Platelet Transfusion Refractoriness (PTR)Phase 2NCT03712618
The SOLID Platelet Study
A Phase 2 study testing Platelet Transfusion - LONG Platelet Transfusion and Platelet Transfusion - SHORT Platelet Transfusion in people with Platelet Transfusion Refractoriness (PTR) and Thrombocytopenia, run by National Institutes of Health Clinical Center (CC) at 1 site in United States.
Trial summary
Background: Platelets are cell fragments in the blood that help it clot. Some people get very low platelet counts during a disease or treatment. Low platelet counts can cause severe bleeding. Some people are not helped by platelet transfusions at the standard transfusion rate. Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Platelet Transfusion Refractoriness (PTR), Thrombocytopenia
- What is being tested?
- Platelet Transfusion - LONG Platelet Transfusion and Platelet Transfusion - SHORT Platelet Transfusion
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 2 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Jun 2019to 31 Jul 2021
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 100 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Ability to comprehend the investigational nature of the study and provide informed consent
- Thrombocytopenia
- Causes of thrombocytopenia may be due to:
- Congenital causes
- Bone marrow
- Hematologic malignancies
Show all 15Show fewer
- Treatment related
- Thrombocytopenia is generally defined as one of the following:
- Platelet count <10K/uL without bleeding
- Platelet count <20K/uL for "complicated prophylaxis" in patients determined to be at increased risk of bleeding or other complications
- Platelet count <50K/uL with evidence of active bleeding, such as intracranial hemorrhage, GI bleeding, pulmonary hemorrhage, uncontrolled epistaxis, hematuria.
- The treating provider may change the platelet transfusion threshold based on the clinical circumstance, patient population, and/or concurrent primary protocol considerations - similar to the PLADO study.
- Diagnosed with PTR, characterized by the following:
- Lack of adequate post-transfusion platelet count increment, defined by, Corrected Count Increment (CCI) <5000/ul at 10-60 min after each of at least 2 consecutive platelet transfusions
- Presence of anti-HLA class 1 type A and/or type B antibody, in the setting of PTR, as defined above, constitutes the HLA alloimmune-mediated subtype of PTR. Presence of one or more HPA antibodies in the setting of PTR, as defined above, constitutes the HPA alloimmune-mediated subtype of PTR. Failure to detect HLA or HPA antibodies will be categorized as non-alloimmune-mediated PTR. .
Who cannot join
- Less than 18-years-old
- Lack of ability to obtain informed consent
- Pregnant female
- Presence of ITP/autoimmune thrombocytopenia
- Immune platelet refractoriness responsive to treatment with IVIg or eculizumab, or other immunosuppressive therapy within the 3 preceding months. This is based on the wide variation in the duration therapeutic antibodies, with the upper limit frequently cited as 3 months.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institutes of Health Clinical Center
Bethesda, Maryland, 20892
About this study
Official title: Short or Long Infusion Duration for Platelets: The SOLID Platelet Study
Background:
Platelets are cell fragments in the blood that help it clot. Some people get very low platelet counts during a disease or treatment. Low platelet counts can cause severe bleeding. Some people are not helped by platelet transfusions at the standard transfusion rate. This is called platelet transfusion refractoriness (PTR). Researchers want to learn more about transfusing platelets so they can make transfusions more effective.
Read more
Objectives:
To study the effects of transfusing platelets more slowly than the standard rate. To obtain data to improve the effectiveness of platelet transfusions in people with PTR and decrease the risk of bleeding in some people.
Eligibility:
Adults ages 18-100 who have very low platelet counts requiring platelet transfusion, and have evidence of PTR
Design:
Participants will be screened with a review their recent NIH medical records. They will have blood drawn.
Participants will have up to three 12-hour treatment blocks. They can have only one block per day. During each block, they will have 2 platelet transfusions in those 12 hours.
One transfusion will take place over 1 hour (SHORT infusion). The other will take place over 4 hours (LONG infusion).
Participants will be randomly put in 1 of 2 treatment groups. This will dictate whether they get the SHORT or LONG infusion first.
Participants will have blood drawn:
- When they enroll
- Right before each transfusion
- 2, 4, and 6 hours after each transfusion
Each blood draw will consist of a complete blood count. Smaller tubes that require only small amounts of blood will be used to minimize the amount of blood drawn.
