An observational study in Hematologic Disorder, Bleeding Disorder and Connective Tissue Disorder, sponsored by American Thrombosis and Hemostasis Network. Recruiting at 76 sites in United States. Per ClinicalTrials.gov, last updated 2026-08-17.
Sponsored by American Thrombosis and Hemostasis Network · Observational
In parallel with the growth of ATHN's clinical studies, the number of new therapies for all blood disorders is increasing significantly. Some of the recently FDA-approved therapies for congenital and acquired hematologic conditions have not yet demonstrated long-term safety and effectiveness beyond the pivotal trials that led to their approval. In addition, results from well controlled, pivotal studies often cannot be replicated once a therapy has been approved for general use.2,3,4,5
In 2019 alone, the FDA has issued approvals for 24 new therapies for congenital and acquired hematologic conditions.6 In addition, almost 10,000 new studies for hematologic diseases are currently registered on www.clinicaltrials.gov.7
With this increase in potential new therapies possible, it is imperative that clinicians and clinical researchers in the field of non-neoplastic hematology have a uniform, secure, unbiased, and enduring method to collect long-term safety and efficacy data. As emphasized in a recently published review, accurate, uniform and quality national data collection is critical in clinical research, particularly for longitudinal cohort studies covering a lifetime of biologic risk.8
This is a longitudinal, natural history observational cohort study being conducted at approximately 150 ATHN-affiliated sites with a target accrual of 3,000 participants. Participants will be followed for a minimum of 15 years on an assigned arm within a cohort; however, arm or module participation may last longer, and participants will continue participation in the arm or module for its duration. Harmonized data elements will be collected at the time of enrollment, semi-annually (every 6 months), annually, ad hoc, and as defined by the terms of individual arms and modules. Data will be collected for participants enrolled in cohort-specific arms and modules.
Each participant will be assigned to a single cohort: Hemophilia, von Willebrand Disease, Congenital Platelet Disorders, Rare Disorders, Bleeding Not Otherwise Specified (NOS), Thrombosis/Thrombophilia, or Non-Neoplastic Hematologic Conditions.
Study arms and study modules are developed to advance the exploration of blood disorders disease specific insights by ATHN and its partners. Arms may branch off into product-specific data collection via Modules to be collected during the study, in conjunction with planned study assessments.
ATHN Transcends
Co- Principal Investigators:
Tammuella Chrisentery-Singleton, MD Ochsner Clinic Foundation American Thrombosis and Hemostasis Network
Michael Recht, MD, PhD, MBA Yale University School of Medicine National Bleeding Disorders Foundation
PUPs Arm
Principal Investigator:
Shannon Carpenter, MD, MS University of Missouri Kansas City School of Medicine Children's Mercy Hospital
ALTUVIIO Module
Principal Investigator:
Shannon Carpenter, MD, MS University of Missouri Kansas City School of Medicine Children's Mercy Hospital
INHIBIT Module
Principal Investigator:
Nicoletta Machin DO, MS Hemophilia Center of Western Pennsylvania University of Pittsburgh Medical Center
Hemophilia Natural History Arm
Principal Investigator:
Fernando Corrales-Medina, MD, FAAP University of Miami-Comprehensive Hemophilia Treatment Center University of Miami-Miller School of Medicine
Rebinyn Module
Co-Principal Investigators:
Lauren Amos, MD University of Missouri Kansas City School of Medicine Children's Mercy Hospital
Guy Young, MD University of Southern California Children's Hospital Los Angeles
Distress Module
Principal Investigator:
Tammuella Chrisentery-Singleton, MD Ochsner Clinic Foundation American Thrombosis and Hemostasis Network
Hemlibra Module
Principal Investigator:
Fernando Corrales-Medina, MD, FAAP University of Miami-Comprehensive Hemophilia Treatment Center University of Miami-Miller School of Medicine
Hemophilia Gene Therapy Outcomes Arm:
Co-Principal Investigators:
Janice M. Staber, MD Iowa Hemophilia and Thrombosis Center University of Iowa Stead Family Children's Hospital
Ulrike M. Reiss, MD Hemophilia Treatment Center St. Jude's Children's Research Hospital
