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Evaluating a new treatment for patients resistant to heparin during heart surgery

Phase 3, Double-blind, Placebo-controlled, Multicentre Study on the Efficacy and Safety of Human Plasma Derived Antithrombin (Atenativ) in Heparin-Resistant Patients Scheduled to Undergo Cardiac Surgery Necessitating Cardiopulmonary Bypass

PHASE3 · Octapharma · NCT06096116

This study is testing a new treatment called Atenativ to see if it can help heart surgery patients who don't respond to heparin feel better and have safer surgeries.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment120 (estimated)
Ages18 Years to 85 Years
SexAll
SponsorOctapharma (industry)
Locations27 sites (Stanford, California and 26 other locations)
Trial IDNCT06096116 on ClinicalTrials.gov

What this trial studies

This phase 3 study aims to assess the efficacy and safety of Atenativ, a human plasma-derived antithrombin, in patients who are resistant to heparin and are scheduled for cardiac surgery requiring cardiopulmonary bypass. The study will compare two different doses of Atenativ against a placebo to determine its effectiveness in restoring heparin responsiveness. Eligible participants include adults aged 18 to 85 who meet specific criteria related to their heparin resistance and surgical plans. The study is designed to provide insights into improving surgical outcomes for this patient population.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 85 who are scheduled for cardiac surgery and exhibit heparin resistance.

Not a fit: Patients who are not heparin-resistant or those who have recently taken certain anticoagulant medications may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of heparin-resistant patients undergoing cardiac surgery, leading to better surgical outcomes.

How similar studies have performed: Other studies have explored treatments for heparin resistance, but this specific approach using Atenativ is novel and has not been widely tested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Planned cardiac surgery with CPB
2. Heparin-resistant patients (pre-CPB Hemochron ACT less than 480 s in the measurement taken between 2-5 minutes following intravenous administration of 500 U/kg UFH)
3. Patients between 18 and 85 years of age, inclusive
4. Freely given written or electronic informed consent
5. In female patients of childbearing potential, a pre-existing negative pregnancy test within 14 days prior to surgery

Exclusion Criteria:

1. Receiving, or have received within the timeframes specified, one or more of the following medications prior to the start of surgery:

   1. vitamin K antagonists (within 3 days)
   2. direct oral anticoagulants (within 2 days)
   3. thienopyridines (ticlopidine within 14 days, prasugrel within 7 days, or clopidogrel within 5 days), unless platelet function is satisfactory according to local standard of care assessment
   4. ticagrelor (within 5 days), unless platelet function is satisfactory according to local standard of care assessment
   5. glycoprotein IIb/IIIa antagonist (within 24 hours)
2. Pre-existing coagulopathy, a history of bleeding problems, or a laboratory-diagnosed bleeding disorder (e.g., von Willebrand disease, platelet disorder)
3. Renal insufficiency, defined as serum creatinine level \>2.0 mg/dL
4. Thrombocytosis, defined as platelet count \>400,000 per μL
5. Known hypersensitivity or allergic reaction to antithrombin or any of the excipients in Atenativ, i.e., human albumin, sodium chloride, acetyl tryptophan, caprylic acid
6. History of anaphylactic reaction(s) to blood or blood components
7. Refusal to receive transfusion of blood or blood-derived products
8. Current participation in another interventional clinical trial or previous participation in the current trial
9. Treatment with any IMP within 30 days prior to screening visit

Where this trial is running

Stanford, California and 26 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Acquired Antithrombin Deficiency, heparin resistance, antithrombin deficiency, cardiopulmonary bypass, cardiac surgery

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.