An observational study in Hemophilia a, sponsored by Arkansas Children's Hospital Research Institute. Recruiting at 1 site in United States. Open to male participants aged 30 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-10-05.
Sponsored by Arkansas Children's Hospital Research Institute · Observational
This study will compare bone mineral density in patients with severe hemophilia A receiving prophylaxis with emicizumab or efanesoctocog alfa. Participants will undergo assessments of bone mineral density, bone remodeling biomarkers, thrombin generation, plasmin generation, and joint health over a five-year period. The study aims to evaluate whether differences in prophylactic therapy are associated with differences in bone health outcomes.
Reduced bone mineral density, osteoporosis, and fractures are increasingly recognized in persons with severe hemophilia A. The mechanisms underlying impaired bone health in hemophilia are multifactorial and may include reduced physical activity, chronic joint disease, inflammation, and abnormalities in coagulation-related pathways involved in bone remodeling.
Thrombin has been shown to play an important role in bone metabolism through activation of protease-activated receptor-1 (PAR-1) signaling pathways that influence osteoblast and osteoclast activity. Reduced thrombin generation in severe hemophilia A may contribute to decreased bone formation and increased bone resorption.
Efanesoctocog alfa is an extended half-life factor VIII replacement therapy that maintains higher circulating factor VIII levels and supports thrombin generation. Emicizumab is a non-factor prophylactic therapy that effectively prevents bleeding but does not replace factor VIII. The comparative effects of these therapies on long term bone health have not been well established.
This prospective observational study will compare longitudinal changes in bone mineral density among patients with severe hemophilia A receiving prophylaxis with emicizumab or efanesoctocog alfa over 5 years. Participants will undergo serial dual-energy X-ray absorptiometry (DXA) assessments and evaluation of bone remodeling biomarkers, inflammatory cytokines, thrombin generation, plasmin generation, and joint health over a five-year period.
844 studies on the registry are indexed under Hemophilia A; 138 are open to participants now.
This study's planned enrollment of 50 is below the median of 81 across 310 observational studies indexed under Hemophilia A.
Browse Hemophilia A studies →Arkansas Children's Hospital Research Institute is the lead sponsor of 122 studies on the registry; 25 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients that are seen at dedicated Hemophilia treatment Centers
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
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.
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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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
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.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants with severe hemophilia A receiving prophylaxis with efanesoctocog alfa as part of routine clinical care. Participants will undergo longitudinal assessments of bone mineral density, bone remodeling biomarkers, thrombin generation, plasmin generation, and joint health over a five-year period.
Participants with severe hemophilia A receiving prophylaxis with emicizumab as part of routine clinical care. Participants will undergo longitudinal assessments of bone mineral density, bone remodeling biomarkers, thrombin generation, plasmin generation, and joint health over a five-year period.
Longitudinal change in femoral neck bone mineral density (g/cm²)
Bone mineral densitometry
Time frame: Baseline and annually through 5 years.
Longitudinal change in Lumbar spine (L1-L4) bone mineral density (g/cm²)
Bone mineral densitometry
Time frame: Baseline and annually through 5 years.
Longitudinal change in total hip bone mineral density (g/cm²)
Bone mineral densitometry
Time frame: Baseline and annually through 5 years.
Longitudinal Change in Bone Remodeling Biomarkers and Cytokines
PINP, CTX-I, OPG, RANKL, IL-1β, IL-6, and TNF-α
Time frame: Baseline and annually through 5 years.
Change in Thrombin Generation and Plasmin Generation Parameters
Simultaneous Thrombin and Plasmin Generation Assay
Time frame: Baseline and annually through 5 years
Plan to share: No — Individual participant data will not be shared with with other researchers , and each participating site has access to only their centers data; however , aggregated data will be included in future publications and will be made available toparticipating centers following study completion
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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