Read the detailed description
Platelet transfusion can be a life-saving procedure in preventing or treating serious bleeding in patients who have low and/or dysfunctional platelets. Treatment of blood cancer and other blood diseases, as well as bone marrow transplantation, is not possible without platelet transfusion support. Unfortunately, 15- 25% of chronically transfused patients platelet counts will stop responding to these transfusions, putting them at risk for serious bleeding complications. The development of human leukocyte antigen (HLA) antibodies is responsible for 4- 8% of this platelet transfusion refractoriness. The presence of HLA antibodies is a clinical complication that is generally managed by the selection of products that are negative for the antigens for which the patient has antibodies. Often, for patients with chronic and ongoing need, this selection is facilitated by targeted recruitment of donors with known HLA types (i.e., types that lack antigens cognate to the patients known antibodies and are thus predicted to be compatible). However, for very broadly HLA- alloimmunized patients, compatible products may be exceedingly scarce or completely unavailable, precluding the ability to consistently provide products the patient will likely increment from. This research protocol is designed to evaluate the efficacy of a 4-hour continuous infusion of single donor, apheresis platelets in overcoming both alloimmune-mediated and non-alloimmune-mediated platelet refractoriness. We hypothesize that when we transfuse patients over a long duration, who have platelet refractoriness, the platelet counts will increase to higher numbers for an extended period of time in the peri-transfusion period when compared to shorter transfusion intervals.
- Being tested
- Platelet Transfusion - LONG Platelet Transfusion, Platelet Transfusion - SHORT Platelet Transfusion
- Keywords
- Platelet Transfusion Refractoriness, Continuous Platelet Transfusion
- Medical subject headings
- Thrombocytopenia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Platelet Transfusion - LONG Platelet TransfusionBiological
Platelets transfused over 4-HOURS
Platelet Transfusion - SHORT Platelet TransfusionBiological
Platelets transfused over 60-minutes
| Study group | Role | What they receive |
|---|---|---|
| Group A: LONG then SHORT transfusion | Active comparator | Subjects with thrombocytopenia (due to congenital causes, bone marrow failure, hematologic malignancies, and treatment-related) randomized to receive LONG platelet transfusion (Transfused over 4-HOURS via infusion pump or gravity) with follow up until 6 hours and then SHORT platelet transfusion (Transfused over 60-minutes via infusion pump or gravity) with follow up until 6 hours for a combined total of 12 hours. Subjects may receive up to two further subsequent blocks (one per day) to be administered to a subject in alternating order of SHORT and LONG platelet transfusions, for a maximum number of three blocks per subject. Receives: Biological: Platelet Transfusion - LONG Platelet Transfusion; Biological: Platelet Transfusion - SHORT Platelet Transfusion |
| Group B: SHORT then LONG transfusion | Active comparator | Subjects with thrombocytopenia (due to congenital causes, bone marrow failure, hematologic malignancies, and treatment-related) randomized to receive SHORT platelet transfusion (Transfused over 60-minutes via infusion pump or gravity) with follow up until 6 hours and then LONG platelet transfusion (Transfused over 4-HOURS via infusion pump or gravity) with follow up until 6 hours for a combined total of 12 hours. Subjects may receive up to two further subsequent blocks (one per day) to be administered to a subject in alternating order of LONG and SHORT platelet transfusions, for a maximum number of three blocks per subject. Receives: Biological: Platelet Transfusion - LONG Platelet Transfusion; Biological: Platelet Transfusion - SHORT Platelet Transfusion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Adjusted Platelet Increment Area Under the Curve (AUC)
The adjusted platelet increment area under the curve (AUC), obtained between 0-hours and 6-hours after start of the platelet transfusion. The AUC (i.e., AUC above the pretransfusion complete blood count (CBC) platelet count, minus the AUC below the pre-transfusion CBC's platelet count) determined by the 0-hour, 2-hour, 4-hour, and 6-hour CBC platelet concentrations, calculated using the trapezoid rule. Adjustment to the measured AUC done for the number of platelets transfused during the two transfusion periods (LONG and SHORT Transfusion durations) in one block.
