Condition category
Haematological Disorders
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Platelets are blood cells that help the blood clot. They are an important first line of defence against bleeding. Platelet numbers may be low if a person doesn’t make enough platelets or if their platelets are broken down too quickly once they are made. People with low platelet counts are more vulnerable to bleeding. If they undergo surgery or start to bleed, a transfusion of platelets taken from blood donors is often needed to stop the bleeding. Platelet transfusions have a number of disadvantages: supplies are limited, they are expensive, there can be side effects such as bacterial infections and allergic reactions, and some patients do not benefit. Von Willebrand factor (vWF) naturally occurs in the body and causes platelets to stick to sites of injury to stop bleeding. Initial tests have been performed on the blood of volunteers with normal platelet counts. Their blood was treated to lower the platelet count. Adding vWF to the blood samples considerably improved the way their platelets worked. This study aims to investigate in the laboratory if adding vWF to blood from people with low platelet counts could improve the way the platelets work so that platelet transfusions are no longer needed.

Who can participate?
Patients aged 18 or over with low platelet counts (e.g., immune thrombocytopenic purpura or a bone marrow failure syndrome such as myelodysplastic syndrome).

What does the study involve?
Patients with low platelet counts will be asked if they will give extra blood for a laboratory investigation when they next have blood taken. The volume of extra blood is equivalent to three teaspoons and will be rapidly remade by the body. Patients will be asked questions about medications and recent food that they have eaten, as these can cause changes in the test results. The blood samples will be analysed in the laboratory. Firstly the patient’s platelet count will be rechecked. If there are more than 50 billion platelets per litre, it will not be analysed further. If there are less than 50 billion per litre then further tests will be performed to see how well the platelets are working. vWF will then be added to the blood samples and the tests will be repeated.

What are the possible benefits and risks of participating?
There are no direct benefits for patients who agree to take part in the study. We hope that this study will allow us to identify new ways to treat bleeding for patients with low platelet counts in the future. The risk of any complication from extra blood being taken is minimal.

Where is the study run from?
Churchill Hospital (UK).

When is the study starting and how long is it expected to run for?
From April to September 2015.

Who is funding the study?
Investigator initiated and funded (UK).

Who is the main contact?
Dr Michael Desborough

Trial website

Contact information



Primary contact

Dr Michael Desborough


Contact details

NHS Blood and Transplant
John Radcliffe Hospital
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

VWF platelet study: a pilot observational study of von Willebrand factor for moderate or severe thrombocytopenia


vWF Platelet Study

Study hypothesis

To determine whether the addition of intermediate purity factor VIII (a source of von Willebrand factor) to the donated blood of thrombocytopenic patients improves their platelet function.

Ethics approval

NRES Committee North West - Haydock, 11/02/2015, ref: 15/NW/0138

Study design

Observational single-centre trial

Primary study design


Secondary study design

Trial setting


Trial type


Patient information sheet


Immune thrombocytopenic purpura or thrombocytopenia due to bone marrow failure


Platelet function will be tested on blood donated by patients. These tests will be repeated after addition of intermediate purity factor VIII.

Intervention type



Drug names

Primary outcome measure

Normalisation of platelet function, measured with a platelet function analyser 200 adenosine diphosphate/collagen cartridge after addition of intermediate purity factor VIII

Secondary outcome measures

1. Normalisation of platelet function, measured with microfluidics using collagen as an agonist under arterial shear force conditions after addition of intermediate purity factor VIII
2. Normalisation of platelet function, measured with a platelet function analyser 200 P2Y2 cartridge after addition of intermediate purity factor VIII

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 18 years or over
2. Confirmed diagnosis of immune thrombocytopenic purpura or a bone marrow failure syndrome such as myelodysplastic syndrome
3. Platelet count less than 50x10^9/l

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Any inherited platelet disorder or von Willebrand disease
2. Use of an antiplatelet agent (e.g. aspirin or clopidogrel) in the 7 days before blood sampling

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Churchill Hospital
Old Road Headington
United Kingdom

Sponsor information


NHS Blood and Transplant

Sponsor details

R&D Administration
NHS Blood and Transplant
500 North Bristol Park
BS34 7QH
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type


Funder name

Investigator initiated and funded (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

To be confirmed at a later date

Intention to publish date

Participant level data

Available on request

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

21/12/2020: Internal review. 01/11/2016: Changed recruitment end date from 30/09/2015 to 31/03/2017 28/10/2016: Study end date changed from 01/12/2015 to 31/03/2017