HEMGENIX Module
Co-Principal Investigators:
Janice M. Staber, MD Iowa Hemophilia and Thrombosis Center University of Iowa Stead Family Children's Hospital
Ulrike M. Reiss, MD Hemophilia Treatment Center, St. Jude's Children's Research Hospital
Severe VWD Natural History Arm:
Co-Principal Investigators:
Robert F. Sidonio, Jr., MD, MSc Aflac Cancer and Blood Disorders Center, Hemophilia of Georgia Center for Bleeding and Clotting Disorders
Angela C. Weyand, MD C.S. Mott Children's Hospital, University of Michigan Medical School, Ann Arbor
Congenital Platelet Disorders Natural History Arm:
Principal Investigator Sanjay Ahuja, MD Innovative Hematology, Indiana Hemophilia \& Thrombosis Center
Glanzmann Thrombasthenia Module:
Co-Principal Investigators:
Divya Citla-Sridhar, MD University of Arkansas for Medical Sciences Arkansas Children's Hospital
Meera Chitlur, MD Central Michigan University, Children's Hospital of Michigan
Hemophilia Cohort
This cohort includes three Arms and six Modules:
Previously Untreated Patients (PUPs) Arm This is a pediatric focused Arm of PUPs with hemophilia A or B of any severity.
Efanestoctocog alfa (ALTUVIIIO®) Module The purpose is to investigate the safety, tolerability, and effectiveness of efanesoctocog alfa (ALTUVIIIO®) in PUPs with severe hemophilia A.
INHIBIT Module This is an observational study assessing the rate of inhibitor formation in young children with severe hemophilia A in the current treatment era.
Hemophilia Natural History Arm This Arm is investigating the safety, effectiveness, and practice of treatment for people with hemophilia.
Emicizumab (Hemlibra®) Module All participants treated with Hemlibra® are eligible to participate.
Distress Module Participants with Congenital Hemophilia A or B, 18 years of age or older, will be followed longitudinally for 2 years or from time of enrollment for a total planned study duration of 3 years
Nonacog beta pegol (Rebinyn®) Module The Rebinyn® Module is a prospective study in hemophilia B participants without inhibitors.
Hemophilia Gene Therapy Outcomes Arm This Arm is investigating the safety and effectiveness of gene therapy in people with hemophilia.
Etranacogene dezaparvovec (HEMGENIX®) Module This is an observational study to characterize the effectiveness and safety of HEMGENIX® in participants with hemophilia B.
Congenital Platelet Disorders (CPD) Natural History Arm:
The CPD Arm is investigating the natural history of the safety and efficacy of hemostatic therapies (such as platelet transfusions, desmopressin, antifibrinolytics, recombinant factor VIIa) in the prevention or treatment of bleeding events (on demand, surgery, prophylaxis) in adult and pediatric participants with inherited congenital platelet disorders..
Glanzmann Thrombasthenia (GT) Module:
This Module is a study of bleeding symptoms, treatments, and treatment outcomes in patients with Glanzmann thrombasthenia.
Von Willebrand Disease Cohort No arms or modules open at this time.
Rare Disorders Cohort No arms or modules open at this time.
Bleeding NOS No arms or modules open at this time.
Thrombosis/Thrombophilia No arms or modules open at this time.
Non-Neoplastic Hematologic Conditions No arms or modules open at this time.
609 studies on the registry are indexed under Hematologic Diseases; 108 are open to participants now.
This study's planned enrollment of 3,000 is above the median of 250 across 127 observational studies indexed under Hematologic Diseases.
Browse Hematologic Diseases studies →American Thrombosis and Hemostasis Network is the lead sponsor of 8 studies on the registry; 3 are open to participants now.
Counted across the registry records on this site, refreshed daily.
This is a real-world study in which participants with congenital or acquired blood disorders will be enrolled.
Participants who meet the following inclusion criteria and none of the exclusion criteria are eligible for enrollment in one of the open disease-specific arms.
Inclusion Criteria:
Exclusion Criteria:
1. Does not qualify for inclusion in a currently activedisease-specific arm; participants may be eligible to enroll as future cohorts and arms are activated; 2. Unable to give or assent 3. Unwilling to perform study procedures
Cohort Participant Selection
Each participant is to be enrolled in the cohort for which they qualify as defined below.
