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Testing concizumab for treating haemophilia A and B

Open-label Study Investigating Efficacy, Safety and Pharmacokinetics of Concizumab Prophylaxis in Children Below 12 Years With Haemophilia A or B With or Without Inhibitors

Phase 3 Interventional Novo Nordisk A/S · NCT05135559

This study is testing a new medication called concizumab to see if it can help prevent bleeding in people with haemophilia A or B.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment153 (estimated)
SexAll
SponsorNovo Nordisk A/S Industry-sponsored
Drugs / interventionsconcizumab
Locations99 sites (San Diego, California and 98 other locations)
Trial IDNCT05135559 on ClinicalTrials.gov

What this trial studies

This study evaluates the effectiveness of concizumab, a new medication, in preventing bleeds in patients with haemophilia A or B, regardless of the presence of inhibitors. Participants will self-administer the medication daily using a pen-injector over a period of 2 to 4 years, depending on the availability of the drug in their country. The primary goal is to demonstrate both the efficacy and safety of concizumab for this patient population.

Who should consider this trial

Good fit: Ideal candidates include males under 12 years old with severe congenital haemophilia A or moderate/severe congenital haemophilia B, particularly those with inhibitors.

Not a fit: Patients with mild haemophilia or those who do not meet the specific inclusion criteria may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly reduce bleeding episodes for patients with haemophilia A and B.

How similar studies have performed: Previous studies on similar treatments for haemophilia have shown promising results, indicating potential for success with this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Informed consent/assent obtained before any study-related activities. Study-related activities are any procedures that are carried out as part of the study, including activities to determine suitability for the study.
* Diagnosis of congenital severe haemophilia A (FVIII below 1%) or moderate/severe congenital haemophilia B (FIX (coagulation factor IX) below or equal to 2%), or congenital haemophilia with inhibitors.
* For arm 1 only: Male aged below 12 years of age at the time of signing informed consent.
* For arm 1 only: Patients with inhibitors (haemophilia A with inhibitors or haemophilia B with inhibitors)

  1. Patients with HAwI (haemophilia A with inhibitors) with historical medical records of a total of at least 26 weeks of on-demand treatment (On-demand or PPX treatment qualifying for this study is understood as patient-treatment solely for bleeds with intravenous coagulation factor-containing products) within the last 52 weeks prior to enrolment (For patients below 1 year of age that have been diagnosed with haemophilia \<1 year prior to enrolment, historical medical records from time of diagnosis will suffice as long as medical records of a total of at least 26 weeks of relevant treatment is available).
  2. Patients with HBwI (haemophilia B with inhibitors) with historical medical records of a total of at least 26 weeks of on-demand treatment (On-demand or PPX treatment qualifying for this study is understood as patient-treatment solely for bleeds with intravenous coagulation factor-containing products) within the last 52 weeks prior to enrolment (For patients below 1 year of age that have been diagnosed with haemophilia \<1 year prior to enrolment, historical medical records from time of diagnosis will suffice as long as medical records of a total of at least 26 weeks of relevant treatment is available).
  3. Patients with HBwI regardless of the regimen and duration of previous haemophilia treatment (On-demand or PPX treatment qualifying for this study is understood as patient-treatment solely for bleeds with intravenous coagulation factor-containing products)
* For arm 1 only: Patients without inhibitors (haemophilia A or haemophilia B)

  1. Patients with historical medical records of at least 52 weeks of on-demand treatment (On-demand or PPX treatment qualifying for this study is understood as patient-treatment solely for bleeds with intravenous coagulation factor-containing products; Surgery related PPX or short-term PPX (e.g., in relation to a severe bleed) is not allowed) during the last year prior to enrolment and with at least 3 documented treated bleeds (For participants less than (\<) 2 years of age there is no limitation for number of documented treated bleeds in the medical history) during this period
  2. Patients with historical medical records of a total of at least 26 weeks of PPX (prophylaxis) treatment (On-demand or PPX treatment qualifying for this study is understood as patient-treatment solely for bleeds with intravenous coagulation factor-containing products) within the last 52 weeks prior to enrolment (For patients below 1 year of age that have been diagnosed with haemophilia \<1 year prior to enrolment, historical medical records from time of diagnosis will suffice as long as medical records of a total of at least 26 weeks of relevant treatment is available)
* For arm 2 only: Male patients (regardless of age) previously treated with concizumab via compassionate use.

Exclusion Criteria:

* Known or suspected hypersensitivity to study intervention or related products.
* Known inherited or acquired coagulation disorder other than congenital haemophilia.
* Ongoing or planned Immune Tolerance Induction treatment.
* History of thromboembolic disease (aIncludes arterial and venous thrombosis including myocardial infarction, pulmonary embolism, cerebral infarction/thrombosis, deep vein thrombosis, other clinically significant thromboembolic events and peripheral artery occlusion.). Current clinical signs of or treatment for thromboembolic disease. Patients who in the judgement of the investigator are considered at high risk of thromboembolic events (Thromboembolic risk factors could include, but are not limited to, hypercholesterolemia, diabetes mellitus, hypertension, obesity, smoking, family history of thromboembolic events, arteriosclerosis, other conditions associated with increased risk of thromboembolic events).

Where this trial is running

San Diego, California and 98 other locations

+49 more sites — see ClinicalTrials.gov for the full list.

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 Haemophilia A and B With and Without Inhibitors
Last reviewed 2026-06-15 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.