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Reduced-Dose Versus Full-Dose Alteplase for High-Risk Pulmonary Embolism (REDSTEM)

14 september 2026 bijgewerkt door: Kristina Svennerholm, Sahlgrenska University Hospital

Reduced-Dose Versus Full-Dose Systemic Thrombolysis for High-Risk Pulmonary Embolism: A Multicentre, Randomised, Open-Label, Blinded-Endpoint Trial

High-risk pulmonary embolism is a life-threatening condition requiring immediate reperfusion therapy. Full-dose systemic thrombolysis is recommended as first-line treatment, but its use is limited by the risk of major bleeding, including intracranial hemorrhage. Reduced-dose systemic thrombolysis may reduce bleeding while maintaining clinical efficacy, but this strategy has not been adequately evaluated in patients with high-risk pulmonary embolism.

REDSTEM is an international, multicenter, randomized, adaptive, open-label, blinded-endpoint phase 4 trial comparing reduced-dose alteplase with standard full-dose alteplase in adults with acute high-risk pulmonary embolism. The trial will assess whether reduced-dose alteplase preserves early clinical efficacy while reducing severe clinically significant bleeding. Participants will be followed for up to 12 months.

Studie Overzicht

Toestand

Nog niet aan het werven

Gedetailleerde beschrijving

Systemic thrombolysis is recommended as first-line reperfusion therapy for high-risk pulmonary embolism. However, bleeding complications limit its use in clinical practice and contribute to undertreatment of eligible patients. Existing evidence from small randomized trials, observational studies, and meta-analyses suggests that lower-dose thrombolysis may improve safety while maintaining efficacy, but previous studies have included mixed-risk pulmonary embolism populations and only a limited number of patients with high-risk pulmonary embolism.

REDSTEM was designed to evaluate whether a reduced-dose alteplase strategy can provide a more favorable balance between efficacy and safety compared with standard full-dose alteplase in patients with high-risk pulmonary embolism. The study uses randomized treatment allocation, blinded endpoint adjudication, independent safety monitoring, and an adaptive design allowing sample-size re-estimation if required.

The trial includes early clinical assessments during the acute phase and follow-up through 12 months to evaluate clinical outcomes, safety, functional recovery, quality of life, and health care resource utilization.

Studietype

Ingrijpend

Inschrijving (Geschat)

400

Fase

  • Fase 4

Contacten en locaties

In dit gedeelte vindt u de contactgegevens van degenen die het onderzoek uitvoeren en informatie over waar dit onderzoek wordt uitgevoerd.

Studiecontact

Studie Contact Back-up

Studie Locaties

      • Copenhagen, Denemarken
        • Rigshospitalet
        • Contact:
          • Jesper Kjaergaard, MD, PhD
      • Bergen, Noorwegen, 5021
        • Haukeland University Hospital
        • Contact:
          • Lasse Melvear Gii, MD, PhD
      • Drammen, Noorwegen, 3004
        • Drammen Hospital
        • Contact:
          • Jonas Pivoriunas, MD, PhD
      • Grålum, Noorwegen, 1714
        • Ostfold Hisptal
        • Contact:
          • Hans Joakim Myklebust-Hansen, MD
      • Lörenskog, Noorwegen, 1478
        • Akershus University Hospital
        • Contact:
          • Hamza Nahoui, MD
      • Oslo, Noorwegen, 0450
        • Oslo University Hospital, Ullevål
        • Contact:
          • Mari Asphjell Björnaas, MD, PhD
      • Stavanger, Noorwegen, 4021
        • Stavanger University Hospital
        • Contact:
          • Trond Johan Cooper, MD
      • Falun, Zweden
        • Falun Hospital
        • Contact:
          • Jessica Silfverberg, MD
      • Gothenburg, Zweden
        • Sahlgrenska University Hospital/Östra
        • Contact:
          • Katarina Glise Sandblad, MD, PhD
      • Jönköping, Zweden
        • Ryhov County Hospital
        • Contact:
          • Antheia Kissopoulou, MD, PhD
      • Lund, Zweden
        • Skåne University Hospital, Lund
        • Contact:
          • Marcus Ohlsson, MD
      • Malmö, Zweden
        • Skåne University Hospital, Malmö
        • Contact:
          • Marcus Ohlsson, MD, PhD
      • Mölndal, Zweden
        • Sahlgrenska University Hospital/Mölndal
        • Contact:
          • Louise Martinell, MD, PhD
      • Norrtälje, Zweden
        • Norrtälje Hospital
        • Contact:
          • Sune Forsberg, MD, PhD
      • Skövde, Zweden
        • Skaraborgs Hospital Skövde
        • Contact:
          • Freyr Einarsson, MD
        • Contact:
          • Erik Ullemark, MD
      • Stockholm, Zweden
        • Danderyd Hospital
        • Contact:
          • Nina Olausson, MD, PhD
      • Stockholm, Zweden
        • Karolinska University Hospital, Solna
        • Contact:
          • Therese Djärv, MD, PhD
      • Stockholm, Zweden
        • Karolinska University Hospital, Huddinge
        • Contact:
          • Therese Djärv, MD, PhD
      • Stockholm, Zweden
        • Capio S:t Göran's Hospital
        • Contact:
          • Rickard Markgren, MD, PhD
      • Stockholm, Zweden
        • Södersjukhuset, Stockholm South General Hospital
        • Contact:
          • Jacob Hollenberg, MD, PhD
      • Umeå, Zweden
        • University Hospital of Umeå
        • Contact:
          • Johanna Pennlert, MD, PhD
      • Uppsala, Zweden
        • Uppsala University Hospital
        • Contact:
          • Sofia Vikman, MD, PhD
    • Västra Götaland County

