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Platelet Function in Patients With Hemophilia A

This study is enrolling participants by invitation only.
ClinicalTrials.gov Identifier:
First Posted: March 20, 2014
Last Update Posted: August 25, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Baxter Healthcare Corporation
Information provided by (Responsible Party):
Alan D. Michelson, Boston Children's Hospital

Abnormalities in the gene encoding Factor VIII (FVIII) results in hemophilia A, an X-linked recessive bleeding disorder with a prevalence of 1 in 5000 males. Hemophilia A patients are classified into 3 different categories based on residual FVIII activity compared to normal: mild (6-40%), moderate (1-5%) and severe (<1%). This categorization correlates to some degree with bleeding phenotype, but does not completely define it. Some patients with hemophilia A bleed less often than others despite identical plasma FVIII levels. The cause(s) of this phenotype heterogeneity in hemophilia A remains largely unknown, despite a number of studies of possible factors.

Activated platelets, in addition to their role in primary hemostasis, play a major role in secondary hemostasis (coagulation) by providing a phospholipid surface to which coagulation factors bind. A role for platelets in the hemorrhagic propensity of hemophilia A has been suggested in the past, but only a small number of studies have been performed with limitations in assays performed and numbers of patients. The purpose of the present study is to determine whether platelet reactivity in severe hemophilia A patients is associated with past bleeding frequency and/or predicts future bleeding frequency.

Hemophilia A

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Decreased Platelet Function as a Cause of Increased Bleeding in Patients With Hemophilia A

Resource links provided by NLM:

Further study details as provided by Alan D. Michelson, Boston Children's Hospital:

Primary Outcome Measures:
  • The percentage of coated platelets. [ Time Frame: 2 years ]

Secondary Outcome Measures:
  • Platelet reactivity. [ Time Frame: 2 years ]
  • The number of procoagulant platelet-derived microparticles. [ Time Frame: 2 years ]

Biospecimen Retention:   Samples With DNA
whole blood

Estimated Enrollment: 36
Study Start Date: March 2015
Estimated Study Completion Date: June 2018
Estimated Primary Completion Date: June 2018 (Final data collection date for primary outcome measure)

Information from the National Library of Medicine

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Ages Eligible for Study:   2 Years to 18 Years   (Child, Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients with severe hemophilia A who do not have inhibitors against FVIII and who have a bleeding history of at least 6 months.

Inclusion Criteria:

  • Patients with severe hemophilia A who are being prophylactically treated with FVIII.
  • Age of at least 2 years.
  • Bleeding history of at least 6 months.
  • IRB-approved informed consent.

Exclusion Criteria:

  • Presence of FVIII inhibitors.
  • Greater than 7 days since active bleeding.
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02093065

United States, Massachusetts
Boston Children's Hospital, Boston Hemophilia Center
Boston, Massachusetts, United States, 02115
Sponsors and Collaborators
Boston Children’s Hospital
Baxter Healthcare Corporation
Principal Investigator: Alan D Michelson, MD Boston Children’s Hospital
  More Information

Responsible Party: Alan D. Michelson, Professor of Pediatrics and Professor of Medicine, Harvard Medical School Director, Center for Platelet Research Studies Director, Thrombosis and Anticoagulation Program Boston Children's Hospital / Dana-Farber Cancer Institute, Boston Children's Hospital
ClinicalTrials.gov Identifier: NCT02093065     History of Changes
Other Study ID Numbers: BCH-CPRS-hemophilia A
First Submitted: March 19, 2014
First Posted: March 20, 2014
Last Update Posted: August 25, 2017
Last Verified: August 2017

Keywords provided by Alan D. Michelson, Boston Children's Hospital:
severe hemophilia A
coated platelets

Additional relevant MeSH terms:
Hemophilia A
Blood Coagulation Disorders, Inherited
Blood Coagulation Disorders
Hematologic Diseases
Coagulation Protein Disorders
Hemorrhagic Disorders
Genetic Diseases, Inborn
Factor VIII