Could a lower dose of a Clot-Buster be safer and still effective for dangerous blood clots in the lungs?

NCT ID NCT04430569

First seen Jul 01, 2026 · Last updated Jul 01, 2026

Summary

This study tests whether a reduced dose of the clot-dissolving drug alteplase, given alongside standard blood thinners, can improve outcomes for people with intermediate-high-risk pulmonary embolism (a serious blood clot in the lungs). About 800 adults with confirmed acute pulmonary embolism will receive either the reduced-dose alteplase or a placebo, and researchers will track deaths, worsening heart function, and recurrent clots. The goal is to find a safer balance between breaking up dangerous clots and avoiding severe bleeding.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance

Alteplase

What this could lead to

If successful, this could establish a safer, effective dosing strategy for clot-busting drugs in pulmonary embolism, reducing complications while maintaining benefit.

What could go wrong

This is a single trial with 800 participants; results may not apply to all patients. Even a reduced dose carries bleeding risk, and the lower dose might prove less effective than standard therapy.

Disclaimer Read more

This is a summary of the original study . Summaries may miss details or leave out important information. Before applying or accepting participation, make sure you have read and understood the full study. Curemydisease.com takes no responsibility whatsoever for anything missed, misunderstood, or acted upon as a result of our summary — we know it does not capture everything.

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Conditions

The condition(s) this trial relates to.

pulmonary embolism

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • AP-HM - Hôpital de la Timone