Deelname Criteria

Onderzoekers zoeken naar mensen die aan een bepaalde beschrijving voldoen, de zogenaamde geschiktheidscriteria. Enkele voorbeelden van deze criteria zijn iemands algemene gezondheidstoestand of eerdere behandelingen.

Geschiktheidscriteria

Leeftijden die in aanmerking komen voor studie

  • Volwassen
  • Oudere volwassene

Accepteert gezonde vrijwilligers

Nee

Beschrijving

Inclusion Criteria:

  1. Participant aged 18 years or older.
  2. Acute pulmonary embolism verified by computed tomography pulmonary angiography or pulmonary angiography. In hemodynamically unstable participants unable to undergo immediate imaging, presumed pulmonary embolism may be diagnosed based on bedside echocardiographic findings consistent with acute right ventricular pressure overload and high clinical suspicion of pulmonary embolism, provided that alternative causes of hemodynamic instability have been reasonably excluded. In such cases, the treating clinician must have independently decided to initiate thrombolytic therapy irrespective of study participation, and confirmatory imaging demonstrating pulmonary embolism must be performed as soon as clinically feasible.
  3. High risk for early death, defined by at least one of the following:

    1. High-risk pulmonary embolism according to European Society of Cardiology criteria:

      • Cardiac arrest with return of spontaneous circulation;
      • Obstructive shock, defined as systolic blood pressure <90 mmHg or use of vasopressors to maintain systolic blood pressure ≥90 mmHg despite adequate filling status, together with end-organ hypoperfusion such as elevated serum lactate >2 mmol/L, altered mental status, or cold clammy skin;
      • Persistent hypotension, defined as systolic blood pressure <90 mmHg or a drop in systolic blood pressure ≥40 mmHg for longer than 15 minutes, not caused by new-onset arrhythmia, hypovolemia, or sepsis.
    2. Abnormal right ventricular function on echocardiography or computed tomography pulmonary angiography, defined as right ventricular/left ventricular ratio ≥1.0, and elevated cardiac troponin above the local upper reference limit, and acute respiratory failure not primarily caused by underlying lung disease, defined as requiring facemask oxygen supplementation ≥12 L/min, high-flow nasal oxygen, or non-invasive ventilation with FiO2 ≥60% to reach oxygen saturation ≥94%.
  4. Female participants of childbearing potential must have a negative urine or serum pregnancy test.