Measured: 0-6 hours post transfusion
Secondary outcomes (1)
Participants With Bleeding During the Peri-transfusion Period
The efficacy of continuous platelet infusion on bleeding outcomes was assessed by number of participants with bleeding grade 1 or higher, measured during the peri-transfusion period by daily hemostatic assessments using the World Health Organization (WHO) bleeding scale. The WHO Bleeding Scale is a standardized tool used to assess and grade the severity of bleeding from 0-4:
Grade 0: No bleeding. Grade 1: Petechiae (small, pinpoint hemorrhages). Grade 2: Mild blood loss. Grade 3: Gross blood loss (visible blood loss). Grade 4: Debilitating blood loss (severe blood loss that causes weakness)
Measured: One day before the first Transfusion Block until one day after the last Transfusion Block; up to 5 days total
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Oct 2018
- Study start10 Jun 2019
- Primary completion31 Jul 2021
- Study completion31 Jul 2021
Why it stopped: Due to recruitment difficulty
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Platelet Transfusion Refractoriness (PTR)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 2 participants (actual)
Sponsor and investigators
- Lead sponsor
- National Institutes of Health Clinical Center (CC)
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Willy A Flegel, M.D., Principal investigator, National Institutes of Health Clinical Center (CC)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03712618
- Sponsor's protocol ID
- 190005
- Other IDs
- 19-CC-0005
- Status last verified
- Feb 2025
- First submitted
- 18 Oct 2018
- Last updated
- 9 May 2025
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data will be shared in de-identified format
Study at a glance
From the registry record, last updated by the sponsor on 9 May 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Short or Long Infusion Duration for Platelets: The SOLID Platelet Study
- ClinicalTrials.gov ID
- NCT03712618
- Acronym / sponsor ID
- 190005
- Keywords
- Platelet Transfusion Refractoriness, Continuous Platelet Transfusion
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Due to recruitment difficulty
- Enrolment
- 2 participants (actual)
- Lead sponsor
- National Institutes of Health Clinical Center (CC)US National Institutes of Health
- Study start
- 10 Jun 2019 (actual)
- Primary completion
- 31 Jul 2021 (actual)
- Study completion
- 31 Jul 2021 (actual)
- First posted
- 19 Oct 2018 (actual)
- Results
- Posted 9 May 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Background:
Platelets are cell fragments in the blood that help it clot. Some people get very low platelet counts during a disease or treatment. Low platelet counts can cause severe bleeding. Some people are not helped by platelet transfusions at the standard transfusion rate. This is called platelet transfusion refractoriness (PTR). Researchers want to learn more about transfusing platelets so they can make transfusions more effective.
Objectives:
To study the effects of transfusing platelets more slowly than the standard rate. To obtain data to improve the effectiveness of platelet transfusions in people with PTR and decrease the risk of bleeding in some people.
Eligibility:
Adults ages 18-100 who have very low platelet counts requiring platelet transfusion, and have evidence of PTR
Design:
Participants will be screened with a review their recent NIH medical records. They will have blood drawn.
Participants will have up to three 12-hour treatment blocks. They can have only one block per day. During each block, they will have 2 platelet transfusions in those 12 hours.
One transfusion will take place over 1 hour (SHORT infusion). The other will take place over 4 hours (LONG infusion).
Participants will be randomly put in 1 of 2 treatment groups. This will dictate whether they get the SHORT or LONG infusion first.
Participants will have blood drawn:
- When they enroll
- Right before each transfusion
- 2, 4, and 6 hours after each transfusion
Each blood draw will consist of a complete blood count. Smaller tubes that require only small amounts of blood will be used to minimize the amount of blood drawn.