Hemophilia Cohort
Inclusion Criteria:
Participants who meet any of the following inclusion criteria are eligible for enrollment into this cohort:
Exclusion Criteria:
None
Von Willebrand Disease Cohort
Inclusion Criteria:
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
1. Meeting the definition of VWD or low VWF per most recent international guidelines
Exclusion Criteria:
None
Congenital Disorders Cohort
Inclusion Criteria:
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
Exclusion Criteria:
1. Platelet disorders secondary to medications or other substances
Rare Disorders Cohort
Inclusion Criteria:
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
1. Have an established Rare Coagulation Disorder (RCD) diagnosis of one of the following:
Exclusion Criteria:
None
Bleeding NOS Cohort
Inclusion Criteria:
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
Exclusion Criteria:
None
Thrombosis/Thrombophilia Cohort
Inclusion Criteria
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
1. Have a prior history of arterial or venous thrombosis. 2. Participants with a known congenital or acquired thrombophilia with or without thrombosis.
a. Common congenital thrombophilias: i. Protein C deficiency ii. Protein S deficiency iii. Antithrombin deficiency iv. Factor V Leiden v. Prothrombin gene mutation b. Rare genetic factors i. Hyperhomocysteinemia c. Indeterminate genetic factors i. Elevated factor VIII ii. Elevated factor IX iii. Elevated factor XI iv. Elevated lipoprotein (a) d. Acquired thrombophilias i. Lupus anticoagulant ii. Anti-cardiolipin antibodies/Beta2 glycoprotein antibodies iii. Antiphospholipid syndrome
Exclusion Criteria Acquired thrombophilia secondary to medications ( pills or hormone replacement therapy), overweight or obesity, smoking, cancer, pregnancy, surgery, injury, prolonged inactivity/bedrest, heart failure, inflammatory bowel disease, or kidney disease
Non-Neoplastic Hematologic Conditions Cohort
Inclusion Criteria
Participants who meet the following inclusion criteria are eligible for enrollment into this cohort:
1. Having any congenital or acquired non-neoplastic hematologic disorder not included in any other cohort
Exclusion Criteria None
Arm/Module Participant Selection
Previously Untreated Patients Arm
Inclusion Criteria:
Exclusion Criteria
INHIBIT Module
Inclusion Criteria:
1. Diagnosis of severe factor VIII deficiency with baseline factor VIII level \<1% 2. Initiating or plan to initiate prophylaxis with emicizumab or factor replacement 3. Factor concentrate exposure, Fresh Frozen Plasma (FFP), cryoprecipitate, and single donor platelets ≤3 EDs 4. ≤5 years of age
Exclusion Criteria
Efanesoctocog alfa (ALTUVIIIO®) Module
Inclusion criteria:
Exclusion criteria:
Hemophilia Natural History Arm
Inclusion Criteria
Exclusion Criteria
Nonacog beta pegol (Rebinyn®) Module
Inclusion Criteria:
Exclusion Criteria:
Emicizumab (Hemlibra®) Module
Inclusion Criteria:
Exclusion Criteria:
1. Unable or unwilling to comply with the protocol
Distress Module
Inclusion Criteria:
Exclusion Criteria:
Hemophilia Gene Therapy Outcomes Arm
Inclusion Criteria
Exclusion Criteria None
Etranacogene dezaparvovec (HEMGENIX®) Module
Inclusion Criteria:
Etranacogene dezaparvovec (HEMGENIX®) Cohort
FIX Prophylaxis Cohort
Exclusion Criteria, both cohorts:
1. Have been treated with etranacogene dezaparvovec in a clinical trial prior to commercial availability. These patients are still eligible for enrollment in the Gene Therapy Outcomes Arm, and their data may be collected for separate analysis.