Exclusion Criteria:

  1. Catastrophic pulmonary embolism, defined as ongoing cardiac arrest and/or need for extracorporeal cardiopulmonary resuscitation and/or immediate VA-ECMO as judged by the treating physicians.
  2. Known hypersensitivity to alteplase or any of its excipients.
  3. Contraindication to systemic thrombolysis with one or more of the following:

    • History of hemorrhagic stroke;
    • Ischemic stroke within the previous 6 months;
    • Central nervous system neoplasm;
    • Major trauma, major surgery, or major head injury within the previous 3 weeks;
    • Active life-threatening bleeding, bleeding into a critical organ or area, or known severe bleeding diathesis;
    • Chronic use of full-dose oral or parenteral anticoagulation before presentation.
  4. The participant has already received reperfusion treatment for the index pulmonary embolism before randomization, including systemic thrombolysis, surgical embolectomy, or catheter-directed intervention.
  5. Pregnancy.
  6. Current participation in another study that would interfere with participation in this trial.
  7. Any other condition that would put the participant at unacceptable risk from the trial interventions as judged by the treating clinician.
  8. In countries where required by national regulations: lack of affiliation to a social security system or equivalent health insurance coverage.

Studie plan

Dit gedeelte bevat details van het studieplan, inclusief hoe de studie is opgezet en wat de studie meet.

Hoe is de studie opgezet?

Ontwerpdetails

  • Primair doel: Behandeling
  • Toewijzing: Gerandomiseerd
  • Interventioneel model: Parallelle opdracht
  • Masker: Enkel

Wapens en interventies

Deelnemersgroep / Arm
Interventie / Behandeling
Experimenteel: Reduced-Dose Alteplase
Participants randomized to reduced-dose systemic thrombolysis will receive alteplase 0.6 mg/kg body weight, up to a maximum dose of 50 mg, administered intravenously over 15 minutes.
Alteplase 0.6 mg/kg body weight, maximum 50 mg, administered as an intravenous infusion over 15 minutes
Andere namen:
  • Reduced-dose systemic thrombolysis, Low-dose alteplase, tPA
Actieve vergelijker: Full-Dose Alteplase
Participants randomized to standard full-dose systemic thrombolysis will receive alteplase 1.5 mg/kg body weight, up to a maximum dose of 100 mg, administered as a 10 mg intravenous bolus over 1 to 2 minutes followed by a 90 mg intravenous infusion over 2 hours.
Alteplase 1.5 mg/kg body weight, maximum 100 mg, administered as a 10 mg intravenous bolus over 1 to 2 minutes followed by 90 mg as an intravenous infusion over 2 hours.
Andere namen:
  • Full-dose systemic thrombolysis, Standard-dose alteplase, tPA

Wat meet het onderzoek?

Primaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
Incidence of composite efficacy endpoint
Tijdsspanne: Within 7 days after randomization
Incidence of a composite endpoint comprising all-cause mortality within 7 days, cardiopulmonary resuscitation and/or veno-arterial extracorporeal membrane oxygenation within 7 days, recurrent pulmonary embolism within 7 days, clinical deterioration within 24 hours, and lack of clinical improvement at 6 hours.
Within 7 days after randomization
Key secondary endpoint - Incidence of severe clinically significant bleeding
Tijdsspanne: Within 7 days after randomization
Incidence of severe clinically significant bleeding, defined as major bleeding according to International Society on Thrombosis and Haemostasis criteria or bleeding requiring urgent medical intervention.
Within 7 days after randomization

