation for any reason, including but not limited to:
Cohort B
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:
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.
High bleeding risk, defined as any of the following:
Hepatic disease with coagulopathy, including but not limited to:
Cancer types not eligible as the sole diagnosis:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Vortosiran
Drug: Vortosiran
Drug: Placebo
Vortosiran, active drug.
Placebo that is identical in appearance of active IMP.
Primary objective
To evaluate the effect of two dose levels of vortosiran on coagulation Factor XI (FXI) activity.
Time frame: At Week 8
Primary endpoint
Percentage change from baseline in FXI activity, compared with placebo.
Time frame: Baseline to Week 8.
Secondary objective
To evaluate the safety of vortosiran at two dose levels.
Time frame: Up to week 56
Secondary objective
To assess the plasma exposure of vortosiran after dosing
Time frame: 0 [pre-dose] to 24 hours after dosing.
Secondary objective
To evaluate the effect of 2 dose levels of vortosiran on FXI antigen concentration.
Time frame: At week 16
Secondary Objective
To evaluate the effect of 2 dose levels of vortosiran on specific blood coagulation test aPTT.
Time frame: At week 16
Secondary objective
To evaluate the effect of 2 doses of vortosiran on specific blood clotting test PT-INR.
Time frame: At week 16
Start is estimated for Oct 2026; primary completion for Jul 2027, 9 months later.
Of 27 phase 2 interventional studies under Venous Thromboembolism, half reached primary completion within 26 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 50. This study's planned 9 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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