A Phase 4 interventional study of Reduced-dose alteplase and Full-dose alteplase in Pulmonary Embolism Acute, sponsored by Sahlgrenska University Hospital. Not yet recruiting at 23 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by Sahlgrenska University Hospital · Phase 4, Interventional, and Treatment
Among 26 studies in Pulmonary Embolism with a site in Sweden — 4 open to participants now, 5 under way, none of them phase 3. Pulmonary Embolism · Sweden.
Among the 26 studies in Pulmonary Embolism with a site in Sweden, this one is the 14th largest by planned enrollment of the 17 interventional ones that give a count, is one of 3 that started in 2026, is the only one in phase 4, and was the 26th registered.
832 studies on the registry are indexed under Pulmonary Embolism; 171 are open to participants now.
Browse Pulmonary Embolism studies →4 of the 26 studies in Pulmonary Embolism with a site in Sweden are open now. Recruiting first, the newest first:
Sahlgrenska University Hospital · Sites in Sweden
Karolinska Institutet · Sites in Sweden
Sahlgrenska University Hospital · Sites in Sweden, Denmark
A study can be open while its sites in Sweden have not opened yet or have stopped. Only those recruiting at a site in Sweden →
Of the 129 Pulmonary Embolism studies recruiting now, 109 (84%) set no upper age limit and 5 (4%) stop at 75 or younger; 9 take children under 18; 9 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.
26 studies; the count open now beside each. This study's row is marked.
First in 1990; this study’s year is marked. 3 started in 2026.
This study's planned enrollment of 400 is above the median of 174 across 429 interventional studies indexed under Pulmonary Embolism.
Median enrollment 3,202 across the 17 interventional studies, 800 across the 8 observational. Of the 21 that completed or were terminated, 8 (38%) have results posted.
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15 of 26 have an industry lead sponsor. The 10 most frequent:
Sahlgrenska University Hospital is the lead sponsor of 263 studies on the registry; 68 are open to participants now.
Sahlgrenska University Hospital has 3 studies filed under Pulmonary Embolism — fewer than ten, so there is no comparison to draw.
None of the studies under way reaches primary completion within a year.
Among the 26 studies in Pulmonary Embolism with a site in Sweden, from their registry updates:
Nothing recorded among them since 2026-09-25.
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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.
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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
High risk for early death, defined by at least one of the following:
High-risk pulmonary embolism according to European Society of Cardiology criteria:
Exclusion Criteria:
to systemic thrombolysis with one or more of the following:
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.
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.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
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.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Drug: Reduced-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.
Drug: Full-dose alteplase
Alteplase 0.6 mg/kg body weight, maximum 50 mg, administered as an intravenous infusion over 15 minutes
Also known as: Reduced-dose systemic thrombolysis, Low-dose alteplase, tPA
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.
Also known as: Full-dose systemic thrombolysis, Standard-dose alteplase, tPA
Incidence of composite efficacy endpoint
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 after the start of IMP administration.
Time frame: Within 7 days after randomization
Key secondary endpoint - Incidence of severe clinically significant bleeding
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.
Time frame: Within 7 days after randomization
All-cause mortality
Incidence of death from any cause.
Time frame: At 7 days and 30 days after randomization
Pulmonary embolism-related mortality
Incidence of pulmonary embolism-related death.
Time frame: At 7 days and 30 days after randomization
Cardiopulmonary resuscitation and/or VA-ECMO
Incidence of cardiopulmonary resuscitation and/or veno-arterial extracorporeal membrane oxygenation.
Time frame: Within 7 days after randomization
Incidence of clinical deterioration
Incidence of clinical deterioration within the first 24 hours. During IMP administration, clinical deterioration is defined as life-threatening haemodynamic or respiratory decline requiring CPR, endotracheal intubation due to worsening life-threatening respiratory failure, or initiation of VA-ECMO. After IMP administration, clinical deterioration additionally includes an increase in SCAI SHOCK stage. The blinded CEC independently adjudicates whether and when SCAI deterioration occurred. A restricted eCRF calculation determines whether the deterioration occurred after IMP completion.