Secundaire uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
All-cause mortality
Tijdsspanne: At 7 days and 30 days after randomization
Incidence of death from any cause.
At 7 days and 30 days after randomization
Pulmonary embolism-related mortality
Tijdsspanne: At 7 days and 30 days after randomization
Incidence of pulmonary embolism-related death.
At 7 days and 30 days after randomization
Cardiopulmonary resuscitation and/or VA-ECMO
Tijdsspanne: Within 7 days after randomization
Incidence of cardiopulmonary resuscitation and/or veno-arterial extracorporeal membrane oxygenation.
Within 7 days after randomization
Incidence of clinical deterioration
Tijdsspanne: Within 24 hours after randomization
Incidence of life-threatening hemodynamic or respiratory decline requiring cardiopulmonary resuscitation, endotracheal intubation, or VA-ECMO, or an increase in SCAI SHOCK stage after investigational medicinal product administration.
Within 24 hours after randomization
Lack of clinical improvement assessed by SCAI SHOCK stage and oxygen requirement
Tijdsspanne: At 6 hours after randomization
Incidence of unchanged SCAI SHOCK stage or unchanged or rising fraction of inspired oxygen required to maintain oxygen saturation of at least 94%.
At 6 hours after randomization
Time to clinical stabilization based on predefined hemodynamic and respiratory criteria
Tijdsspanne: From randomization until clinical stabilization, assessed up to 7 days after randomization
Time from randomization to the time point at which predefined hemodynamic or respiratory stabilization criteria have been continuously fulfilled for at least 30 minutes
From randomization until clinical stabilization, assessed up to 7 days after randomization
Incidence of recurrent pulmonary embolism
Tijdsspanne: At 7 days and 30 days after randomization
Incidence of objectively confirmed recurrent pulmonary embolism.
At 7 days and 30 days after randomization
Initiation of invasive or non-invasive mechanical ventilation
Tijdsspanne: Within 7 days after randomization
Incidence of initiation of invasive or non-invasive mechanical ventilation.
Within 7 days after randomization
Win ratio for efficacy
Tijdsspanne: Within 7 days after randomization
Win ratio based on all-cause mortality, cardiopulmonary resuscitation and/or VA-ECMO, clinical deterioration, lack of clinical improvement, recurrent pulmonary embolism, and time to clinical stabilization.
Within 7 days after randomization
Net clinical benefit
Tijdsspanne: Within 7 days after randomization
Composite net clinical benefit including severe clinically significant bleeding, all-cause mortality, cardiopulmonary resuscitation and/or VA-ECMO, recurrent pulmonary embolism, clinical deterioration, and lack of clinical improvement.
Within 7 days after randomization
Rescue treatment
Tijdsspanne: Before clinical stabilization, up to 7 days after randomization
Need for rescue treatment, defined as additional alteplase, catheter-directed intervention, surgical embolectomy, or VA-ECMO before stabilization.
Before clinical stabilization, up to 7 days after randomization
ICU or high-dependency unit length of stay in days
Tijdsspanne: Within 30 days after randomization
Length of stay in intensive care unit and/or high-dependency unit.
Within 30 days after randomization
Hospital length of stay
Tijdsspanne: Within 30 days after randomization
Length of hospital stay.
Within 30 days after randomization
Major bleeding
Tijdsspanne: At 48 hours, 7 days, and 30 days after randomization
Incidence of major bleeding according to International Society on Thrombosis and Haemostasis criteria.
At 48 hours, 7 days, and 30 days after randomization
Bleeding requiring urgent medical intervention
Tijdsspanne: At 48 hours, 7 days, and 30 days after randomization
Incidence of severe bleeding requiring urgent medical intervention.
At 48 hours, 7 days, and 30 days after randomization
Intracerebral bleeding
Tijdsspanne: Within 7 days after randomization
Incidence of intracerebral bleeding.
Within 7 days after randomization

Andere uitkomstmaten

Uitkomstmaat
Maatregel Beschrijving
Tijdsspanne
All-cause mortality at 12 months
Tijdsspanne: At 12 months after randomization
Incidence of death from any cause.
At 12 months after randomization
At 12 months after randomization
Tijdsspanne: At 12 months after randomization
Incidence of objectively confirmed recurrent pulmonary embolism.
At 12 months after randomization
Persistent dyspnea assessed using the modified Medical Research Council scale
Tijdsspanne: At 3 months and 12 months after randomization
Persistent dyspnea assessed using the modified Medical Research Council scale.
At 3 months and 12 months after randomization
Functional status assessed using the Post-VTE Functional Status Scale
Tijdsspanne: At 3 months and 12 months after randomization
Functional status assessed using the post-VTE functional status (PVFS) scale. Scores range from 0 to 4, where 0 indicates no functional limitations and 4 indicates severe functional limitations. Higher scores indicate worse functional status. Death before the scheduled assessment is recorded as grade D.
At 3 months and 12 months after randomization
Exercise tolerance assessed using the 6-minute walk test
Tijdsspanne: At 3 months and 12 months after randomization
Exercise tolerance assessed using the 6-minute walk test, reported as distance walked in meters. A greater distance indicates better exercise tolerance.
At 3 months and 12 months after randomization
Persistent right ventricular dysfunction assessed by echocardiography
Tijdsspanne: At 3 months and/or 12 months after randomization
Persistent right ventricular dysfunction according to echocardiography report, when performed as clinically indicated.
At 3 months and/or 12 months after randomization
Pulmonary embolism-specific quality of life assessed using the PEmb-QoL questionnaire
Tijdsspanne: At 3 months and 12 months after randomization
Pulmonary embolism-specific health-related quality of life assessed using the Pulmonary Embolism Quality of Life (PEmb-QoL) questionnaire. The PEmb-QoL summary score ranges from 0 to 100, with higher scores indicating worse health-related quality of life.
At 3 months and 12 months after randomization
Health-related quality of life assessed using EQ-5D-5L
Tijdsspanne: At 3 months and 12 months after randomization
Health-related quality of life assessed using the EuroQol 5-Dimension 5-Level (EQ-5D-5L) instrument.
At 3 months and 12 months after randomization
Chronic thromboembolic pulmonary hypertension
Tijdsspanne: At 12 months after randomization
Incidence of chronic thromboembolic pulmonary hypertension.
At 12 months after randomization
Health care resource utilization
Tijdsspanne: During 12 months after randomization
Cost of health care resource utilization during the 12-month follow-up period.
During 12 months after randomization