    Marseille, 13000, France

  • AP-HP - Hôpital Bichat-Claude-Bernard

    Paris, 75018, France

  • AP-HP - Hôpital Tenon

    Paris, 75020, France

  • AP-HP - hôpital Bicêtre

    Le Kremlin-Bicêtre, 94270, France

  • AP-HP - hôpital Henri-Mondor

    Créteil, 94010, France

  • AP-HP - hôpital européen Georges-Pompidou

    Paris, 75015, France

  • Antonius hospital

    Sneek, Netherlands

  • Augustinerinnen Hospital

    Cologne, 50678, Germany

  • Azienda Ospedaliera Careggi - Firenze

    Florence, 50134, Italy

  • Bucuresti - Spitalul Clinic de Urgenta Sf. Pantelimon

    Bucharest, Romania

  • CHU Liège

    Liège, 4000, Belgium

  • CHU d'Angers

    Angers, 49933, France

  • CHU de Besançon - Hôpital Jean-Minjoz

    Besançon, 25030, France

  • CHU de Brest - Hôpital de la Cavale Blanche

    Brest, 29000, France

  • CHU de Clermont-Ferrand - Hôpital Gabriel Montpied

    Clermont-Ferrand, 63000, France

  • CHU de Grenoble - Hôpital Michallon

    La Tronche, 38700, France

  • CHU de Nice - Hôpital Pasteur

    Nice, 06000, France

  • CHU de Saint-Étienne - Hôpital Nord

    Saint-Etienne, 42055, France

  • CHU de Strasbourg - Hôpital Civil

    Strasbourg, 67000, France

  • CHU de Toulouse - Hôpital Rangueil

    Toulouse, 31000, France

  • CHU de Tours - Hôpital Trousseau

    Chambray-lès-Tours, 37170, France

  • Cardiology Clinic, Clinical Center of Niš

    Niš, Serbia

  • Cardiology Clinic, Emergency Center, Clinical Center of Serbia

    Belgrade, Serbia

  • Catharina hospital

    Eindhoven, Netherlands

  • Centro Hospitalar de Lisboa Norte/ Hospitalde Santa Maria

    Lisbon, Portugal

  • Centro Hospitalar de Lisboa Ocidental

    Lisbon, Portugal

  • Centro Hospitalar de Setubal

    Setúbal, Portugal

  • Centro Hospitalar do Porto

    Porto, Portugal

  • Cologne Universität Herzzentrum

    Cologne, 50937, Germany

  • DRK Kliniken Berlin Köpenick

    Berlin, 10117, Germany

  • Dresden, Städtisches Klinikum

    Dresden, 01067, Germany

  • Düsseldorf, Augusta-Krankenhaus

    Düsseldorf, 40472, Germany

  • Foothills Medical Centre

    Calgary, Alberta, Canada

  • Freiburg Universität

    Freiburg im Breisgau, 79085, Germany

  • Geneva University Hospital

    Geneva, 1205, Switzerland

  • Greifswald, Univ.-Medizin

    Greifswald, 17489, Germany

  • HCL - Centre Hospitalier Lyon-Sud, Pierre-Bénite

    Lyon, 69495, France

  • HCL - Hôpital Edouard Herriot

    Lyon, 69000, France

  • Haaglanden hospital

    The Hague, Netherlands

  • Hamilton General Hospital - Hamilton Health Sciences Corporation

    Hamilton, Ontario, Canada

  • Hannover, Medizinische Hochschule Hannover

    Hanover, 30625, Germany

  • Hospital Bellvitge

    Barcelona, 08907, Spain

  • Hospital Cartagena

    Cartagena, Spain

  • Hospital Clinic

    Barcelona, 08036, Spain

  • Hospital Galdakao

    Galdakao, 48960, Spain

  • Hospital Garcia de Orta

    Almada, Portugal

  • Hospital Germans Trias i Pujol

    Badalona, 08916, Spain

  • Hospital La Fe

    Valencia, 46026, Spain

  • Hospital Pedro Hispano

    Matosinhos Municipality, Portugal

  • Hospital Ramón y Cajal

    Madrid, 28034, Spain

  • Hospital Virgen del Rocío

    Seville, 41013, Spain

  • Humanitas Hospital - Milano

    Milan, 20089, Italy

  • Hôpital du Valais

    Sion, 1951, Switzerland

  • Iasi - St Spiridon Emergency Conty Hospital

    Iași, 700111, Romania

  • Institute for Lung Diseases of Vojvodina, Sremska Kamenica

    Novi Sad, Serbia

  • Institutul de Boli Cardio-Vasculare Timisoara

    Timișoara, Romania

  • Isala hospital

    Zwolle, Netherlands

  • Jewish General Hospital

    Montreal, Quebec, Canada

  • Juravinski Hospital - Hamilton Health Sciences Corporation

    Hamilton, Ontario, ON L8V 1C3, Canada

  • KU Leuven

    Leuven, 3000, Belgium

  • Kingston Health Sciences Centre

    Kingston, Ontario, Canada

  • Leipzig, Univ.-Klinikum

    Leipzig, 4103, Germany

  • London Health Sciences Centre

    London, Ontario, Canada

  • Maasstad hospital

    Rotterdam, Netherlands

  • Mainz Universitätsmedizin, CTH

    Mainz, 55131, Germany

  • Mainz, Katholisches Klinikum

    Mainz, 55131, Germany

  • Martini hospital

    Groningen, Netherlands

  • Medical University of Bialystok

    Bialystok, Poland

  • Medisch Spectrum Twente

    Enschede, Netherlands

  • Ordensklinikum Linz GmbH Elisabethinen

    Linz, 4020, Austria

  • Ospedale Ca Foncello - Treviso

    Treviso, 31100, Italy

  • Ospedale San Giuseppe - Empoli

    Empoli, 50053, Italy

  • Spedali Riuniti - Cremona

    Cremona, 26100, Italy

  • Spitalul Judetean de Urgenta Baia Mare

    Baia Mare, 430031, Romania

  • Spitalul Judetean de Urgenta Constanta

    Constanța, 900591, Romania

  • The Ottawa Hopsital, General and Civic campuses

    Ottawa, Ontario, Canada

  • Tübingen, Univ.-Klinikum

    Tübingen, 72076, Germany

  • UCL Brussels

    Brussels, Belgium

  • Ulm, Universitätsklinikum

    Ulm, 89081, Germany

  • University Hospital Ancona / Ospedali Riunit

    Ancona, 60020, Italy

  • University Medical Centre Ljubljana

    Ljubljana, 1000, Slovenia

  • University of Perugia

    Perugia, 06123, Italy

  • University of Warmia Mazury in Olsztyn - School of Medicine

    Olsztyn, 11-041, Poland

  • Universitäts-Herzzentrum Freiburg - Bad Krozingen

    Bad Krozingen, 79189, Germany

  • Universitätsmedizin Mannheim UMM

    Mannheim, 68167, Germany