Congenital Platelet Disorders Arm
Inclusion Criteria
Platelet adhesion defect
Platelet aggregation defect
Agonist receptor defects
Platelet signaling defects
Platelet Granule disorders
Dense granule storage pool disorder
Alpha granule storage pool disorder
Platelet cytoskeletal structure defects
MYH9 associated disorders (myosin heavy chain)
Other mutations
Other Congenital thrombocytopenias
Exclusion Criteria
Glanzmann Thrombasthenia (GT) Module
Inclusion Criteria
Exclusion Criteria None
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
This cohort includes three Arms and six Modules: Previously Untreated Patients (PUPs) Arm Efanestoctocog alfa (ALTUVIIIO®) Module INHIBIT Module Hemophilia Natural History Arm Emicizumab (Hemlibra®) Module Nonacog beta pegol (Rebinyn®)Module Distress Module Hemophilia Gene Therapy Outcomes Arm Etranacogene dezaparvovec (HEMGENIX®) Module
This cohort includes one Arm and Module: Congenital Platelet Disorders (CPD) Natural History Arm Glanzmann Thrombasthenia (GT) Module
No arms or modules
No arms or modules
No arms or modules
No arms or modules
No arms or modules
To determine the safety of therapies used in the treatment of participants with congenital or acquired non-neoplastic, bleeding and clotting disorders and connective tissue disorders with bleeding tendency (blood disorders).
Safety will be measured by those events in the European Safety Surveillance (EUHASS)1: 1. Allergic or other acute events 2. Treatment-emergent side effects of therapy 3. Transfusion transmitted infections 4. Inhibitor development 5. Thrombosis 6. Cardiovascular events 7. Malignancies 8. Neurological events 9. Death In addition to the modified EUHASS endpoints, the following events will be collected as adverse events of special interest (AESI): 1. The occurrence of thrombotic microangiopathies, injection site reactions and cases of potential drug-induced liver injury 2. The development of anti-drug antibodies, to be measured and confirmed, if feasible 3. Severe, unanticipated bleeding 4. Hospitalizations 5. Glomerulonephritis 6. Any arm or module-specific AESI as stated in their corresponding Safety Assessment section Additional safety events of interest may be collected.
Time frame: 15 years
To establish a platform to support study arms and modules for participants with blood disorders.
For each Arm, a brief set of data elements of interests will be developed and reported for study participants.
Time frame: 15 years
To describe medication dosing regimens in participants with blood disorders.
This objective will be evaluated by: 1. Determining the number of participants who initiate and/or switch treatment with non-factor products and participants' reasons for initiating and/or switching treatment with non-factor products 2. Determining the number of participants who do not initiate treatment with non-factor products 3. Determining the number of participants who switch between different non-factor products and the participants' reasons for switching non-factor products 4. Determining the number of participants who discontinue treatment with non-factor products and participants' reasons for discontinuing treatment with non-factor products
Time frame: 15 years
To describe real-world effectiveness of therapies used for participants with blood disorders.
1. Health care utilization as measured by number and type of visits and hospitalizations per year 2. Patient reported outcomes (PROs) as measured by the Patient Reported Outcomes Measurement Information System (PROMIS®) Profile 29/25/Parent Proxy, Global Adherence Rating (GAR) (ages 7 and older), CATCH, and EQ-5D5L
Time frame: 15 years
To grow and evolve the ATHN Transcends Biorepository for current and future research through the collection of biospecimens from participants enrolled on this protocol
All participants have the option to provide consent to have specimens stored in the ATHN Transcends Biorepository. Samples will be collected as needed, including at the Baseline Visit, Annual Visit, and at Study Exit Visit (if not collected at your Annual Visit), as funding allows.
Time frame: 15 years
To describe bleeding events, changes in overall bleeding, and annualized bleeding rate (ABR) as measured by individual bleeding components.
This objective will be calculated per ISTH Bleeding Assessment Tool (ISTH BAT), participant completed Treatment and Bleed log, and if applicable, a Pictorial Bleeding Assessment Chart (PBAC), for relevant diagnoses.
Time frame: 15 years
Plan to share: No
Started Sep 2020 (actual). Primary completion is estimated for Jun 2035, 177 months after the start.
Of 47 non-industry observational studies under Hematologic Diseases, half reached primary completion within 45 months of starting (the median), counting those still running; a quarter within 13 and three quarters within 190. This study's planned 177 months is above that.
Counting every sponsor, half of 64 studies reached it within 51 months; a quarter within 16 and three quarters within 78.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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American Thrombosis and Hemostasis Network