Medewerkers en onderzoekers

Hier vindt u mensen en organisaties die betrokken zijn bij dit onderzoek.

Onderzoekers

  • Hoofdonderzoeker: Kristina Svennerholm, Sahlgrenska University Hospital / University of Gothenburg

Publicaties en nuttige links

De persoon die verantwoordelijk is voor het invoeren van informatie over het onderzoek stelt deze publicaties vrijwillig ter beschikking. Dit kan gaan over alles wat met het onderzoek te maken heeft.

Algemene publicaties

Studie record data

Deze datums volgen de voortgang van het onderzoeksdossier en de samenvatting van de ingediende resultaten bij ClinicalTrials.gov. Studieverslagen en gerapporteerde resultaten worden beoordeeld door de National Library of Medicine (NLM) om er zeker van te zijn dat ze voldoen aan specifieke kwaliteitscontrolenormen voordat ze op de openbare website worden geplaatst.

Bestudeer belangrijke data

Studie start (Geschat)

1 december 2026

Primaire voltooiing (Geschat)

31 januari 2030

Studie voltooiing (Geschat)

31 januari 2031

Studieregistratiedata

Eerst ingediend

2 september 2026

Eerst ingediend dat voldeed aan de QC-criteria

10 september 2026

Eerst geplaatst (Werkelijk)

14 september 2026

Updates van studierecords

Laatste update geplaatst (Werkelijk)

17 september 2026

Laatste update ingediend die voldeed aan QC-criteria

14 september 2026

Laatst geverifieerd

1 september 2026

Meer informatie

Termen gerelateerd aan deze studie

Plan Individuele Deelnemersgegevens (IPD)

Bent u van plan om gegevens van individuele deelnemers (IPD) te delen?

JA

Beschrijving IPD-plan

De-identified individual participant data underlying the published results may be shared upon reasonable request after publication. Access will require approval by the sponsor and principal investigator, a scientifically sound proposal, scientific collaboration with the trial investigators, compliance with applicable ethical, regulatory, data protection, and consent requirements, and a signed data sharing agreement.

IPD-tijdsbestek voor delen

After publication of the trial results.

IPD-toegangscriteria voor delen

Reasonable request, subject to approval by the sponsor and principal investigator and applicable legal, ethical, and data protection requirements.

IPD delen Ondersteunend informatietype

  • LEERPROTOCOOL
  • SAP

Informatie over medicijnen en apparaten, studiedocumenten

Bestudeert een door de Amerikaanse FDA gereguleerd geneesmiddel

Nee

Bestudeert een door de Amerikaanse FDA gereguleerd apparaatproduct

Nee

Deze informatie is zonder wijzigingen rechtstreeks van de website clinicaltrials.gov gehaald. Als u verzoeken heeft om uw onderzoeksgegevens te wijzigen, te verwijderen of bij te werken, neem dan contact op met register@clinicaltrials.gov. Zodra er een wijziging wordt doorgevoerd op clinicaltrials.gov, wordt deze ook automatisch bijgewerkt op onze website .

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