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Assessing Atenativ for patients with congenital antithrombin deficiency during surgery or delivery

A Multicenter, Prospective, Open-label, Uncontrolled Phase 3 Study to Assess the Efficacy, Safety and Pharmacokinetics of Atenativ in Patients With Congenital Antithrombin Deficiency Undergoing Surgery or Delivery

Phase 3 Interventional Octapharma · NCT04918173

This study tests whether Atenativ can help prevent blood clots in patients with congenital antithrombin deficiency during surgery or childbirth.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment38 (estimated)
Ages12 Years to 80 Years
SexAll
SponsorOctapharma Industry-sponsored
Locations30 sites (Washington D.C., District of Columbia and 29 other locations)
Trial IDNCT04918173 on ClinicalTrials.gov

What this trial studies

This study evaluates the effectiveness of Atenativ in preventing thrombotic and thromboembolic events in patients with congenital antithrombin deficiency who are undergoing surgical procedures or delivery. It includes adult patients aged 18 to 80, as well as a small group of adolescents aged 12 to 17 for pharmacokinetic assessment. The study aims to determine the incidence of these events when Atenativ is administered during high-risk situations. The research is conducted at multiple locations across the United States.

Who should consider this trial

Good fit: Ideal candidates include adults with documented congenital antithrombin deficiency and a history of thrombotic events, as well as pregnant patients scheduled for delivery.

Not a fit: Patients without congenital antithrombin deficiency or those not undergoing high-risk surgical procedures or delivery may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could significantly reduce the risk of thrombotic events in patients with congenital antithrombin deficiency undergoing surgery or delivery.

How similar studies have performed: Other studies have shown promising results with similar interventions in managing thrombotic risks, suggesting potential for success in this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Adult male or female patients ≥18 and ≤80 years of age. Solely in the US, 4 male or female patients between ≥12 and \<17 years of age will be enrolled into the PK phase, and subsequently in the treatment phase, if applicable
2. Documented congenital antithrombin deficiency, defined by plasma activity level of antithrombin ≤60% from medical history
3. Personal or family history of TEs or TEEs (except for PK patients)
4. For the Treatment Phase: either a) non-pregnant surgical patients scheduled for elective surgical procedure(s) known to be associated with a high risk for occurrence of TEs or TEEs, or b) pregnant patients of at least 27 weeks gestational age who are scheduled for caesarean section or delivery
5. For female patients of childbearing potential entering the PK Phase who are not known to be pregnant, and for female surgical patients of childbearing potential entering the Treatment Phase for any procedure other than caesarean section or delivery, a negative urine pregnancy test at screening and at baseline
6. Patient has provided informed consent

Exclusion Criteria:

1. Requires emergency surgery or emergency caesarean section
2. Has undergone surgery within the last 6 weeks
3. History or suspicion of another hereditary thrombophilic disorder other than antithrombin deficiency (e.g., activated protein C \[APC\] resistance/Factor V Leiden, Protein S or C deficiency, prothrombin gene mutation \[G20210A\], or acquired \[lupus anticoagulant\] thrombophilic disorder)
4. Malignancies, renal failure (patients on renal replacement therapy), or severe liver disease (aspartate aminotransferase \[ASAT\] \>5 times the upper limit of normal)
5. Body mass index \>40 kg/m2 (for non-pregnant patients, only)
6. Known hypersensitivity or allergic reaction to antithrombin or any of the excipients in Atenativ
7. History of anaphylactic reaction(s) to blood or blood components
8. Refusal to receive transfusion of blood-derived products
9. Administration of any antithrombin concentrate or antithrombin-containing blood product within 14 days of either of the two phases of the study
10. Prior diagnosis of heparin-induced thrombocytopenia
11. TE or TEE within the last 6 months
12. Female patients who are nursing at the time of screening\*
13. Have participated in another investigational study within the last 30 days
14. Persons dependent on the sponsor, the investigator or the centre of investigation
15. Persons placed in an institution by administrative or judicial order

    * criterion does not include female patients who plan to breastfeed after giving birth

Where this trial is running

Washington D.C., District of Columbia and 29 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 → Find more trials like this →
Conditions Congenital Antithrombin Deficiency
Last reviewed 2026-06-13 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.