Time frame: Within 24 hours after the start of IMP administration
Lack of clinical improvement assessed by SCAI SHOCK stage and oxygen requirement
Lack of clinical improvement at 6 hours is defined as unchanged SCAI SHOCK stage in participants included according to ESC high-risk PE criteria or, for participants included due to respiratory failure criteria without fulfilling ESC high-risk PE criteria, unchanged or increasing FiO₂ required to maintain SpO₂ ≥94% and/or unchanged or decreasing PaO₂/FiO₂ ratio
Time frame: At 6 hours (+1h) after the start of IMP administration
Time to clinical stabilization based on predefined hemodynamic and respiratory criteria
Time from the start of IMP administration (T0) to the time point at which the predefined clinical stabilisation criteria have been continuously fulfilled for at least 30 minutes. For participants included according to ESC high-risk PE criteria, haemodynamic stabilisation is defined as SBP ≥90 mmHg or MAP ≥65 mmHg without vasoactive drugs or mechanical circulatory support during this period. For participants included due to respiratory failure without ESC high-risk PE, respiratory stabilisation is defined as SpO₂ ≥94% (or a predefined target) with facemask oxygen ≤8 L/min or HFNO/NIV with FiO₂ ≤50%, without intubation, maintained for at least 30 minutes.
Time frame: From the start of IMP administration until clinical stabilization, assessed up to 7 days after randomization
Incidence of recurrent pulmonary embolism
Incidence of objectively confirmed recurrent pulmonary embolism.
Time frame: At 7 days and 30 days after randomization
Initiation of invasive or non-invasive mechanical ventilation
Incidence of initiation of invasive or non-invasive mechanical ventilation.
Time frame: Within 7 days after randomization
Win ratio for efficacy
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.
Time frame: Within 7 days after randomization
Net clinical benefit
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.
Time frame: Within 7 days after randomization
Rescue treatment
Need for rescue treatment, defined as additional alteplase, catheter-directed intervention, surgical embolectomy, or VA-ECMO before stabilization.
Time frame: Before clinical stabilization, up to 7 days after randomization
ICU or high-dependency unit length of stay in days
Length of stay in intensive care unit and/or high-dependency unit.
Time frame: Within 30 days after randomization
Hospital length of stay
Length of hospital stay.
Time frame: Within 30 days after randomization
Major bleeding
Incidence of major bleeding according to International Society on Thrombosis and Haemostasis criteria.
Time frame: At 48 hours, 7 days, and 30 days after randomization
Bleeding requiring urgent medical intervention
Incidence of severe bleeding requiring urgent medical intervention.
Time frame: At 48 hours, 7 days, and 30 days after randomization
Intracranial bleeding
Incidence of intracranial bleeding.
Time frame: Within 7 days after randomization
All-cause mortality at 12 months
Incidence of death from any cause.
Time frame: At 12 months after randomization
Recurrent pulmonary embolism at 12 months
Incidence of objectively confirmed recurrent pulmonary embolism.
Time frame: At 12 months after randomization
Persistent dyspnea assessed using the modified Medical Research Council scale
Persistent dyspnea assessed using the modified Medical Research Council scale.
Time frame: At 3 months and 12 months after randomization
Functional status assessed using the Post-VTE Functional Status Scale
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.
Time frame: At 3 months and 12 months after randomization
Exercise tolerance assessed using the 6-minute walk test
Exercise tolerance assessed using the 6-minute walk test, reported as distance walked in meters. A greater distance indicates better exercise tolerance.
Time frame: At 3 months and 12 months after randomization
Persistent right ventricular dysfunction assessed by echocardiography
Persistent right ventricular dysfunction according to echocardiography report, when performed as clinically indicated.
Time frame: At 3 months and/or 12 months after randomization
Pulmonary embolism-specific quality of life assessed using the PEmb-QoL questionnaire
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.
Time frame: At 3 months and 12 months after randomization
Health-related quality of life assessed using EQ-5D-5L
Health-related quality of life assessed using the EuroQol 5-Dimension 5-Level (EQ-5D-5L) instrument.
Time frame: At 3 months and 12 months after randomization
Chronic thromboembolic pulmonary hypertension
Incidence of chronic thromboembolic pulmonary hypertension.
Time frame: At 12 months after randomization
Health care resource utilization
Cost of health care resource utilization during the 12-month follow-up period.
Time frame: During 12 months after randomization
Plan to share: Yes — 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.
Supporting information: Study protocol, Statistical analysis plan
Time frame: After publication of the trial results.
Access criteria: Reasonable request, subject to approval by the sponsor and principal investigator and applicable legal, ethical, and data protection requirements.
Start is estimated for Dec 2026; primary completion for Jan 2030, 37 months later.
Of 24 phase 4 interventional studies under Pulmonary Embolism, half reached primary completion within 47 months of starting (the median), counting those still running; a quarter within 32 and three quarters within 82. This study's planned 37 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 Oct 2026. You cannot join it, but the record below documents what was studied.
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Sahlgrenska University Hospital →