Detailed description
Platelet transfusion can be a life-saving procedure in preventing or treating serious bleeding in patients who have low and/or dysfunctional platelets. Treatment of blood cancer and other blood diseases, as well as bone marrow transplantation, is not possible without platelet transfusion support. Unfortunately, 15- 25% of chronically transfused patients platelet counts will stop responding to these transfusions, putting them at risk for serious bleeding complications. The development of human leukocyte antigen (HLA) antibodies is responsible for 4- 8% of this platelet transfusion refractoriness. The presence of HLA antibodies is a clinical complication that is generally managed by the selection of products that are negative for the antigens for which the patient has antibodies. Often, for patients with chronic and ongoing need, this selection is facilitated by targeted recruitment of donors with known HLA types (i.e., types that lack antigens cognate to the patients known antibodies and are thus predicted to be compatible). However, for very broadly HLA- alloimmunized patients, compatible products may be exceedingly scarce or completely unavailable, precluding the ability to consistently provide products the patient will likely increment from. This research protocol is designed to evaluate the efficacy of a 4-hour continuous infusion of single donor, apheresis platelets in overcoming both alloimmune-mediated and non-alloimmune-mediated platelet refractoriness. We hypothesize that when we transfuse patients over a long duration, who have platelet refractoriness, the platelet counts will increase to higher numbers for an extended period of time in the peri-transfusion period when compared to shorter transfusion intervals.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Group A: LONG then SHORT transfusion | Active comparator | Biological: Platelet Transfusion - LONG Platelet Transfusion, Biological: Platelet Transfusion - SHORT Platelet TransfusionSubjects with thrombocytopenia (due to congenital causes, bone marrow failure, hematologic malignancies, and treatment-related) randomized to receive LONG platelet transfusion (Transfused over 4-HOURS via infusion pump or gravity) with follow up until 6 hours and then SHORT platelet transfusion (Transfused over 60-minutes via infusion pump or gravity) with follow up until 6 hours for a combined total of 12 hours. Subjects may receive up to two further subsequent blocks (one per day) to be administered to a subject in alternating order of SHORT and LONG platelet transfusions, for a maximum number of three blocks per subject. |
| Group B: SHORT then LONG transfusion | Active comparator | Biological: Platelet Transfusion - LONG Platelet Transfusion, Biological: Platelet Transfusion - SHORT Platelet TransfusionSubjects with thrombocytopenia (due to congenital causes, bone marrow failure, hematologic malignancies, and treatment-related) randomized to receive SHORT platelet transfusion (Transfused over 60-minutes via infusion pump or gravity) with follow up until 6 hours and then LONG platelet transfusion (Transfused over 4-HOURS via infusion pump or gravity) with follow up until 6 hours for a combined total of 12 hours. Subjects may receive up to two further subsequent blocks (one per day) to be administered to a subject in alternating order of LONG and SHORT platelet transfusions, for a maximum number of three blocks per subject. |
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (15 listed)
- Ability to comprehend the investigational nature of the study and provide informed consent
- Thrombocytopenia
- The treating provider may change the platelet transfusion threshold based on the clinical circumstance, patient population, and/or concurrent primary protocol considerations - similar to the PLADO study.
- Diagnosed with PTR, characterized by the following:
Key exclusion criteria (5 listed)
- Less than 18-years-old
- Lack of ability to obtain informed consent
- Pregnant female
- Presence of ITP/autoimmune thrombocytopenia
- Immune platelet refractoriness responsive to treatment with IVIg or eculizumab, or other immunosuppressive therapy within the 3 preceding months. This is based on the wide variation in the duration therapeutic antibodies, with the upper limit frequently cited as 3 months.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Platelet Transfusion - LONG Platelet TransfusionPlatelets transfused over 4-HOURS | Biological | Group A: LONG then SHORT transfusion, Group B: SHORT then LONG transfusion |
| Platelet Transfusion - SHORT Platelet TransfusionPlatelets transfused over 60-minutes | Biological | Group A: LONG then SHORT transfusion, Group B: SHORT then LONG transfusion |
Primary outcome
Adjusted Platelet Increment Area Under the Curve (AUC)
Time frame: 0-6 hours post transfusion
The adjusted platelet increment area under the curve (AUC), obtained between 0-hours and 6-hours after start of the platelet transfusion. The AUC (i.e., AUC above the pretransfusion complete blood count (CBC) platelet count, minus the AUC below the pre-transfusion CBC's platelet count) determined by the 0-hour, 2-hour, 4-hour, and 6-hour CBC platelet concentrations, calculated using the trapezoid rule. Adjustment to the measured AUC done for the number of platelets transfused during the two transfusion periods (LONG and SHORT Transfusion durations) in one block.
1 secondary outcome
Participants With Bleeding During the Peri-transfusion Period
Time frame: One day before the first Transfusion Block until one day after the last Transfusion Block; up to 5 days total
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 May 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- NIH Clinical Center Detailed Web PageLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. Data will be shared in de-identified format
Related trials for Platelet Transfusion Refractoriness (PTR)
Not yet recruitingPhase 3
Acalabrutinib Maleate and Bortezomib for Patients With HLA Antibodies
Hematological Malignancies, Platelet Transfusion Refractoriness (PTR)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Willy A Flegel, M.D. principal investigator
National Institutes of Health Clinical Center (CC)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Platelet Transfusion - LONG Platelet Transfusion and Platelet Transfusion - SHORT Platelet Transfusion in people with Platelet Transfusion Refractoriness (PTR) and Thrombocytopenia, run by National Institutes of Health Clinical Center (CC) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 15 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 9 May 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 9 May 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Adjusted Platelet Increment Area Under the Curve (AUC) (time frame: 0-6 hours post transfusion). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 May 2025.